A1-10 CURTAIN WALLS.pdf

NPQS A1-10 Curtain Walls

National Productivity and Quality Specifications (NPQS)

A1-10 Curtain Walls

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CONTENTS Page 1. 1.1 1.2 1.3 1.4 1.5

GENERAL Scope Related Sections Standards Trade Preamble Definitions and Abbreviations

3 3 3 3 5 6

2. 2.1 2.2

PERFORMANCE REQUIREMENTS System and Component Requirements Design Considerations

8 8 13

3. 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11

MATERIALS/COMPONENTS Types of Curtain Wall General Material Requirements Glass Glazing accessories Sealants Aluminium Stainless Steel Components Mild Steel Components Accessory Elements Drainage Other Types of Panels

20 20 20 20 24 24 25 28 28 29 32 33

4. 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10 4.11 4.12

DESIGN AND WORKMANSHIP Design Preparation of Component for Fabrication and Assembly Finishes on Aluminium Components Fabrication: Frame Assembly Fabrication: Factory glazing work Fabrication: Factory Sealant Work Fabrication: Structural Silicone Glazing Units Fabrication: Steelwork and Steel Components Fabrication: Operable Vents in Curtain Wall Fabrication: Tolerances Transportation and Handling Installation

34 34 35 36 38 38 38 39 40 41 41 42 42

5. 5.1 5.2 5.3

VERIFICATION AND SUBMISSION Submissions Samples and Mock-ups Testing

47 47 52 53

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1.

GENERAL Read with the General Requirements section, and all other contract documents.

1.1

Scope This section covers the work requirements for curtain walling systems in building facades. It covers systems involving mainly glass panels supported by various forms of aluminium or steel components, including operable panels that may serve as windows. For systems involving mainly metal panels refer to section A1-40 “Metal Cladding”, for conventional framed windows refer to section A1-20 “Windows”. BMU and other cleaning equipment for the curtain wall are installed to proprietary supplier’s specifications and are not covered in this section.

1.2

Related Sections Read this Work section in conjunction with the relevant requirements of the other work sections including the following:

1.3

A1-20

Windows

A1-30

Sun-screens and Louvres

A1-80-3

External Painting and Coating

Standards Unless otherwise agreed by the SO, ensure all of the Works comply with the relevant requirements of the Standards and Codes listed below or referenced in the body of the Specification. Alternative Standards and Codes may be proposed for approval by the SO, provided it can be demonstrated that the alternative Standards and Codes comply with the requirements of the standards specified. All Standards and Codes quoted are the current version, unless specific year references are noted. Singapore Standards SS 96

Curtain Walls

SS 341

Safety glazing, materials for use in buildings (Human impact considerations)

SS381

Materials and performance tests for aluminium curtain wall

Other Standards BS 6399-1 BS 6399-2

Loading for buildings – Part 1: Code of practise for dead and imposed loads Loading for buildings – Part 2: Code of practice for wind loads

BS 5889

Specification for one-part gun grade silicone based sealants

BS 6262

Code of practice for glazing for buildings.

BS 6262-4

Code of practice for glazing for buildings – Safety related to human impact.

BS 6375- 1

Performance of Windows. Classification for weathertightness. Performance of Windows. Specification for operation and strength

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BS 6375-2

characteristics.

BS EN 5721

Glass in buildings – basic soda lime silicate glass products. Definitions and general physical and mechanical properties

BS EN 572 2

Glass in buildings – basic soda lime silicate glass products. Float glass.

BS 5250

Code of practice for control of condensation in buildings

BS 5950

Structural use of steelwork in buildings

BS 6496

Specification for powder organic coatings for application and stoving to aluminium alloy extrusions, sheet and preformed sections for external architectural purposes.

BS 6497

Specification for powder organic coatings for application and stoving to hot dip galvanised hot rolled steel sections sheet and preformed steel sheet for windows and other associated external architectural purposes.

BS EN 485

Aluminium and aluminium alloys – Sheet, strip and plate.

BS EN 5733

Aluminium and aluminium alloys - chemical composition and form of wrought products.

BS1161

Aluminium alloy sections for structural purposes

BS EN 755

Aluminium and aluminium alloys – Extruded rod/bar, tube and profiles.

BS 3887

Specification for anodic oxide coatings on wrought aluminium for external architectural applications

BS 5713

Specification for hermetically sealed flat double glazed units

BS 6206

Specification for impact performance requirement for flat safety glass and safety plastics for use in buildings.

BS 4255-1

Rubber used in preformed gaskets for weather exclusion from buildings. Specification for non-cellular gaskets

AAMA 2605

Voluntary specification, performance requirements and test procedures for superior forming organic coatings on aluminium extrusions and panels

ASTM C1036

Standard specification for Flat Glass

ASTM C1048 –97b

Standard Specification for Heat-Treated Flat Glass-- Kind HS, Kind FT coated and Uncoated Glass

ASTM C1172 – 96e1

Standard Specification for Laminated Architectural Flat Glass

ASTMC509-00

Standard Specification for Elastomeric Cellular Preformed Gasket and Sealing Material

ASTM-E773

Standard Test Method for Accelerated Weathering of Sealed Insulating Glass Units

ASTM – E774 -97

Standard Specification for the Classification of the Durability of Sealed Insulating Glass Units.

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1.4

ASTM C1249-93

Standard Guide for Secondary Seal for Sealed Insulation Glass Units for Structural Sealant Glazing Application.

ASTM C1376-97

Standard Specification for Pyrolitic and Vacuum Deposition Coatings on Glass.

CIBSE

Handbook on Thermal performance

DIN 18516 Pt 4

Bimetallic corrosion

PD 6484

Commentary on corrosion at bimetallic contacts and its alleviation

CWCT

Standard and guide to good practice in curtain walling

Trade Preamble 1.4.1

Contractor’s Design Proposal and Submissions

The design intent including dimensions, types and locations of the curtain wall systems for the project are indicated in the drawings and schedules. Based on the information supplied, engage qualified and experienced personnel to carry out and submit the following items for the SO’s acceptance: 1.4.1.1

Develop all necessary details for the fabrication and installation of the curtain wall / glazed roof system(s), and to meet with the performance requirements as set out in clause 2 below. Details to develop may include sizing of components, structural support, accessories, joints, waterproofing and connections to the building etc. Interfaces with the rest of the building are to be clearly developed.

1.4.1.2

Carry out detailed structural design of all elements of the curtain wall system to be submitted to the SO and the authorities for approval.

1.4.1.3

Propose a regime of testing, verification, quality control for the entire works.

1.4.1.4

Propose manufacturers and products for components of the curtain wall systems when requested by the SO.

1.4.1.5

Propose method of fabrication, erection/installation.

1.4.1.6

Propose details of primary and secondary line of weather/waterproofing seals, drainage and pressure equalisation strategies.

The details shown in the drawings are intended to be indicative of the profiles and type of detailing required for the work. Develop details not shown so that the character is similar to those included within the documents. Achieve the design intent as established in the documents to all circumstances and conditions to ensure design is consistent throughout the works. 1.4.2

Shop Drawings

Prepare coordinated shop drawings incorporating all developed details. 1.4.3

Submission to BCA

Engage a PE (Structural) to carry out the structural design of the curtain wall and submit for BCA approval as a Qualified Person for the design.

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1.4.4

Co-ordination with other Works

Co-ordinate the curtain wall works, particularly the interfaces with the following work packages and trades: a. Main structural frame supporting the curtain wall system b. Lightning Protection c. Mechanical and Electrical Services including down pipes etc. which entails penetrations and attachments d. Walls and masonry e. Windows and doors

1.4.5

Provide Spare Materials

Deliver to site in strong protective packages marked for identification, and store where directed, components and materials for future replacement and repair. Refer to PSD for list. 1.4.6

Warranty

Provide in accordance with the contract conditions for the entire curtain wall works. Include all components and accessories and product warranties from the manufacturers of the component parts of the façade system as indicated in the PSD. 1.4.7

Maintenance Manual

Prepare and submit a maintenance/replacement manual covering all components and accessories. Refer to the General Requirements section, clause 1.4.8 for details. 1.4.8

Quality Control Plan

Prepare and submit a Quality Control Plan for SO’s acceptance. 1.5

Definitions and Abbreviations The following definitions and abbreviations appear within this work section: a.

AS

Australian Standard

b.

ASHRAE

American Society of Heating, Refrigerating and Airconditioning Engineers

c.

BCA

Building and Construction Authority

d.

BCR

Building (Control) Regulations or their equivalent

e.

ASTM

American Society for Testing and Materials

f.

BMS

Building Management System

g.

BMU

Building Maintenance Unit (Also known as Gondola system, Façade Maintenance Unit)

h.

BS

British Standard

i.

EPDM

Ethylene propylene diene monomer.

j.

IGU

Insulating glazing unit (Also known as a double glazing unit)

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k.

PVF2

Polyvinylidene fluoropolymer coating

l.

CFC

Chlorofluorocarbons

m.

HCFC

Hexafluorocarbons

n.

GASP

Grazing angle surface polarimeter

o.

EPDM

Ethylene propylene diene monomer

p.

SAA

Standards Association of Australia

q.

SA

Standards Australia

r.

SHGC

Solar Heat Gain Coefficient

s.

PVB

Poly vinyl butyral

t.

UV

Ultra-violet

u.

SS

Singapore Standard

v.

STL

Sound Transmission Loss value.

w.

RSCS

Residual Surface Compressive Stress

x.

Significant Surfaces

All visible surfaces and other surfaces exposed to the external environmental including any drained and ventilated cavities and pressure equalisation chambers.

y.

OTTV

Overall Thermal Transmission Value

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2.

PERFORMANCE REQUIREMENTS

2.1

System and Component Requirements Take into account the following system and component requirements and design principles in the planning, design and construction of the curtain wall systems: 2.1.1

Curtain Wall Systems: Fully Unitised Curtain Wall

2.1.1.1

Characteristics

Note characteristics of the system as follows: a. Prefabricated glazed aluminium panels installed directly to brackets. b. Interfacing panels. c. Vertical joints formed by split mullions. d. Horizontal joints or stack joint to consist of an upper sill section sitting inside a lower gutter head. e. The perimeter sections consist of: i. Male mullion ii. Female mullion iii. Gutter Head – at top of panel iv. Sill section – at foot of panel. f.

The panel may also feature intermediate transom and dummy mullions (ie. mullions that do not form part of the interlocking perimeter).

2.1.1.2

System Requirements

Unitised Curtain Wall Systems to be/have a. Split mullions, stack joints, intermediate mullions and spandrel zones that comply with Pressure Equalised design principle set out in clause 0. b. Spilt mullions that accommodate tolerances and differential movements between adjoining panels due to thermal effects and buildings movements. c. Stack Joints that accommodate tolerances and differential movements between adjoining panels due to thermal effects and buildings movements and differential movements between floors. d. Gutter splices between panels featuring aluminium splice sections and fully sealed. e. Dead loads supported directly on male mullions. f.

Supports to the female split mullion section, by means of dead load blocks, dead load angles, additional brackets or structural gutter splices when the weight of the panel is in excess of 300kg.

g. Corner panels that are either L shaped or feature a split corner mullion. Where split corner mullions are used a full assessment of the panels’ ability to accommodate building sway in both directions is required.

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h. Split mullions designed on the basis that loads are distributed in proportion to their stiffness. i.

Glazing stabilises mullion flanges.

j.

Internal flanges designed with restraints to building.

2.1.2

Curtain Wall Systems: Semi-unitised / Cassette Systems

2.1.2.1

Characteristics

Note characteristics of a semi unitised / cassette system as follows: a. Prefabricated, glazed panels mounted on a site installed sub frame. b. Sub frame consists of mullions, and perhaps transoms erected into position between slab edges. c. Vertical movements between floors are accommodated in sliding splice joints of mullions. d. Glass is glazed into cassette frames that form air seals against the sub frame. e. Cassettes are secured to the sub frame by means of clips and fixings. 2.1.2.2

System Requirements

Semi Unitised / Cassette Systems to be/ have: a. Cavities between cassette elements that are pressure equalised as set out in clause 0. b. Mullion joints that are fully spliced and sealed. Seals shall allow for predicted movements. c. Cassette restraints that make provision for anticipated movements particularly those associated with the mullion splice. d. Cassette frames designed with sufficient strength and rigidity consistent with rear air seals and restraint positions e. Brackets to structure directly to mullions.

2.1.3

Curtain Wall Systems: Stick Curtain Wall System

2.1.3.1

Characteristics

Note characteristics of the Stick Curtain Wall as follows: a. Mullions, and transoms erected into position between slab edges complete with gaskets where detailed. b. Gaskets and small joint sealant between mullions and transoms as required c. Vertical movements between floors are accommodated in sliding splice joints of mullions. d. Glass is frameless glazed on site, with minimum use of wet seals.

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2.1.3.2

System Requirements

Stick Curtain Wall system to be/have: a. Machined mullions and transoms delivered to site b. Brackets to main structure supporting mullions c. Mullion joints that are fully spliced and sealed. Seals shall allow for predicted movements d. Allowance for tolerance and thermal expansion at transom – mullion connections e. Glazing support and back-pans with jointing consistent with the predicted movements, particularly those associated with the mullion splice. f.

Covers and clips with jointing consistent with predicted movements.

2.1.4

Pressure Equalisation

Unless noted otherwise design the weatherproofing of all systems and joints to be pressure equalised thus incorporating the following features: a. A rain-screen: This prevents the majority of water entering joints. b. An air seal: Design this for the full wind load. This allows the effective pressurisation of the cavity. Design the system so that water penetrating the cavity does not reach the air seal. c. A cavity between the rain-screen and air seal. This cavity is to be: i. Sufficiently ventilated and bounded by baffles, seals etc so that there is no air pressure difference across the rain-screen. ii. Drained so that any water entering the cavity flows to outside. Use of face sealed system and elements are not acceptable without explicit approval. 2.1.4.1

Vapour Barriers

Where a vapour barrier and separate weathering membrane are present in the same wall construction, the vapour barrier shall have a lower permeability than the outer membrane. 2.1.5

Operable Vent

The operable vents shall maintain the following under the full structural design load, when all tolerances are accommodated and the most onerous combination of movements occur (including wind sway). Operable vents within curtain wall are to be / have: a. Pressure equalised systems with drained cavities. Face sealed systems will be unacceptable. b. Secondary drainage system behind the weathering seals, that drains to the outside c. Drainage of water from rebates to outside. d. Ventilation of the edges of the double glazed units, panes and panels. e. Internal air seal and vapour barrier

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f.

Eliminate standing water on/or around the edge of double glazed units, panes and panels.

g. Sufficient edge cover on all glazing and panels to: i. Achieve weathering and edge capture around their perimeter, and; ii. Achieve acceptable clearances between metal framing and glass edges. h. Glazing unit replacement without the need to dismantle the primary framing members i.

Stainless steel hinges, screws, stays, mechanisms and locks and die cast zinc stops.

j.

Steel or brass keys.

k. Top hung to a limit of 150 mm from the vertical. The limiting device capable of being undone only by authorised personnel. l.

An operating stay type mechanism with the following features: i. Allow the opening light to be held open in incremental positions up to the maximum restricted open position. ii. A friction adjustment screw to adjust the degree of friction required, enabling the window to be held open in incremental positions. iii. When the opening light is closed the mechanism shall not protrude into the room iv. The stay mechanism to be fastened to both the opening light and the frame and only capable of being undone by deliberate action.

2.1.6

Doors

Doors within curtain wall are to be / have: a. Sufficient strength and robustness to withstand the static and dynamic loads that occur during use. Where necessary reinforce point of attachment to the curtain wall system. See drawings for opening extent and direction. b. Intruder alarms and wired for easy connection by others to the Building Management System, where indicated in clause 3.1. c. Ironmongery as indicated in clause 3.1. Note that all ironmongery is to be fully rebated into the surrounding framing elements. 2.1.7

Louvres

2.1.7.1

General

Louvres within curtain wall are to be / have: a. Free area as stated in the PSD. Demonstrate compliance to BS EN 13030. b. Integral rain traps and non-ferrous bird/insect mesh. c. Louvre blades in extruded aluminium d. Each blade fixed to perimeter frame without any visible exposed fixing e. Collars with flanges to receive ductwork by others. Material for collars to be non ferrous metals for a zone of at least 300mm from the inside face of the louvers. 11 Version 1.0

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f.

Inactive louvers: provide 3mm nominal thickness aluminium blank off panels, finished to match louvers

g. Active louver: provide grade 1.44xx (formerly 316) Stainless steel birdmesh screen behind louvre. Opening dimension of mesh not to exceed 15mm. 2.1.7.2

Weather-resistant Louvres

a. Louvre extrusion to include an edge channel to be drained at ends b. The design of louvres to meet the relevant codes and the requirement of acoustics and ventilation. c. Weatherproof louvres to be tested according to BS EN 13030 to achieve the classification below: Louvre design flow rates classification Water penetration classification

Discharge loss classification

Limiting core velocity

A

2

2 m/s

B

2

4 m/s

C

2

6 m/s

2.1.8

Glazing Design

These systems shall: a. Be designed as pressure equalised glazing details where possible. b. Incorporate a secondary drainage system behind the weathering seal that drains to the outside. c. Allow complete drainage of water from rebates to outside. d. Allow ventilation of the edges of the double glazed units, panes and panels. e. Incorporate an internal air seal and vapour barrier that also act as second line of defence against water ingress. f.

Eliminate standing water on or around the edge of double glazed units, panes and panels.

g. Provide the following when all tolerances are accommodated and the most onerous combination of movements occur (including wind sway): i. sufficient edge cover on all double glazed units, panes and panels to maintain weathering and structural performance around their perimeter. ii. clearance to edges of all glass panes or panels everywhere around their perimeter

2.1.9

Spandrel Box

Provide a back pan to the rear of spandrel areas of the curtain wall. The back pan shall consist of an aluminium (minimum thickness 2mm) or Zincalume (minimum 12 Version 1.0

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thickness 1.5mm) sheet. This back pan shall provide a continuous, completely sealed barrier against vapour transmission, air and secondary water penetration seal between the back pan and the adjacent framing members. No part of the spandrel box to be in contact with the spandrel glass or coating. Design the thickness and fixing of the back pan to accept full design loads. If the spandrel glass is transparent (ie. no pacifier applied to glass), coat the back pan so as to make the appearance of the spandrel glass identical to the vision glass. Provide insulation to the back pan. Provide a minimum 50mm air space between the spandrel glass and the insulation or back pan. Provide for this space to be drained and pressure equalised. 2.1.10

Structural Silicone Glazing

Unless specifically described as otherwise in the design intent drawings, do not rely on structural silicone as the sole means of support of glass, metal sheet, stone or compressed sheet façade elements. Captively support these façade elements on two sides, and design the element to be capable of structurally spanning between those captive restraints. Use structural silicone to restrain the other sides of glazing panels where they are not supported by other means. 2.1.11

Fixing and Bracketing

Allow for the following within the fixings and bracketing: a. All movements and dimensional changes that may occur in the building and within the cladding itself. b. The worst combination of tolerances and constructional inaccuracies as specified. c. Adjustments by small increments in all directions. d. Any reduction in safe working loads in fixings due to their spacing, location in areas of tension, near edges or proximity to cast in inserts/existing fixings, or thickness of shims. Use locking nuts, spring washers or application of an approved locking fluid or wire ties to achieve this. e. The possibility of reinforcement being encountered and the fixing position being moved where post drilled or site fixings are used into a concrete frame. f.

All fixings outside or through the air seal to be stainless steel. All bracketry outside the air seal to be stainless steel or aluminium.

g. Chemical anchors must be a proprietary, mixed in cartridge and injectable type.

2.1.12

Steel Reinforced Aluminium

Steel reinforcing sections incorporated within aluminium extrusions to be hot dip galvanised if they are external to air seal. Separate the metals by an approved isolator to prevent bimetallic corrosion. 2.2

Design Considerations Account for the following when carry out the design proposals in clause 1.4.1

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2.2.1

Loading Criteria

2.2.1.1

Loading general

Transmit all the design loads and any temporary loading that may arise from construction of the curtain wall / roof system to the building structure via the points of attachment as designed, with an adequate margin of safety defined by relevant codes, standards or industry references appropriate to each material and product. 2.2.1.2

Gravity loading

Support the curtain wall /roofing self weight and transmit this weight safely back to the supporting structure without overstressing or permanently deforming any components 2.2.1.3

Wind loading

a. Withstand loading from inside and outside the building, using a basic wind speed V=35m/s and terrain appropriate for the location or based on figures from a wind tunnel test. b. Support the design dynamic pressure and transmit these loads back to the supporting structure without overstressing or permanently deforming any of components. Take account of all applicable local pressure coefficients. c. Sustain no permanent damage to panels, framing members or anchors when tested at both positive and negative applications of the design wind loads multiplied by a factor of 1.5. Framing members shall not be buckled. Panels, beads and capping pieces shall remain securely held and gaskets shall not be displaced. d. Determination of design pressure:

2.2.1.4

i.

The design wind pressures are indicated in the PSD. Propose wind pressures for specific areas based on BS 6399 in conjunction with other recognised international wind codes.

ii.

Any derived wind pressure for external surfaces to be greater than 0.5kPa. Internal elements shall subject to a minimum of 0.3kPa.

iii.

Submit all design pressures proposed to the SO for review and acceptance.

Impact loading

Satisfy the requirements of Tables 3 and 4 of BS 8200 "Design of non-loadbearing vertical enclosures". The maximum visually acceptable dent in any metal surface is 10mm in diameter and 3mm in depth. 2.2.1.5

Maintenance loading

a. Sustain and safely transmit a static load of 0.5 KN applied horizontally through a square of 100 mm side on any framing, metal or stone panelling in vertical or near vertical curtain wall. b. Sustain and safely transmit a static load of 0.5 KN applied at right angles to a square of 100 mm side on all framing of glazed canopies. Sustain and transmit foot traffic loading of 1.5 KN applied to glazing at mid pane at right angles to a square of 100 mm side. c. Sustain and safely transmit a loading of 0.25kN/m² applied to all non-accessible canopies and sunshades with a dimension greater than 600mm. Sustain and safely transmit a loading of 0.75kN/m² applied to all accessible canopies. 14 Version 1.0

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d. Sustain and transmit all loads including dynamic effects from maintenance gantries, platforms and ladders. Sustain and safely transmit loads at BMU restraint points as advised by the BMU manufacturer. e. Window cleaner eye bolts: gondola restraints at every 20m vertically f.

Coincident wind pressures for maintenance load to be based on wind speed of 22m/s.

2.2.1.6

Barrier loading

Where the curtain wall or its sub-frame provides protection to a fall, sustain and safely transmit as a minimum, each of the following static horizontal loads acting separately: a. Loads as required by Schedule 4 of the BCR. b. 0.75 kN/m for all occupied spaces acting in all directions at a height of 1.0 m above finished floor level. c. A uniformly distributed load of 1.0 kN/m² and a point load of 0.5kN acting on any part, up to and including 1.0 m above finished floor level. In the absence of a rail or transom resist the lateral load with a glass panel. Any glass panel shall consist of safety glass as defined in BS 6206. Sustain and safely transmit crowd loading if noted in the PSD. 2.2.1.7

Loading from temporary conditions

Sustain and safely transmit any temporary loading that may arise from lifting, storing, transporting, hoisting and installing the curtain wall or glazed roof systems, or loads from other works that may affect the works. 2.2.1.8

Combinations of loading

Sustain and safely transmit combinations of loads determined in accordance with the procedures set out in BS6399. 2.2.1.9

Vibration and Repetitive Loading

The works and the interfaces to resist becoming loose due to the effects of vibrations, or cyclic effects of load, deflections and thermal expansion. 2.2.1.10

Locked-in Stresses

Consider all stresses generated by movements, thermal effects and fixings consistent with joint provision. 2.2.1.11

Safety and Thermal Stresses

Ensure that no glass or glazing combination develops stresses that may lead to damage of glass, glazing materials, components and/or framing systems. Conduct a thermal stress analysis to verify that all glazing that is not heat strengthened or toughened is thermally safe and will not be susceptible to heat cracking. Take into account shading stresses that might occur from adjacent components and buildings including shading devices. Where analysis indicates thermal cracking may occur, use heat treated glass as appropriate. 2.2.1.12

Curtain wall framing deflection limits for serviceability under load

Achieve deflection limits as follows under 1.0 times design load for serviceability:

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a. Framing members generally - at both positive and negative applications, the maximum frontal deflection shall not exceed 1/200 of the span of the member measured between points of attachment to the building, or 20 mm, whichever is the lesser. b. Framing members supporting single glazing - the maximum deflection shall not exceed 1/125 of their length measured along the pane edge. c. Framing members supporting double glazing units - the maximum deflection to not exceed 1/175 of their length measured along the unit edge, or 15 mm, whichever is the lesser, or more restrictive limits if set by the unit manufacturer. d. Vertical deflection of framing members and transoms, which support the weight of glazed panels, to not exceed 1/400 of their length. e. All framing members are to recover fully from the above deflections when the loads are removed. f.

Aluminium panels-maximum horizontal deflection for out of plane loads to not exceed 1/90 of span.

g. Glass panels-maximum horizontal deflection for out of plane loads to not exceed 1/60 of span.

2.2.2

Climatic and Environmental Criteria

2.2.2.1

Weather resistance

a. Limit airflow through the curtain walls from the exterior surface to the interior surface through any of its joints, to the values below, when subjected to wind induced pressures or suctions across the cladding as indicated in the PSD. b. There are no regions of concentrated airflow through the curtain wall at any interfaces. c. Prevent leakage of water into the interior of the building from the outer face of the assembly, resulting from wind pressure kinetic energy, gravity, surface tension, or capillary action with any combination of wind and precipitation likely to be experienced, up to and including 600 Pa static pressure for any period of 5 minutes, and 900 Pa dynamic pressure, for 3 second periods at random intervals and precipitation Intensity of 0.05(L/m².s) d. Prevent water leakage into those parts of the curtain wall or glazed roof that would be adversely affected by the presence of water. Any water that may take place within the curtain wall is to be drained within the curtain wall and discharged to the outside. Leakage is defined as: i. Any water that appears on the inside face of the curtain wall ii. Water that is not contained in a purpose-built containing drainage area. iii. Water that is likely to wet insulation, fixtures and finishes, reveal linings or sills. e. Maintain weather tightness under the specified imposed loads and thermal, structural or other movements.

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2.2.2.2

Thermal performance and solar gain

Achieve the performance levels using climatic data given in the PSD. 2.2.2.3

Condensation performance

Prevent the formation of condensation on visible surfaces, interstices or locations where it is unable to drain. Any water that may collect due to condensation on curtain wall is to be drained to the outside. 2.2.2.4

Thermal stress

Prevent cracking to glass, stone and ceramic materials caused by thermal stress through appropriate jointing, strength of materials, thickness etc. 2.2.3

Building Movements

2.2.3.1

Sources of movement

Accommodate the following movements in combination, without any reduction in the specified performance: a. Changes in dimension and shape of building elements arising from building movements, including settlement, shrinkage, elastic shortening, floor beam deflections, creep, wind sway, twisting and racking and thermal and moisture movement. b. Changes due to movement of any joint in the supporting structure or building frame. c. Deflection of curtain wall panels and framing members under design dead loads and live loads. Account for these in the design. d. Thermal and moisture induced movements of the curtain wall or glazed roof. Account for these in the design. e. Barometric pressure changes. Determine these for design, taking account of the climate of Singapore and at the supplier of components including IGU’s. Take account of the structural movement as described above and advised by the project structural engineer. Refer to the PSD for further guidance and data for calculation input. 2.2.4

Structural Tolerances

Unless otherwise advised by the SO, assume the following tolerances on the building structure and fabric: Floor levels (floor to floor)

±20mm

Slab edge plan dimensions

±30mm

Columns and wall location on plan in all directions

±20mm

Verticality

H/500

Inserts (line and level)

±10mm

Masonry set-out

±15mm

Floor and ceiling finish level

±5mm

Floor and ceiling position from grid

±5mm

Wall finishes position from grid

±5mm

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External finishes level

±20mm

Gather any additional data required from the SO. Submit for review to the SO any additional assumptions concerning strength values, loadings etc. 2.2.5

Fire and Smoke Performance

2.2.5.1

Non-combustible materials

Do not include materials that readily support combustion or add significantly to the fire load or give off toxic fumes. Achieve surface spread of flame and fire propagation Class O classification when tested in accordance with BS 476: Parts 6 & 7 internally and externally. Obtain approval from SO to any material or component not complying with Class O. 2.2.5.2

Fire and smoke stopping

Continuous fire stopping at the separation of floors to achieve 2 hour fire rating unless otherwise directed. Prevent the passage of smoke from floor to floor in accordance with the requirements of CP 3.12.3 and BS 476: Parts 20-24. 2.2.5.3

Fire Access Panels

Fire access panels shall consist of breakable glass. Where used all toughened or tempered glass to be heat soaked. Internal and external access to the Fire Access Panel shall comply with the requirements of the FSSB. The bottom of the fire access panel to be no more than 900mm from the internal floor level. 2.2.6

Acoustic and Noise Performance

2.2.6.1

Acoustic performance

a. Achieve the STL or NC values given in the PSD. b. Achieve resistance to flanking and floor to floor sound transmission (STC) as set out in the PSD. 2.2.6.2

Noise

Reduce drumming, creaking, rattling, whistling and any other noises from the curtain wall such that it is not audible to occupants. Include anti drumming material for all horizontal panels up to 20° and fins. 2.2.7

Functionality

2.2.7.1

Appearance

a. Achieve the mandatory geometry and presented on the Architect’s drawings. b. Achieve colours and appearances presented on the Architect’s drawings.

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2.2.7.2

Operating opening windows

Meet the recommendations of B.S. 8213: Part 1 in respect of reach distances to ensure the safe operation of opening panes by users. 2.2.7.3

Security Performance

Design fasteners so that they cannot be released from the outside by the insertion of a thin blade or other simple tool. 2.2.7.4

Infestation

Curtain wall and associated components are to be able to resist attack or infestation by micro-organisms, fungi, insects, reptiles, birds or bats and rodents. Have no unbaffled openings in the curtain wall or glazed roof that permits entry of insects, reptiles, birds or bats and rodents. 2.2.8

Constructability

Design the system to maximise prefabrication. Factory finished elements to be erected directly with minimal site works. Prefabricate elements of the sub-frame (i.e. secondary structural frame works to support curtain wall on to building structure). No site welding or tack welding will be permitted, unless incorporated into the design and clearly identified on submission drawings. 2.2.9

Lightning Protection

Comply with the requirements of CP 33-1. Co-ordinate as necessary between the curtain wall and the main lightning protection systems for the building and propose appropriate connection points. Components are to be fully bonded electrically to achieve electrical continuity of the building envelope. No external tapes will be accepted. Unless the location has been agreed with the SO. 2.2.10

Design for Durability

Do not use carbon steel in locations subject to wetting or condensation or where this will result in corrosion; shortening their design life or compromising safety in long or short-term; or, causing rust staining; or, establishing a bimetallic cell with other metals or carbon. Identify at tender stage, materials and components which under normal service conditions cannot meet the durability expected and design to allow for their monitoring and replacement.

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3.

MATERIALS/COMPONENTS

3.1

Types of Curtain Wall Refer to the PSD for the types and requirements of Curtain Wall and component for this project.

3.2

General Material Requirements 3.2.1

Volatility

All materials and components are to be free from volatile components that may migrate with time, or evaporate and re-condense onto other components. 3.2.2

Compatibility

Select, design and install materials to prevent bimetallic corrosion. Ensure all materials for the curtain wall and glazed roof are compatible with the other materials around them within their range of influence throughout the service life. 3.3

Glass 3.3.1

General Requirements for Glass

3.3.1.1

All Glass

All base supply glass are to be/have: a. Float glass b. Comply with the requirements of BS EN 572 parts 1 and 2 and q3 of ASTM C1036. c. Clean cut, without significant edge faults that produce risk of breakage (including feathered edges, shells or other imperfections) and free from bubbles, inclusions, cracks, rippling, dimples, sleeks or other defects. d. Cut to accurate sizes in the factory. e. Assessed for optical and visual faults as described in BS EN 572-2. Spot faults to be no worse than category C. There will be no linear / extended faults. Optical faults to be within the limits set in BS EN 572-2. f.

No local defects producing irregular reflections.

g. Glazing more than 3m above the ground with unsupported edges to be laminated. h. Glazing that is inclined by more than 15° from vertical or horizontal to be laminated. Do not use Toughened (Tempered) glass in situations where breakage could result in glass falling more than 4 metres to an occupied area, unless specifically approved. 3.3.1.2

Thickness

The thickness and dimensions of glass shown on the drawings are minimum thicknesses, not prescribed thicknesses or dimensions. Calculate the glass thicknesses, using the recommendations in the relevant standards or validated proprietary design methods to meet the structural, environmental, acoustic and safety requirements. 20 Version 1.0

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3.3.1.3

Visual Quality

a. Visual distortions of views and reflections to minimised. b. Visual quality of views and reflections to be established using visual mock-ups. c. Glass used for visual mock-ups to follow actual composition where possible.

3.3.2

Heat Strengthened Glass

3.3.2.1

Heat strengthened glass to / be:

d. Comply with the requirements of ASTM 1048- for Kind HS glass. e. Tempered on a roller hearth furnace eliminating tong marks f.

Conform to the following requirements in the horizontal heat treatment process: i. Maximum bow:

0.1%

ii. Roller wave: All thicknesses 0.15mm depth maximum between peaks and troughs iii. Edge dip:

0.25mm maximum

g. Identification marks indicating its nature and processor to be located in the bottom left when viewed from inside. h. Locate roller marks on heat treated glass parallel to the sill (horizontal) 3.3.2.2

Heat Treatment

Prior to heat treatment glass must comply with the requirements for ‘all glass’. Prior to heat treatment: a. Grind flat edges to a small arris. b. Dubb Corners. c. Grind out small shells and/or chips. d. Maximum chip/shell diameter 2 mm. e. Not more than four randomly placed chip/shells in any single pane of glass. Demonstrate by the prime manufacturer’s testing that the residual surface compressive stress in the glass is between 35N/mm² and 45N/mm² when measured by GASP in accordance with ASTM F218-95 (2000). Demonstrate the uniformity of RSCS over the area of the panel by either GASP or other tests as approved by the SO. 3.3.3

Fully Toughened Glass

3.3.3.1

Toughened glass to be / have:

a. Conform to SS 341 and ASTM 1048-97b Kind FT. b. Tempered on a roller hearth furnace eliminating tong marks. c. Conform to the following requirements in the horizontal toughening process: i. Maximum bow:

0.1%

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ii. Roller wave: All thicknesses 0.15mm depth maximum between peaks and troughs iii. Edge dip:

0.25mm maximum

d. Location of Identification marks indicating its nature and processor to be agreed with the SO. e. Locating of roller marks on heat treated glass parallel to the sill (horizontal) Heat soak test all toughened glass for a minimum of 8 hours at 290° C, in accordance with DIN 18516 Part 4, to convert nickel sulphide inclusions greater than 40 µm in diameter from the α phase to the ß phase so that the glass will fracture in the test. The manufacturer shall, upon request, show by statistical analysis of test data that the probability of failure is less than one in 130 tonnes, or by pr EN 14179 to reduce the likelihood of breakage to 1 in 400 tonnes. Provide the SO with copies of temperature log records for each batch and any statistical analysis of the test data. 3.3.3.2

Heat Treatment

Prior to heat treatment glass must comply with the requirements for ‘all glass’. Prior to heat treatment a. Grind flat edges to a small arris. b. Dubb Corners. c. Grind out small shells and/or chips. d. Maximum chip/shell diameter 2 mm. e. Not more than four randomly placed edge located chip/shells in any single pane of glass. Demonstrate by the prime manufacturer’s testing that surface compressive stress in the glass is greater than or equal to 100 N/mm² when measured by GASP in accordance with ASTM F218-95 (2000). 3.3.4

Laminated glass

3.3.4.1

Laminated glass to have / be:

a. Comply with ASTM C1172. b. PVB interlayer complying with BS 6206 Class A. c. Edge steps less than 0.5mm in toughened or heat-treated glass. Annealed glass laminate shall have no step. d. Bear identification marks indicating its nature and processor. e. Panes to have autoclaved edges. Protect the interlayer material from the effects of moisture absorption in service including clouding, shrinking back, degassing and de-lamination. f.

Ensure that the interlayer is compatible with glazing sealants. Undertake a compatibility test plus accelerated weathering to ensure that leeching does not occur into the interlayer.

3.3.5

Frit coated glass

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a. Comply with requirements of ASTM C 1376-97. b. Ceramic ink applied to areas of heat-treated glass using the silk screen process. i. Fuse the ceramic ink to the surface of the glass during the heat treatment process. ii. Ceramic ink to be permanent, durable and resistant through the design life of the curtain wall. c. Resistance to attack from mechanical damage or abrasion, during normal use and maintenance. d. Resistance to weathering, fading or discolouration due to attack from climatic conditions, UV or atmospheric pollutants. e. The screen printed face of the glass facing the inside of the building in the final construction. Refer to clause 3.1 and drawings for pattern. Submit samples to the SO prior to manufacture. 3.3.6

Insulating glazed units

Insulating glazing units to be / have: a. Hermetically sealed complying with BS5713. b. Mechanically applied primary poly-isobutylene seal located between glass and spacer providing a continuous vapour proof barrier of a minimum width of 2mm and a secondary two part silicone sealant extending around the perimeter of the unit. c. The design of the secondary seal consistent with the glazing details. Where the unit is supported by structural sealant or clips to the spacer bar the secondary seal to be designed for the effects of wind and barometric pressures. d. Aluminium alloy spacers with a natural or black finish (refer to clause 3.1) and sufficient rigidity for their purpose. Formed to accommodate seals and to contain desiccant. e. All breather tubes nipped closed prior to installation. f.

All corners and joints fabricated so as to ensure a water vapour tight construction.

g. Dessicant of molecular sieve Type 3A complying with ASTM-E-774.

3.3.7

Low Emissivity Coating

Low emissivity coating to be / have: a. Emissivity less than 0.2. b. Nominally neutral in colour and uniform in tone, hue, colour, texture, pattern and opacity. c. Consistent appearance to the glazed units. Allowable pinholes in coated surfaces: i. Diameter 0.8-1.2 mm (2 within 300x300mm) ii. Diameter 1.2-1.6 mm (1 per sheet) iii. Diameter 1.6 mm and above not allowed 23 Version 1.0

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d. Any edge deletion of coatings stopped within 0.5mm of the primary seal.

3.4

Glazing accessories 3.4.1

Setting blocks

Setting blocks to be / have a. Comply with BS2571 b. Polychloroprene, EPDM or dense heat cured silicone rubber. c. Shore A Hardness of 80-90 Durometer. d. No compounds that could leach out over time and cause staining, or deterioration of adjacent materials. Demonstrate this by compatibility testing.

3.4.2

Location blocks

Location blocks to be/have: a. Comply with BS2571 b. Polychloroprene, EPDM of dense heat cured silicone rubber. c. Shore A Hardness of 60-70 Durometer. d. No compounds that could leach out over time and cause staining, or deterioration of adjacent materials.

3.5

Sealants Sealants shall be compatible, non-staining and fit for their intended purpose. If the compatibility of material is unknown then, SO shall request to provide compatibility test results from the sealant manufacturer. 3.5.1

Weather Seal

Select and install in accordance with BS 6213. Design sealant geometry (and cross section) to accommodate the anticipated substrate movement. Use in accordance with the manufacturer’s directions, particularly relating to the use of primers. Sealants to be / have: a. Design of the seals and selection of glazing materials (eg. Backing rod, glazing tapes) submitted to the sealant supplier for approval b. ·Low modulus – E less than 0.4MPa (@ 100% elongation) c. +/- 50% elongation capacity d. Glazing materials as recommended by sealant manufacturer. Selection to be based on proposed glazing and curing procedures. e. Backing rod to be 25% wider than joint width

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f.

Primers and joint preparation materials - as recommended by the sealant manufacturer.

g. Colour selection of any visibly exposed sealants as advised by the SO.

3.5.2

Frame and Small Joint Sealant

Sealants used between aluminium frame elements to be / have: a. Compatible with aluminium surfaces and finishes. b. Able to accommodate predicted frame movements and distortions. c. Colour selection of any visibly exposed sealants as advised by the SO.

3.5.3

Structural Sealants

Determine structural silicone bite requirements from design wind pressure and panel size, using the sealant manufacturer’s recommended procedure. Design joints in accordance with the sealant manufacturer’s recommendation for glue-ratio. Provide documentation of the sealant manufacturer’s requirements for the particular substrates of the project regarding joint size, limitations, backer rod, mixing, cleaning, surface preparations, priming and applications, temperature and humidity of glazing conditions and any other criteria which may affect sealant performance. Structural silicone supplier to be submitted and accepted by the SO Primers to be the same brand manufacture as the sealants used and to be compatible with the substrate and all adjacent materials. The colours of all visible sealants are to be approved by the SO. 3.5.4

Non-Structural Sealants

Silicone sealants to comply with BS 5889. Polysulphide sealants to comply with BS 4254 and BS 5214. Polyurethane sealants to comply with BS 5215. Do not use acid curing sealants or acrylic sealants for frame seals or smoke flashings. 3.6

Aluminium 3.6.1

Extrusions

a. Aluminium shall have the chemical composition and temper appropriate for its function, exposure and applied finish. b. Use Grade 6061 T5 of BS 1474 for exposed anodised aluminium extrusions c. Use Grades 6061, 6063 or 6106 of temper class T5 or T6 of BS 1474 for other locations d. The extrusions shall have the webs, walls, and flanges of sufficient thickness and eliminate permanent distortion of elements in the finished Works. e. Structural design of aluminium extrusions to comply with requirements of BS 8118 f.

Comply with BS EN 486, BS EN 573-3, BS EN 755 and BS 1161.

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g. Minimum wall thickness in structural parts to be 2.5mm. h. Minimum wall thickness for covers, trims and other visible elements to be 1.2mm i.

Platforms, webs, flanges, races and screw flutes of sufficient size to satisfy all structural requirements and eliminate distortion to the finished surfaces.

3.6.2

Sheet, strip and plate

a. Alloys to comply with BS EN 485-3 b. Not less than 1.6mm thick for hidden flashings. c. Not less than 3mm thick for components exposed to view or to impact. d. Chemical composition and temper to be suitable for application and anticipated exposure and loading.

3.6.3

Aluminium Finishes

All visible surfaces of aluminium extrusions, pressings and the like shall be shop finished prior to assembly. Finishes refer to clause 3.1, Colour and gloss level to be nominated by the SO. Coating systems shall be selected for durability, colour fastness and resistance to damage. All finish coated aluminium sheeting and window transoms (horizontal top surface) shall be protected during manufacture and erection. 3.6.3.1

Polyester Powder Coating

Comply with the minimum requirements of BS6496. Use a single supplier and applicator throughout production to ensure consistency of appearance. Coat all significant surfaces with the following minimum (unless noted otherwise): a. Dry film thickness of 40 microns. b. If a two coat system is used, the top coat is to have a minimum thickness of 25 microns. The coatings are to be free of flow lines, streaks, blisters, pin holes, tears, damage and other surface defects. Visual inspection for scratches, dents and blemishes to be from 1m under normal diffused daylight. Apply the coating using an applicator approved by the polyester powder manufacturer and agreed by the SO. Coating finish, colour and gloss level –Refer to clause 3.1 and the drawings. 3.6.3.2

Polyvinylidene Fluoride (PVF2) Coating

a. General i. Carry out in accordance with the Paint Manufacturer’s instructions. Apply by a PVF2 Coating Applicator licensed by the Paint Manufacturer and agreed by the SO. ii. Finish to aluminium components to comply with AAMA 2605. when tested by an independent testing laboratory. 26 Version 1.0

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iii. The colour coat to not contain less than 70% PVF2 resin. b. Performance Criteria i. For colours and gloss levels: Refer to clause 3.1. ii. The number and types of coats: In accordance with the Paint Manufacturer’s specification for the specified particular paint system(s) noted in clause 3.1. iii. Coat all significant surfaces coated with the following minimum (unless noted otherwise) dry film thickness in microns: 1. Barrier

25

2. Primer

10

3. Colour

30 average (25 minimum at any point)

4. Clear

10

c. The cured film to be dense and consistent, with no seeding and free from flow lines, streaks, pin holes, blisters, tear damage and other coating defects/surface imperfections when viewed from a distance of 1 metre under normal diffused daylight. 3.6.3.3

Anodised Aluminium

a. General i. Anodic oxidation of wrought aluminium shall comply with the minimum requirements of BS3987, except that the film thickness to be as follows: 1. At no point on the significant surface shall the absolute local minimum thickness be less than 20 microns; 2. The average minimum thickness on a single component shall not be less than 25 microns; 3. The maximum average coating thickness on a single component shall not exceed 35 microns. ii. The preferred method of anodising is electrolytically coloured anodised aluminium as described in clause 2.6 of BS 3987. Dyed anodised aluminium method is not acceptable. iii. The anodising to be carried out by an Anodiser subject to the approval of the SO. Use the same Anodiser for the duration of the Works. The Anodiser shall operate an ISO 9001 approved quality assurance system. b. Materials: Materials shall comply with Appendix C of BS 3987 and other performance criteria detailed in this specification. c. For extrusions, aluminium alloy 6063 is appropriate for anodising. For plates and sheets the appropriate material is Alcan J57S or proven technical equivalent. Any diversification from these nominated material are to be reviewed and approved by SO.

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3.7

Stainless Steel Components 3.7.1

Plate, sheet, strip

To comply with BS EN 10029, BS EN 10048,BS EN 10258, BS EN 10259, BS EN 10088 as appropriate. Stainless steel components to be austenitic, complying with BS EN 10088 grades: a. X2CrNi18-10 (formerly 304 S11) for concealed locations only b. X5CrNi18-9 (formerly 304 S31) for concealed locations only c. X2CrNiMo17-12-2 (formerly 316 S11) for exposed locations only d. X2CrNiMo18-14-3 (formerly 316 S13) for exposed locations only All stainless steel to be passivated following machining, welding or finishing. Unless noted otherwise, grade 1.44xx (formerly 316) to be used for visible components, in all other circumstances grade 1.34xx (formerly 304) to be used. 3.7.2

Fasteners

To comply with BS EN ISO 3506-1 and BS EN ISO 3506-2. Fasteners are not to be visible. Use Grade A4 for fasteners exposed to wetting, in all other circumstances use grade A2. 3.8

Mild Steel Components 3.8.1

Mild Steel Members

a. Comply with the structural steelwork specification for requirements relating to secondary steel framing. b. For exposed structural steel elements i. tolerances of this specification are applicable. ii. Finishes as indicated in the drawings or clause 3.1 iii. All joints and connections to be submitted for review as assembly drawings in 1:1 or 1:2 scale. c. Hot rolled steel complying with the requirements of BS EN 10025. d. Hot rolled sections to BS 4: Part 1, SS 470:Part 2 and BS EN 10021-1, tubes to BS 6323: Parts 1, 2 & 3 and angles to BS 4848: Part 4. e. Cold formed pre-galvanised steel sections to BS EN 10142, BS EN 10143, BS EN 10147 f.

Steel sheet to BS 1449: Part 1.

3.8.2

Steelwork Corrosion Protection and Paint Finishes

3.8.2.1

Painting

Finishes to structural steelwork shall be dependant upon the location of the finished element. Refer to structural specifications on steelwork protection for painting of steelwork. 28 Version 1.0

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Refer colours and gloss levels of any exposed items to the SO. Finished surfaces to be: a. Dense and consistent b. Free from flow lines, streaks, pin holes, blisters, tears, lumps and other coating defects or surface imperfections when viewed from a distance of 1 metre under normal diffused daylight. 3.8.2.2

Hot Dip Galvanising

a. Hot dip galvanise all hidden and external mild steel components after forming and drilling in accordance with BS EN 1461 for items less than 5mm thick and BS 5493 for items more than 5mm thick. The coating mass to be an average of 600 g/m² and a minimum of 550 g/m². b. Finish the galvanising to achieve a ‘High Surface Quality’ (HSQ) surface where it is to be painted over. The Galvaniser is to allow the paint manufacturer to inspect and approve that the galvanised surface has been prepared to their requirements and that the appropriate primer has been applied to the prepared surface before the barrier coat is applied. c. Where component is too large to galvanise, use paint as Protective system and refer to section A1-80-3 clause 3.1. d. Isolate all galvanised steel components in direct contact with, but not totally encased in, cementitious surfaces with thin dense PVC or EPDM isolation packs. Do not use bituminous paint.

3.9

Accessory Elements 3.9.1

Insulation

3.9.1.1

Thermal/ fire stopping/ sound deadening insulation to be

a. Inert, durable, rot and vermin proof, CFC and HCFC free. b. Not capable of supporting mould fungal or bacteria growth. c. Capable of maintaining the specified performance throughout the service life of the curtain wall. d. An approved mineral wool e. At 50mm minimum thickness. f.

Maximum U-value for insulation to be 0.11 W/m².°C.

g. Reinforced aluminium foil backing factory applied to the insulation h. With a minimum density of 60kg/m³ i.

With melt point in excess of 1000°F.

j.

Be supported within the prefabricated panel by a continuous aluminium angle or equivalent.

Where the insulation is placed behind the spandrel glass (in front of a back pan) maintain a minimum 50mm air space between the spandrel glass and the insulation.

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3.9.1.2

Insulation accessories, pins, fixings

All fixing pins and accessories to be manufactured from materials which will provide a life equal to that of the metal finishes and result in the insulation maintaining its position, not to sag or delaminate for the duration of its design life. 3.9.2

Spandrel Back Pans

Spandrel back pans to be / have: a. Provide a continuous, completely sealed barrier against vapour transmission as well as providing an air and secondary water penetration seal between the back pan and the adjacent framing members b. Designed for full cladding design pressure if the spandrel is pressure equalised. Under pressure no part of the shadow box to be in contact with the spandrel glass or coating c. Designed to drain to the outside any condensation forming on the spandrel. d. Aluminium or zincalume e. Minimum thickness as indicated in the PSD. f.

Coated or lined with material as indicated in the PSD to achieve aesthetic requirements.

g. Colour and gloss level to be nominated by the SO. Finishing to be carried out by an applicator/anodiser and approved by the coating manufacturer and SO. Make provision in the visual mock-up to trial select the back pan colour.

3.9.3

Gaskets

Gaskets to be extruded EPDM complying with the provisions of BS 4255-1 or cellular profiled rubber to ASTM-C509. Inner gaskets of drained and ventilated or pressure equalised curtain walling systems must be formed in a complete frame with sealed joints. Vulcanised rubber gaskets to have factory moulded corner joints. All gaskets/ weatherseals/ spacers are to have continuous mechanical attachment to framing members. Adhesive attachment is not acceptable. All gaskets must be resistant to oxidation, ozone and UV degradation. Gaskets in contact with silicone sealants are to be heat cured silicone rubber, chemically compatible with the silicone sealant and suitable for the specific purpose intended. Sponge gaskets/ weatherseals/ spacers are to be extruded black neoprene or silicone rubber and conform to ASTM C509 (for neoprene). Gasket manufacturer to be approved by the SO. 3.9.4

Fixings and Fasteners

3.9.4.1

General

The selection and usage of fixings is to be strictly in accordance with the manufacturers recommendations.

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Where the visual appearance is of prime concern exposed fixings are not allowed and the fixing details are to be approved by SO. 3.9.4.2

Stainless steel

Use the following stainless steel fixings and fasteners with stainless steel and aluminium, or with non-metallic components wherever wetting may occur: a. grade A4 to BS 6105 where exposed to wetting. b. grade A2 to BS 6105 where not visible, subject to agreement with SO. Stainless steel fasteners may have hardened tips of other composition for self-drill and self-tap screws only. 3.9.4.3

Mild steel

Use the following mild steel bolts with mild steel components. a. Ordinary bolts and nuts to BS EN 24032, BS EN 24033, BS EN 24034.All plain and tapered washers to BS 4320, Form E. b. Nuts to BS 4190 for grade 8.8. c. The use of zinc plating to BS 1706 – Fe/Zn 8 is acceptable where serrated fixings are used.

3.9.5

Brackets

Use stainless steel or aluminium brackets and stainless steel fixings wherever wetting may occur (including condensation), otherwise painted or galvanised carbon steel brackets may be used. Brackets to be / have: a. Resist all loads, movements and dimensional changes that may occur in the building due to thermal changes, deflections, settlement and creep. b. Allow for construction tolerance in the all components and structure. c. Adjustable by small increments in and out, up and down and side Use lock nuts to prevent loosening due to movements and/or vibrations. State the torque values for tightening all bolts and the maximum allowable shim dimension in the shop drawings. (Not to be greater than 10mm) 3.9.6

Cast-in anchors

Use Cast in anchors unless otherwise agreed with SO. Post-fixed anchors will not be accepted. Anchors to be hot dipped galvanised after fabrication to give coating of 5070 microns or of stainless steel grade A4 to BS 1449 Part 2. 3.9.7

Fire Stops

Fire stops should be / have a. Type of rating approved by FSB. b. Based upon mineral fibre of appropriate density. c. Held captive by metal trays or clips mechanically fixed to the edge or underside of the slab. d. Designed to allow for movement. 31 Version 1.0

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e. Smoke-stop compound where necessary to maintain fire integrity.

3.9.8

Flashings and smoke barrier

Flashings and smoke barriers visible externally or internally shall be of aluminium sheet, grade 3003 or 5005 with finish to match the curtain wall. Flashings and smoke barriers not visible externally shall be aluminium sheet grade 3003 or 5005. 3.9.9

Separating/Isolating Materials

Separating material are to be compatible with any material with which it comes into contact and isolating material should be non-conducting, non-compressible and nonwater absorbing. 3.9.10

Backing sheet

The backing sheet behind the weatherproof louvres made from mild steel galvanised and paint finish to match the colour of the louvres. The sides of backing sheet shall be fixed to mullion. 3.9.11

Bird screen mesh

Bird screen shall be made from wire finish to match the louvres. The area of opening shall meet the requirements of Free Area calculation for ventilation. 3.9.12

Hardware/ Ironmongery

Provide to operable elements, such as doors, fire doors or opening sashes including smoke ventilators, hardware purpose-made for the element or recommended for the purpose by the window or door manufacturer and reviewed by the SO. The aluminium framing systems are to be designed to accommodate the requirements of the proposed hardware in clause 3.1 or shown in the drawings. Unless noted otherwise, hardware shall be 316 grade stainless steel with No.8 polished finish where exposed. All mechanisms and operable devices to be rated for external use with minimal maintenance. Provide a full hardware schedule confirmation for all windows and doors to SO for review and approve. 3.9.13

Welding consumables

Welding consumables shall comply with BS EN 12072 and/or BS EN 1600 as appropriate 3.10

Drainage Comply with SS CP 26, SS CP 89 and manufacturer’s recommendations. 3.10.1

Gutters and Gutter Support

Use: f.

Stainless steel grade 304.

g. Galvanised mild steel.

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3.10.2

Wire Mesh Gutter Covering

Comply with the requirements of ENV. Use: a. Stainless steel grade 304. b. Galvanised mild steel.

3.10.3

Rainwater Down Pipes

Ductile Iron Pipes and fittings to BS 460. uPVC pipes and fittings to SS 141. 3.10.4

Holder Bats

Use: a. Stainless steel grade 304. b. Galvanised mild steel.

3.11

Other Types of Panels 3.11.1

Stone

Refer to section A1-60 “Stone Cladding” clause 3.3 for the selection of stone to be used as spandrel panels. 3.11.2

Metal Panels

Refer to section A1-40 “Metal Cladding” clause 3.0 for general material requirements.

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4.

DESIGN AND WORKMANSHIP

4.1

Design 4.1.1

Structural design

4.1.1.1

General

a. Design in accordance with the following codes and standards: i. BS 6262 Glazing ii. BS 8200 non load bearing vertical enclosures for buildings iii. BS 8118 Aluminium iv. BS 5950 Steelwork b. Undertake the design to achieve the performance requirements in accordance with the standards and codes. In the absence of specific guidance any design approaches and factors of safety to be agreed with the SO for the materials and components used. c. Submit calculations to the SO. for review. d. Prepare submit and obtain approval for all submissions required by any statutory authorities for the curtain wall. e. Take account of any reduction in safe working loads in fixings due to their spacing, location in areas of tension, near edges or proximity to cast in inserts/existing fixings, or thickness of shims. 4.1.1.2

Loading

Review wind pressures specified and prepare calculations for review to address any omissions, over or under estimates or for areas of specific cladding. All revisions or deviations from the specified wind pressures are to be approved by the SO. Determine cladding design pressures and other loadings to be used in the design in accordance with procedures established in performance requirements and recognised Codes and Standards. Submit this to the SO for review. 4.1.1.3

Cast-in anchor design

Design cast-in anchors and their connection to the building structure in order to resist dead loads, live loads, wind loads, and all building movements, individually and in combination. All fixings are to accommodate the worst combination of structural and curtain wall tolerances, determine loading by considering eccentricity and provide capacity calculation for a number of loading. Identify locations of cast in anchors and incorporate in the shop / erection drawings. 4.1.1.4

Components subject to the full wind load

Design the air seal and all components external to this to resist the full cladding design pressure. Design horizontal sunshades for a minimum of 1.0 x design wind pressure.

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4.1.2

Design for thermal and condensation performance

a. Use insulation to provide adequate (refer to value set out in clause 3.1) level of performance. b. Assess the heat transferred through windows, curtain walls and other thermally complex glazing by 2 dimensional numerical analysis. Use software validated against benchmarks. Summarise the results of the assessment as thermal transmittance (U-values) for the central and perimeter zone of each relevant cladding type. Calculate overall U values for each relevant cladding type as a weighted average of constituent areas, with the weighting method defined. Submit to the SO confirmation that the design meets the thermal requirements as specified. c. Where particularly complex localised penetrations of conductive material pass through the cladding system, carry out 3-dimensional analysis of the heat flow if directed by the SO. d. Take into account the internal and external surface heat transfer resistances. Quote these resistances and the parameters that affect them. Take into account the effects of any airspaces, porous materials, and the thermal interaction between elements of the facade.

4.1.3

Design of glazing

Carry out detail design of glazing including determination of glass thickness, types and treatments to comply with performance requirements. Submit this design to the SO for review and approval. 4.1.4

Design of structural silicone glazing systems

a. Undertake detail design of structural silicone glazing systems (calculations to be endorsed by the engaged PE). b. Submit to the SO for review: i. Certification from the sealant manufacturer that the sealant manufacturer has carried out a print review of all sealant details and tested the contact surfaces and finds them suitable to use with the proposed sealant. The certificates to confirm that the sealant will not stain the surfaces to which the sealant will be applied. These certificates confirming suitability, adhesion and staining are to be accompanied by test results on production substrates performed in accordance with recognised procedures. ii. The sealant manufacturer’s calculations for structural sealant joint sizes determined from the design wind pressure and panel size.

4.2

Preparation of Component for Fabrication and Assembly 4.2.1

Submissions

a. Submit samples prototypes and demonstrations of fabrication as required by SO.and set out in clause 5.1

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b. Following review and approval of samples, prototypes and demonstrations, ensure all subsequent materials and workmanship are of the same or better standard.

4.2.2

Machining, Supplied Materials and Component

4.2.2.1

General

a. Store all materials in accordance with suppliers requirements as applicable. b. Store all materials in dry locations with minimal temperature and humidity. Avoid damage or infestation by animals or insects c. Monitored stored materials and report any corrective action to damaged elements d. Ensure full traceability of all deliveries and processes. 4.2.2.2

Methods

a. Select methods used for fabrication that will achieve the specified performance. b. Maximise use jigs and computer controlled tools wherever appropriate to achieve accuracy. c. Use the correct tools for each task and equipment that is well maintained. Do not use blunt and worn tools. d. Carry out grinding, cutting, shaping and finishing materials using tools, techniques and ancillary materials that will not contaminate curtain wall components with particles or substances, which could disfigure, stain or corrode them. e. Use experienced operatives skilled in using the techniques involved. f.

Undertake the assembly of components under factory controlled conditions

4.2.2.3

Marking

Mark components and materials clearly wherever this is required in order to identify: a. Strong points for lifting, permit assembly or installation in a particular sequence; b. Interlocks occur; or c. Confusion that can foresee-ably arise between upper and lower faces, left and right handed pieces, top and bottom, or d. Lengths close but critically different from one another. Mark in such a way as not to affect the performance of the Works with removable or marks that will be concealed when installed. 4.3

Finishes on Aluminium Components 4.3.1

Powder Coating

4.3.1.1

Significant Surfaces

Note all significant surfaces on drawings and provide the SO with written confirmation from the powder coating applicator that full coverage in accordance with this specification is achieved.

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4.3.1.2

Fabrication requirements

Fabrications to be from either pre-finished or finished machine lengths. Grind smooth all welds, burrs and other edge machining to the requirements of the powder coating applicator prior to coating. Provide drain holes where necessary. Ensure uniformity of colour, texture and gloss, on the completed elevations, between adjacent panels and/or components within the approved control samples. Agree with the powder coating applicator, a sequence for coating the various elements in consistent batches. 4.3.1.3

Performance Criteria for the Powder Coating

Prior to the commencement of production provide a copy of the powder manufacturers certificate confirming that the powder coating complies with the minimum performance requirements stipulated in Section two of BS6496. Unless agreed with SO, the powder coating shall meet the requirements of both the artificial and natural weathering tests. 4.3.2

PVF2

4.3.2.1

Technical Procedures

The following standards are applicable: a. Performance criteria

AAMA 605.2.92

b. Paint matching

BS3900 part D1

c. Process testing

AAMA 605.2.92

d. Applicator QA/QC

BS5750 and/or ISO9000

Carry out in full compliance with the Paint Manufacturer's Agreement. 4.3.2.2

Workmanship

Fabrications to be from either pre-finished or finished machine lengths. Visible or exposed areas of un-coated metal or unsealed crevices open to the exterior are unacceptable. When coating is carried out after machining, arrange for satisfactory jigging points. Provide drain holes where necessary. Submit two sample joints to the SO for approval, prior to fabrication. Grind smooth all welds, burrs and other edge machining to the requirements of the powder coating applicator prior to coating. Provide drain holes where necessary. Ensure uniformity of colour, texture and gloss, on the completed elevations, between adjacent panels and/or components within the approved control samples. Agree with the applicator, a sequence for coating the various elements in consistent batches. 4.3.3

Andodising

4.3.3.1

Significant surfaces

All visible surfaces and other surfaces exposed to the external environmental conditions to be deemed to be significant surfaces. These shall include any Note all significant surfaces on the drawings and provide the SO with written confirmation from the Anodiser that full coverage in accordance with this specification is achieved.

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4.3.3.2

Anodising conditions

Carry out anodising under conditions of acceptable good practice for architectural applications. Hold the processing conditions constant for the duration of the period required for completion of the contract. Keep records of these conditions and make available for inspection in the event of a dispute as to the quality of the finished anodic coating. 4.3.3.3

Anodising process

The anodic finish colour to be as specified by the SO or as noted in the drawings. 4.4

Fabrication: Frame Assembly Provide stable, clean surfaces and supports for the assembly Ensure the ends of all components are correctly prepared prior to assembly. Ensure all fasteners and fixing are installed with appropriate force and that no fixings are loose or overstressed. All sealant works to be tooled and neatly finished Ensure no ventilation or drainage holes are blocked.

4.5

Fabrication: Factory glazing work Comply with the recommended guidelines set out in BS 6262 Sections 7, 8 and 9 Remove any protective tapes from the edges of insulating glazed units. Ensure all surfaces are clean. Prime surface of the frame and glass as recommended by the finalised glazing procedures. Install glazing units with at least 5mm clearance at the sides and top from the framing, and 6mm at the bottom with allowance for water to drain freely. Install gaskets without incorrect distortion such as stretching or compression of length, or folding back of wiper seals.

4.6

Fabrication: Factory Sealant Work Apply and cure sealants in accordance with their manufacturer’s directions on minimum and maximum temperature and RH conditions. Use appropriate backer rods, tapes, surface preparation and primers in accordance with the design details shown on the submitted drawings and the manufacturer’s recommendations Clean all surfaces immediately prior to sealing Prime surfaces as required and protect during any drying period. Protect adjacent surfaces with masking tape while applying sealant Achieve the depth to width geometry. Ensure sealants are well bonded to intended surfaces and use tapes and isolators to prevent three-sided adhesion. Tool off sealants neatly leaving smooth, neat seals in all visible locations. Use small joint sealant in crevices where extrusions abut or mitre together.

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Clean excess sealant from adjoining surface minimise movement of panels prior to sealant setting. 4.7

Fabrication: Structural Silicone Glazing Units 4.7.1

Procedures

Obtain and review procedures from the specialist supplier/manufacturer for fabricating structural silicone glazing units: a. Documentation of the sealant manufacturer’s requirements for the particular substrates of the construction including joint sizes, limitations, requirements for mixing, cleaning, surface preparation, priming and application. b. Glazing procedures including frame assembly, cleaning, priming (if necessary), gunning, tooling, frame handling after glazing and curing. c. Silicone batch logging procedures to record all batches used including batch manufacture, date and arrival date of each batch at the fabrication works. d. Details of sealant testing to be carried out to ensure continued high quality of silicone being used on a batch or shift basis whichever is the least. e. Details of tensiometer and any other testing equipment as required. f.

Details of substrate testing carried out on a daily basis to ensure continued high quality of and consistency of silicone adhesion to the substrate.

g. Frame logging at time of assembly, which shall include identifying every panel by a unique number. The glazing record for each panel shall include silicone type, batch reference and date, curing time, date of application, glazier's name, and temperature and humidity measured inside the factory at a nominated time of each day. h. Details of de-glazing to ensure quality of the silicone joints. 3 no. frames for each type of structurally bonded glazing to be chosen at random by the SO and deglazed. The quality of the de-glazed units to be assessed against the requirements for cohesion, adhesion, tear resistance and compatibility as defined by the sealant manufacturer. i.

Details of procedures to deal with non-conformities. The procedure shall provide for the identification of all frames of unacceptable quality and their re-glaze or rejection. When non-conformity is established as a result of a random de-glaze, then the SO shall call for further de-glazing of the frames glazed on the same day and using the same silicone batch as the rejected frame.

4.7.2

Sealant Works

Carry out works in accordance with the agreed procedures above Complete structural sealant works in a continuous operation for any single element Handling of panels to be consistent with setting periods of sealant 4.7.3

Production Records

Obtain review and approve factory production control records specific to the fabrication of the project structural glazing units, from the specialist supplier demonstrating that all procedures above have been satisfactorily followed.

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Submit these records and approval to the SO. 4.8

Fabrication: Steelwork and Steel Components 4.8.1

General

Unless otherwise agreed carry out metal arc welding process in accordance with BSEN 1011: Part 3: 2000 together with other requirements in this specification. Ensure welding consumables used for arc welding of stainless steel comply with BSEN 12072: 2000 and BSEN 1600: 1997. Choose welding consumables to ensure that the mechanical properties of the weld metal are not less than those required for the parent metal. Prepare joints in accordance with BSEN 1011: Part 3: 2000. Take precautions to ensure cleanliness of the connection prior to welding. Use all welding consumables and methods in accordance with the Codes. Ensure all work are carried out by fully qualified trades persons with suitable experience in the required fields. 4.8.2

Application of Finish Coatings

4.8.2.1

Hot Dip Galvanising

Clean steel after chemical descaling so that all rust, mill scale, oil, grease and other foreign matter are removed, leaving a clean surface of metal. Reinstate all transport and erection abrasions, site welds, etc., by thoroughly wire brushing all affected areas to achieve a clean sound substrate and patch coating with an inorganic zinc silicate film thickness of 100 microns. 4.8.2.2

Paint Finish to Structural Steelwork

Structural steel to be paint finished in the factory or paint shop after galvanising as follows (site painting will only be permitted for touching up of the paint film): Prior to painting, degrease all galvanised surfaces, then apply paint treatment. Remove oil and grease with a suitable de-greasing solvent, take care when using solvents that a film of oily residue does not remain after the solvent has evaporated. Do not use slow evaporating solvents (Paraffin, etc.). Use only clean rags and brushes. Two pack epoxy primer: Ensure substrate preparation is equal to manufacturers recommendation. Barrier Coat: Apply 2-pack high build epoxy micaceous iron oxide sealer to 125 microns DFT. Finish Coat: Apply Satin and metallic finish recoatable polyurethane to between 75100 microns DFT in 2 coats. All colours to be approved by the SO. Apply all painting in accordance with this specification and section C5-20. Do not carry out painting in the shop or on site (where essential) when: a. Relative humidifies are above 85%. b. Temperatures are above 30°C. c. The temperature is less than 3°C above the dew point. 40 Version 1.0

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d. Weather conditions are unsuitable, such as high winds, rain and excessive temperatures. Adequately protect all areas to be painted onsite against the weather to the satisfaction of the SO. Apply all coating materials in a neat workmanlike manner by skilled personnel working under experienced supervisors and in accordance with the manufacturer’s recommendations. Unless specified otherwise all paint to be spray applied. Carry out painting in a covered area remote from any abrasive blast cleaning operations. Round all sharp edges and corners to the steelwork prior to painting to an approximate radius of 5mm. Remove all weld spatter, flux residues, oil and grease, abrasive dust and other paint contaminants. Remove all moisture and ensure surfaces are dry before coating. Provide certificates of coating adhesion and of uniformity of coating as directed by the SO. 4.9

Fabrication: Operable Vents in Curtain Wall Fabricate operable vents to the standards set out in Section 5 of SS212. Stake and crimp corners of operable vents within curtain wall. If hardware fixings require local stiffening of curtain wall frame, then proper reinforcement to be provided in order to fix the hardware securely

4.10

Fabrication: Tolerances 4.10.1

Curtain wall framework

The following maximum allowable tolerances for all curtain wall frameworks should be followed: a. ±1.5 mm on length on mullion b. ±1.0 mm on length on transoms c. ±1.5 mm on straightness of mullions d. ±1.0 mm on straightness of transoms e. ±2° accuracy on angles between mullions and transoms f.

±1mm on sides and ±2mm on diagonals on spandrel and vision panel opening positions

Above tolerances are not cumulative 4.10.2

Glazing

The following maximum allowable tolerances for individual panes of glass should be followed: a. ±2.0 mm on height and width b. ±1.0 mm on straightness of edges c. Tolerances on insulating glazed units allowed by BS 5713.

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4.11

Transportation and Handling 4.11.1

General

Method statements are required for all stages from the production of the panels through to installation on site. Methods to minimise handling, repacking and lifting of panels. Panels to be stored directly after fabrication allowing for the setting and curing of sealants. Crates and packing to provide resistance to damage, the ingress of moisture and infestation All elements to be stored and protected against degradation due to weathering, distortion and damage by other construction activities. 4.11.2

Temporary Protection

Fully protect all coated surfaces vulnerable to damage during handling and installation or by subsequent site operations. Provide weather resistant protective coverings and remove from areas inaccessible after installation. They to be partially removable and replaceable for access to fixing points during installation and/or subsequent site operations. For protective tapes in direct contact with the coating, use a low tack, self-adhesive type in white or any colour lighter than the coating to be covered. Apply and remove in accordance with the recommendations of the powder manufacturer guidelines. Do not keep protective tapes in contact with coated surfaces for longer than 6 months. 4.12

Installation 4.12.1

Submissions

Submit method statements to the SO for review, describing how it is proposed to install the works. Submit samples, prototypes and demonstrations of installation as required by SO. 4.12.2

Cast-in anchors

Clean out all cast-in anchors. Verify correct position and security of connection to building structure prior to erection of components 4.12.3

Installation of fixings

Install fixings in accordance with their manufacturer’s instructions and procedures. Ensure the strength grade combination of bolts, nuts and washers is as specified. Use a torque spanner to achieve correct tightening of fixings to achieve correct tension load and avoid under / overstressing, Use lock-nuts to prevent loosening. At least one clear thread shall show above the nut.

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4.12.4

Installation Generally

Following review of samples, prototypes and demonstrations all subsequent materials and workmanship are to be the same or better standard. Use jigs laser lines, and computer controlled methods wherever appropriate to achieve accuracy. Use the correct tools for each task and equipment that is well maintained. Do not use blunt and worn tools. Do not carry out grinding, cutting, shaping and finishing of materials using tools, techniques and ancillary materials that will contaminate curtain wall components with particles or substances, which could disfigure, stain or corrode them. Use experienced operatives skilled in using the techniques involved. Control the installation weather conditions by shading and shelter as appropriate to ensure performance requirements are met. 4.12.5

Line and level survey

Undertake a survey of line and level and condition of structure to verify its acceptability to receive curtain wall. Inform the SO should the survey indicate that the structure is outside the line and level variations that may be catered for by the proposed curtain wall system setting out marks. Use removable marking or place marks in locations where they will be concealed in the Works when installed. 4.12.6

Handling of materials and components

Handle curtain walling materials and units by designed strong points only. 4.12.7

Erection Tolerances

Erect the curtain wall to the more onerous of the following permitted deviations: Line:

± 2 mm in any structural bay width.

Level:

± 2 mm in any one structural bay.

Plumb:

± 2 mm in any one storey height.

Plane:

± 2 mm in any one storey height or structural bay width.

Intersection:

± 2 mm in alignment in any direction between any two adjoining panels, at a 4-way intersection of panels.

NB: Tolerances are not cumulative. Construct joints between components to the following permitted deviations: a. Within the length of any joint (including in line continuations across transverse joints) the greatest width shall not exceed the least width by more than 10%. Any variation to be evenly distributed with no sudden changes. b. The offset end elevation between nominally in-line edges across a transverse joint to be not more than 10% of the width of the transverse joint. c. The offset in plan or section between flat faces of adjacent panels across any joint shall not be more than 10% of the width of the joint or 1.5 mm whichever is lesser.

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d. Tolerances are not cumulative.

4.12.8

Installation of structural silicone glazing units

Handle all units by strong points Ensure gravity supports and setting blocks are properly located and that design shear stresses in the structural silicone seals are not exceeded. Prepare surfaces for weather seals prior to sealing in accordance with sealant manufacturers directions Protect weather seals from excess heat rainfall and humidity during application and cure. Do not block drainage holes when applying weather seals. 4.12.9

Site glazing work

Install glazed units in accordance with their manufacturer’s instructions and procedures. Comply with the recommended guidelines set out in BS 6262 Remove any protective tapes from the edges of insulating glazed units. All roller wave to be horizontal Install glazing units with at least 5mm clearance at the sides and top from the framing, and 6mm at the bottom with allowance for water to drain freely. Install gaskets without incorrect distortion such as stretching or compression of length, or folding back of wiper seals. Do not undertake any site applied structural silicone glazing. 4.12.10

Site Sealant Work

Apply and cure sealants in accordance with their manufacturer’s directions on minimum and maximum temperature and RH conditions. Achieve the depth to width geometry. Prevent three-sided adhesion. Protect adjacent surfaces with masking tape while applying sealant Use appropriate backer rods, tapes, surface preparation and primers as manufacturer’s directions. Tool off sealants neatly 4.12.11

Installation of fire and smoke stopping

Install fire and smoke stopping at all voids and penetrations between compartments at designated locations to achieve the specified fire and smoke stopping performance. Support smoke stopping with galvanised steel sheets. Provide smoke seal where necessary to maintain fire integrity.

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4.12.12

Protection and Cleaning

Protect vulnerable coated surfaces; glass, metal edges, corners and features. Apply temporary removable protection against damage from following trades or operations and the anticipated hazards. Use materials for temporary protection that are compatible with and subsequently removable from the surface and finishes without detriment to the finish. Obtain the component suppliers and finishers approval of removal methods. Cleaning methods to be strictly in accordance with manufacturers instructions. Unless agreed otherwise by the SO protection should remain in place until all work potentially damaging to the components or their finish has been undertaken. Undertake a final builder’s clean of the Works including removal of all temporary protection prior to completion. Use permanent building gondola for cleaning with SO’s agreement. 4.12.13

Repair

Notify the SO of all non-compliances and damage. Submit all repair methods for review by the SO prior to works commencing. Replace any damaged components in the curtain wall unless otherwise agreed by the SO. Warrant all repairs. 4.12.13.1 Polyester Powder Coat Remedial Works Site rectification of damage will be subject to the approval of the SO and only permitted subject to the submission and approval of a specification and method statement endorsed by the powder manufacturer. The rectification of damage shall not invalidate the coating warranty. All remedial works to be subject to trials to SO’s acceptance. Submit repair record sheets to the SO on completion of the works together with the coating Warranty documents. 4.12.13.2 PVF2 Possible Site Repairs Submit to the SO for approval, a detailed method statement for possible site repairs to coated components. Obtain endorsement from the Paint Manufacturer that any remedial works carried out in accordance with it, shall not invalidate the coating Warranty. Carry out all remedial works to the acceptance of the SO. Log and submit repair record sheets together with the coating Warranty documents. 4.12.13.3 Galvanised Coating to Mild Steel Repair all damage to galvanised steel as follows a. Carefully abrade area around damage to give smooth feathered edges to all paint layers affected. b. Apply full protective system, overlapping surrounding area by 25mm minimum. Repair all damaged galvanising using two coats of a two-pack epoxy polyamide zincrich paint containing a minimum of 92% zinc dust in the dry film which to be built up to an equivalent zinc coating in mass/m2. Paint all cut ends and holes as above to give an equivalent zinc coating in mass/m2.

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Subject all remedial works to trials. Present approved trial sample to SO as a control sample. Log repair record sheets submit on completion of the Works together with the coating Warranty documents.

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5.

VERIFICATION AND SUBMISSION

5.1

Submissions 5.1.1

Tender submissions

Submit the following information with the tender: a. Outline strategic method statement covering the Works. b. Access proposals. c. Drawings and full descriptions of principle components and assemblies. These must illustrate clearly: i. All material descriptions and sources including metal parts, gaskets, glass, flashings, seals, linings, stops, finishes, fixings and fasteners, vapour barriers, insulation, interlayers, setting blocks, thermal breaks, ii. Proposed extrusion supplier iii. The means of anchoring curtain wall and glazed roofs iv. Tolerances allowed for v. Movements allowed for on perimeter of component live and dead load movements in the structure and curtain walls and glazed roofs, thermal expansions and contractions, moisture induced movements, shrinkages in structure and curtain walls and glazed roofs, creep effects or other source vi. Detailing between curtain walls and glazed roofs and opening illustrating junctions with adjacent structure, cladding and finishes to ensure weathertightness, thermal insulation (including avoidance of cold bridging), vapour barrier continuity and sound insulation. vii. Junctions of principle components viii. Glass thickness and net glass area ix. Glazing configurations, glass type, condition, and solar performance data x. Metal thickness, jointing details and location of fixings xi. Position of weather and air seals xii. Vapour barrier and seals xiii. Methods of ventilation and drainage of the curtain walls and glazed roofs and details of any openings d. The Design Wind Load used (including all local coefficients and calculation method) e. Details of all actuators and mechanisms used for opening vents in the curtain walls and glazed roofs f.

Test certificates for the curtain walls and glazed roofs weathertightness

g. Name of Contractor’s Professional Structural Engineer and confirmation of his PI cover h. Independent Testing Authority to be employed for off site testing curtain walls and glazed roofs specimen and on site hose testing the prototype installation i.

Details of proposed curtain walls and glazed roofs installer

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j.

Details of the type and frequency of maintenance required in order to meet the expected design life.

k. Details of any components or materials that will not provide the expected design life together with information on how these materials will be replaced. l.

The name of the PVF2 coating applicator and colour control limits

m. Outline quality plan proposals illustrating the level of checking undertaken and who will carry out what checks. n. Draft deed of warranty identifying warranty periods for the principal components together with any limitations on these

5.1.2

Work submissions

5.1.2.1

Shop Drawings

Submit shop drawings to the SO for review and approval a. Prepare Shop Drawings showing clear and complete details of each assembly, component and connection together with all information relative to their fabrication, material, surface treatment and erection. b. Prepare the Shop Drawings in a professional manner by a person experienced in this type of drafting. ‘Mark-ups’ and ‘overnotes’ on the Drawings shall not be accepted as Shop Drawings. c. Maintain a full register of all shop drawings that shall contain as a minimum: i. Drawing number ii. Drawing title iii. Revision number iv. Name of superintending officer responsible v. Date of issue d. The shop details shall include but not limited to: vi. Marking plans and elevations at 1:50 scale showing the location of and marking proposed for each member. vii. Scale drawings, descriptions and statements, as required. viii. Set up plans and elevations at 1:50 for locating cast-in anchors and inserts. ix. Sectional details at 1:1 of all typical and non-typical Facade elements and associated elements including interfaces and flashings with adjacent panels, structure and/or other cladding elements. Sills transoms, mullions, internal and external corner and at all openings. x. Layout of the facade system assembly (including associated steel framing and associated elements). The layout to be indicated on sectional plans, vertical sections, and elevations of the building face. xi. Sectional details of all roof parapets and features including interfaces with structure and curtain walls and glazed roofs xii. Dimensions of overall assembly relative to location of cast-in elements.

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xiii. Attachment for handling, transportation and erection. xiv. Procedures and sequence to produce distortion-free components and assemblies. xv. Identification of type and extent of protective coating to be applied. 5.1.2.2

Method Statements

Submit method statements for SO’s acceptance including: a. Method of assembly for each Facade type including assembly tolerances, and isometric or axonometric and exploded views of typical i)

transom junctions

ii)

mullion sleeve detail (stick systems)

iii)

four way joint including sleeve (modular systems);

iv)

panel to panel joints (panel or unitised system).

b. Methods of assembly, jointing, sealing and fixing of spandrel panels and other facing panels, particularly where joined edge to edge. c. Details of shadow box spandrels. d. Method of draining the assembly, including details showing: i)

fully pressure equalised (p.e.) drained joints; and

ii)

location, number and size of weepholes.

e. Marking plans, sections and details of all secondary structural steel supports, frames, subframes and the coating / fire protection thereof, f.

Method of installation/erection including: i)

type and location of anchors and other attachments to be cast or otherwise built in to the building structure;

ii)

erection of support steelwork;

iii)

erection tolerances;

iv)

accurate locations and full size details of machined slots, keyholes and other penetrations in frame extrusions for lifting and installing the units;

v)

junctions and trim to adjoining surfaces;

vi)

caulking and flashing; and

vii)

locations of visible heads of fastenings.

g. Provision for differential vertical or horizontal movements, including i)

thermal expansion and contraction;

ii)

column shortening; and

iii)

frame deflections.

h. Method of glazing, including i)

rebate depth;

ii)

edge restraint;

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i.

j.

iii)

clearances and tolerances; and

iv)

gazing gaskets and sealant beads.

Methods of meeting performance requirements for thermal insulation, fire resistance, smoke barrier, sound transmission, and the like, including i)

spandrel backing; and

ii)

closing off and sealing the assembly against other building elements such as soffits, stonework and parapets.

Methods of meeting lightning protection requirements including all electrical connection points.

k. Hardware, fittings and accessories including visible heads of fasteners. Fabrication shall not commence until the Shop Drawings have been reviewed and permission to proceed has been obtained from the S.O. 5.1.2.3

Computations

Submit computations for all members and fixings (other than the main steel framing), and including Curtain Wall, roof glazing and associated works. Computations shall include: a. Table of contents b. Basic data c. Narrative on structural principles, philosophy and assumptions d. Summary of deflections and stresses e. Summary of joint movements f.

Summary of geometric properties cross-referenced to die drawings

g. Summary of fixing loads and loading pattern on building edge beams h. Summary of fixing analysis i.

Summary of structural silicone bite including thermal effects

j.

Summary of structural silicone tensile tests and derivation of allowable stresses

The computations shall make reference to concept drawings and marking plans. Test reports from a recognised laboratory may be acceptable in lieu of calculations for some components e.g. concrete inserts, earthquake deflections, screw capacities and deflections. 5.1.2.4

Design Certification

Provide certification from the engaged Professional Structural Engineer in clause1.4.3, that the design of the facade and glazed roof systems meet the requirements of the specification and all associated codes and standards, in a form acceptable to BCA. 5.1.3

Certification of Materials

During the design phase, obtain material certificates for submission along with the design drawings, calculations and other submissions to SO for approval. These certificates shall indicate the grade, strength, size, finish etc, and that all applied coatings, finishes and the like have been applied to the relevant standards specified. Include certification for at least the following materials: 50 Version 1.0

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a. Glass b. Aluminium (coated and uncoated, sheet, pressings and extrusions) c. Aluminium surface finishes d. Steel and stainless steel Sections e. Bolts, Screws, Fixings For certification from structural silicone and other sealant manufacturers, indicate that the sealant manufacturer has reviewed all sealant details and tested all contact surfaces, and endorses suitability for use with the proposed sealant and the purpose intended. Further, the sealant manufacturer(s) are to certify that the sealants used are compatible with and will not stain the surfaces with which they are in contact and no leakage or contamination from run-off water will occur. 5.1.4

Maintenance submission

Produce a Maintenance Manual for the curtain wall. Submit a draft copy of the proposed Maintenance Manual to SO before Completion. Develop the manual in parallel with the design and include at least the following information: a. Full record of the Works done. b. Details of any Works omitted, along with the reasons and implications on overall performance. c. Details of any additional Works, along with the reasons and implications on overall performance. d. The name, address and telephone number of each supplier, fabricator, finisher, installer etc. involved in the Works. e. A clear and concise description of the construction used to form the various elements within the curtain wall. It to be set out in chapters dealing with each element in turn. Its contents to be comprehensively tabulated and its text crossreferenced. It to be illustrated with sketches and Trade Literature and shall refer to the 'as-built' drawings. f.

Copies of material, components and finishes certification and test reports as required by the Contract Documents.

g. A method statement showing the means of access to all parts of the curtain wall with recommended safe loadings. h. A method statement covering the procedures for replacement of damaged or otherwise defective materials or components, and materials and components that have a design life less than the design life of the curtain walls and glazed roofs and will therefore require replacement during its life. i.

Recommendations and procedures for routine maintenance, lubrication, cleaning, suitable cleaning agents and painting.

j.

Requirements for periodic inspection especially structural silicone glazing.

k. A full set of as-built construction drawings, updated to include any changes made up to the time of completion. Amend the draft Maintenance Manual document to take account of any review comments made by S.O.

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Submit the final document at conclusion of the Works and prior to completion. 5.1.5

Warranty

Provide warranty for the whole curtain wall system and components at completion. Obtain a warranty from the structural silicone glazing specialist supplier confirming that the structural silicone design detail drawings and installation have been checked and approved. List in the warranty the drawings and details that have been approved. 5.1.6

Quality Control Plan

Prepare and submit a Quality Control Plan to SO’s acceptance, for design, fabrication and installation in accordance with SS ISO 9001-2000. 5.2

Samples and Mock-ups 5.2.1

Samples, prototypes and demonstrations - general

Submit samples, prototypes and demonstrations as specified. Following review of samples, prototypes and demonstrations, ensure all subsequent materials and workmanship are of the same or better standard. 5.2.2

Visual mock-up

Following detail design and prior to production, fabricate and build at the contractors yard or other place as directed by the SO, a full size visual mock up. Undertake any modifications throughout the curtain walls and glazed roofs identified from the mock-up, by the SO in order to meet the performance requirements and design intent. The visual mock-up should feature full size glass panels following the production methods and specification of that proposed for the typical panels. The visual acceptance of the glass is to be assessed using the visual mock-up. 5.2.3

Additional Samples and Mock-ups

Refer to PSD for details of submission and timing in addition to those specified. 5.2.4

Control Samples:

5.2.4.1

Aluminium Finishes

a. This clause applies to all aluminium finishes b. Prior to commencement of coating submit to the SO the following samples showing the variations in colour, texture and gloss: i. 2 (or more if required) extrusions, typical for the works, each 1200 mm long showing the lower and upper range limits. ii. 2 (or more if required) plates typical for the works, but not less than 1200 mm x 200 mm each showing the lower and upper range limit(s). c. Label and sign each sample in four separate locations and arrange for the samples to be cut into 5 equal sizes. The samples shall then be distributed as follows: iii. The - Contractor. iv. The SO (2 No. Samples).

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v. The Coating Applicator. vi. The Sub-contractor if any. d. Keep these for at least the duration of the Works and use to agree or otherwise any disputable finishes in the works. 5.2.4.2

Glass

Any glass panels from the visual mock-up to be retained for later reference as control samples. 5.2.4.3

Stone

Following the requirements of A1-60. 5.2.4.4

Metal Panels

Full size or 600mm x 600mm metal panels, complete with typical edge conditions and finishes to be prepared as control samples. These samples to include typical perimeter fixings. 5.2.4.5

Other components

Refer to the PSD for other control samples to be retained of other assemblies such as sunshades, louvers and frames, 4 way joints, hardware, etc. 5.3

Testing 5.3.1

Schedule of Tests

Refer to the PSD for the schedule of tests required for this project. 5.3.2

Testing - general

Submit method statements to the SO for review, describing how it is proposed to undertake to test the Works Test the Works and achieve results that verify to the SO that the performance requirements herein have been met. 5.3.3

Component Tests & Certificates

5.3.3.1

Aluminium

Perform mechanical materials tests and chemical composition analysis on aluminium billets and sample extrusions. Provide copies of test certificates upon request. 5.3.3.2

Aluminium Finishes

a. Generally i. Test the finish to aluminium components shall meet or exceed the requirements of AAMA 605.2 when tested by an independent testing laboratory for the following properties: 1. Adhesion 2. scratch resistance 3. gloss 4. pencil hardness 53 Version 1.0

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5. dry film thickness 6. abrasion resistance 7. solvent resistance 8. chalking 9. colour change 10. boiling water 11. water immersion 12. resistance to mortar 13. resistance to acetic acid/salt spray 14. resistance to humidity 15. weathering 16. impact ii. The Powder coat finish to aluminium components to meet or exceed the requirements of BS 6496 when tested by an independent testing laboratory. iii. Ensure that the above mentioned tests on painted aluminium are carried out and submit test reports indicating compliance of finish with all the above enumerated requirements as well as manufacturer’s published literature. Test samples to be taken at random from production runs. b. Testing and Verification iv. Provide certificates of coating adhesion and of uniformity of coating in accordance with AS 1650 for galvanised coatings, and AS 1580 Method 408.4 for paint coatings. Comply with Classification 1 of that standard for paint adhesion. v. Ensure that the dry film thickness of the galvanising to steel elements is tested to ensure that minimum film thickness is achieved. c. Colour vi. Comply with the Sampling procedures and plans set out in BS6001: Part 1 (ISO2859/2) for general inspection Level 2, AGL = 1% on each colour and finish used in the Works. Carry out these inspections in the powder coating plant prior to fabrication. d. Applicators Certificate vii. Provide the SO with certificates which state that the finish complies with the requirements of this specification.

5.3.4

Glass

Conduct testing to demonstrate and verify requirements of section clause 3.3 5.3.5

Stone

Conduct testing to determine and verify the properties and durability of stone as defined in A1-60. 54 Version 1.0

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5.3.6

Factory testing of structural silicone glazing

Require the structural sealant manufacturer to test the structural sealant proposed for the Works as below. Submit test certificates to the SO for review. 5.3.6.1

Compatibility

Test for compatibility of the sealant used with all substrate materials including aluminium, finishes, glass, glass coatings, gaskets, setting blocks, backing rods etc. 5.3.6.2

Adhesion

Carry out tension and shear tests to rupture. The results shall note whether cohesive or adhesive failure occurred in the tension rupture tests. Submit results and certificates of compliance of results with acceptable values to the SO. 5.3.7

Weathertightness and Load Testing of Curtain Wall Specimen

5.3.7.1

General

Carry out weather-tightness test prior to the commencement of production and prior to any site installation. Test a specimen complying with the SO’s requirements. Refer to the drawings indicating required specimen size and features. 5.3.7.2

Previously tested systems

If a relevant, valid test certificate from a recognised Independent Testing Authority is available for the same curtain wall system and with a similar size and geometry, provide such certificate at the time of tender. Existing test certificates should prove the weathering and structural performance of the proposed system. Subject to the review of the S.O. that the certificates are acceptable, no off-site weathertightness and load testing of specimens is required. 5.3.7.3

Procedure for testing

Should a relevant, valid test certificate not be available from previous testing: a. Carry out Weather Performance and Structural Testing using an independent testing authority accredited by the appropriate National Authority such as SPRING. All measurement devices used in the tests to be calibrated, to National Standards and shall have current calibration certificates available for inspection. b. Build the test specimen in accordance with the shop drawings and submit method statement of the testing to the SO prior to undertaking the test. Align the test specimen in the same orientation as on the completed building. The Independent Testing Authority shall witness the installation of the test specimen and shall record any modifications to the agreed details and method statements on a set of the test specimen assembly drawings prepared by the Contractor. The specimen shall also be used as a check of proposed assembly and erection methods. c. Refer to clause 5.3.5 for the Testing standard and design parameters of the test. d. The sequence of testing to be: i. Pre-test ii. Structural Testing (deflections) iii. Air Permeability 55 Version 1.0

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iv. Water Ingress v. Any thermal testing and air and water retest vi. Any racking / imposed deflections and air and water retest vii. Proof Load viii. Any BMU / Maintenance load tests e.

Where failures occur propose amendments to the SO for approval and retest.

f.

Submit a test report and certificate produced by the Independent Testing Authority verifying compliance with the performance requirements and design intent for review by the SO.

g. Dismantle the specimen when authorised to do so by the SO. The Independent Testing Authority shall witness the dismantling of the test specimen and shall record any variations to the agreed details and method statements on a set of the test specimen assembly drawings prepared by the Contractor, and shall also record the extent of water penetration into the system. h. Ensure that any modifications identified from the specimen test are included on the drawings prior to any site installation being carried out. i.

Incorporate any modifications of the curtain wall identified from the test after review by the SO. throughout all parts of the curtain wall Works on the building.

5.3.7.4

Reporting

Submit a test report and certificate produced by the Independent Testing Authority verifying compliance with the performance requirements and design intent for review by the SO. a. Date of test, and of report. b. Identification of the areas tested. c. A note of the weather conditions particularly wind strength and direction at the time of test. d. The duration of the test with at statement of how water was applied, where the test started, how it was progressed and where it finished. e. A statement that the test carried out was in accordance with the standards referred to in this document, or a full description of any deviation from the standards previously agreed by the S.O. f.

A statement that the test was successful, or alternatively, a note of any leakages through and/or directly below the area being tested, together with an indication of the severity of leakage.

g. Name and author of report.

5.3.8

Acoustic test

Propose and submit details for acoustic tests as specified in clause 5.3.1.

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5.3.9

Site hose testing

a. Submit method statements to the SO for review, describing how it is proposed to hose test the Works in accordance with AAMA 501.2 Field check of Metal curtain walls for water leakage. b. Test all differing window units, test is to cover three adjacent units in width and two storeys high. c. Test external and internal corners two units on either side of the corner and two storeys in height. d. Submit proposed locations to the S.O. for review. e. Undertake site hose testing on the installed curtain wall and glazed roofs prior to completion f.

The area inside the building at and below the test area to be checked for leaks.

g. Submit test results and certificates verifying that the curtain wall meets the performance requirements and design intent Where the performance criteria specified in this document are not met: a. Report this to the SO. b. Open up the failed area of curtain wall in the presence of the SO. c. Identify the cause of failure d. Submit the proposed remedial measures to the S.O. for review before proceeding e. Carry out remedial work f.

Re-test the area.

Continue this procedure until the curtain wall meets the performance requirements and design intent. Ensure that any modifications are incorporated into all similar areas of the curtain wall on the building. 5.3.10

Site load testing of cast-ins

Provide manufacturer’s statement or calculations certifying that the cast in inserts supporting the bracket fixings for the façade elements will resist the types of loading required and will satisfy the following criteria: a. No permanent deformation of the insert at 1.5 times design working load b. No failure of the insert at twice design working load; and c. No failure of structural concrete at three times the design working load d. Mechanically test a minimum of 2% of fixings on site

5.3.11

Testing of Sealants

5.3.11.1

Compatibility

Provide test certificates for each sealant used to confirm compatibility of the sealant with all surrounding materials including finishes (PVF2, paint etc.), glass coatings, glazing gaskets, setting blocks, spacers, backing fin, steel, aluminium, etc. Compatibility means that the sealant will not cause staining of the adjacent material at any time during the service life of the facade, nor will the adjacent material affect the performance of the sealant. 57 Version 1.0

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5.3.11.2

Weatherseals and Air seals

Test wet sealants prior to installation on site. Check at least 3 tests of each type of detail, at 3 separate locations, using the "Hand Pull" method to ASTM C794-01. Test dry weather seals (gaskets) and air seals in the actual position and on the actual substrates for the relevant seal. 5.3.11.3

Structural Silicone Seals

Include at least the following in the documentation, preparation, installation and testing of structural silicone seals: a. Silicone batch logging procedures to record all batches used including silicone batch manufacture date and arrival date of each batch at the premises. b. Frame logging at time of assembly will include identifying every panel by a unique number. Glazing records will then provide information on each panel (by its number) including silicone type and batch, date of silicone installation, glazier's name, temperature and humidity measured inside the factory at a nominated time each day. c. Deglazing to ensure quality of the silicone seals will be done periodically. Frames will be chosen at random as follows: d. 1out of the first 10 frames (frames 1 to 10) e. 1out of the next 40 frames (frames 11 to 50) f.

1 out of the next 50 frames (frames 51 to 100)

g. 1 out of each 100 frames for the remainder of the project. h. Establishment of an acceptance criteria for the periodic de-glazing. Establishment of a procedure in case a frame is rejected. This shall include deglazing of frames glazed on the same day with the same silicone batch as the reject frame. The procedure shall provide for the identification of all frames of unacceptable quality and their re-glaze or rejection.

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