July 5, 2017 | Author: lwin_oo2435 | Category: Structural Load, Corrosion, Screw, Specification (Technical Standard), Aluminium
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NPQS A1-30 Sun-screens and Louvres

National Productivity and Quality Specifications (NPQS)

A1-30 Sun-screens and Louvres

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1. 1.1 1.2 1.3 1.4

GENERAL Scope Related Sections Standards Trade Preamble

3 3 3 3 4

2. 2.1


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3. 3.1 3.2 3.3 3.4 3.5 3.6 3.7

MATERIALS AND COMPONENTS Types of Screen and Louvre Systems General Requirements Aluminium Frames Stainless steel Frames Screws and Fixings Sealants Paint and Finishes

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4. 4.1 4.2 4.3

WORKMANSHIP Fabrication Installation Protection and Cleaning

11 11 11 12

5. 5.1 5.2 5.3 5.4

VERIFICATION AND SUBMISSION Submissions Samples and Mock-ups Inspection Tests

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


Scope This section covers the requirements for the fabrication and installation of louvres, sun-breaker and screens to the façade of a building. It covers Aluminium and Steel components. Concrete components are regarded as concrete cladding, refer to section A1-50 “Architectural Precast Concrete Cladding” for work requirements. For timber components refer to section A3-50 “External Timberwork”.


Related Sections Read this work section in conjunction with the relevant requirements of the other work sections including the following: 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 26 Ordinary Portland cement SS117 Hot dip galvanising coatings on iron and steel articles. SS 212 Aluminium Alloy Windows Other Standards BS EN 13030 Ventilation for Buildings – Terminals – Performance Testing of louvers subjected to simulated rain BS EN 3506-1 Mechanical properties of corrosion resistant stainless steel fasteners. Bolts screws and studs BS 6213 Selection of Construction Sealants. BS 5889 Silicone sealants BS 8118 Aluminium BS 6399 Loading BS 5250 handbook Condensation prediction BS 8200 BS1474, BS EN 486, BS EN 573-3 BS EN 755 BS1161 PD 6484 AAMA 2065

Code of practice for the design of non –loadbearing external vertical enclosures for buildings Aluminium extrusions Aluminium and aluminium alloys –chemical composition and form of wrought products Aluminium and aluminium alloys Specification for aluminium alloys for structural purposes Bimetallic corrosion Voluntary specification, performance requirements and test procedures for superior performing organic coatings on

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aluminium extrusions or panels Aluminium and aluminium alloys. Anodic oxidation coatings Metal finishing Thermoset powder coating for architectural applications of aluminium and aluminium alloys

AS 1231 AS 3715


Trade Preamble 1.4.1

Contractor’s Proposals and Submissions

The design intent and types of screens and louvres for the project are set out in clause 3.1 and in the drawings. Based on the information, submit the following items for SO’s acceptance:

Develop all necessary details for the fabrication and installation of the system(s), to meet with the performance requirements as set out in clause 2.1 below. Details to develop may include shape and sizing of components, structural support, accessories, joints, waterproofing and connections to the building etc.

Propose manufacturers and products for components of the systems when called for.

Propose method of fabrication, erection/installation.

Propose details of weather/waterproofing.


Co-ordination with other Works

Co-ordinate the works particularly the interface with the following trades: External masonry walls, windows and doors. External curtain wall, metal cladding and precast cladding. 1.4.3

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. 1.4.4

Submission to Authorities

Engage a PE (Structural) as a QP to carry out the design of the structural supports for the systems and to submit for BCA approval. 1.4.5


Provide a ten-year warranty in accordance with contract conditions for the systems including all components and accessories for the specified performance. 1.4.6

Maintenance Manual

Refer to the PSD for any requirement to provide a maintenance manual. 1.4.7

Quality Control Plan

Refer to the PSD for any requirement to provide a quality control plan.

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Contractor’s Brief When carrying out the proposals as set out in clause 1.4.1, take account of the following requirements: 2.1.1

Resistance to Loading

Loading general

Withstand loading from inside and outside the building determined in accordance with CP3 using a basic wind speed V=35m/s and terrain appropriate for the location. Transmit all the design loads to the building structure via the anchors as designed with an adequate margin of safety appropriate to each material and product

Gravity loading

Support the self weight of the screen and louvres and transmit this weight safely back to the supporting structure without overstressing or permanently deforming any components.

Wind loading

Support the design dynamic pressure and transmit these loads safely back to the supporting structure without overstressing or permanently deforming any of components. Account shall be taken of all applicable local pressure coefficients. 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. Permanent deformation to framing members shall not exceed 1/500 of the span measured between points of attachment to the structure after loading. In the case of building frames the calculated stress of all combined forces shall not exceed 1.33 times the appropriate maximum permissible stress in the short term.

Determination of design pressure

Determine the design pressures and other loadings to be used in the design of the screen and louvres in accordance with procedures established in agreed Codes and Standards. Submit the design pressures to the S.O. for review.

Impact loading

Satisfy the requirements of Tables 3 and 4 of BS 8200 "Design of non-loadbearing vertical enclosures" for category B in table 2. The maximum visually acceptable dent in the metal surface is 10mm in diameter and 3mm in depth.

Maintenance loading

Sustain and safely transmit a static load of 500 N applied horizontally through a square of 100 mm side on any framing in vertical or near vertical screen and louvres. Sustain and safely transmit a loading of 0.25kN/m² or 0.75kN applied to all systems with a horizontal dimension greater than 600mm.

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Sustain and safely transmit loads at BMU restraint points as advised by BMU manufacturer (or a default value of 3.5kN) in any direction.

Barrier loading

Where the metal screen and louvres or its sub-frame provides protection to a fall, sustain and safely transmit safely each of the following static horizontal loads acting separately: 0.75 kN/m for all occupied spaces acting in all directions at a height of 1.0 m above finished floor level, 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. Sustain and safely transmit crowd loading if requirement confirmed by SO.

Loading from temporary conditions

Sustain and safely transmit any temporary loading that may arise from lifting, storing, transporting, hoisting and installing the screen and louvres or other Works that may affect the screen and louvres.

Vibration and Repetitive Loading

Resist working loose of anchors and other components due to the effects of vibrations, or cyclic effects of load, deflections and thermal expansion.

Locked in Stresses

Avoid the introduction of locked-in stresses that may be detrimental to the performance of the louvres and screens.

Framing deflection limits for serviceability under load

Determine the positive and negative design loads in all directions from the most onerous combination of loads. Achieve serviceability deflection limits under the combined design loads not exceeding 1/200 of the span of the member measured between points of attachment to the building, or 20 mm, whichever is the lesser. All framing members are to recover fully from the above deflections when the loads are removed. Horizontal panels – dead load deflections to be less than L/180. 2.1.2

Building Movements and Structural Tolerance

Ensure that performance, appearance and proper functioning of the Works are not affected by any movements, settlement, deflection, expansion or contraction which can be expected to occur in the building or the construction process. Junction between the louvres and screens and adjacent work by others shall be formed to accommodate possible structural deflections or movement in that adjacent element without distortion to the Works, or disintegration of joints between works.

Structural Movement and Movement Between Works by Others

Accommodate the following movements in combination; without any reduction in the specified performance: a. Deflections and movements of the structure and building wall under design loads.

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b. 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. c. Changes due to movement of any joint in the supporting structure or building frame. d. Deflection of framing members under design dead loads and live loads. Incorporate these calculations in the design. e. Thermal and moisture induced movements of the screens and louvres. Incorporate these in the design based on maximum range of temperature and humidity. Refer to the PSD for design movements and deflections to account for.

Structure Tolerances

Accommodate tolerances on structure and window openings as indicated in the PSD to the respective works. 2.1.3


Take cognisance to the environment for which the Works are to be applied, Paying particular attention to the Daily and seasonal variations in humidity and temperature in the Tropics. 2.1.4


Include any measures necessary to ensure that the surface finishes are uniform in colour and texture and appearance throughout.

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Types of Screen and Louvre Systems Refer to the PSD for the types of screens and louvres and component requirement for this project.


General Requirements 3.2.1

Screen Systems

Screen systems shall (be / have): Replacement without the need to dismantle the primary framing members. Ironmongery as set out in clause 3.1 3.2.2

Louvres Systems

Louvre systems shall (be / have): Drainage system for any water passing the louvers or condensing within unit to drain to the outside. Replacement without the need to dismantle the primary framing members. 3.2.3

Material Compatibility

Select, design and install different materials to prevent bimetallic corrosion. 3.3

Aluminium Frames 3.3.1


Designation 6063, temper T6 of BS 1474 unless otherwise agreed with SO Comply with BS EN 486, BS 8118, BS EN 573-3, BS 1161 and BS EN 755 Minimum wall thickness in structural parts shall be 1.2mm Platforms, webs, flanges, races and screw flutes of sufficient size to satisfy all structural requirements and eliminate distortion of elements in the works. 3.3.2

Sheet, strip and plate

Alloy complying with BS EN 485-3. Not less than 1.6mm thick for hidden flashings, not less than 2mm thick for components exposed to view or to impact Stainless Steel Components. 3.3.3

Finishes to Aluminium


Shop finish all visible and all other surfaces of aluminium exposed to the external environment, .Finish after any fabrication processes likely to damage the finish i.e. folding of sheet, but prior to assembly into units..

PVF2 Coating

Resin content 70%, to meet requirements of AAMA 2605. 8 Version 1.0

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Refer to PSD for number of coats.

Polyester Powder Coat

Heavy duty external grade polyester powder coat that conforms to AS 3715. Finish shall be applied to all internal surfaces.

Anodised Aluminium

Anodic oxidation of wrought aluminium shall comply with AS 1231 with thickness grade AA25. 3.4

Stainless steel Frames 3.4.1


Stainless steel shall conform to the following standards unless otherwise specified. 3.4.2

Plate, sheet, strip

Comply with BS EN ISO 3506-1 and BS EN ISO 3506-2. Unless otherwise noted, grade 1.44xx (formerly 316) shall be used for all visible components, in all other circumstances grade 1.34xx (formerly 304) shall be used. Unless otherwise noted, grade A4 shall be used for visible fasteners, in all other circumstances grade A2 shall be used. Select the fastener property class so as to meet the performance criteria specified. 3.5

Screws and Fixings All screws and fixings to be corrosion resistant and selected to resist any bi-metallic corrosion.


Sealants Select and install in accordance with BS 6213. Silicone sealants shall comply with BS 5889. Polyurethane sealants shall comply with BS 5215. Design sealant geometry (and cross section) to accommodate the anticipated substrate movement. Do not use acid curing sealants. Non-structural sealants-approved low modulus silicone (exposed or concealed) or approved polyurethane sealant (concealed). Use in accordance with the manufacturer’s directions, particularly relating to the use of primers. Refer colour selection of any visibly exposed sealants to the SO. Sealants shall have: Backing rods- Non-gassing polyethylene closed cell foam Primers and joint preparation materials- as recommended by the sealant manufacturer.

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Paint and Finishes For site applied finishes refer to options set out in A1-80-3 “External Painting and Coating” clause 3.1. Refer to clause 3.1 for finishes on each louvre and screen type.

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Fabrication 4.1.1


Select methods used for fabrication that will achieve the specified performance. Use jigs and computer controlled tools wherever appropriate to achieve accuracy. Carry out grinding, cutting, shaping and finishing materials using tools, techniques and ancillary materials that will not contaminate louvre or screen components with particles or substances which could disfigure, stain or corrode them. 4.1.2


Mark components and materials clearly wherever this is required in order to identify strong points for lifting, permit assembly or installation in a particular sequence; or interlocks occur; or confusion could foreseeably arise between upper and lower faces, left and right handed pieces, top and bottom, or lengths close but critically different from one another. Mark in such a way as not to affect the performance of the louvres and screens with removable or marks that will be concealed when installed. 4.1.3

Fabrication tolerances

Achieve the following maximum allowable tolerances for metal louvres and screens a. ±1.5 mm on length b. ±1.5 mm on straightness c. ±2° accuracy on angles d. ±1mm on sides and ±2mm on diagonals of opening positions


Factory 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. Use appropriate backer rods, tapes, surface preparation and primers as manufacturer’s directions. Tool off sealants neatly Use small joint sealant in crevices where extrusions mitre together. 4.2

Installation 4.2.1

Line and level survey

Undertake a survey of line and level and condition of structure and openings to verify acceptability to receive louvres and screen.

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Setting out marks

Use removable marking or place marks in locations where they will be concealed when the louvre and screens are installed. 4.2.3

Handling of materials and components

Handle louvres and screens by designed strong points only. 4.2.4

Erection Tolerances

Install the louvres and screens to the following permitted deviations: The tolerances are not cumulative. Horizontal and vertical position on elevation from site datum Horizontal position relative to adjoining wall finishes Level: Plumb: Plane: Intersection:


± 10 mm. ± 2 mm ± 2 mm in any one structural bay. ± 2 mm in any one-storey height. ± 2 mm in any one storey height or structural bay width. ± 2 mm in alignment in any direction between any two adjoining louvres or screens


Install fixings in accordance with their manufacturer’s instructions and procedures. 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. Where required seal the heads of bolts and fixings. 4.2.6

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 recommended by the manufacturers Prevent three-sided adhesion. Use backer rods, tapes, surface preparation and primers as manufacturer’s directions. Tool off sealants neatly on completion. 4.3

Protection and Cleaning Protect vulnerable coated surfaces;. Apply temporary removable protection against damage from following trades or operations and the anticipated hazards. Materials used for temporary protection shall be compatible with and subsequently removed from the surface and finishes without detriment to the finish. Propose methods for removal for SO’s acceptance.

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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. Replace any damaged components in the louvres and screens. Concession to this requirement will only be given if the contractors proposed repair procedure is authorised by the SO and complete and warranted repair of the damage is achieved.

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Submissions 5.1.1

Tender Submissions

Submit the following information with the tender: Details of proposed louvres and screens noted in clause 3.1. Include copies of technical data relating to each of the material types. 5.1.2

Work Submissions

Prepare an installation strategy, setting out the sequence of work.

Supply a specimen of warranty.

Shop Drawings

Prepare shop drawings, which shall include: Elevations at a minimum of 1:50 of all facades setting out the members together with the support system, All components to be individually identified. Detail drawings at 1:10 of all component types Details of all junctions at 1:1 Details of support fixings at 1:5 Fabrication shall not commence until shop drawings have been reviewed and approved by the SO. Allow 21 days for SO review. 5.1.3

Certification of Materials

Provide the SO with certification from the manufacturer of the materials/components, set out in clause 3.1 certifying that the respective material is of the correct grade, strength, size, finish, etc, and is in accordance with the relevant codes and standards specified. 5.1.4

Maintenance Submissions

Include the following information in the maintenance manual and logbook. a. Cleaning methods



Submit the warranty for SO acceptance upon completion of the works. 5.1.6

Quality Control Plan Submission

Prepare and submit the quality control plan for SO’s acceptance prior to starting work.

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Samples and Mock-ups 5.2.1


Subsequent to acceptance of Contractor’s detail design and prior to production, fabricate and build at locations as directed the following mock up sample for the SO to review. 1,500mm long length of louvre or screen including end support, any intermediate supports and connection details back to the structural support. Where louvre/screen punctures the exterior cladding include the details for weatherproofing the cladding. Undertake any modifications throughout the screen and louvre system identified from the mock-up by the SO in order to meet the performance requirements and design intent. Refer to the PSD for additional mock-up requirements.


Inspection No items.


Tests No items

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