a1-40 Metal Cladding

July 5, 2017 | Author: lwin_oo2435 | Category: Window, Structural Steel, Specification (Technical Standard), Extrusion, Glasses
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NPQS A2-40 Skylights

National Productivity and Quality Specifications (NPQS)

A2-40 Skylights

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NPQS A2-40 Skylights



1.0 1.1 1.2 1.3 1.4

GENERAL Scope Related Sections Standards Trade Preambles

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2.0 2.1


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3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9

MATERIALS AND COMPONENTS Type of Skylights Glazing Aluminium Frames Stainless Steel Frames Timber Frame Material Compatibility Sealants Screws and Fixings Safety Signs

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4.0 4.1 4.2 4.3 4.4 4.5 4.6

WORKMANSHIP General Integration with Roof Drainage Seals Contact with Cementatious Material Fixing Accessories

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5.0 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 skylights as a component installed as parts of a roof system. It does not cover self-supporting structural glass roofs.


Related Sections Read this work section in conjunction with the relevant requirements of the other work sections including the following: A3-50 External Timberwork


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 submitted to 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 current version, unless specific year references are noted. Singapore Standards SS 341

Safety glazing materials for use in buildings (human impact considerations)

Other Standards BS EN 485-3

Aluminium and aluminium alloys – sheet, strip and plate. Tolerances on shape and dimensions for hot-rolled products

BS EN 572-2

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

BS EN 573-3

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

BS EN 755-1 to 9

Aluminium and aluminium alloys - extruded rod/bar, tube and profiles

BS EN 10088-1

Stainless steel-list of stainless steel

BS EN 10088-2

Technical delivery conditions for semi finished products, bars and rods for general purposes

BS EN 10088-3

Technical delivery conditions for semi finished products, sheet/plate, strip for general purposes

BS EN 12020-2

Aluminium and aluminium alloys. Extruded precision profiles in alloys EN AV 6060,6063-Tolerances, dimensions and forms

BS EN ISO 3506-1

Mechanical properties of corrosion resistant stainless steel fasteners. Bolts, screws and studs

BS EN ISO 3506-2

Mechanical properties of corrosion resistant stainless steel fasteners. Nuts.

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BS 476-20

Fire tests on building materials and structures. Method for determination of the fire resistance of elements of construction

BS 1161

Specification for aluminium alloy sections for structural purposes

BS 3987

Specification for anodic oxide coating on wrought aluminium for external architectural purposes

BS 4842

Specification for liquid organic coatings for application to aluminium alloy extrusions, sheet and preformed sections for external architectural purposes, and for the finish on aluminium alloy extrusions, sheet and preformed sections coated with liquid organic coatings.

BS 5215

Specification for one part polysulphide sealant

BS 5588-11

Fire precautions in the design, construction and use of buildings. Codes of practice for shops, offices, industrial, storage and other similar buildings

BS 5713

Specification for hermetically sealed flat double glazing units

BS 5889

Specification for one part gun grade silicone sealant

BS 6206

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

BS 6213

Guide to the selection of constructional sealants

BS 6496

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

BS 8118

Structural use of aluminium

AS 3715

Metal finishing. Thermoset powder coating for aluminium and aluminium alloys

ASTM C1036-01

Standard specification for flat glass

ASTM C1048-97

Standard specification for heat-treated flat glass kind HS, kind FT coated and uncoated glass

ASTM C1172-96

Standard specification for laminated architectural flat glass

ASTM D3935-00

Standard specifications for polycarbonate (PC) unfilled and reinforced material

AAMA 2605-98

Voluntary specification, performance requirements and test procedure for superior performing organic coatings on aluminium extrusions and panels. Series: Components, coatings and finishes

DIN 18516 Part 4

Bimetallic corrosion

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Trade Preambles 1.4.1

Contractor’s Submissions

The intended type and locations of skylight are indicated in the Drawings. Engage qualified and experienced personnel to carry out and submit the following items to the SO:

Develop all necessary details for the skylights based on the design drawings.

Produce shop and erection drawings to enable the fabrication and installation of the skylights.

Design for the appropriate structural support for the skylight system. Engage a PE (civil) to review and endorse on the design for submission to SO.

Develop waterproof details for the junction between the skylight and the roof.

Submit names of manufacturer’s for major components.


Shop Drawings

Prepare coordinated shop drawings incorporating all developed details. 1.4.3

Co-ordination with other Works

Co-ordinate the skylight works, particularly the interfaces with the following work packages and trades: a. Main roof and roof support structure b. Suspended ceilings c. Lightning Protection


Provide Spare Materials

No item. 1.4.5


Provide warranty in accordance with the contract conditions for the following items: a. Aluminium works. b. Glazing. Refer to the PSD for warranty requirements. 1.4.6

Maintenance Manual

Prepare and submit a maintenance/replacement manual covering all components and accessories including suppliers contact information. Refer to the General Requirements section, clause 1.4.8 for details. 1.4.7

Quality Control Plan

Prepare and submit a quality control plan to the SO.

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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

Dead Loads

The self-weight and other associated dead loads of the skylight are to be supported and transferred to the main building structure. 2.1.2

Fire Resistance

Comply with the requirements of the FSSD and any additional requirements of other statutory authorities having jurisdiction over the works. Refer to clause 3.1 for the required fire rating of the skylight system for the project. Glazing components to conform to BS 5588 Surface spread of flame – Class 1 BS 476. 2.1.3

Live Load to Skylights.

Allow for human access loading to skylight without deformation or compromise to weather shield.

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Type of Skylights Refer to the PSD for the specific types and component requirements of skylight works for this project.


Glazing 3.2.1


Form glazing with at least the lowest layer being laminated heat strengthened panes. The laminated panes are to: a. Comply with SS 341. b. Have PVB interlayer complying with BS 6206 Class A. c. Have edge steps less than 0.5mm in toughened or heat-treated glass. d. Bear identification marks indicating its nature and processor. Protect the interlayer material from the effects of moisture absorption in service including clouding, shrinking back, degassing and delamination. Take into account, that the interlayer is compatible with glazing sealants. 3.2.2

Glass, General

All glass are to: a. Comply with the requirements of SS 341, clause 3.2. b. Be clean cut, without significant edge faults (including feathered edges, shells or other imperfections) and free from bubbles, inclusions, cracks, rippling, dimples, sleeks or other defects. c. Be cut to accurate sizes in the factory. d. Be assessed for optical and visual faults as described in BS EN 572-2. Spot faults to be no worse than category C. There are to be no linear/extended faults. Optical faults to be within the limits set in BS EN 572-2. e. Have no local defects producing irregular reflections.


Heat Treatment

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.

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Heat Strengthened Glass

Heat strengthened glass are to: a. Comply with the requirements of SS 341, clause 3.2. b. Be tempered on a roller hearth furnace eliminating tong marks c. Conform to the following requirements in the horizontal heat treatment process: i)

Maximum bow 0.2%


Roller wave: All thicknesses 0.15mm depth maximum between peaks and troughs


Edge dip: 0.25mm maximum

d. Have identification marks indicating its nature and processor. Demonstrate by the prime manufacturer’s testing that surface compressive stress in the glass meets the requirements of SS 341 clause 3.2. 3.2.5

Toughened Glass

Toughened glass, to: a. Comply with SS 341. b. Be tempered on a roller hearth furnace eliminating tong marks c. Conform to the following requirements in the horizontal toughening process: i)

Maximum bow: 0.2%


Roller wave: All thicknesses 0.15mm depth maximum between peaks and troughs


Edge dip: 0.25mm maximum

d. Have identification marks indicating its nature and processor. Location to be agreed with SO. Heat soak test all toughened glass for a minimum of 8 hours at 290 C, in accordance with DIN 18516 Part 4, to convert all nickel sulphide inclusions greater than 40 µm in diameter to the ß phase so that the glass will fracture in the test. After the test the probability of failure in service should be less than one in 130 tonnes. Upon request, show by statistical analysis of test data that the probability of failure is not greater than the value quoted above. Demonstrate by the prime manufacturer’s testing that surface compressive stress in the glass meets the requirements of SS 341 clause 3.2. 3.2.6

Insulating Glazed Units

Insulating glazing units are to have: a. Hermetically sealed complying with BS 5713. b. Mechanically applied primary polyisobutylene seal located between glass and spacer providing a vapour proof barrier, which is continuous and of a minimum width of 2mm, and a secondary two part silicone sealant extending around the perimeter of the unit.

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c. Aluminium alloy spacers with a natural or black finish and sufficient rigidity for their purpose. They are to be formed to accommodate seals and contain desiccant. d. All breather tubes nipped closed prior to installation. e. All corners and joints to be fabricated so as to ensure a water vapour tight construction.


Aluminium Frames 3.3.1


Extrusions- from designated treated alloy 6063 T4, 6035 T5 or 6063 T6 complying with BS1474 unless otherwise agreed with SO Comply with BS 8118, BS EN 573-3, BS 1161 and BS EN 755 Minimum wall thickness in structural parts = 2.5mm Platforms, webs, flanges, races and screw flutes of sufficient size to satisfy all structural requirements and eliminate distortion of elements in the works. Fabricate sheet material ancillary members from designed alloys 1100,2005,3032,0r comply with BE EN 485. 3.3.2

Finishes to Aluminium General

Shop finish all visible and all other surfaces of aluminium exposed to the external environment, including drained and ventilated cavities and pressure equalisation chambers. Finishing is to be applied to all external surfaces after any fabrication processes likely to damage the finish i.e. folding of sheet.

PVF2 Coating

Resin content 70%, to meet requirements of AAMA 2605 and BS 4842. Refer to clause 3.1 for number of coats.

Polyester Powder Coat

Apply heavy duty external grade polyester powder coat conforming to BS 6496, to all external surfaces.

Anodised Aluminium

Comply with BS 3987 for anodic oxidation of wrought aluminium, with thickness grade AA25. Coating thickness on the surface/s shall not be less than 20 microns. 3.4

Stainless Steel Frames 3.4.1


Conform to the following standards for stainless steel, unless otherwise specified. 3.4.2

Plate, sheet, strip

Comply with BS EN ISO 3506-1 and BS EN ISO 3506-2.

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Unless otherwise noted, use grade 1.4401 (formerly 316) for all visible components; in all other circumstances use grade 1.4301 (formerly 304). Unless otherwise noted, use grade A4 for visible fasteners; in all other circumstances use grade A2. Select the fastener property class so as to meet the performance criteria specified. 3.5

Timber Unless otherwise specified all timber to be Kapur, Chengal or Balau. Moisture content when fitted to be between 10-15%, moisture content between adjacent timbers to be no more than 3%. Pressure impregnate all timber, impregnation system to approval of the SO. Fire retardant treatment system to the approval of the SO. Season and kiln dry timber after treatment. 3.5.1

Timber Surface Treatment

Refer to section A3-50 “External Timberwork”, clause 3.3. 3.6

Frame Material Compatibility Select, design and install different materials to prevent bimetallic corrosion.


Sealants 3.7.1


Select and install in accordance with BS 6213. Design sealant geometry (and cross section) to accommodate the anticipated substrate movement. Do not use acid curing sealants. 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.

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Silicone sealants: Comply with BS 5889.

Polyurethane sealants: Comply with BS 5215.

Non-structural sealants: Approved low modulus silicone (exposed or concealed) or approved polyurethane sealant (concealed).




Other Components

Backing rods: Non-gassing polyethylene closed cell foam

Primers and joint preparation materials: As recommended by the sealant manufacturer.

Screws and Fixings All screws and fixings to be corrosion resistant and selected to resist any bi-metallic corrosion. 3.8.1

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 skylights to be / have: a. Pressure equalised systems with drained cavities. Face sealed systems are not acceptable. 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 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: h. Where edge cover is required on glazing and panels, provide sufficient to: i. Achieve weathering and edge capture around their perimeter, and; ii. Achieve acceptable clearances between metal framing and glass edges. i.

Glazing unit replacement without the need to dismantle the primary framing members


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

k. Steel or brass keys. l.

Top hung the limiting device capable of being undone only by authorised personnel.

m. An operating stay type mechanism with the following features:

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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. The stay mechanism to be fastened to both the opening light and the frame and only capable of being undone by deliberate action.


Safety Signs Where noted in clause 3.1, provide barriers and warning signs if the form allows easy entry onto the glazing. Warning signs to read NO WALKING ON GLAZING in red letters no smaller than 50mm in height and to consist of a material and printing that will not degrade.

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General Install units in accordance with manufacturer’s instructions for the creation of a waterproof junction between the skylight and the roof covering.


Integration with Roof Where shown on the drawings, form upstands in the roof construction to allow for the creation of a waterproof detail between the skylight and the roof.


Drainage Where glazing extrusions are used to form the skylight framing, ensure that the horizontal members drain into the verticals and that the joint between is sealed. The vertical members are to drain clear of the upstand with a turndown at the end to prevent water entering the upstand junction.


Seals Install Neoprene or Epdm seal where required to seal the head and base of the glazing.


Contact with Cementatious Material Apply bituminous paint to units in contact with cementatious material.


Fixing Accessories Provide fixing accessories whose corrosion resistance will provide a service life equal to that specified for the component. Select materials which will not result in bi-metallic corrosion.

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Submissions 5.1.1


Include in construction program, event for submission of the following information: a. Name of the skylight manufacturer and inclusion of copies of technical data relating to system proposal. b. Name of Sub-Contractor, if any. c. Information of current or completed similar jobs during the previous 5 years and details of Quality Control Procedures adopted.


Design Submissions

Prepare an installation strategy, containing the following information, prior to the preparation of detailed shop drawings. a. Sequence of construction b. Method statements c. Means of accommodating the skylight within the roof construction d. Specimen of warranty


Fabrication Submissions

Shop Drawings

Where specified, prepare shop drawings, particularly include the following items: a. Layout of all skylights with scale 1:50 including location of all structural steel work or upstands in the roof construction. b. Section through the skylight and roof construction at scale1:5. Do not commence fabrication until shop drawings have been reviewed and permission to proceed has been obtained from the SO.

Certification of Materials

Provide the SO with certification from the manufacturer of the following materials /components, 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. a. Glass b. Frame finish


Maintenance Submissions

Include the following information in the maintenance manual and logbook. a. Cleaning methods for glazing and metal / timber parts 15 Version 1.0

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Submit the warranty upon completion of the works. 5.1.6

Quality Control Plan Submission

Prepare and submit the quality control plan to the SO prior to starting fabrication work. 5.2

Samples and Mock-ups 5.2.1


Submit one sample of each component of the skylight system to the SO prior to ordering material. 5.2.2


Refer to the PSD for any mock-up panels required for the project. 5.3

Inspection No item.


Tests 5.4.1

Water Tests

Undertake water test on all skylights as part of the test for the particular main roof construction.

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