1.0 GENERALLY
1.1 Glass shall be as specified and approved and is to comply with the relevant B.S or S.S codes. It shall be free from blemishes, bubbles, specks, scratches, waves and other defects. All glass shall bear the label of its manufacturer. Samples of all glass shall be submitted to the S.O for approval before ordering.
1.2 The shading coefficient and thermal conductance of the glass shall be stated in SI units. Where reflective glass are specified; the reflective coating shall comply with the Authorities' requirement of not more than 10% reflectivity.
1.3 Glass shall be butted to suit the opening, leaving a clearance of 1.6mm all round. 1.4 Glass shall be delivered with factory labels attached and stacked in near vertical
position on timber, felt or other resilient edge strips. Keep glass clean and dry during delivery and storage.
1.5 Glass sample shall be submitted (min size 600 x 600) to S.O for approval for each glass type.
1.6 All site dimensions shall be taken before cutting glass. Edges of panes shall be clean cut and free from imperfections. All glass shall be cut accurately to fit frames with necessary clearance and shall be set to give full bedding on the entire width of frame. 1.7 A suitable form of protection shall be afforded to all edges of glass and shall not be
removed until immediately before fixing on site. Should shop or site conditions necessitate deviation from the above requirements, the proposed glazing procedures shall be submitted in writing for the S.O’s approval prior to starting the work.
2.0 SPECIAL REQUIREMENTS FOR WINDOWS AND GLAZED DOORS
2.1 Notwithstanding the approval of glass endorsed by the S.O, the Contractor shall be responsible for the following:-
a) All design, methods and procedures in respect of fabrication, preparation, delivery, installation and protection of glasswork of various types required.
b) Obtaining and strictly complying with manufacturer's recommendations and instructions for handling, preparation and installation of their respective glass products.
c) Re-confirming that installation conditions are proper and acceptable for glasswork of types required; by thorough examination, in advance, of all details respective to glasswork required herein.
d) All as necessary to provide structurally sound, effective and durable glasswork and of first quality workmanship as intended under these specifications.
2.2 Putty
Glazing to wood shall be best linseed oil putty. Glazing to metal shall be with approved proprietary mastic or with the manufacturer's approved materials and methods. Wood rebates are to be primed before puttying. No putty is to be painted until 14 days after glazing.
2.3 Float Glass
Float glass shall be as specified and approved. Minimum thickness is 6mm.
2.4 Obscured Glass
Obscured glass shall be plain rolled, sand blasted and to be cut and glazed so that the direction and face of the pattern is the same throughout.
2.5 Wired Glass
Wired glass shall be Georgian-wired glass and where required to be "lined up", it is to be cut so that the wires in adjacent panes line up both horizontally and vertically.These are to be used for fire rated doors with vision panels (at Staircases).
2.6 Tinted Glass
Glass shall be as specified and approved. Tinted glass shall be of approved colour with a shading co-efficient of 0.75 or such minimum standards as approved by the Authority and to the approval of the S.O. The tint for glass shall be fast. Should any deterioration develop after glazing under normal conditions of use, then any such affected glazing shall be replaced entirely at the Contractor's expense.
2.7 Glass Louver Blades
Glass louver blades are to have all arises ground down smooth and shall be from an approved manufacturer.
2.8 Tempered Glass
Tempered glass shall be used at the full-height glass doors and lift car doors. Proper identifications of tempered glass property is to be shown on one corner of each glass panel.
2.9 Laminated Glass
Unless otherwise specified, the laminated clear glass panels shall be 12.68mm laminated clear heat-strengthened glass, consisting of the following composition:
6mm thick clear heat strengthened glass
2 x 0.34mm thick high penetration resistant (HPR) polyvinyl butyral (PVB) interlayer,
6mm thick clear heat strengthened glass.
The technical properties of the 12.68 mm thk laminated clear heat-strengthened glass shall be as follows:
Visible transmission : 82% Visible reflection : 8% Shading co-efficient : 0.92
U' value : 5.5 w/m2 K
2.9 Glazing Without Beads
Glass shall be well-bedded and back puttied, and secured with springs (to wood) or glazing clips (to metal). Front putty is to be neatly finished to stop 1.6mm from the sight line of the rebate.
2.10 Glazing With Beads
Unless a bedding strip is used, glass shall be well bedded and back puttied.
Where bedding strip is specified, this shall be of wash leather, folded around the edge of the glass.
2.11 Proprietary Product
Proprietary glass system where required shall be those as specified and the works shall be carried out strictly to manufacturer’s instruction.
2.12 Mirrors
Mirrors shall be 6mm thick and of first quality polished plate glass copper backed mirror as specified with beveled edge all round and shall be fixed with chromium plated dome-headed screws unless otherwise stated.
Mirrors shall be fixed to 6mm thick first grade glass on 10mm thick marine plywood backing supported all round on timber framing. Refer to architectural details for mirrors at toilet areas.
3.0 GLAZING INSTALLATION
3.1 Glazing materials and methods to comply in all respects with the recommendations of the manufacturer of the panel to be glazed for the highest quality installation.
3.2 It is essential that glazing methods allow for expansion and contraction of all components within the system.
3.3 Glazing shall be performed by skilled workmen in accordance with the best trade practices, and without springing or forcing. All instructions from the glass and glazing materials manufacturer shall be followed.
3.5 All adjoining surfaces not to receive glazing materials shall be protected against staining or damage of any kind.
3.6 Glazing rebates shall be clean, dry and free of any materials that might adversely affect the bond and seal of the glazing materials or the proper drainage of the rebate 3.7 All glass and glazing materials shall be suitably primed, unless recommended
otherwise in writing by the manufacturer and approved by the SO.
3.8 All approved sealant shall match the color of the aluminum framing or glass.
3.9 Setting blocks shall be approved 90 durometer neoprene rubber of the full width of the rebate and not less than 10mm thick and placed at the glass quarter points. They shall be of a length recommended by the glass manufacturer and be placed in such a way as not to interfere with water drainage of the glazing rebate.
3.10 Jamb blocks shall be used on each glass unit supported on four sides. The blocks shall be approved 90 durometer neoprene and shall be placed at the top and bottom of the rebate 3mm clear of the glass edge.
3.11 Face spacers shall be approved 60 durometer neoprene rubber, continuously applied around the perimeter of each glazed opening on both inside and outside faces.
3.12 Approved exposed sealant shall be installed so that top surfaces of the sealant beads are sloped to drain water away from the glass. All exposed sealant surfaces shall be tooled smooth.
3.13 Sealant tapes or ribbons, where used, shall be mitered joints at each corner. Glass shall be centered in each opening to provide the recess and clearances recommended by the glass manufacturer and approved by the SO.
4.0 CARE OF GLASS
4.1 Glass on site shall be stored in a dry, sheltered and well-ventilated location. It shall be stored in racks in a near vertical position with means to secure the glass against wind loading.
4.2 Stacked glass on opened cases containing glass must not be subjected to direct sunlight, because build-up of heat within the stack can give rise to high thermal stress resulting in breakage. Glass shall be inspected periodically for possible moisture damage. On no account should glass be allowed to stand on or lean against materials that might damage the edges.
4.3 During installation and throughout the Contract period, the Contractor shall cover and protect all glass against damage by staining, abrasion, wet cement and breakage, etc.
5.0 COMPLETION REQUIREMENTS
5.1 Exposed surfaces shall be clean and free from dust, dirt, fingerprints; scratches, warping, waviness; broken unit, chips or cracks; stains; discoloration or other defects or damage. All damaged and defective panes shall be replaced to the satisfaction of the SO at the Contractor's own cost.
5.2 Exterior installation shall be airtight and watertight throughout; free from leaks or entry of water, wind or air into or through interior of concealed structure; other than via waterways or provisions for drainage as particularly provided for and approved.
5.3 Each lite or panel shall be set plumb, level, square and accurately positioned to locations required, adjacent like limits accurately aligned.
6.0 WARRANTY
The Contractor shall provide warranty for Glazing works for a period of ten (10) years
from the date of Certificate of Substantial Completion of the Works. The
warranty is to cover the quality of material against abnormal deterioration, leakage of water and air, glass leakage or cracking, delamination of glass, edge separation and staining by sealant.