Friday, October 30, 2009

Light fitting specification

The following provides an example specification that can be used in a contract for the installation of the light fittings in a multi-storey office building.

All light fittings shall be designed to prevent ingress of vermin, accidental contact with any live part and to minimize the ingress of dust and dirt. Materials which may be liable to be attacked by termites or other insects shall be avoided.

All outdoor fittings shall be vandal, corrosion, rust-protected and fully weatherproof by means of carefully chosen materials, protective painting and sealing, gasketing and the application of protective compounds.

Each fitting shall be constructed and erected as to be easily accessible for inspection and maintenance.

Each fitting shall be complete with bulbs, tubes, control gears, suspension rods or chain, fixing brackets etc.

Terminals and contacts, as far as possible, shall be shielded as to afford protection from accidental contact. All terminals shall be suitable for connection with metal conduit, to meet with fire regulations.

Sample of each type of fittings must be submitted to the S.O. for approval prior to commencement of manufacture and/or installation.

All fittings, accessories and components in any items supplied shall be uniform of their type, similar parts being interchangeable.

Incandescent lamps
Tungsten filament lamps shall be of bayonet cap general service pattern, internally frosted and shall be suitable for operating on a 240/250 volts A.C. system. The ratings shall be as stated in the drawings.

Fluorescent lamps
All fluorescent tubes shall be of the standard 26mm diameter energy saving type having a color temperature of approximately 6200 degree K (daylight color) if not otherwise stated with, bi-pin lamp cap.

Unless otherwise specified, all fluorescent tubes shall be of switch-start type.

Compact fluorescent lamps
Where SL lamps are specified, they shall be the type of fluorescent lamp integrated with low pressure gas discharge ballast and starter and with Edison screw lamp cap (B22). The wattage of the lamps shall be 9, 13 or 18 as specified in the drawings.

Where PL lamps are specified, they shall be of the type with unique single-ended fluorescent lamps with two pin connection with instant start adapters. The lamp base shall be incorporated with capacitor. The lamp wattage shall be 7, 9, 11, or 13 as specified in the drawings.

Discharge lamps
Where gas discharge lamps are specified, they shall be the type with good color rendering and complete with necessary control gear such as ballasts, capacitors and igniters. The ratings of the lamps shall be as specified in the drawings.

Fluorescent lamp lighting fixtures
All fixtures must be fabricated by manufacturers registered with Director General of Electrical Department, and be approved with The National Testing Department.

The housing, base frame, cover plates and reflector of the fixtures shall be constructed of sheet steel of a thickness not less than 20 SWG.

The sheet steel body shall be designed such that it can be fixed to ceiling or the surface by suspension or on a separate detachable tray.

An adequate mains input terminal block marked “L” and “N” together with a substantial earthing terminal shall be riveted, welded or brazed to the base frame.

Retractable type spring load lamp holders fitted with lamps cap earthing contact housed in a white plastic moulding shall be suitable for direct attachment to the base frame.

All materials liable to corrosion shall be suitably protected and sheet steel surfaces shall be prepared, painted and finished white in stove or vitreous enamel.

Ballasts shall be of the switch start, vacuum/pressure impregnated in polyester resin type comply to B.S. 2818 Part1 or MS. 141: 1973. They shall be compact in design and silent in operation and of the “low loss” type with losses not exceeding 6.5 watts. One ballast shall be used to control one fluorescent tube only.

All capacitors for power factor correction shall be suitable for operating on 250 volts, single phase, 50 Hz at a temperature between -10 degree to 100 degree Centigrade and shall ensure a power factor of not less than 0.85 lagging.

Starter switch shall be of the two pin small metal canister glow type.

All internal wiring shall be heat resistant type and suitably identified by color coding and shall be neatly arranged and adequately supported.

All diffusers, unless otherwise stated, shall be made from tough translucent prismatic plastic of UV-stabilized polystyrene of not less than 2.5mm thick and free from blemishes.

All louvered diffusers, unless otherwise stated, shall be made from UV-stabilized polystyrene material with silver-metallized and parabolic 13mm x 13mm x 11mm cells.

All diffusers and louvered diffusers shall be mounted onto the steel frame which hinged onto the frame work of the fixtures and form a detachable dustproof cover.

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