ALUMINIUM SHEETS are extensively used for roofing because of its following characteristics.
TECHNICAL DATA OF GALVALUME SHEETS
FIRE RESISTANCE: It is a non-combustible and non-flammable material & also non-sparking.
LIGHTNING: Metal covered and metal frame buildings offer the safest possible shelter during electrical storms. Because of its high electrical conductivity, it offers excellent protection from lighting damage. It is, however, always recommended that Aluminium ( and NOT COPPER ) lighting conductor systems should always be used on or next to an Aluminium roof. This is essential to take care of the bi-metallic corrosion between Aluminium and copper.
ECONOMY IN SUPPORTING STRUCTURES: The superimposed weight of Aluminium building sheets on the substructure is very small. This ensures lighter supporting structurals. The purlin spacings can also be increased considerably ensuring reduction in the number of purlins.
WIND: Aluminium roofing sheet is amply strong to resist wind forces specified by IS:875.
THERMAL MOVEMENT: Aluminium has a relatively high coefficient of linear expansion, 0.000024 per degree centigrade. Lateral expansion of sheeting is readily accommodated by the corrugations/ troughs. Expansion and contraction in the length of long sheets should be allowed for by providing oversize holes for fixing and correspondingly large sealing washers.
CONDENSATION: In most industrial buildings the relative humidity of the inside air is not high enough for condensation to be a problem. However, in case of this problem, the most effective answer is a lined roof with a continuous, impervious vapor barrier - such as bituminized aluminium foil or a suitable paint system- on the room face of the lining. If a vapor barrier is impracticable, good ventilation of the air gap between the aluminium skin and the insulation is essential. Condensation can arise from cooling, by radiation on a cold clear night, of metal roofs. Experience indicates the good ventilation is an adequate remedy, especially as on a cold clear night the atmosphere tends to be dry and condensation light and readily evaporated. Condensation drip in a building can be avoided in the design stage by ensuring that the roof has sufficient slope.
ACOUSTIC: The drumming of rain on the metal roof should be allowed for in the design. In lined buildings, the air space between the roof materials usually reduces the noise to tolerable levels, A significant reduction in sound can be made by the provision of an over-purlin space or over-purlin lining.
HYGIENE: Premises intended for the storage, handling and preparation of food, cereals, etc. demand smooth, non-toxic, non-absorbent and easily cleaned surfaces. Aluminium satisfies all these requirements and may further assist in the maintenance of hygienic conditions by looking, as well as being, clean. Further, aluminium is vermin and insects proof.
HEALTH HAZARD: Aluminium Building Sheets pose no health hazard to the users.
CRYOGENIC PROPERTIES: Low temperatures have the effect of improving the mechanical and elastic properties of Aluminium. At sub-zero temperatures, the strength of Aluminium alloys is higher than at room temperatures, without rendering the alloy brittle; the ductility remains as high and sometimes higher than at room temperature.
From 0 Deg C to -73 Deg C- The differences are negligible.
At 196 Deg C - Tensile strength 30% higher than at room temp.
Yield strength 20% higher than at room temp.
At 268 Deg C - Tensile strength 50% higher than at room temp.
Yield strength 35% higher than at room temp.
Aluminium profiled building sheet is an excellent material for cladding applications in the extremes of cold.
RESALE VALUE: Unlike other competitive materials, aluminium building sheets fetch very high returns on scrap even after prolonged usage.
APPEARANCE: Aluminium profiled building sheet can look outstanding in its simplest form - plain mill finish. It provides a pleasing architectural beauty to all kinds of buildings with a touch of distinctive modernity.
Aluminium Sheets can be used extensively and economically as a roof and side/wall cladding material in the following areas:
Warehouses / Godown / Storage Sheds.
Conveyor Gantry Housing.
Cold Storage Sheds.
Green Houses/Garden Houses.
Prefabricated building for residential accomodation, site office.
Military / Police barracks, small godown, motor garage, primary school, medical dispensary etc.
Exhibition Pavilion Stalls.
Insulation protection of fuel storage tanks and industrial boilers.
Permanent Awnings in Ships and Streamers.
Wall Panels for high rise buildings.
Interior Partition Walls.
False ceiling for large hall, etc.
Insulation bonded sandwich panels.
Pre painted / Anodised building sheets for decorative applications.
Roof and Side cladding of all kinds of industrial shed / warehouses.
Aircraft hangers /conveyor gantry housing.
Prefabricated buildings / Bunk houses / Tents /Kiosks / Exhibition pavilions.
Ship awning / Boiler & fuel storage tank insulation cover.
Wall panels for high rise buildings / partition walls / false ceiling for large halls.