The standard outlines the specifications for wood wool building slabs, focusing on their dimensions, weight, mechanical strength, thermal insulation, and acoustic absorption. It applies to two categories of slabs: lightweight for non-structural applications and heavy-duty for load-bearing purposes, ensuring their suitability for partitions, ceilings, wall panels, and roof insulation in construction.
Overview
The standard outlines the specifications for wood wool building slabs, focusing on their dimensions, weight, mechanical strength, thermal insulation, and acoustic absorption. It applies to two categories of slabs: lightweight for non-structural applications and heavy-duty for load-bearing purposes, ensuring their suitability for partitions, ceilings, wall panels, and roof insulation in construction.
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Frequently Asked
The standard encompasses wood wool building slabs made from chemically treated wood wool combined with an inorganic cement binder, compressed and cured for construction use. It primarily specifies slabs of 25 mm thickness, commonly used for acoustic purposes, but includes slabs of other thicknesses. These slabs serve functions such as sound absorption, insulation, and structural partitioning, with defined requirements for size, weight, acoustic properties (for 25 mm slabs), and mechanical performance.
The standard allows nearly any timber species to be utilized, provided it meets the necessary density and quality criteria suitable for producing wood wool fibers compatible with magnesium-oxy-chloride cement bonding. There is no restriction to specific species, though softwoods like pine, fir, and spruce or locally available hardwoods with adequate fiber quality are commonly used in practice, enabling flexibility based on regional timber availability.
The permissible tolerances for the slabs are ±6 mm for length, ±4 mm for width, and ±2 mm for thickness. Additionally, the slabs must maintain uniform thickness, rectangular and parallel faces, and edges that are reasonably square and clean. Deviations from rectangular shape along the slab edges should not exceed 5 mm. Thickness measurement follows the procedure outlined in the standard’s Appendix A to ensure accuracy.
Thermal conductivity of wood wool slabs is determined using the guarded hot plate method in accordance with IS 3346-1966. Testing is performed with a hot plate maintained at 30°C and a cold plate at 25°C. The slabs must exhibit a maximum thermal conductivity of 0.08 W/m·K or less, ensuring effective thermal insulation properties suitable for building applications.
For 25 mm thick slabs with rigid backing, the minimum sound absorption coefficients specified by the standard, measured via the reverberation chamber method (IS 8225), range from 0.1 at 125 Hz to 0.5 at frequencies of 2000 Hz and above. These values demonstrate moderate to good absorption performance, particularly improving at higher frequencies, making these slabs effective for acoustic treatment in buildings.
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