Standard Wood-Wool Insulation Boards/Slabs



INTRODUCTION


Duratex® (Lip-braced boards) are a continous length of Duratex® standard board with unique lipped inter locking galvanised steel edge reinforcement, which together with adequate density (as per DIN - 1101) provides spans upto 3000 mm. Duratex® Range of Roof decking has a unique combination of properties which provides designers with a versatile product for a wide variety of applications. It provides lightness with structural strength and excellent thermal, acoustic and fire resisting characteristics, which with the clean interlocking steel edge profile lines and texture of its soffit, allows economics for example, by the omission of a suspended ceiling.

It is widely used for flat or pitched roofing for any type of building and is also suitable for floors, permanent shuttering partitions and exterior cladding. Duratex® is an acceptable material under Building Regulatations and is manufactured to a density in excess of (BS-1105, 1972, DIN-1101, IS : 3308-1981). The Duratex® range of roof decking combines lightness (weight approx. 28kg/m2) with structural strength, good thermal and acoustic properties plus excellent fire-protection. Wood-wool board with lip-braced edge technology are very popular and widely used in building construction in most part of the world especially in Europe, Africa, South & North America and South East Asian, Countries. Galvanised steel-channel of DurateX® lip-braced boards when adequately connected, are considered to provide lateral restraint to supporting beams. Its inherent thermal properties satisfy many common requirements and meet more stringent demands with little additional expense. Duratex® lip-braced slabs are available in 50 and 75mm thickness and to any required lengths ranging as 1200, 1500, 1800, 2000, 2500 & 3000 mm length. Each slab is 600 mm wide with following tolerances: Length +0, -6mm, width +0, -4mm and thickness +0, -2mm. Further, these slabs are available as normal textured and pre-screeded slabs. Pre-screeded slabs are used when slabs are laid to falls, the pre-screeded deck provides a base upon which to apply roof-finishes, thus elminating in-situ screeds. The normal thickness of the slab is not affected (approx. weight is 5 kg/m2 in addition to self weight.

DESCRIPTION

Long wood fibres of selected species stabilised by chemical impreganation both under temperatre and pressure and further mineralised are compressed to half of their thickness under pressure (19 tons/ft2) in a Band-Form-Hydrostatic machine.

MANUFACTURE

Duratex® lip-braced boards are manufactured to receive the unique lipped edge reinforcement which is fitted under pressure, providing permanent bond, good alignement and ensuring even distribution of concentrated loads. The combination of adequate density plus an unbroken length of slabs provides the structural strength for spans upto 3000 mm. These long span units provide a soffit of clean-lines, which when left exposed, is virtually maintenance free. In addition the surface provides high Acoustic absorption.

PERFORMANCE

Strength:Using the recommended spans, Duratex® range of roof deckings complies with loading requirement of BS-648:1964.
Fire Resistance:Duratex® Boards have been tested to the relevant parts of BS-476 and possess:

  • Good-Fire-Resistance-Rating when evaluated as per BS-476, (Part-8), 1972 180-834(1975), IS-3809(1979)
    • 1 hour for 50mm pre screeded.
    • 2 hour for 75mm pre screeded when tested to BS-476
  • Surface spread of flame (both sides of surfaces) (Zero - Achieved class-I when tested to BS-476 (part-7), 1971
  • Minimum Fire Propogation Highest rating class '0' when tested to BS-476.
Biological:Resists dry rot and fungal growths and is impervious to all forms of vermin and termites.
Thermal Conductivity:
NATURAL PRE-SCREEDED
65%rh, 20 c, 2% moisture content 0.065/m c 0.081w/m c
65%rh, 20 c, 8% moisture content 0.077/m c 0.087w/m c

Thermal Comparison:
Duratex Slab-50mm Brickwork-764mm Concrete-890mm

Acoustic: Duratex® boards provides good sound insulation and absorption. When tested for sound absorption on various sound frequencies, the test results as per ASTM C-384(1958) show Noise Reduction Coefficient (NRC) as 0.57 (when tested as per
standing wave test) and 0.68 NRC (under reverbration test).
Durability: Immersed in water for ten-years, there appears no sign of deterioration whilst wet or upon drying. It is unaffected by
climatic changes and is resistant to chemicals and other corroding agents.
High Control:
  • In accordance to : BS : 1105,1972 and DIN-1101 are exercised on the basic raw materials and the final product.
  • As there are no available Indian Standards relating to edge-reinforcement inter-locking wood-wool boards .

DELIVERY TO SITE AND STORAGE

The units are delivered to site with appropriate accessories, the slabs must be stacked flat and protected from rain or moisture. Accidently if wetting does occur, they must be allowed to dry. Breakage or distortion of the units may result owing to careless handling or incorrect stacking.

INSTALLATION

The length of bearing of a unit on to the structural steel section or a manufactured concrete must not be less than 50 mm (as per figure above) after making allowance for all movements of the structure. The grooved edge channels of the slabs are tongued with the help of a key-wedge to the adjacent units so as to give a flush joint and the units positioned so that the ends (which are secured to the supports with the fixings) come into contact. Screeds or roof finishes are then applied. Some care in handling on site is needed to protect units until laid, in-situ screeding shall be of a dry mix to avoid possible staining of the soffit. However when laying wet-screed, temporary support must be incorporated to avoid difflection.

PRECAUTION

Slabs must not be used as a working area during construction, and crawl boards must be used to support the weight of wheel-barrows or similar concentrated loads. The units are capable of with standing normal pedestrian traffic likely to occur during construction work.