GB2340166A - Glazing seal - Google Patents

Description

2340166 GLAZING SEAL The present invention relates to a glazing seat for a

timber screen and in particular a glazing seal for use in imparting good fire resistance to the timber screen even if made of softwood.

In accordance with the present invention there is provided a glazing seal t - comprisinii: a strip comprising a core of incombustible fibre. e.g. refractory fibre, coated with an intumescent material.

Althouizh the fibre core may be porous, it is sealed by the intumescent material and thus the seal as a whole has low aas permeability.

The inturnescent material may be based upon the compound commonly kno%,,,, n as aluminiurn trihvdrate, although this is believed an aluminiurn hydroxide (Al(OH)3)' The invention is further described below by way of example with reference to the accompanying drawing, which shows a section through an edge portion of a glazed timber screen according to the invention and incorporating glazing seals according to the invention.

Referring to the drawing a glass pane 1 is mounted in a timber frame formed from lengths 2 of softwood. The edge portions of the pane 1 are each located between a pair of seals 3 according to the invention.

Each seal 3 Is in the form of a strip having a porous longitudinal central core Z-- 4 of compacted refractory fibres loosely held together by a small amount of binder. Although the core 4 is porous or permeable it is sealingly coated with an inturnescent material 5 based on aluminium trihvdrate. the inturnescent material compleLelv surrounding the cross-section of the core, whereby the seal as a whole is non-permeable to gas.

The inturnescent material used is based on aluminIUM L171hydrate and is available from Sealmaster Limited. of Pampisford, Cambridgeshire. England. under the name Fire2laze (Registered trade mark).

The seals 3 and the edge portion of the pane 1 are accommodated in a groove defined between two softwood beads 6 which are attached to the length 2 of softwood bv screws. a liner 7. also of Fireidaze. beino provided between the beads and the len2th of softwood.

The seals 3 are stuck to the beads 6 and the glass pane I using Firegla7t. The seals are further secured to the beads 6 with pins.

It will be understood that the entire periphery of the glass pane I is sealed to the timber frame in the manner described above.

At elevated temperature. as under Eire conditions, the inturnescent material 5 inturnesces. The core 4 has low thermal conductivity and thus, together with the inturnesced material 5, functions as a heat insulator. The core 4 and the inturnesced material 5 also act as a gas barrier to prevent hot gases passing from the one side of the screen to the other.

A timber screen such as described above, P-lazed with wired soda-lime Plass (Pyroshield manufactured by Pilkin2ton) in accordance with BS476 Part 22 3 was sub'ected to a 60 minute glazed screen test. Most surprisingly the screen 1 I= achieved a fire ratin2 of 67 minutes, even though softwood ignites rather easily. PreviousIN it had been thought that glazed timber screens had to be made from hardwood %v ith a density in excess of 650 kg,"cu.m. in order to achieve a fire rating of 60 minutes or more.

0- In the testt seals between the glass pane 1 and the beads prevented hot gases from passing from the interior of the furnace to the outside and causing Janition. Also they insulated the timber from the glass vrhich become very hot and above the auto-lp-nltion temperature of the wood for the greater part of the test. Finallv the seals kept the edge of the glass cool, thereby preventin the glass from slumping out of the frame. In the later stages of a 60 minute test this becomes verv important as the beads on the fire side are fully charred and tend to fall awav leavina the inturnescent material as the onlv form of insulation on the P- lass edge.

It is believed that the unexpectedly high fire rating was achieved because the components of the glazing seal functioned synergistically.

The 21azino seals according to the invention allow the use of renewable softwood timber and also certain hardwoods which have unusually poor fire performance for their density e.g. ash and maple. Thus the glazing seal according to the invention has extended the range of timbers that can be used for fire resisting 60 minute screens to any that are used in nonfire resisting screens.

4 Instead of pins, staples mav be used, in addition to the Fireglaze.. to secure the the seals to the beads. However it is not essential to use pins! staples or other means in addition to the Fire2laze to secure the seals to the beads.

The refractory fibre may be Rockwool, vitreous silicate fibre or ceramic fibre.

Claims (7)

1. I A glazing seal comprising: a strip comprising a core of' incombustible fibre coated with an inturnescent material.
2. 2. A glazing seal according to claim 1, wherein the incombustible fibre is refractory fibre.
3. 3. A glazing seal according to claim 1, wherein the fibre core is porous or permeable and sealed by the inturnescent material.
4. 4. A glazing seal according to any precedinp- claim, A-herein the inturnescent material is based upon aluminium trihydrate.
5. 5. A glazing seal substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.
6. 6. A glazed timber screen incorporating at least one glazing seal according to any preceding claim.
7. 7. A glazed timber screen according to claim 6. being of softwood or hardwood having poor fire performance.

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