GB2155982A

GB2155982A - Fire-resistant glazing systems

Info

Publication number: GB2155982A
Application number: GB08407138A
Authority: GB
Inventors: Keith Richard Patterson
Original assignee: MANN MCGOWAN FABRICATIONS LIMI
Current assignee: MANN MCGOWAN FABRICATIONS LIMI
Priority date: 1984-03-19
Filing date: 1984-03-19
Publication date: 1985-10-02
Also published as: GB2155982B; GB8407138D0

Abstract

A fire-resistant glazing system for glazing an aperture in a fire- resistant door or other surround 10 comprises a pane 18 of Georgian wired glass secured by beads 22 formed of hardwood having a density of at least 650 kg/m<2>. Each bead 22 has a chamfered upper face forming an angle of at least 110 DEG with the surface of the pane 18 and is secured by screws 26 which each extend under the opposite bead. Strips 20, 21 of intumescent material capable of generating a pressure of at least 10 atmospheres are interposed between the pane 18 and the respective beads 22. The system provides one-hour fire resistance to BS 478 Part 8: 1972 for panes of up to 1.2 m<2>. <IMAGE>

Description

SPECIFICATION Fire-resistant glazing systems This invention relates to fire-resistant glazing systems for glazing apertures in such constructional elements as, for example, internal doors, screens and partitions.

BS 476 Part 8: 1972 lays down stringent requirements for fire-resistance and there is not currently available for one of the above constructional elements a glazing system for glazing an aperture more than 300 mm square which has untreated hardwood beads and will afford one hour fire-resistance under the conditions prescribed by the above British Standard.

In one currently-available system one hour fire-resistance is achieved at the expense of appearance as the system necessitates the use of a rectangular-section frame which is of anomalous surface finish; does not present a pleasing profile; and does not hide the fibrillation which so often results from cutting an aperture in a wooden or wooden-surfaced constructional element.

We have previously proposed a glazing system which did not suffer from the abovementioned drawbacks and could be used to glaze apertures of an area of up to 1.2 m2.

However, our earlier system offered only halfhour fire-resistance.

According to the present invention there is provided a fire-resistant glazing system for glazing an aperture in a fire-resistant surround, for example a door leaf, screen or partition, comprising a hardwood bead of a density of at least 650 kg/m2 positioned on each side of a marginal edge portion of a glass pane, each bead being secured to the surround by fixings which extend thereinto under the other bead and having a chamfer of at least 11-0 with respect to the surface of the pane, and an intumescent strip interposed between said edge portion and a side face of each bead, the strip comprising a pressuregenerating intumescent material having properties such that on foaming it forms a hard mass which adhers to the glass and other adjacent surfaces to form both a smoke and gas seal and a support for the pane, if softened by heat, and protrudes slightly above the chamfered surface to provide a heat shield therefor.

A suitable form of intumescent strip is that manufactured by Chemie Linz AG of Linz, Austria and designated "Type 500", which can generate a pressure of up to 10 atmospheres.

If desired a further strip of such intumescent material may be interposed between the surround and the side faces of the pane and each of the above-mentioned intumescent strips.

Preferably the beads have a chamfer of about 1 20' with respect to the surface of the pane and are formed with a bolection to cover the margins of the surround.

A glazing system according to the present invention will not only provide one-hour fireresistance to BS 476 Part 8: 1972 for panes of an area up to 1.2 m2, but will also present a pleasing profile and natural finish, which is not impaired or hidden by the need to apply intumescent varnish.

Although the invention may be carried out in a variety of ways, one particular embodiment thereof will now be described, by way of example, with reference to the single figure of the accompanying drawing which is a section through a door leaf glazed according to the present invention.

In the drawing the reference 10 denotes a door leaf having major faces 12,14 and an end face 16 defining an aperture therein glazed by a pane 18 of 6 mm Georgian wired glass.

The marginal edge portion of the pane 18 is flanked by two "Type 500" intumescent strips 19 comprising intumescent core material 20 received in an extruded thermoplastics sheath 21. Each strip 19 is held firmly against the glass by a hardwood bead 22 having a bolection moulding 24 which overlies the margins of the respective major faces 1 2,14. The chamfered upper face 25 of each bead 22 forms an angle of 20 to a plane normal to the adjacent surface of the pane 18.

Each bead 22 is held in place by a series of countersunk screws 26 which extend into the leaf 10 under the opposite bead 22. On the outbreak of fire the core material 20 in the strips 19 intumesces, generating a pressure of up to 10 atmospheres which is mainly expanded in compacting itself between the opposed surfaces of the pane 18 and the bead 22 to form a hard mass which adhers to said surfaces and thus supports the glass and prevents it from collapsing when softened by the high ambient temperatures. The hard mass does of course also function at an earlier stage as a very effective smoke and gas seal between the door leaf 10 and the pane 18.

A small proportion of the pressure generated on intumescence is, however, utilised in a direction perpendicular to the main direction and small beads of material 20 exude at the exposed edges of the strips 19 which shield the adjacent chamfered face 26 from heat radiated through the pane 18.

1. A fire-resistant glazing system for glazing an aperture in a fire-resistant surround, for example a door leaf, screen or partition, comprising a hardwood bead of a density of at least 650 kg/m2 positioned on each side of a marginal edge portion of a glass pane, each bead being secured to the surround by fixings

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Fire-resistant glazing systems This invention relates to fire-resistant glazing systems for glazing apertures in such constructional elements as, for example, internal doors, screens and partitions. BS 476 Part 8: 1972 lays down stringent requirements for fire-resistance and there is not currently available for one of the above constructional elements a glazing system for glazing an aperture more than 300 mm square which has untreated hardwood beads and will afford one hour fire-resistance under the conditions prescribed by the above British Standard. In one currently-available system one hour fire-resistance is achieved at the expense of appearance as the system necessitates the use of a rectangular-section frame which is of anomalous surface finish; does not present a pleasing profile; and does not hide the fibrillation which so often results from cutting an aperture in a wooden or wooden-surfaced constructional element. We have previously proposed a glazing system which did not suffer from the abovementioned drawbacks and could be used to glaze apertures of an area of up to 1.2 m2. However, our earlier system offered only halfhour fire-resistance. According to the present invention there is provided a fire-resistant glazing system for glazing an aperture in a fire-resistant surround, for example a door leaf, screen or partition, comprising a hardwood bead of a density of at least 650 kg/m2 positioned on each side of a marginal edge portion of a glass pane, each bead being secured to the surround by fixings which extend thereinto under the other bead and having a chamfer of at least 11-0 with respect to the surface of the pane, and an intumescent strip interposed between said edge portion and a side face of each bead, the strip comprising a pressuregenerating intumescent material having properties such that on foaming it forms a hard mass which adhers to the glass and other adjacent surfaces to form both a smoke and gas seal and a support for the pane, if softened by heat, and protrudes slightly above the chamfered surface to provide a heat shield therefor. A suitable form of intumescent strip is that manufactured by Chemie Linz AG of Linz, Austria and designated "Type 500", which can generate a pressure of up to 10 atmospheres. If desired a further strip of such intumescent material may be interposed between the surround and the side faces of the pane and each of the above-mentioned intumescent strips. Preferably the beads have a chamfer of about 1 20' with respect to the surface of the pane and are formed with a bolection to cover the margins of the surround. A glazing system according to the present invention will not only provide one-hour fireresistance to BS 476 Part 8: 1972 for panes of an area up to 1.2 m2, but will also present a pleasing profile and natural finish, which is not impaired or hidden by the need to apply intumescent varnish. Although the invention may be carried out in a variety of ways, one particular embodiment thereof will now be described, by way of example, with reference to the single figure of the accompanying drawing which is a section through a door leaf glazed according to the present invention. In the drawing the reference 10 denotes a door leaf having major faces 12,14 and an end face 16 defining an aperture therein glazed by a pane 18 of 6 mm Georgian wired glass. The marginal edge portion of the pane 18 is flanked by two "Type 500" intumescent strips 19 comprising intumescent core material 20 received in an extruded thermoplastics sheath 21. Each strip 19 is held firmly against the glass by a hardwood bead 22 having a bolection moulding 24 which overlies the margins of the respective major faces 1 2,14. The chamfered upper face 25 of each bead 22 forms an angle of 20 to a plane normal to the adjacent surface of the pane 18. Each bead 22 is held in place by a series of countersunk screws 26 which extend into the leaf 10 under the opposite bead 22. On the outbreak of fire the core material 20 in the strips 19 intumesces, generating a pressure of up to 10 atmospheres which is mainly expanded in compacting itself between the opposed surfaces of the pane 18 and the bead 22 to form a hard mass which adhers to said surfaces and thus supports the glass and prevents it from collapsing when softened by the high ambient temperatures. The hard mass does of course also function at an earlier stage as a very effective smoke and gas seal between the door leaf 10 and the pane 18. A small proportion of the pressure generated on intumescence is, however, utilised in a direction perpendicular to the main direction and small beads of material 20 exude at the exposed edges of the strips 19 which shield the adjacent chamfered face 26 from heat radiated through the pane 18. CLAIMS

1. A fire-resistant glazing system for glazing an aperture in a fire-resistant surround, for example a door leaf, screen or partition, comprising a hardwood bead of a density of at least 650 kg/m2 positioned on each side of a marginal edge portion of a glass pane, each bead being secured to the surround by fixings which extend thereinto under the other bead and having a chamfer of at least 110 with respect to the surface of the pane, and an intumescent strip interposed between said edge portion and a side face of each bead, the strip comprising a pressure-generating intumescent material having properties such that on foaming it forms a hard mass which adheres to the glass and other adjacent surfaces to form both a smoke and gas seal and a support for the pane, if softened by heat, and protrudes slightly above the chamfered surface to provide a heat shield therefor.

2. A system as claimed in Claim 1 and additionally comprising a further strip of intumescent material interposed between the surround and at least an end face of the pane and intumescent strip on each side thereof.

3. A system as claimed in Claim 1 or 2, in which the intumescent strips are capable of generating a pressure of up to 10 atomospheres.

4. A system as claimed in Claim 1, 2 or 3, in which each bead has a chamfer of about 1 20' with respect to the surface of the pane.

5. A system as claimed in any preceding Claim, in which each bead is formed with a bolection to cover the respective margin of the surround.

6. A system as claimed in any preceding Claim, in which each bead is rectilinear.

7. A fire-resistant glazing system, substantially as herein described with reference to the accompanying drawing.

8. The features as herein disclosed, or their equivalents, in any patentably novel selection.