GB2373259A

GB2373259A - Firewall

Info

Publication number: GB2373259A
Application number: GB0103325A
Authority: GB
Inventors: Brian Watson
Original assignee: C A GROUP Ltd
Current assignee: C A GROUP Ltd
Priority date: 2001-02-09
Filing date: 2001-02-09
Publication date: 2002-09-18
Anticipated expiration: 2021-02-09
Also published as: GB2373259B; GB0103325D0

Abstract

An apparatus for constructing a firewall comprises periodically mounted spacer assemblies separating an inner liner 102 and an outer skin 103 of a firewall. Each spacer assembly consists of a steel ferrule 104 and elongate spacer bar 106 mounted to the inner skin 102 by means of a steel bolt 105. A thermal insulating element 107 of high density rock fibre material is mounted between each spacer bar 106 and the outer skin 103. The remaining space between the inner liner 102 and outer skin 103 is filled with flexible slabs 108 of insulating material of a lower density than that of insulating elements 107.

Description

Apparatus For Constructing n FirewnH, and Fircwall Incorporating Such An 'ntus I The present invention relates to an apparatus for constructing a firewall, and to a firewall zn constructed using such apparatus.

I Firewalls are constructed to slow the transfer of fire and heat from one side of a wall to the other. A known firewall construction is shown in cross-section in Figure 1. The Figure shows a firewall 1 having an inner liner 2 and an outer sheet 3, both of which are constructed of a rigid material such as steel. The inner liner 2 and outer sheet 3 are supported by the supporting steelwork (not shown) of the building and supported spaced a predetermined distance apart by means of periodically spaced spacer arrangements, each of which comprises a steel ferrule 4 mounted to the inner liner 2 by means of a long bolt 5, which also passes through an elongate spacer bar 6 of Z-shaped cross-section. A layer of insulating material 7 provided on a roll is supported between the spacer bar 6 and the outer sheet 3 such that an air gap 8 (generally of minimum thickness 20mm) exists between the insulating material 7 and the inner liner 2. As a result, the air gap 8 provides thermal insulation which prevents heat being transferred from the inner liner 2 directly to the insulating material 7.

The prior art firewall shown in Figure 1 suffers from the drawback that the level of thermal insulation is limited by the thickness of insulation possible, since if the insulating material 7 is too thick, visual or structural damage can occur to the outer sheet 3. For example, it is difficult to reliably fasten the spacer bar 6 to the outer sheet 3 when compressible insulating material 7 is located between the spacer bar 6 and the outer sheet 3. It is also difficult to reliably maintain the air gap 8, since the firewall is generally constructed using insulating material 7 on a long roll, and is often constructed by personnel located in an access platform in a variety of outdoor, such as windy, conditions.

A further type of prior art firewall is shown in cross-section in Figure 2. As shown in Figure 2, a firewall I has an inner liner 2 and outer sheet 3, spaced apart by periodically spaced spacer assemblies comprising a steel ferrule 4 mounted to the inner liner by means of a bolt 5 which

also passes through a spacer bar 6, as in Figure 1. The arrangement of Figure 2 differs from that of Figure I in that the sheet of insulating material 7 of Figure 2 is mounted to the inner liner 2 by means of the steel ferrules 4 such that a desired minimum thickness d (typically 8 mm) of insulating material 7 is maintained between ferrule 4 and inner line ! 2 However, this prior art arrangement suffers from the drawback that it is difficult to maintain a thickness of 8 mm

of insulating material 7 between the steel ferrule 4 and the inner liner 2, since the ferrule 4 either ZD cuts the insulation (making it ineffective) or the connection of the ferrule 4 to the inner liner 2 0 may become unstable because of the compressibility of the insulating material.

There is a very strong preference among persons skilled in the art to use low density insulation material provided on a roll. As a result, both of the prior art firewall constructions described above also suffer from the drawback that in order to achieve the desired degree of thermal insulation, the firewall must be constructed of greater thickness than many standard (i. e. nonfirewall) thicknesses. In order to avoid visually undesirable discontinuities at the boundary of a firewall and a conventional wall, therefore, the conventional (i. e. non-firewall) wall must be constructed with the same (i. e. greater) thickness of the firewall, which results in inefficient and costly use of building materials.

Preferred embodiments of the present invention seek to overcome the above disadvantages of the prior art.

According to an aspect of the present invention, there is provided an apparatus for constructing a firewall, the apparatus comprising :

at least one spacer means adapted to be mounted between inner and outer layers of a wall ; at least one respective thermal insulation element having a respective first density and adapted to be located between the or each spacer means and one of said inner or outer layers of the wall ; and a plurality of flexible thermal insulation slabs having a respective second density, lower than the or each said first density, for location between said inner and outer layers of the wall. By providing insulating elements having a respective first, higher density, and blocks of a respective second, lower density, this provides the surprising advantage that the insulation requirements of the wall can be fulfilled without compromising the mechanical strength of the wall as a result of attempting to create a narrow, high density region and a wide, lower density region of insulation from a single strip of material provided on a roll, since the higher density insulation element can under certain circumstances provide a stable structural bearing surface This advantage is especially surprising in view of the strong preference among persons skilled in the art for constructing firewalls using insulation of a single, low density provided on a roll.

The present invention has the further advantage that under certain circumstances, the firewall can be constructed with a thickness no greater than that of a standard wall, which provides the advantage that the thickness of a standard wall adjacent to the firewall does not need to be constructed with a greater thickness than necessary to avoid discontinuities at the boundary with the firewall.

In a preferred embodiment, at least one said insulation element includes rock fibres.

I In a preferred embodiment, at least one said spacer means includes a support element adapted to be mounted to the inner or outer layer of the wall, and a respective spacer bar adapted to be mounted to the corresponding support element.

In a preferred embodiment, each said support element is made substantially of steel.

According to another aspect of the invention, there is provided a firewall comprising inner and outer wall elements and an apparatus as defined above.

I A preferred embodiment of the invention will now be described, by way of example only and not in any limitative sense, with reference to the accompanying drawings in which :- Figure 1 is a cross-sectional view of a first type of prior art fire wall ; Figure 2 is a cross-sectional view, corresponding to Figure 1, of a second type of prior art firewall ; and Figue 3 is a cross-sectional view of a firewall embodying the present invention

I Referring to Figure 3, a firewall 101 includes an inner liner 102 and an outer skin 103, each of 0 ZD which is formed from a rigid material such as steel and is mounted to the supporting steelwork (not shown) of the building Spacer assemblies are periodically mounted between the inner liner 102 and outer skin 103, each spacer assembly comprising a steel ferrule 104 mounted to the inner liner 102 by means of a bolt 105, the bolt passing through an elongate spacer bar 106 of Z-shaped cross-section. A thermal insulating element 107 of high density rock fibre insulation is mounted between each spacer bar 106 and the outer sheet 103 of the wall. The remaining space between the inner liner 102 and outer sheet 103 is filled with flexible slabs 108 of insulating material of a density lower than that of the insulating elements 107.

i The insulating elements 107 provide structural bearing surfaces which enable a rigid and compact construction to be achieved without jeopardising the structural strength of the firewall by compressing insulating material provided on a roll. The use of flexible slabs 108 of insulating material enables the remaining space to be filled with insulating material, but because the insulation is provided in the form of slabs 108, as opposed to being provided on a roll, the construction of the firewall is made much easier, especially when the firewall is constructed in difficult circumstances, such as in windy outdoor conditions by personnel located in an access platform.

It will be appreciated by persons skilled in the art that the above embodiment has been described by way of example only, and not in any limitative sense, and that various alterations and modifications are possible without departure from the scope of the invention as defined by the appended claims.

Claims

1. An apparatus for constructing a firewall, the apparatus comprising I at least one spacer means adapted to be mounted between inner and outer layers of a wall ; at least one respective thermal insulation element having a respective first density and adapted to be located between the or each spacer means and one of said inner or outer layers of the

wall ; and y a plurality of flexible thermal insulation slabs having a respective second density, lower than the or each said first density, for location between said inner and outer layers of the wall.

2. An apparatus according to claim 1, wherein at least one said insulation element includes rock fibres.

3. An apparatus according to claim 1 or 2, wherein at least one said spacer means includes'a support element adapted to be mounted to the inner or outer layer of the wall, and a respective spacer bar adapted to be mounted to the corresponding support element.

4. An apparatus according to claim 3, wherein at least one said support element is made substantially of steel.

5. An apparatus for constructing a firewall, the apparatus substantially as hereinbefore described with reference to Figure 3 of the accompanying drawings.

6. A firewall comprising inner and outer wall elements and an apparatus according to any one of the preceding claims.