Fire Glazing

Fire-resistant glass is normally used to prevent fire spread and to provide a safe
escape route and safe access for fire-fighters. The national documents providing 
guidance on how to meet Building Regulations (e.g. Approved Document B for 
England and Wales) show where fire-resistant barriers are required. If an alternative approach has been taken to demonstrate compliance with Building Regulations, such as a fire safety engineering design study, then the applications for fire-resistant glass must be specified in the appropriate design report. 

The areas of application for integrity-only or integrity and insulation performance 
are given in the appropriate guidance to the Regulations, or in the appropriate design report if the building is subject to a fire safety engineering study. 

The specified glazed system must have appropriate evidence of performance based 
on appropriate test information. This evidence may be provided either in a test 
report, or in an assessment report or by third party certification. The test evidence that is provided must be appropriate to both the application and the specific glazed system that is to be installed. 

Fire certificates are provided by the Fire Service to approve certain premises and 
are not applicable to individual products, systems, assemblies or installations. 
Under new Regulations, fire certificates are to be phased out during 2006 and 
replaced by making the Responsible Person, i.e. the building or business owner, 
responsible for ensuring that appropriate fire precautions and safety measures are 
in place. Product certificates may be referred to in the context of third-party 
certification schemes, but these are voluntary and not obligatory. The appropriate 
evidence of performance for a fire-resistant glazed system is normally a test or an 
assessment report, which must be provided by the supplier on request.

Standard toughened glass is not able to withstand the thermal shock generated
during a fire and it must not be used where fire-resistant barriers are required. 
There are a number of specially modified toughened soda-lime glass types available for fire-resistant applications in very specific framing systems, or special glass 
compositions such as toughened borosilicates that can be used, but both types are strictly subject to manufacturers’ specific guidance on their use.

Never make assumptions. In all cases appropriate proof of performance must be
available related to appropriate test evidence.

The pane size will vary according to the glass and framing system, always subject to
the availability of appropriate test evidence. In every case, contact the glass 
manufacturer or supplier for the maximum glass sizes tested and the associated framing system details.

Different glass types will require different amounts of edge cover according to their
individual requirements. Manufacturers/suppliers will provide appropriate guidance, 
which must be followed. Modified toughened soda-lime glasses are particularly 
sensitive to edge cover which is generally a maximum of 10mm cover. If the edge 
cover is too great for this type of glass then premature failure is far more likely.

Normal glazing codes of practice must be followed. Glass in any application must
never be glazed tightly. Expansion allowances can be especially critical for modified toughened soda-lime glass types. The glass manufacturer/supplier will define 
expansion allowance required.

PVB laminated safety glass does not have any fire-resistant properties and it must 
not be used in fire-resistant applications. Safety glass types with fire-resistant properties are available, based upon special inter-layers.

Only limited increases in tested pane sizes are allowed, according to assessment. The evidence provided by the glass manufacturer/supplier will provide the maximum pane size allowed for each particular system. 

This is only possible if there is test evidence that the modified dimension meets the
fire-resistance performance. Details will be made available by the glass manufacturer/
supplier.

This information can only be identified by reference to the approved glazing systems, and the size of bead will vary according to the glass and system chosen. 

This may be possible but only if the alternative has documented evidence showing that it can be used with the glass and framing system. If this evidence is not available, contact the gasket or seal supplier for confirmation of acceptability. 

The glazing seal has to be appropriate for the chosen system based on test evidence. Standard glazing seals must not be used for fire-resistant glazing.

This depends on the door leaf being used, as each door manufacturer will have tested different sizes of glass with their door leaf types. Maximum glass size can also depend on the glazing system being used in the door. The test or assessment information for the specific door leaf and glazed system will dictate the allowable maximum glass size and glass aspect ratio. It should be noted, that great care needs to be taken when cutting apertures into door leaves because this can adversely affect the fire-resistance performance of the door and this must only be done according to the door manufacturer’s guidance and instruction. Impact safety may also limit maximum glass size: if the glass has a class C impact safety rating then glazed door panels are limited to a maximum of 900mm.

Various shapes are possible but the types and sizes will depend upon the evidence available for the door leaf and the glazing system. If the evidence is unavailable for the required shape, then the shape must not be used. It should be noted that great care needs to be taken when cutting apertures into door leaves because this can adversely affect the fire-resistance performance of the door. 

Different timbers have different burning characteristics and can influence the performance of the door or framing system. An alternative timber should not be used unless there is appropriate fire test evidence. 

The minimum section will be the size that can be demonstrated to work with the chosen fire-resistant glass. This can be identified by reference to fire test report. Contact the glass manufacturer/supplier for the appropriate information.

Yes, in certain cases. For insulation glass types, in particular, square beads present few problems but integrity-only glass types require more detailed consideration as transferred heat can lead to bead ignition on the protected face. Partial insulation glass types may also allow the use of square beads, subject to appropriate evidence of performance based on tests. 

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