Frequently Asked Questions - Fire-resistant


1 What information does NSG Group need to help me?

We need to know what the glass is being glazed into and the size. If the glass is more than 10 degrees from vertical then we need to know this as well. You should have a guide to the period of protection expressed in minutes of integrity or minutes of integrity and insulation.

2 Where can I get more information?

We publish fire test summaries that show sizes and glazing systems that can be adopted.

Fire resistance is defined in BS 476: Part 20: 1987 as the ability of an element of building construction to withstand exposure to a standard temperature, time and pressure regime without loss of its fire separating function or loadbearing function or both for a given time.

Pilkington Specifire™ incorporates all the information you need to choose the right product for your application. We recommend that you check with your local authority to see which level of fire resistance is applicable for your project. Click on the link below to use Pilkington Specifire™:

3 What glass test standards should I look for?

The glass and glazing system should have been tested to BS476 Part 22 for non load bearing walls or the European Standards appropriate to the application. There are a range of tests within BS476 and the EN standards for different locations. Please contact us for further information. Pilkington have test data for both British and European standards.

4 What is integrity?

Integrity is defined in BS 476: Part 20: 1987 as, "The ability of a specimen of a separating element to contain a fire to specified criteria of collapse, freedom from holes, cracks and fissures and sustained flaming on the unexposed face. This is measured for a time period and is expressed as 30-minute lots, i.e. 30 minutes, 60 minutes etc.

5 What is insulation?

Insulation is defined in BS 476: Part 20: 1987 as, "The ability of a specimen of a separating element to restrict the temperature rise of the unexposed face to below specified levels". This requires, in a test, that the unexposed face rises on average by no more than 140°C and in any single position by no more than 180°C. This is expressed in 30-minute lots, i.e. 30, 60 etc.

6 What about radiation?

Limits on heat radiation are not specified in UK Building Regulations although Pilkington Pyrostop™ and Pilkington Pyrodur™ products do provide some protection because they become opaque in a fire. The period depends on the grade of product. Radiation is measured in the European Standards but not in the British ones.

7 How do I choose a framing system?

The frame system supporting the glass is critical to the performance as is the quality of installation. The frame construction effects the period over which the glass performs. There are options in timber, steel and aluminium for screens. Refer to our product literature and fire test summaries.

8 Can anyone fit the glass?

The smallest changes to detail can affect the performance of the screen and experienced qualified fixers should be used.

9 Does size matter?

The size and proportions of glass do make a difference to the period the glass can hold back a fire. Look for test data appropriate for the size of glass you wish to use.

10 Can fire glass be used horizontally?

Yes, but only in accordance with our specific horizontal fire tests. Please check with our Technical Advisory Service on (01744) 69 2000 for guidance.