Successful fire test on light steel floor

As part of a development programme into the use of light steel framing, SCI has carried out the first industry sponsored fire test on a light steel floor that achieves 90 minutes fire resistance to the BS EN 1365 fire test. The work was sponsored by Corus Strip Products UK and members of the Light Steel Framing Group.

Light steel load‑bearing frames are increasingly used in buildings of up to 8 storeys for which longer periods of fire resistance may be required.  The introduction of the new BS EN 1365 fire test regime has required an extensive programme of re-testing, as it is more severe than the former BS 476- 20 test due to the use of plate thermocouples in the BS EN test.

As part of the Light Steel Framing Group activities, a fire test to BS EN 1365 was carried out at the Building Research Establishment in order to provide generic guidance for the light steel framing industry.  The configuration of the light steel floor also satisfies the proposed Robust Standard Detail for acoustic performance in order that the information is widely applicable to practice. 

The tested floor span was 4.5m and the imposed load was 250kg per square metre. The calculated load ratio for the floors joists in the tests was 0.3 (using S 350 steel) to BS 5950-8. 

The fire test supported the applied load for 93 minutes. Importantly, the joist temperature remained at less than 100ºC for over 80 minutes and so they would be essentially undamaged and re-usable, even after a severe fire.

The full information from this test will be used in the update of SCI publication P129: Fire Resistance of Cold Formed Steel Members.

For further information, please contact:

Mark Lawson 
SCI Professor of Construction Systems at the University of Surrey
Email m.lawson@stel-sci.com
Tel: +44 (0) 1344 631027