Expanded polystyrene and fire safety

by Tania Wannenburg
epsasa jnl13.2

Architects and specifiers can now confidently incorporate EPS in designing energy-efficient and cost-effective building solutions, by using StyFRene.  

Recent tests have confirmed the fire-retardant properties of StyFRene expanded polystyrene (EPS) FR grade thermal insulating board. The tests concluded that EPS does not support the spread of flames.

Architects and specifiers can now confidently incorporate EPS in designing energy-efficient and cost-effective building solutions, by using StyFRene.  

The tests, commissioned by the Expanded Polystyrene Association of South Africa (EPSASA), were conducted by Firelab CC, based on the premises of the Council for Scientific and Industrial Research (CSIR) in Pretoria.  They were carried out in line with the protocol defined in SANS 428:2006 – “Fire performance classification of thermal insulated building envelope systems”.

SANS 428 covers the fire safety evaluation requirements for thermal insulated building envelopes, such as under-roof and side-cladding insulating materials, liners, insulated wall and roof panels, insulated ceilings and insulated wall and ceiling coating systems.

This testing protocol requires that large-scale fire testing of thermal insulation materials (SANS 10177:11) must be done in a facility that simulates the real-world, end-use conditions in which the product is typically installed.

EPS StyFRene boards of 120mm thickness, and without any facing material, were used in all the tests. EPSASA generally recommends 80mm to 120mm EPS boards for ceiling and roof applications, depending on climatic conditions.

Continuous improvements in FR grade EPS, in the polystyrene raw material, and fire-retardant properties and processing, have resulted in a material that has again passed the testing criteria and classified as fire-safe.  

The test results show that although EPS StyFRene does deform and melt in proximity to fire, it does not actually catch alight: The material simply disintegrates into small snowflake-like fragments. There are no flaming droplets.

The test report concludes that from a fire safety point of view, the FR grade EPS thermal insulation system, as tested under specific test conditions, may be used as part of the thermal insulated building envelope in industrial and commercial buildings as an under-roof insulation material.

It is nonetheless important to note that these test results do not relate to fire resistance, which entails different testing criteria and testing methods. Furthermore, factors such as adequate roof ventilation and/or sprinkler protection should be considered in individual installations, taking account of the specific wall and roof configurations, to ensure the fire-safe design of any building, according to SANS 10400:T. suppliers should be asked to verify their products’ conformity to the test materials.

The material would be classified as combustible in terms of SANS 10177-5:2012, but no fire propagation was noted during the SANS 10177-11 large-scale fire test.

The following can be concluded for the 120mm thickness unfaced EPS insulation material (BASF Styropor KF 262) as tested and installed over-purlin, and tested in accordance with SANS 10177-11:

• The material is classified as combustible (B).

The classification awarded to the material based on the performance as tested in accordance with the SANS 428 protocol is summarised as follows:
1.     Class B / B1 / 2 / H only (UNSPR).
2.    The performance of the material when installed as a side-cladding insulation was not evaluated.
3.    The suitability of this material when installed above an automatic sprinkler protection system was not evaluated.

In general, provision of adequate roof ventilation and/or a sprinkler protection system for each individual installation would need to be considered based on the size, slope and configuration of the roof, and should be part of the fire-safe design of the building to satisfy the requirements as stipulated by SANS 10400-T.

Tel: (011) 805 5002
E-mail: aaamsa@iafrica.com
Website: www.epsasa.co.za

You may also like