top of page

Understanding BS 476-21:1987 – Fire Resistance Testing for Load-bearing Elements

When it comes to building safety, BS 476-21:1987 stands as a paramount standard in the UK construction industry. This crucial guideline prescribes the methodologies for evaluating the fire resistance of essential load-bearing elements in a structure, ensuring that buildings are not just aesthetically pleasing but are built to withstand potential fire threats.

A man looking outward in a red background

What is BS 476-21:1987?

The BS 476-21 standard serves as a cornerstone in determining the fire resistance of load-bearing beams, columns, floors, flat roofs, and walls. Notably, beams and columns undergo assessment based on their load-bearing capacity. Conversely, dividing elements like floors, ceilings, and walls are evaluated in terms of three pivotal factors: load-bearing capacity, integrity, and insulation.

Overview of the Standard

BS 476-21 works in tandem with BS 476-20, which lays out the foundational principles for these assessment methods. BS 476-21 delves into specifics, detailing procedures for determining the fire resistance of load-bearing building elements when exposed to the stipulated heating and pressure conditions as presented in BS 476-20.

This standard outlines the requirements for specimen selection and its design, construction, and the conditions under which they're tested. It serves as a comprehensive guide, catering to beams, columns, floors, flat roofs, and walls.

Furthermore, while BS 476-21 addresses methods for load-bearing elements with definitive fire resistance, BS 476-23 takes on components contributing to a structure's overall fire resistance. Any modifications made to the methods in BS 476-21, as opposed to BS 476-8, can be found in the preamble to BS 476-20.

Products Under BS 476-21 Fire Resistance Testing

Various products fall under BS 476-21's fire resistance testing. These include:

- Insulated materials such as calcium silicate board, mineral wool board, glass wool board, and the like.

- Light fixtures encompassing Downlight, LED light, LED Ceiling light, etc.

- Structural components like ceilings, floors, walls, and roofs.

Difference between BS 476-21 & BS EN 1365?

While both BS 476-21 and the BS EN 1365 series are concerned with the fire resistance of load-bearing elements, they stem from distinct standards systems, one British and the other European, each with its unique scope. BS 476-21 casts a wider net when it comes to addressing load-bearing elements, while the BS EN 1365 series boasts multiple volumes dedicated to various structural components such as floors, roofs, balconies, walkways, stairs, beams, and columns, addressing them individually. This comprehensive approach positions the BS EN 1365 series as the preferred choice. Furthermore, it holds wide recognition across the European Economic Area, rendering it an optimal selection for manufacturers seeking to maximise their product's market potential.

Are you looking to find out more information? Contact us at or call us on 01355 433122; our experienced team will be happy to help.


bottom of page