What is Crib 7?

For the full guide to BS 5852 Crib 5 and when Crib 7 applies, see: BS 5852 Crib 5: A Complete Guide for Interior Designers and Specifiers.

Crib 7 uses a larger wooden crib than Crib 5. That is the right answer, but here is the explanation.

In the UK there are various tests for the flammability of fabrics, varying in their applicability to domestic and contract environments such as hotels and hospitals. Fabric treated to a Crib 5 standard is suitable for most contract uses. Crib 7 is a more stringent test, and fabric that passes it is suitable for more hazardous environments such as prisons and offshore installations.

During testing, the fabric is spread over a frame and exposed to a burning wooden crib placed on or beneath it. The larger the crib, the more intense the ignition source. The Crib 7 crib is larger than the Crib 5 crib, so the fabric is exposed to a more severe flame.