Fire resistance tests for loadbearing elements - Stairs Ingestion-build-68772 then you will find BS

then you will find BS ISO/IEC 27005 very useful in providing additional guidance on the subject of risk

This European Standard gives the definitions and general terms

Annex F (informative) Live crustaceans guide

equal to or less than 3 mm

Enclosures and protective covers

Fire resistance tests for loadbearing elements - Stairs Ingestion-build-68772 then you will find BSBS EN 1365 6: 2004 specifies a method for determining the fire resistance of stairs, with or without applied fire protection systems in respect of loadbearing capacity and with no separating function. This document is used in conjunction with BS EN 1363 1.