BS 476-23 is the 23rd part of the multiple series that describes procedures for determining the contribution made by components to the total fire resistance of a structure or other elements used in conjunction with them when subjected to the relevant heating and pressure conditions specified in BS 476-20. The methods are applicable to suspended ceilings protecting steel beams and intumescent seals for use in conjunction with single-acting, latched timber fire-resisting door assemblies.
BS 476-23 on components to the fire resistance of a structure is useful for:
The suspended ceiling is a horizontal membrane and its associated suspension system which is provided below, and not in direct contact with, the structural, unprotected steel beams for the express purpose of protecting them from a fire environment, and which does not incorporate any loadbearing member of the structure.
BS 476-23 provides the requirements for specimen selection and/or its design and construction, the edge conditions, the equipment including any special apparatus or instrumentation, and the procedures and criteria as they apply to components that make a contribution to the fire resistance of a complete assembly.
Overall, BS 476-23 will help you to determine the effective, protection that is provided by a suspended ceiling to a standard supporting construction of steel beams and specified concrete deck when exposed to specified conditions of heating and pressure from below.