ISO 12472:2002 specifies a test method for determining the effective sealing capability of intumescent materials or systems in the context of sealing door-to-frame clearances in timber door assemblies. The method is suitable for evaluating the efficacy of exposed intumescent sealing systems used in conjunction with timber fire resisting doors of up to 1 h fire resistance. It is not suitable for comparing concealed intumescent seals. The results can be applied to proven, single-acting, single-leaf, latched, timber door assemblies of sizes up to that given in the field of direct application.