A Point to Note in the Draft Code of Practice for Fire Safety in Buildings 2011: Smoke Toxicity Assessment of Burning Materials

A draft updated code of building fire safety in Hong Kong was just released in end September 2011. Effect of smoke toxicity on tenability limits was not yet specified clearly. Only temperature of smoke layer, visibility and carbon monoxide concentration were mentioned on specifying smoke effect on tenability limits. The necessity of specifying smoke toxicity on tenability limits properly is pointed out in this short note. Earlier experimental data reported on studying smoke toxicity of burning video compact disc boxes in a cone calorimeter were taken as an example. The effects to human beings are proposed to be assessed based on the fractional exposure dose with carbon dioxide and carbon monoxide measured at least. Empirical correlation expressions including other toxic gases should be derived from cone calorimeter tests under high heat fluxes; and real-scale tests under postflashover fires.