What is BS 7904 - Guide to smoke measurement units about?   
BS 7904 focuses on guidance to smoke measurement units. The aim of BS 7904is to provide best industry guidance in the development of standardized test methods that will minimize fire hazards.
BS 7904 describes the theory of optical measurement of smoke. It describes the different parameters measured, gives examples of the commonly used units, and describes relationships between different parameters. It also reviews some commonly used optical test methods for smoke measurement.
Who is BS 7904 - Guide to smoke measurement units for?  
BS 7904 on the guide to the development of fire tests is relevant to: 
- Testing laboratories
- Materials and products manufactures
- Fire safety engineers
- Regulatory bodies
Why should you use BS 7904 - Guide to smoke measurement units? 
Smoke which consists of airborne particulates and aerosols reduces visibility because of light absorption and scattering. This has the potential of impeding victims' escape from fires because low visibility creates difficulties in locating escape routes and seeing escape signs.
BS 7904 provides information on theoretical aspects and units, and analysis of units used in standard methods. This helps in understanding of smoke measurement units is essential when attempting to predict full scale experimental results from small scale tests results.
