Estimating Clothing Insulation Values

From BS ISO 9920: “Ergonomics of the thermal environment – Estimation of the thermal insulation and evaporative resistance of a clothing ensemble”

Two methods may be used to obtain an insulation value for a clothing ensemble:

• Estimate the insulation from Tables contained in the standard
• Calculate the insulation for particular clothing based on what is actually worn (eg shoes, socks, T-shirt etc.), the material from which each item is made, and the surface area that each item covers.   

However, it is usually appropriate to use the first method.  For example the table below represents typical work clothing worn in much of the UK.  For more specific information you are advised to refer to the standards BS EN 27243 or BS ISO 9920 or alternatively the tabulated values in the Risk Assessment Aids/Tools document.

Look for the clothing that is most representative of what the worker wears and obtain an estimated clothing insulation value for that clothing.  This will be the value used in a Quantitative Risk Assessment.

These insulation values are for specific clothing ie clothing made from specific materials, with a particular fit etc.  It may be sufficient to use estimated insulation values from the clothing values provided in the standard (as shown above) without needing to be too exact.