Handheld Health and Safety Monitors

In some cases gas, vapour or dust is present all the time or for long periods. Refineries and chemical complexes should thus be divided into areas of risk of release of gas, vapour or dust known as zones. The type and size of these hazardous areas is determined using area classification. An occupational exposure limit is an upper limit on the acceptable concentration of a hazardous substance in workplace air for a particular material or class of materials. Risk assessment of substances and new instrumental analysis methods can improve analytical detection limits