1) Explosion protection 2) Measuring instrument 
An explosimeter is a device which is used to measure the amount of combustible gases present in a sample. When a percentage of the lower explosive limit (LEL) of an atmosphere is exceeded, an alarm signal on the instrument is activated. `Explosimeter` is a registered trademark of MSA. The device, also called a combustible gas detector, operates .....
a device for measuring the concentration of potentially explosive fumes.