Governed by the international standard IECEx 60079-11, intrinsic safety is one method for making Ex products safe to use in hazardous areas. It means the product is safe by its very nature. For example, the energy used by the product is so low that it cannot possibly ignite anything.
This is the key term used by companies who are looking for maximum safety when purchasing equipment. Following the IECEx 60079-11 standard, compliant products are marked with the letter “I” and a subscript letter “a,” “b,” or “c” as follows: ia (zone 1 and 2), ib (zone 1 only) or ic (zone 2 only).