Non-Electrical Certification
In 2016 standards ISO/IEC 80079-36 and ISO/IEC 80079-37 were published, meaning that for the first time non-electrical equipment for use in explosive atmospheres can achieve IECEx certification.
IEC 80079-36 is the standard which covers the basic method and requirements for non-electrical equipment and IEC 80079-37 covers non-electrical equipment for types of protection ‘constructional safety’ (“c”), ‘control of ignition sources’ (“b”) and ‘liquid immersion (“k”).
Non-Electrical Equipment meeting the requirements of EN ISO 80079-36:2016 shall be marked with the Ex-marking code “h”; non-electrical equipment meeting the requirements of EN ISO 80079-37:2016 supplemental to those of EN ISO 80079-36:2016 shall also be marked with the Ex-marking code “h”.
There is no additional marking with regard to the specific Type(s) of protection applied. In accordance with EN ISO 80079-36:2016 – clause 9, and EN ISO 80079-37:2016 – clause 10, the description of the type(s) of protection, e.g. “c” (constructional safety), applied is given in the instructions manual of the equipment.
Route to Compliance.

Safety integrity level (SIL)
What is SIL
According to Wikipedia, “Safety integrity level (SIL) is defined as a relative level of risk-reduction provided by a safety function, or to specify a target level of risk reduction. In simple terms, SIL is a measurement of performance required for a safety instrumented function (SIF).”