HI 770XHD GD indirect-fired heaters have an optionally available combustible gas detection system.
It continuously samples air surrounding the heater for hydrocarbons presence. If detected - even trace amounts - the burner is immediately shut down to avoid possible ignition of combustible vapor.
The simple option comprises gas sensor, gas detection system, engine air shutoff, and strobe indicator. The ExP-rated gas detector monitors continuously to pick up all types of hydrocarbons. These include resulting nearby fuel spills, diesels vapors, etc.
Complete heater gas detection option information is yours free for the asking.