Shunt trip as a method of protection for C1D1

[PAW2006]

Hello,
I have a C1D1 location with Hydrogen gas. the area has a gas detection monitor that is part of a larger gas monitoring system. I've been asked if a piece of electrical equipment fed by a shunt trip breaker that's tripped by a signal from the gas detection montor is a valid way to protect for haz class.
I've only ever worked with explosion proof wiring methods, pressurized cabinets and and intrinsically safe methods.
Is anyone familiar with this alledged gas monitoring and shunt trip method?
Thanks

 

[weressl]

Hello,
I have a C1D1 location with Hydrogen gas. the area has a gas detection monitor that is part of a larger gas monitoring system. I've been asked if a piece of electrical equipment fed by a shunt trip breaker that's tripped by a signal from the gas detection montor is a valid way to protect for haz class.
I've only ever worked with explosion proof wiring methods, pressurized cabinets and and intrinsically safe methods.
Is anyone familiar with this alledged gas monitoring and shunt trip method?
Thanks

API 500 does have allowance of reducing an inadequately ventillated indoor environment from Div. 1 to Div. 2. All your equipment within that area that is not suitable/listed for Div. 2 should have the power removed by an automatic disconnect @ 40% LEL . A shunt trip breaker would satisfy that requirement. (IMO shunt trip breakers are always a dicey proposition as it requires power to trip the device. An electrically held contactor would be a better choice.)

 

[PAW2006]

I'm looking into placing the equipment (a small pump of somekind) outside the C1D1 or even C1D2 spheres but am not sure the location will be acceptable to the user

Also, the customer mentioned he could guarantee a certain number of air changes in the room per unit time

NEC 500.2 defines a Combustible Gas Detection System as a "protection technique" but I didn't see any further mention of it.

I'll continue research on the net
Thanks for the reply
PAW