I'm on an offshore oil platform where we are commissioning new temp quarters to house personnel. All feeder breakers on the platform are shunt tripped using a 24 VDC coil so everything fails open in an emergency event. For some reason the buildings were sent out with shunt trip coils in the breakers so a signal has to be sent to the breaker for it to trip. I would think that you would want to stay with a U.V. coil in this situation so if in a fire or gas event all power would be removed from the building. Also, since commissioning the buildings we've found a few of these coils bad on a few of the breakers but, you don't know this until you actually try a trip and the breaker doesn't open up. In that case a building could be powered up with a bad shunt trip coil and in an emergency the breaker wouldn't open up. Is this just engineering preference?