It's made of metal and it looks like it's been covered in some sort of paint to prevent it from corroding. It's 3'8 high and about 14 across. At the top there is a cross cut into the metal which is almost equal in height and width (though slightly longer in height). It's something I inherited from a relative and I'd love to learn more about it. What I know is it's Swiss and from the 15th century.
The ones that are not working need what is called a door lock actuator they are a mechanical/electrical part inside the door that physically moves the lock from one position to the other.
BB100 does not mention this. There are circumstances that justify shutdown for example in a gas fired crucible in a steel works, or in a kitchen if people are evacuating due to the fire alarm and may forget to shut off the cookers, or bunsen burners in a school lab. I cannot think of any guidance that requires it as a matter of course. It is sometimes used as a backwards way to shut down the HAV systems in a fire - this is used for convenience since all the contol gear and switching is often connected back to the flame failure device. It may also be a compensating measure- for example in shopping centres gass mains should not be routed through malls, I guess if a shut off was provided this may be ok. It would be interesting to hear other opinions on this, it does seem to be happening almost universally these days and can be a real nuisance due to the time it takes to start up equipment again afterwards.
