pressure test

I’ve started a barn conversation for myself and it seems I’m required to have an air brick if I have a log burner. Even a 4kw. As the building could be classed as a new build? I know that building are pressure tested and wondered how this works if an air brick has to be installed. Any advice...

Morning all. How long should a healthy cooling system be able to hold pressure when tested with a pressure tester? The car in question is a diesel Focus (not sure what engine or age, as it's not mine)! The chap suspects a head gasket problem. Apparently they have a weakness in a plastic...