re the question on checking airflow, airflow to me means air speed, which will be different on different days, however if you mean free air, then i measure it, if the property has airbricks i use a vent measuring stick which is basically a turned aluminium stick with 5,6,7,8,9,10mm turned sections, this allows me to know the inside dimension of the air brick, then i do the usual calculation to determine what the total free air is to the solum, i then measure the floor vent and check the appliance data badge to determine whether the supplied free air meets the requirement of the appliance, i also phone the local Building Control office to check if the area i'm working in is known to have a Radon Gas Issue, if so i duct the vent to outside, (i made the last bit up)
LOL @ the last bit!
Well we both use the same system basically as we use to check also for flooring.
Well all i can conclude to that is that there alot of plumbers who dont check as the lack of vent (maybe caused by blocked airbricks, builders rubble, etc) can cause masive issues with floorcoverings along with the issues of unsafe gas appliances.
But who is to say the outside airbricks never got covered up after the gas appliance was installed?
PS, your highly tuned aluminum measuring device. Do you have this calabrated? I hear that they can give wrong readings with temperature change.
TBH i dont i just like to be a devil with some things, for the life of me i can never remember what it is actually called, im sure someone will remind me, it is actually quite a useful toy, usually pick them up free at the trade shows, but you can buy them
Lol, you are taking the pee now mate.