An interesting subject which rarely surfaces and reveals little information.
Most of the facts and figures seem ignored by manufacturers in their usual ‘open specs’, perhaps because they saw them as less meaningful and having less punch, compared to more obvious statistics like door thickness, weight, grades of steels etc?
There are some facts and figures out there, but bear in mind most of the big old doors with the hefty pressure systems were booming in the 1920s and 30s- at a time when some ‘interesting’ claims were specified, along with the obligatory use of the shortest bloke within 20 miles of the factory for publicity photographs etc- all part of the competition between them back then. The concepts, calculations and engineering behind it all was undoubtedly seriously clever stuff, but even then, mathematics on paper, physics in theory and the full size 3-D product in the real world don’t always match up- like some of the other facts and figures I’d take them with a pinch of salt.
I know Chubb have revealed some figures for their old treasury doors in the past, and I posted some pressure details in my thread on the big Italian Parma doors a year or so back. Parma apparently attained incredibly high pressure from their system which was many thousands of kilos from memory, which I think was suggested to be much higher than most at the time, but who knows, you can probably make of it what you want.
It’d be interesting to see if anyone with old literature has anything with references to pressure systems and the figures involved.
