A very large majority of the SWPS' have been adopted by the ASME B & PV codes. These are not quite as simple and straight forward as they might seem on the surface however. I strongly recommend going to Walt Sperko's website: www.sperkoengineering.com as he is Vice-Chair of ASME IX and has elaborated quite a bit on HOW to use these SWPS.' In my own opinion, having used them before, they are a fantastic tool!