Could professional and knowledgeable contributors please be aware that they are confusing us in the real world with the usage of their collections of TLAs (Three Letter Acronyms). These are fine in the work place, but are useless and irritating elsewhere.
I agree that there are some that are known by all but there are many that are peculiar to specific areas of plumbing, electricity, etc and in the end an answer becomes useless if it cannot be understood because of shortcuts in the language.
Rob