Hm = minimum available head, in metres headHs = height of the highest outlet within the dwelling, inmetresHx = minimum head required at any fixture outlet, in metreshead是 什么意思 啊 ？哪位前辈能告诉？急需！
Hs = height of the highest outlet within the dwelling, in
metres
Hx = minimum head required at any fixture outlet, in metres
head
是 什么意思 啊 ？哪位前辈能告诉？急需！
