All pipe fittings are to be made of the same stuff as pipe. No fittings are to be put on pipe unless specified. If you do, straight pipe becomes crooked pipe. Be sure to specify the direction you are going when ordering. All flanges must be cast or forged of very best quality iron metal, close grained, free from blow holes, lumps, cavities, pock marks, pin pricks, and warts, otherwise we can't use them.
Gaskets are to be used to fill space between flanges.
Gaskets are to be made of metal, rubber, plastic, paper, or some kind of goop - do not use cow or sheep manure. It cracks when it gets dry. All bolts must have a head on one end and a nut on the other. All piping must be installed with valves. Gate valves have a gate inside.