Galvanized pipe and fittings may be used for stair rails, closet rails, animal pens, gates, etc. Galvanized pipe can be used for water lines although corrosion is inevitable.
Notes and tips:
mipt = male iron-pipe-size thread (also called MPT ('Male Pipe Thread'), MNPT, or NPT(M))
fipt = female iron-pipe-size thread (also called FPT ('Female Pipe Thread'), FNPT)
NPT is National Pipe Thread
Street is an elbow with male threads on one end and female on the other end. This fitting is intended to join a piece of pipe and another fitting at an angle. The term 'street' comes from when this fitting was the first one used to connect to the city main water trunk line in the street.
Reducing tees are labeled end by end by center. Bushings can be used with tees to make up other reducing variations.