ASC Engineered Solutions 21/2X21/2X1 BLK MI TEE

It's a reducing tee with a 2-1/2 inch run (both straight-through ends) and a 1 inch branch outlet. All three openings are female pipe thread, so it threads onto male-threaded pipe nipples or fittings. Use it where you need to pull a 1 inch branch off a 2-1/2 inch line without adding a separate bushing.

Threads are cut to ASME B1.20.1, which is the standard NPT taper thread spec. It mates with any standard NPT-threaded black or galvanized steel pipe and nipples of matching size. Overall dimensions follow ASME B16.3, so the center-to-end geometry matches any other standard malleable iron fitting of the same size.

Black malleable iron is meant for non-potable service: natural gas, fuel oil, compressed air, low pressure steam, and fire sprinkler systems. The black finish is a mill/oil coating, not corrosion protection, so it will rust in a wet aerated line. For domestic water use galvanized fittings instead; for potable water in most jurisdictions you want copper, PEX, or brass rather than any iron fitting.

It is a standard (STD) class fitting, rated per ASME B16.3. That is the ordinary 150 class malleable iron rating used on gas, air, and sprinkler work. If your drawing calls for an extra heavy (300 class) fitting, this is not the right part.

Cast malleable iron conforming to ASTM A197. That is the standard cupola malleable iron grade for threaded pipe fittings, and it is what gives the fitting enough ductility to take thread-in stress without cracking the way gray cast iron would.

The manufacturer part number is 310053004, an ASC Engineered Solutions black malleable iron reducing tee, 2-1/2 x 2-1/2 x 1. Distributors ordering against a submittal should reference that number plus the ASME B16.3 dimensional standard.