ASC Engineered Solutions 1X1X3/8 BLK MI TEE

It's a reducing tee: both run ports are 1 inch and the branch outlet is 3/8 inch. All three openings are female pipe thread (FPT), so pipe or nipples thread into every port. Use it where you need to pull a small 3/8 inch takeoff, like a gauge, drain, or drop leg, off a 1 inch line without adding a bushing.

Black malleable iron fittings are for gas, air, steam, and fire protection or other non-potable service. The black finish is a plain uncoated iron surface with no corrosion protection, so it rusts in wet or potable water service. For water, go to galvanized malleable iron or a copper/CPVC system instead. Natural gas piping is the most common use for this fitting.

Yes, the 1 x 1 x 3/8 black malleable iron tee carries UL/FM recognition, so it can be used on fire protection piping where a listed fitting is required by the AHJ. The 3/8 inch branch is a common size for gauge and drain takeoffs on a sprinkler riser.

A 1 x 1 x 3/8 reducing tee gets you the small branch in one fitting, with one less joint to seal and less overall length than a full-size tee plus a 1 x 3/8 bushing. Fewer joints matters on gas and sprinkler work where every connection is a leak path and gets inspected. Use the full-size tee and bushing only when you may need to open the branch back up to a larger size later.

Yes, as long as the existing fitting is a Class 150 malleable tee. Dimensions are per ASME B16.3 and threads per ASME B1.20.1, both of which are the same across manufacturers, so center-to-end lengths and thread engagement match. You can splice this ASC tee into an existing black iron run without re-measuring the pipe.

The manufacturer part number is 310040209 from ASC Engineered Solutions, described as 1X1X3/8 BLK MI TEE. Each fitting weighs 0.6 lbs, which is worth knowing if you are pricing freight on a bulk order for a build-out.