ASC Engineered Solutions 1/2X3/8 XH BLK MI 90 ELL

XH is extra heavy: a thicker wall and a higher pressure rating than a standard weight (150 class) malleable iron fitting of the same size. Pressure ratings and dimensions both follow ASME B16.3, which is the standard that covers threaded malleable iron fittings in both weights. If the drawing calls out 300 class or extra heavy black iron, this is the weight you want; if it just says black iron 150, standard weight is the cheaper fit.

Yes, the fitting carries UL/FM recognition, which is what an inspector looks for on a sprinkler branch line. Note the finish is black, not galvanized, so it suits wet and dry black steel sprinkler and gas piping rather than corrosive or exposed-to-weather runs.

A reducing 90 does the same job as a same-size elbow plus a reducing bushing, with one less joint to seal and less makeup length. That matters in tight mechanical rooms and behind fixtures where the fitting has to sit close to the wall. The tradeoff is stocking: a straight 1/2 x 1/2 elbow with bushings covers more combinations if you carry a van stock, while the 1/2 x 3/8 reducing ell is the cleaner install when you know the sizes.

By convention on threaded fittings, the first size is the larger run end and the second is the reduced end, so 1/2 x 3/8 means a 1/2 FPT inlet turning to a 3/8 FPT outlet. Both are female, so a reducing 90 like this is symmetrical in use: it doesn't matter which leg faces up, only which pipe size goes in which end.

Order by ASC Engineered Solutions part number 310504006. Each fitting weighs 0.41 lbs, which is useful if you're estimating hanger loads or freight on a bulk pull for a rough-in.

Malleable iron to ASTM A-197 is the material spec on this elbow. It's annealed so it tolerates the stress of being threaded up tight and handles vibration and impact better than plain gray cast iron, which is why it's the standard threaded fitting material for gas, sprinkler, and low pressure steam and water. Forged steel fittings are the step up for high pressure process work; gray cast iron drainage fittings are a different family entirely and not interchangeable with this.