Nibco T-174-A Gate Valve - Bronze, Class 300, Block Pattern, Copper Nickel Alloy Wedge

No. Use in U.S. drinking water applications is prohibited after January 3, 2014, so keep the T-174-A off potable service. It's built for commercial plumbing, heating and HVAC work, and it's the right pick for medium to high pressure steam and general utility service. For domestic water you need a valve that meets the lead-free requirement instead.

The T-174-A is a Class 300 bronze gate valve rated 300 psi (20.7 bar) saturated steam to 421 degrees F (216 degrees C), and 600 psi (41.4 bar) non-shock cold working pressure. That's double the steam rating of a Class 150 bronze gate, which is why it goes on medium and high pressure steam mains and header takeoffs rather than a low pressure heating loop.

Threaded, not solder. The T-174-A takes female NPT (FIPT) threads on both ends, Class 300 threaded end connections. You'll thread it onto male pipe nipples or threaded steel pipe, so no torch work at the valve. If you're running copper tube and want to sweat the valve in, this is not the model for that job.

Eight sizes, 1/4, 3/8, 1/2, 3/4, 1, 1-1/4, 1-1/2 and 2 inch, all female NPT. That covers small instrument and gauge takeoffs at the 1/4 and 3/8 end up through 2 inch branch isolation. Above 2 inch you're into iron body territory for a gate valve of this class.

Rising stem. The stem travels up out of the bonnet as you open the valve, so you need clearance above the handwheel and you get a visual indication of whether the gate is open or shut, which is useful on a steam header where somebody has to confirm position from the floor. In a tight ceiling space or a chase, measure the open height before you commit, or use a non-rising stem gate instead.

Yes, the union bonnet is the reason. The bonnet threads off as a union joint, so you can pull the bonnet and stem for repacking or to service the wedge without cutting the body out of the line. On a steam system that gets cycled, that matters more than almost anything else on the spec sheet. A screwed bonnet valve does not come apart nearly as cleanly.

Yes. The T-174-A is a dezincification resistant bronze valve, body and seat both bronze, with a solid alloy wedge. That matters on water treated with aggressive chemistry or on systems where a standard brass valve loses zinc and goes porous over time. It also conforms to MSS SP-80, the standard specification for bronze gate, globe, angle and check valves.

A gate valve like the T-174-A is a shutoff, full open or full shut, and its solid wedge gives a straight through port with almost no pressure drop when open. That is what you want for isolation on a steam or general utility line where the valve sits open for years. Do not throttle with it, partial opening chews up the wedge and seat. If you need to modulate flow, a globe valve is the right type. A ball valve gets you quarter turn speed, but for high temperature saturated steam service at 421 degrees F the bronze gate with a union bonnet you can repack is the traditional and serviceable choice.

If what's coming out is a threaded bronze gate on FIPT connections in 1/4 through 2 inch, the T-174-A drops into the same threaded joint, since it takes female NPT on both ends. It carries a higher rating than a Class 125 or 150 bronze gate, so going up to it on an existing line is not a downgrade in pressure capability. What it will not do is replace a solder end valve, and it cannot go back into a potable water line regardless of what was there before.

Block pattern describes the body form of the T-174-A, a heavier, more compact bronze body than the standard pattern used on lower class bronze gates. It's part of what carries the Class 300 rating, 600 psi non-shock cold working pressure. Practically, expect a stouter valve than the Class 125 or 150 bronze gate you may be replacing, so check the face to face run in a tight nipple space.