Threaded Pipe Union, Female PT Both Ends
Joins two female-threaded pipe ends and comes apart again by loosening one nut, without turning either pipe. Three-piece union in 202, 304 or 316 stainless steel, 1/8″ to 4″, Class 150.
Product overview
A stainless steel pipe union is the fitting you put in a threaded line at the one place you know you will open it again. It is three pieces: a tail piece on each pipe end and a large nut that draws the two together. To break the joint you back off the nut; nothing else moves. A coupling cannot do that. Once a run is screwed together, a coupling can only come off by turning a pipe, and a pipe bolted to a pump or a valve does not turn. That is the whole reason unions exist.
Ours is shell mold cast in our own plant in Taiwan in 202, 304 or 316 stainless steel and machined after casting, with hex tail pieces and a hex union nut so a wrench sits square on every part. Sizes run 1/8″, 1/4″, 3/8″, 1/2″, 3/4″, 1″, 1-1/4″, 1-1/2″, 2″, 2-1/2″, 3″ and 4″. Both tail pieces carry a female PT taper thread. PT is the Japanese designation for the 55° taper thread that BSPT, R and Rc also describe; it seals on the thread with tape or sealant. It is not the same as NPT, which is a 60° thread and should not be mated with it even where the nominal sizes look alike. If your line is NPT, tell us with the inquiry; NPT is made to order.
The pressure class is 150. On stainless threaded fittings that number is a class designation, not a limit of 150 psi; the working pressure depends on temperature and is set by the fitting standard the class belongs to. For water, air and general fluid lines at ordinary temperatures it carries more than the pipe around it.
Put a stainless steel threaded union on each side of anything that will be serviced: a pump, a strainer, a control valve, a steam trap, a flow meter. Then the item comes out with two nuts and goes back in the same way, and the pipe on either side stays where it is. Choose 304 for water, air and general service, 316 where chlorides are present, and keep the whole run in one grade. It matches our stainless steel hex pipe nipple, threaded 45 degree elbow, threaded pipe cap and pipe cross, so one take-off list covers the whole line.
- Model
- FT-UNION
- Body
- 202, 304 or 316 stainless steel
- Size range
- 1/8″ to 4″
- Thread
- Female PT (BSPT) taper thread, both ends
- Other threads
- NPT made to order
- Pressure
- Class 150
- Operation
- Three-piece union: two tail pieces and a removable union nut
Applications
Every fitting checked for size and thread.
Each fitting is checked for dimensions and thread before shipment.
What is the difference between a pipe union and a coupling?
A coupling is one piece and joins two pipes for good; to take it off you have to turn a pipe. A union is three pieces and comes apart by loosening its nut, with both pipes staying put. Use a union wherever the line will be opened again; use a coupling on runs that stay closed.
Does the pipe have to turn to install it?
No. Screw a tail piece onto each pipe end, bring them together and tighten the nut. That is why a union goes next to pumps, valves and equipment that cannot rotate.
What thread is it?
Female PT taper thread on both tail pieces. PT is the same 55° taper thread as BSPT and Rc. If your line is NPT, tell us with the inquiry; NPT is made to order.
Should I choose 304 or 316?
304 for water, air and general service. 316 where chlorides are present: brine, coastal sites, washdown, most chemicals. Keep the whole threaded run in one grade.
What sizes can I order?
1/8″, 1/4″, 3/8″, 1/2″, 3/4″, 1″, 1-1/4″, 1-1/2″, 2″, 2-1/2″, 3″ and 4″. Mixed sizes in one order are fine; send the list and we quote it together.
Do you make the matching fittings?
Yes. Hex nipples, elbows, caps, crosses, couplings and the rest of the threaded stainless range in the same grades and sizes. Send one take-off list and we quote it as one.
