I just built an extension to my house with 5 bathrooms. I want o pressure test the pipes before I close up the walls. What kind of device do I adapt to the pipes to receive the air from my pump or compressor. I have the pipes all blocked and I have the pressure gauge on the pipe, but I don't know how to get the air in the pipe without it leaking back when I remove the pump?

You could buy a 1.5" PVC x 1/2" female bushing and connect that onto any 1.5" pipe with a coupling.

Then you'll purchase a few 1/2" IPS nipples, a 1/2" IPS shutoff, and a 1/2" IPS tee fitting. In one end of the tee you'll install a 1/2" x 1/8" black or brass bushing and an 1/8" schrader valve. In the other end of the tee you'll connect a pressure gauge that reads between 0-5 PSI into a 1/2" schrader valve. In the other end of the tee you'll connect a pressure guage that reads between 0-5 PSI into a 1/2" coupling. You could also purchase a test guage/schrader valve setup.. see image. Ignore the sizes mentioned in the pic. below... use 1/2" as mentioned above. I included the pic. To show the basic setup we use.

You want to pump the system up to 3 PSI... should hold steady for 15 minutes.

Now, all that being said, we always test our drainage systems with water... right to out the roof. Much easier to work with than air... ;) AT the lowest point we install a test tee (see image) with a test ball that relases the water safely/easily at the end of the test.

If doing 5 bathrooms... you having this inspected? Just curious.

Mark

In addition to Mark's advice...

Only gas system is tested with pressurized air. Waste, vent and water pipes are usually tested with water.

However, for the size of your project, you should have a licensed plumber who should be familiar with testing new plumbing systems.

And I will assume this test is for the building inspector who has to inspect and approve the project ?