Compression fittings are used to join two pipes which may be of different materials, and are often used to join different sections of waste water pipe. This type of fitting employs an olive that goes over each pipe and a compression nut. The idea is to use compression to seal any joints to prevent leaking, these types are popular primarily as they are easy to install and do not require soldering, which also means they can be disassembled when needed unlike a joint which has been soldered. Compression fittings of many kinds are available in the markets which vary from joint compression fittings to bends.
Step 1 – Cutting the Waste Water Pipe
Use a small saw to cut off the excess edge of the waste water pipe to make room for the joint. But remember that the fitting slides over the joint so make sure you leave room for that.
Step 2 – Buffing the Edges
Clean away the edges of the pipe you just cut, you can use a fine grit sand paper or a regular rag to wipe away any burr.
Step 3 – Putting Together the Joint
Over the first section of the pipe place the first nut. Than place the olive on the pipe and slide it along a little distance. Make sure you put the olive the right way in. Next place the fitting over the pipe and push it into position. Tighten it with your hands.
Step 4 – Tightening the Nuts
Use one spanner to hold the fitting in place and the other to tighten the nut with. Tightening a compression fitting is crucial. It is important to not tighten the joint to hard or the pipe will kink and result in leakage. It’s best to tighten just enough, and if there is leakage later on you can just re-tighten it. One complete revolution of the nut should suffice. If you feel that there is resistance in the pipe when you are tightening it, it is because of the pressure against the olive which is being pushed against the pipe; this is a sign that you are just about done tightening the fitting.
Step 5 – Sealing the Compression Fitting
You can use a PTFE tape to seal the compression fitting. It is wrapped around the threads of the compression fitting before tightening; this seals the joint to prevent any leaking. There are also sealing agents available which can be put on top of the fitting. Use the latter once you have determined that your joint is properly tightened.
Step 6 – Tips and Caution
Always remember to support your pipework with clips to ensure it does not displace over time. If your compression fitting leaks, it is probably because the threads were not placed correctly. Disassemble and re-tighten. If it continues to leak, it is likely that the fitting joint is faulty and will require replacing. When attaching a bend to a compression joint, make sure the bend is facing the direction the next pipe will fit in.