Joining methods
Category · 11 entries · Updated
A pipe system is only as good as its joints. These entries explain how each joining method works, what it needs and where it is allowed. They describe methods; they are not step-by-step instructions, and soldering, threading gas pipe and other permitted work belong to licensed trades.
Entries in this category
Push-fit fittingsFittings that seal by pushing tube into an O-ring and locking device; covered by ASSE 1061 for PEX, copper, CPVC and PE-RT.
PEX crimp ringsCopper rings squeezed around PEX over a ribbed insert fitting; made to ASTM F1807 or F2159 and checked with a go/no-go gauge.
PEX clamp (cinch) ringsStainless steel bands with a tab, closed by a ratcheting tool over PEX insert fittings; an ASTM F2098 alternative to copper crimp rings.- PEX expansion fittingsFittings joined by stretching PEX tubing and a ring, then letting the tube shrink back onto the fitting; ASTM F1960 and F2080.
Copper press fittingsCopper or bronze fittings with a rubber sealing element, crushed onto copper tube by a powered press tool; made to ASME B16.51.
Compression fittingsThreaded fittings that seal when a nut squeezes a brass or plastic sleeve onto the tube; common at supply stops and on small tubing.
Soldered (sweat) jointsHow a sweat fitting is soldered to copper tube by capillary action, which solders are lawful for drinking water, and how brazing differs.
Solvent-weld jointsHow solvent cement fuses PVC, CPVC and ABS pipe into fittings, the matching cement and primer standards, and set and cure times.
Threaded pipe jointsHow NPT tapered pipe threads seal, common sizes and pitches, thread sealants, and why plastic female threads crack.
Heat-fusion jointsHow socket, butt, saddle and electrofusion joints melt PP-R or polyethylene pipe into one piece; temperatures and standards.
No-hub couplingsThe neoprene-sleeve, stainless-shield coupling that joins hubless cast iron drain pipe: standards, torque and transition types.
Did you know
- One push-fit maker allows plain water as a lubricant when pushing tube into its fittings but forbids every other lubricant. (source: NIBCO Inc.) Read the entry
- A single push-fit fitting made to ASSE 1061 can be designed to accept more than one kind of tube, such as copper, CPVC, PEX and PE-RT. (source: Plastics Pipe Institute and Plastic Pipe and Fittings Association) Read the entry
- One maker's PEX crimp tool sheet gives the same crimped-ring diameter limits for PEX and for older polybutylene pipe installations. (source: Zurn) Read the entry