Garden Hoses and Pipe Tubing

Inside diameter, outside diameter and pressure rating

Tubing has two diameters and fittings care about different ones. Barbed fittings grip the inside diameter, while compression fittings seal on the outside diameter, so a 16 mm acrylic tube needs fittings made for 16 mm. Pressure ratings, such as 200 psi on polyethylene pipe, are stated at a temperature, and plastic loses strength as it warms, so allow a margin for hot water. Garden hose has its own thread, GHT, which is not pipe thread.

End connections tell you how the run attaches. NPT is tapered pipe thread, GHT is the straight thread on garden hose, and UNF is a fine straight thread used on some automotive and hydraulic fittings. Do not mix them without an adapter. Material follows use: polyethylene and rubber suit cold water, brass and 304 stainless steel handle hot water, and clear acrylic is for visible cooling loops.

Hangers, clips and heat-shrink: sizing the small parts

Pipe hangers and clips are sized to the pipe: a clevis hanger for 1-1/2 inch pipe fits that nominal size and carries a stated load, for example 610 lb. Check the load rating, the material, and whether the rod size matches your threaded rod. Stainless 304 resists corrosion outdoors; plated steel suits dry interiors. Space hangers closely enough that the pipe cannot sag when full.

Heat-shrink tubing is chosen by its supplied diameter and its shrink ratio. A 2:1 ratio shrinks to half its original size, so pick a size that slides over the largest part of the connection and still shrinks tightly onto the cable. Sets of 2 to 6 mm cover most small wiring repairs. Use adhesive-lined tubing where moisture could get in.

Questions about Garden Hoses and Pipe Tubing

How do I measure tubing for a fitting?

Measure the outside diameter with calipers or a ruler across the cut end, then check the wall thickness to find the inside diameter. Compression fittings are named by outside diameter; barbs are named by inside diameter. Tubing described as 1/2 inch may mean either, so read the listing.

Is a garden hose safe for drinking water?

Not unless it is marked drinking-water safe. Ordinary garden hoses are made for watering, and some give the water a taste or contain materials not intended for drinking. Look for a clear drinking-water description before using one for fresh-water fills.

What is the difference between 2:1 and 3:1 heat-shrink?

The ratio is how far it shrinks: 2:1 shrinks to half its supplied diameter, 3:1 to a third. A 3:1 tube covers an odd-shaped connector or a wide size change, while 2:1 suits straight cable. Check the shrunk size against the cable, not just the starting size.