Compression Fittings | Adapters, Elbows, Tees & Unions | Apex Flow Solutions

Compression fittings create a leak-tight seal on tubing using a brass ferrule that compresses against the tube wall as the nut is tightened — no soldering, flaring, or special tools required. Apex Flow Solutions stocks brass compression adapters, elbows, tees, and unions from Midland Industries for water lines, instrumentation, refrigeration, and general tubing connections.

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How to Choose Compression Fittings

Compression fittings size by tube OD, not tube ID or nominal pipe size. Measure the outside of your tubing before ordering — common sizes are 1/4", 3/8", 1/2", 5/8", and 3/4" OD. The ferrule inside the nut compresses around this outer surface to form the seal, so the OD must match exactly.

Tubing material affects how well the ferrule seats. Compression fittings work best on copper, brass, aluminum, and rigid nylon tubing. Soft polyethylene or flexible PVC tubing may not support enough wall rigidity for a reliable compression seal — for those materials, consider insert fittings with clamps or push-to-connect fittings designed for poly tubing.

These fittings are suitable for most water, refrigerant, and low-pressure gas applications. They are not designed for high-vibration environments without additional support, as repeated movement can loosen the ferrule over time. For high-pressure or high-vibration service, consider flare or bite-type flareless fittings.