Introduction to Copper Tube Fitting Systems
Copper tubing is used extensively in plumbing, HVAC, refrigeration, medical gas, and process piping. The fitting system determines pressure rating, leak reliability, and installation speed.
Flare Fitting Systems
SAE 37 degree Flare (JIC/AN)
The 37 degree flare is the industry standard for high-pressure hydraulic and instrumentation connections. Tube end expanded to create a conical surface mating with a male cone. Metal-to-metal seal. Pressure ratings up to 6,000 psi. Reusable, vibration resistant. Requires annealed temper copper.
45 degree Flare
Widely used in refrigeration and gas distribution at pressures below 800 psi.
Flareless Fitting Systems
Compression Fittings
Type A (single ferrule): Up to 1,000 psi. Type AC (double ferrule): 2,000+ psi, standard in instrumentation. Front ferrule seals, rear ferrule grips.
Bite-Type Fittings
Sharp-edged ferrule creates mechanical interlock. Swagelok, Parker A-LOK, Let-Lok. Pressures 3,000-10,000+ psi.
Press-Fit Systems
ProPress and similar systems: O-ring seal plus grab ring. Installation in seconds with no soldering. Rated 600 psi at 250 degrees F.
Selection Criteria
Below 150 psi: any type. 150-1,000 psi: flare or double-ferrule. Above 1,000 psi: 37 degree flare or bite-type. High vibration: flare or bite-type preferred. Fastest installation: press-fit (5-10 seconds).
Standards
ASME B16.18/B16.22, B16.23 (flare), B16.24, ASTM B75/B88/B280, SAE J512/J513, MSS SP-105.
CoreMetal Steel supplies copper tubing in types K, L, M from 3mm to 300mm OD with compatible fitting systems.