Copper Tube Specifications
ACR tubing sizes and pressure ratings for HVAC
ACR (Air Conditioning & Refrigeration) Copper Tubing
ACR tubing is sized by actual outside diameter (OD). Clean, dehydrated, and capped for refrigeration use.
| Nominal Size | OD (inch) | OD (mm) | ID (mm) | Wall (mm) | Max Pressure (psig) | Max Pressure (bar) | Typical Use |
|---|---|---|---|---|---|---|---|
| 1/4" | 0.250 | 6.35 | 4.75 | 0.80 | 2,460 | 170 | Liquid line (small systems) |
| 3/8" | 0.375 | 9.53 | 7.92 | 0.81 | 1,670 | 115 | Liquid/suction (1-2 ton) |
| 1/2" | 0.500 | 12.70 | 10.92 | 0.89 | 1,390 | 96 | Suction (2-3 ton) |
| 5/8" | 0.625 | 15.88 | 14.10 | 0.89 | 1,110 | 77 | Suction (3-5 ton) |
| 3/4" | 0.750 | 19.05 | 17.27 | 0.89 | 930 | 64 | Suction (5-8 ton) |
| 7/8" | 0.875 | 22.23 | 20.32 | 0.96 | 860 | 59 | Suction (8-15 ton) |
| 1-1/8" | 1.125 | 28.58 | 26.44 | 1.07 | 740 | 51 | Suction (15-25 ton) |
| 1-3/8" | 1.375 | 34.93 | 32.51 | 1.21 | 680 | 47 | Large commercial |
| 1-5/8" | 1.625 | 41.28 | 38.58 | 1.35 | 640 | 44 | Large commercial |
| 2-1/8" | 2.125 | 53.98 | 50.80 | 1.59 | 580 | 40 | Industrial/chiller |
* Pressure ratings calculated for annealed copper tubing at 100°F (38°C). Reduce ratings at higher temperatures.
Copper Tube Types: K, L, M Comparison
Water supply tubing - sized by nominal (approximate ID). Type indicates wall thickness.
| Nominal | OD (inch) | Type K Wall | Type L Wall | Type M Wall | Applications |
|---|---|---|---|---|---|
| 1/2" | 0.625 | 0.049" | 0.040" | 0.028" | Residential water |
| 3/4" | 0.875 | 0.065" | 0.045" | 0.032" | Main water lines |
| 1" | 1.125 | 0.065" | 0.050" | 0.035" | Commercial water |
| 1-1/4" | 1.375 | 0.065" | 0.055" | 0.042" | Commercial/industrial |
| 1-1/2" | 1.625 | 0.072" | 0.060" | 0.049" | Commercial/industrial |
| 2" | 2.125 | 0.083" | 0.070" | 0.058" | Large distribution |
Type K (Green)
Thickest wall. Underground, high-pressure applications. Most expensive.
Type L (Blue)
Medium wall. Most common for residential water supply. Interior/exterior.
Type M (Red)
Thinnest wall. Lower pressure, drain/vent. Most economical.
Brazing Guidelines
- 1. Use nitrogen purge during brazing to prevent oxidation
- 2. Recommended alloys: BCuP-5 (15% Ag) or BCuP-6 (2% Ag) for copper-to-copper
- 3. For copper-to-brass: Use 45% silver alloy with flux
- 4. Joint clearance: 0.001" - 0.005" for proper capillary action
- 5. Heat tube first, then fitting - draw alloy into joint
Flaring & Swaging
Flare Angles
- • Standard SAE: 45° flare angle
- • Metric (ISO): 37° or 45° depending on standard
- • Use flare nut before making flare
Tube Protrusion for Flaring
- • 1/4" tube: 3/32" above die
- • 3/8" tube: 1/8" above die
- • 1/2" tube: 5/32" above die
- • 5/8" tube: 3/16" above die