Refrigerant Pipe Pressure Drop Calculator
Calculate pressure and saturation temperature losses in refrigerant piping
Pressure Drop Guidelines
Suction line: Max 2-3°F (1-1.5°C) saturation temperature drop | Liquid line: Max 2°F (1°C) drop, keep subcooling adequate | Discharge line: Max 2 psi drop
Compressor above evaporator = positive
Fittings (adds equivalent length)
Calculation Results
Calculation Notes:
• Based on ASHRAE handbook methods for refrigerant piping
• Assumes standard copper tube (Type L for liquid, Type ACR for suction)
• Vertical suction risers add static head loss (~0.5 psi per 3m for R-410A)
• For accurate design, consult manufacturer piping tables
Fitting Equivalent Lengths
| Pipe OD | 90° Elbow | 45° Elbow | Tee (Branch) | Globe Valve |
|---|---|---|---|---|
| 3/8" | 0.24m | 0.12m | 0.49m | 2.4m |
| 1/2" | 0.30m | 0.15m | 0.61m | 3.0m |
| 5/8" | 0.40m | 0.20m | 0.79m | 4.0m |
| 3/4" | 0.46m | 0.24m | 0.91m | 4.6m |
| 7/8" | 0.52m | 0.27m | 1.07m | 5.2m |
| 1-1/8" | 0.67m | 0.34m | 1.34m | 6.7m |
| 1-3/8" | 0.82m | 0.40m | 1.65m | 8.2m |
Values are typical for copper fittings. Actual values may vary by manufacturer.
Pressure Drop Guidelines
Suction Line
- • Max 2-3°F sat. temp drop
- • Velocity: 1000-2500 fpm
- • Min velocity for oil return: 750 fpm horizontal, 1500 fpm vertical
- • P-traps at base of vertical risers
Liquid Line
- • Max 2°F sat. temp drop
- • Maintain subcooling to TXV
- • Velocity: 100-300 fpm
- • Avoid long vertical drops (flash risk)
Discharge Line
- • Max 2 psi pressure drop
- • Velocity: 2000-3500 fpm
- • Min 1000 fpm for oil return
- • Slope toward condenser