Compressed air leak survey
Run a structured leak survey with ultrasonic detection, quantify the loss in CFM and dollars, and prioritize the repairs.
This guide is general field reference for trained, qualified service technicians. It is not a substitute for the original equipment manufacturer's service manual, applicable codes (NEC, OSHA, ASME, local), or the judgment of a licensed professional. Procedures, torque values, pressures, refrigerants, and safety requirements vary by make, model, jurisdiction, and revision. Always verify against current OEM documentation and follow your employer's safety program. Working on compressed-air, electrical, pressure-vessel, and refrigerant systems can cause serious injury or death. By using this guide you accept all risk; AirCompDX and its authors disclaim all warranties and are not liable for any damage, injury, loss, or code violation arising from its use.
Surveying means walking a live plant. Wear hearing protection, watch for moving equipment, and never place a hand near a suspected leak — a pinhole jet at 100 psi can inject air under the skin.
- Ultrasonic leak detector with headphones and a focusing cone
- Tagging kit (numbered leak tags)
- Soapy water bottle for confirmation in noisy areas
- Flow meter or pump-up timing data for baseline
- Camera or tablet for logging locations
- 1Baseline the loss
During a no-production period, run a pump-up/load-time test: leak CFM ≈ (compressor CFM × loaded time) ÷ (loaded + unloaded time). Above 10% of capacity is a system that needs work; many neglected plants run 25–35%.
- 2Divide the plant into zones
Survey by department or header branch so repairs can be assigned and re-verified. A random walk produces a list nobody fixes.
- 3Sweep systematically
Point the detector at every joint, fitting, quick-disconnect, FRL, regulator, hose, and cylinder port. Start at 40 kHz sensitivity high, then reduce sensitivity to pinpoint the source.
- 4Tag and log everything
Number tag on the leak, matching entry in the log with location, component type, estimated size, and a photo. Estimate CFM from orifice size: roughly 1 CFM at 1/64", 6 CFM at 1/16", 26 CFM at 1/8" at 100 psi.
- 5Cost the list
Annual cost ≈ CFM × 0.20 hp/CFM × 0.746 kW/hp × annual hours × $/kWh ÷ motor efficiency. Putting a dollar figure next to each tag is what gets the work order approved.
- 6Prioritize repairs
Fix the largest and the easiest first: quick-disconnects, hose whips, and FRL drains typically make up most of the loss and take minutes each.
- 7Re-verify and lower pressure
Repeat the baseline test after repairs. With leaks down, you can usually drop header pressure 5–10 psi — every 2 psi of reduction saves roughly 1% in energy.
- 8Make it a program
Schedule surveys quarterly or semi-annually. Leak rates return to baseline within 12–24 months in an untended plant.