HFC-227ea Cylinder Weight Loss and Room Integrity Failure
An HFC-227ea total-flooding system protects a 9 m by 6 m by 3 m server room (162 m³). The listed design concentration is 7.0%, and the cylinder nameplate agent weight is 45.0 kg. During the annual inspection, the cylinder weighs 42.9 kg; the cylinder pressure gauge reads in the green, and the last hydrostatic test date is 2016. The room integrity test at 50 Pa produces a hold time of 3.5 minutes. You also find a 30 mm conduit penetration sealed only with expandable foam, a 40 mm door undercut, and an open ceiling damper. The discharge nozzle is at the ceiling grid, but a cable tray now runs 150 mm below it. The owner wants the system returned to service today because the room supports live trading operations. The installing contractor says the weight loss is 'normal' and the hold time is 'close enough.'
1. Determine whether the cylinder can be returned to service. Show your calculation and list the follow-up actions before you sign the inspection tag.
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Calculate the loss: 45.0 kg − 42.9 kg = 2.1 kg. Divide by nameplate: 2.1 ÷ 45.0 = 0.047, or 4.7%. That is just inside the commonly listed 5% tolerance, but it is close enough to require investigation, not a verbal 'normal.' Check the container pressure against the manufacturer's temperature/pressure curve, inspect the valve and gauge for leakage, review discharge and service logs, and verify the hydrostatic test date against the applicable DOT and NFPA 2001 interval. If the container is due for test or shows a pressure abnormality, remove it from service. If it stays, document the weight, establish monthly weighing, and investigate the cause. Do not treat a within-tolerance reading as proof that no leak exists. The room integrity failure is a separate acceptance issue and must be resolved before the system is placed back in service.
2. Evaluate the room integrity result. What must be corrected, and can the system be accepted before re-testing?
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The 3.5-minute hold time is not acceptable. A clean agent enclosure must retain the design concentration long enough for occupants to evacuate and for responders to operate safely; 10 minutes is the usual design target, and 3.5 minutes falls far short. The unsealed 30 mm conduit penetration, the 40 mm door undercut, and the open damper are credible leakage paths. Seal the penetration with a listed firestop system, adjust the door to the listed maximum undercut or install listed gasketing/drop seals, and close or replace the damper with a listed damper that maintains the enclosure. Then repeat the door-fan test at 50 Pa and document the result. Do not accept the system on the contractor's 'close enough' opinion. Acceptance testing is pass/fail against the design and listing, not a judgment call. The owner's trading schedule does not change the life-safety acceptance criteria; if the room must remain operational, provide an interim fire watch and a documented impairment procedure.
3. Assess the nozzle obstruction. What checks and corrections are needed, and why does 150 mm matter?
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The cable tray at 150 mm below the nozzle can distort the discharge pattern, prevent proper mixing, and leave a blind area in the room. Check the nozzle listing for minimum clearance from obstructions, required height above the protected hazard, spacing, and 360-degree pattern. Also verify that the nozzle is listed for the room height and that the agent quantity and nozzle flow match the design. Relocate the cable tray or the nozzle so the listed clearance is maintained; do not simply bend the tray or remove a nozzle. After correction, confirm the discharge time is within the listed maximum, usually 10 seconds for this agent, and that no other obstructions such as light fixtures or ductwork block the pattern. Document the as-built nozzle location and clearance. The system should not be signed off until the enclosure, cylinder, and discharge pattern all meet the listed design.