Description of Driving Event:
Exhausters were running to provide simulation of altitude conditions in a combustor rig when the mishap occurred. The equipment operators were short-handed and, as a result, a certain amount of confusion existed. A valve at the discharge end of the exhausters was inadvertently closed. The reduced flow caused the inlet pressure to rise because a continuous quantity of air was being supplied to the exhauster inlet from the compressors in the system. As a result, the pressure at the exhauster inlet increased to almost atmospheric. The exhausters then became compressors and generated a discharge pressure level high enough to rupture the inverted, dished head of the exhauster header located 50 feet downstream. The inverted, dished head was 8 feet in diameter and 3/8 inches thick located 16 inches underneath the floor level. A hole about 30 feet in diameter was blown in the roof of the building located 35 feet above the floor level. A large number of windows were broken and the reinforced concrete floor in the vicinity of the rupture was destroyed.
Lesson(s) Learned:
- Exhausters designed for vacuum services can become pumps and cause severe damage to vacuum systems by overpressurization.
- Operators of stationary equipment such as exhausters and compressors can make damaging mistakes when rotated between facilities having different controls and operating procedures.
Recommendation(s):
- Install warning and relief devices in exhaust line piping to prevent accidental excessive pressure build-up.
- Standardize controls, relief devices, and operating procedures for all such facilities so that operator training will be simplified and minimized.
Evidence of Recurrence Control Effectiveness:
N/A
Documents Related to Lesson:
N/A
Mission Directorate(s):
N/A
Additional Key Phrase(s):
- Facilities
- Industrial Operations
- Pressure Vessels
Additional Info:
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