Exploding Hydraulic Piston Accumulator

An industrial mechanic was killed when the hydraulic piston accumulator he was repairing exploded. To fix a leaky seal inside the accumulator, he drained the hydraulic oil, but not the nitrogen gas (N2). He did not realize the N2 had produced extreme pressure on the accumulator’s end-cap and piston, which blew out in an explosion and struck his abdomen.

Hydraulic accumulators are pressure storage reservoirs that use nitrogen gas to act as a shock absorber for hydraulic systems.

Recommended Preventive Action

  • Before disassembling any type of accumulator, always release the gas to reduce the internal pressure to atmospheric.
  • When releasing the gas, have it dissolve in a bucket of water.
  • Always use N2 when pressurizing accumulators.
  • Never carry out welding or tapping on accumulators.
  • All service, repairs and troubleshooting should be done by trained, authorized persons only.
  • Provide suitable training so maintenance personnel can learn how to use, service and repair equipment safely and effectively.
  • Discuss proper use of service and repair equipment at safety meetings.
  • Discuss medical complications associated with oil and air injection injuries.
  • Always follow the manufacturer’s recommendations.
  • Write a job safety analysis (JSA) of correct techniques for servicing or repairing gas-charged hydraulic accumulators.

July 2014

1 800 222-9775