Safety warning over dangers of applying heat to sealed hydraulic cylinders

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Wednesday, 1 July, 2020 - 13:45
Policy & legislation
South Australia

SafeWork SA recently issued a safety alert reminding businesses to have safe systems of work in place when working with hydraulic cylinders and removing seized pins by applying heat.

In November 2019, a worker was unable to remove a seized clevis pin at the bottom of a hydraulic cylinder.

The worker attempted to free the pin by applying heat using an LPG & oxygen torch after other methods failed.

Direct heat was applied over a short amount of time. When the worker heated the pin, a flash flame occurred, engulfing the worker’s head area before self-extinguishing.

A similar incident occurred in Western Australia in 2013 when a worker died when a hydraulic cylinder he was heating with an oxy-acetylene torch exploded.

Both incidents share similarities including:

  • Seized clevis pins on sealed hydraulic cylinders
  • Residual hydraulic fluid within the hydraulic cylinder
  • Heat applied to the cylinder.


The alert said there are a number of risk control measures and PCBUs must ensure that:

  • No heat-producing equipment, such as oxy-acetylene/gas torches and angle grinders to be used on any sealed hydraulic equipment (e.g. lines and cylinders)
  • Hydraulic fluid is totally removed from a system and cylinders are unsealed and left open to atmospheric pressure before applying any form of heat
  • A safe system of work is developed for any maintenance on hydraulic systems, including the removal of seized clevis pins.