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Hammer dropped from height

IMCA has received details of an accident wherein a tool was lost from work at height and fell 6-7 metres to a walkway. No-one was injured.

Work was ongoing to remove an obsolete bracket from a derrick beam. A 1.6 kg hammer in use came loose from its double sealed spring hook and fell 6-7 metres to a walkway below, which at the time of incident was completely sealed off. The hammer, safety wire and two double sealed spring hooks were all tools dedicated and solely used for work in height.

The resulting investigation identified the following direct cause:

  • The finger articulation on the carbine hook was riveted to the spring hook body. However. the spring hook was found to be without this rivet. It might have slid out during the work due to incorrect riveting or the rivet might have been broken in two pieces during the work. The spring hook itself was not deformed or damaged in any way.

and the following contributory factors:

  • The spring hook (length = 54 mm, bow diameter = 25 mm, t = 5mm) is made of solid stainless steel.
  • The spring hook was designed for tension along its longitudinal axis and not for loads directly on its locking mechanism.

The company recommended the following immediate actions:

  • All similar spring hooks have been taken out of use
  • Spring hooks have been temporarily replaced with shackles with split pins

plus the following preventive measures:

  • The spring hooks are to be replaced with a better quality double seal type
  • The vendor has been informed of the incident
  • Relevant findings from the investigation are being distributed appropriately.

Safety Event

Published: 31 January 2006
Download: IMCA SF 01/06

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