Dropped object: Failure of lump hammer
- Safety Flash
- Published on 5 February 2015
- Generated on 26 December 2024
- IMCA SF 02/15
- 3 minute read
A member has reported an incident in which a wooden hammer shaft failed and the head fell to deck.
What happened?
Two personnel were located at the upper main tensioner level of a pipelay tower, removing dowels from the tensioner gear boxes using a spanner wrench, dowel removal tool and the 2kg lump hammer. During this process the personnel were striking the spanner wrench with the lump hammer. On a downward swing of the hammer and at impact with the spanner wrench, the hammer head detached from the shaft and fell approximately 25 meters vertically through the tensioner to the deck below. There were no injuries. Had the falling hammer head struck a person, according to the DROPS calculator it would have caused a fatality.
The purpose of this safety flash is to highlight the hazards of using tools at height which are not specifically designed for use at height, and to reiterate the importance of preventive measures to eliminate the risk of dropped objects.
Pipelay tower showing where hammer fell
Broken lump hammer
Our member’s investigation noted the following:
- This particular brand of hammer had been ordered in 2011 following a similar incident in which a wooden hammer shaft failed and the head fell to deck. These hammers were deemed suitable for use at height at that time due to the design of the wedging system for the hammer head giving a high degree of securing. This particular hammer had been stored on the vessel and brought into service six months prior to the incident.
- The area below had been barriered off and sentries were posted to prevent personnel entering the area.
- The hammer appeared to be sound and the head was not loose prior to use.
- The hammer was not specifically designed for use at height, and the head can (and did) separate from the shaft.
- The reason for the failure was not yet known, the manufacturer claimed to have a design that requires 20% more force to pull the head from the handle than a conventional wedged hammer, but it had nevertheless failed whilst in use.
- Despite inspection prior to use, the hammer showed no defects. A specifically designed hammer for working at height such as from Stop-Drop Tooling, would not have failed in this way as the head cannot come free from the shaft.
- The shaft of the hammer was fitted with a lanyard, there was however no way to prevent the head dropping with this type of hammer.
Our member took the following actions:
- Ensured that this particular brand of hammer was NOT used at height subsequently.
- Supervisors to ensure that tools used for working at height offer complete dropped object prevention, and liaise with their Health & Safety Executive (HSE) Superintendent for advice if new tools are required; . Continued liaison with hammer manufacturer regarding the failure.
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