Stored pressure release near-miss: Small part expelled from hydraulic winch

A member has reported an incident in which a part was expelled from a hydraulic system under pressure, causing a leak of hydraulic oil. The incident occurred when the hydraulics were activated to turn the winch drum to install a new wire rope. There was a loud bang from the hydraulic pack as a sensor was forced out of the unit. The sensor hit the bulkhead to the right. Approximately 2 litres of hydraulic oil was also expelled from the winch onto the deck and bulkhead.

Our member’s findings were:

• Company safe system of work had not been followed – there had been no permission or sanction to test this equipment;
• The hydraulic system had not been commissioned properly. The hydraulic hoses had been fitted the wrong way around;
• The handover between technicians following crew change had not identified these issues.

Our member’s recommendations were:

• Improve communication between crews at handover especially at crew change;
• Formal ‘sanction to test’ should be completed before it is handed over to the responsible person in charge;
• Suitable and sufficient risk assessment and pre-use check list to be created and used for this work and equipment;
• Status and condition of equipment should be clearly defined before planned maintenance is carried out.

Members may wish to refer to the following incidents (search words: ‘safe system’, hydraulic):

• Hydraulic company sentenced after employee loses sight in one eye
• Near-miss: Contained hydraulic oil spillages from cranes

Both incidents relate to inappropriate release of stored hydraulic pressure in which a causal factor was failure to follow a safe system of work.