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OGP Safety Alert #210 – Diving fatality from uncontrolled ascent of lifting bag

May 20, 2009

 

Country: USA

Location: OFFSHORE : Specialist vessel eg diving, construction, survey

Release Date: 5 April 2009

Time incident occurred: —

Type of Activity: Diving, Subsea, ROV

Type of Injury: Other

Function: Production

Applicabale Filter Categories: Human error, System/Equipment failure

In a recent incident on a Diving Support Vessel, A lifting operation was being conducted on the seabed by a saturation diver using a parachute lift bag. An uncontrolled ascent of the load and lifting bag occurred. The diver’s umbilical was entangled in the load and rigging, which pulled him from the seabed at 200 feet to 70 feet from the surface. The diver was rescued back into the diving bell but later died from his injuries.

What Went Wrong?

A 12 000 Kg Parachute Lifting Bag was used for a 6 000 Kg Load, Consequently over inflation of the Lifting bag causing excess lift was easy to achieve. The Risk assessment process should have identified that two smaller lifting bags were used, rather than one large one, so more control of the lifting force being applied could be achieved.

The use of a Hold back line to an anchor point at the seabed, to contain the load should it have excess lift, was identified in the JHA but not applied.

Applying an invertor line from the top of the lift bag to a secure anchor or weight on the seabed, as protection should the Lift bag break free. Was used inadequately. The invertor line was attached to an anchor that was of insufficient weight and consequently was lifted with the uncontrolled ascent of the Lift Bag and load.

Corrective actions and Recommendations

Industry Guidance IMCA D016 rev 3 should be followed. This incudes the use of Hold back lines and anchor points of sufficient SWL to secure the load against uncontrolled ascent. Also the Invertor line should be attached securely to a sufficient anchor point to ensure the lifting bag is secured and inverts should it break free from its rigging.

OGP

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