NOPSEMA, has today released a Safety Alert 64 relating to the use of collared Eyebolts as lifting equipment as a result of a failed lifting activity on a mobile offshore drilling unit (MODU).
MODU crew were replacing the diverter on a MODU facility operating in Australian waters. The new diverter had been placed on its side in a cradle on the main deck for change-out of the flex-joint. Subsequently, the diverter was lifted with the intent of rotating it from the horizontal to its working, vertical axis. When the diverter had been lifted between 1.2 to 1.8 metres above its cradle, one of the two collared eyebolts used for lifting the diverter body sheared, see Figure 1 below. This caused the diverter to rotate and the second eyebolt to become dislodged from the diverter body. The diverter then fell back into the cradle on the main deck. The combined diverter and the running tool weighed approximately 21.7 tonnes and fell a distance of 1.2 to 1.8 metres. No persons were injured in the incident.
The primary immediate causes of the incident were found to be:
- The lifting equipment was configured such that the direction of pull was at an angle to the shaft of the eyebolt, so that a ‘fleet angle’ from the vertical was created. An angular load such as this reduces the Working Load Limit (WLL) of the eyebolt significantly. See Figure 2 below.
- The collar of the eyebolt was not fully flush with the body of the diverter, causing a shearing force due to the fleet angle to be applied to the shaft of the eyebolt, instead of the load being spread across the eyebolt’s collar and the surface of the diverter as per design.
Lift planning was previously addressed in NOPSEMA Safety alert #59 in July 2014, which advised the industry that ‘the detail required in the lifting and rigging plans should be proportional to the complexity and frequency of the operation. Frequent or simple tasks may only require a basic plan while infrequent or complex lifting or rigging operations may require significant engineering.’
You can download the full NOPSEMA Safety Alert 64 here; https://www.nopsema.gov.au/assets/Safety-alerts/A547493.pdf
Significant business impacts to people and assets can and do occur during lifting activities. You should always ensure that all equipment is certified and rated for the activities being conducted. Individuals involved in the activity are certified competent to conduct the activity. A risk assessment has been conducted and documents which identifies if the lifting activity is simple, complex and or complicated. Ensure that a proper engineering lifting plan is provided and followed for complex and complicated lifts. Lastly ensure that all non essential personnel are excluded from the area and barriers are in place.
For assistance contact GHS Health and Safety Consultants at www.ghshealthandsafety.com