Uncontrolled Release of a Blocked Pipe

Near injury caused by little consideration of the risks involved being given when clearing a blocked pipe.

What did the reporter tell us?

A drainpipe was found to be choked: Initially the pipe was blown with air and even filled with water to check if the pipe was clear. A decision was made to clear the blockage by heating the pipe. The result was a sudden release of the clogged material, with the residual pressure causing the blocked material to hit the bulkhead. The person heating the pipe was standing clear but the person assisting was standing right in front of the pipe. Fortunately he had just moved to get some tools when the incident took place. The water used in the pipe converted into steam and released the clogged material under pressure.

The lessons to be learnt

The reporter advised the action taken to prevent similar accidents again:

Always keep clear of both the openings of the choked pipe being cleared. All the personnel are to be briefed regarding the consequences and to take preventive measure while carrying out such jobs.

The company procedure recommends hazard identification by the “brainstorming” method for proper risk assessment and the conducting of a toolbox meeting prior to undertaking any task.

CHIRP Suggests

Such brain storming can form the basis of a toolbox talk.  A culture that encourages toolbox talks would have improved the level of situation awareness and the identification of potential risks. After the first plan failed to achieve the required result, a second toolbox talk should have taken place to incorporate identified actions after a new risk assessment had taken place.

CHIRP suggests that toolbox talks should not be prescriptive but should be designed to stimulate thought and discussion over a wide range of circumstances as part of a good safety culture on board.  Forms can be developed to support toolbox talks, by prompting participants to consider common hazard sources, such as heat, pressure, moving or falling objects, electricity etc.  It is not necessary to keep and file such forms, if that risks them becoming ‘tick box’ exercises.  It is more important that they encourage consideration of the hazards by those involved with the job.  A good Toolbox Talk would identify hazards, which may then need to be subjected to a more formal risk assessment by a competent person or persons.

A good practice shared with CHIRP suggests a traffic light system can be adopted for a toolbox talk, whereby if there are no changes to the planned work the status is ‘Green’. If one item changes the status becomes ‘Yellow’, i.e. stop and think before progressing and the moment a second item changes, the status becomes ‘Red’, i.e. stop work and reassess the risks.