Airline coupling failure

We have received the following report of an incident which occurred during internal cleaning operations in a produced water de-gasser which was being undertaken by two contract cleaners. This vessel had been open for over a week and forced extraction was in place to ensure that fresh air was being drawn in. In line with normal operating procedures the two cleaners were working under air from a breathing apparatus air line unit fed from a breathing apparatus compressor. During the operation a coupling on the air line parted, terminating the primary source of air supply. The problem was immediately recognised by the vessel entry control personnel and both cleaners immediately opened the air supply from their personal secondary supply and withdrew from the vessel to a place of safety.

The inventory of breathing apparatus (BA) air hoses was collected together for inspection and on cursory inspection the male and female connections looked identical on all hoses. The inspection data, certificates and equipment register also did not indicate any difference between the types of hose.

However, on closer inspection the male fitting indicated a slight difference (see below) which appears to prevent satisfactory connection with the female fitting. The pictures below indicate the difference in the appearance of the made up joints. Both joints hold when tested by hand on initial set up, but the dissimilar tubing fitting is not secure if the tubing is flexed, indicating it does not make a tight/locked connection on the make up.

The following key lessons have been noted:

• Male connections were not stabbing fully into the female connection because of the slight differences in the design of the male connectors;
• Back up air systems worked correctly;
• Safety procedures were complied with.

The company involved has made the following recommendations:

• A system is to be put in place to record that equipment has been fully checked each day before being used on a worksite, to include a supervisor’s signature;
• The contractor is to establish how it was that it was supplied with hoses with ‘mixed’ fittings with the project equipment;
• A new set of compatible hoses has been requested of the contractor.