Safety Alert. 03/98. Committed to Safety. N2 cylinder explosion. Background
Committed to Safety
N2 cylinder explosion
An incident occurred recently at a PDO field location where a N2 cylinder failed explosively splitting into 2 large pieces which came to rest 114m from the original location. The valve cylinder was found sheared off.
The cylinder was not in use, being handled, struck or subject to anything other than direct sunlight and, therefore, temperature when it failed.
External appearance of the cylinder parts does not suggest external corrosion. The inside is stained but not corroded.
Cause of the incident
Not directly identifiable, all failed components are under analysis by the manufacturer.
However, the following are possible causes:
Cylinder transport and handling may have contributed in the cause of incident.
Preliminary investigation of parts showed a crack near the cylinder base, older
than the splits caused by the explosion. Further analysis is required to confirm this.
Learning Points and Action to Prevent Recurrence
-Arrange a visual inspection for damage and corrosion purposes of all existing gas cylinders available at site. Regularly inventorise.
-Return the following cylinders back to supplier: 1. Cylinders overdue for test; 2. Dropped and/or damaged cylinders; 3. Empty Cylinders;
-Upon delivery of gas cylinders at site by supplier, confirm all cylinders stamped test dates. Refuse any cylinders ‘out of test’.
-Review and ensure that cylinder handling and vertical storage is carried out with due care and in line with handling procedure.
-Ensure sound storage facilities for gas cylinders. Avoid exposure to corrosive fluids and/or gases.