July 30, 1996
| SUBJECT: | Safety Advisory on The Potential for Sudden Failures of Fiberglass-Wrapped Composite Aluminum Cylinders Following Exposure to Acidic Chemical Cleaning Agents |
The National Institute for Occupational Safety and Health (NIOSH) has recently been informed of an incident at the Humboldt Fire District # 1, near Eureka, California, that involved the rupture of a DOT-E 8059, 4500 PSI, fiberglass-wrapped composite aluminum cylinder. Fortunately, no one was injured when the cylinder ruptured, but considerable damage was done to the fire truck on which the cylinder was being stored. The Institute advises users of self-contained breathing apparatus about this incident and of the need to take the appropriate actions to prevent similar occurrences.
A forensic analysis of the failed cylinder, combined with follow-up investigations at the incident location have determined the probable cause of the cylinder rupture to be exposure to an acidic chemical cleaning agent. Authorities have determined that the failed cylinder was transported from a training exercise to a filling station in a flat bed trailer. A container of a chemical cleaning fluid was present among the cylinders, and was later determined to have spilled during transit, allowing the fluid to come in contact with the cylinder. The fluid was a commercially available aluminum cleaner which contains, among other ingredients, hydrofluoric acid, phosphoric acid, and sulfuric acid. A number of similar cleaning agents are commonly available and used to clean chrome, aluminum wheels, and other metal surfaces. The cylinder rupture occurred approximately 6 days after exposure to the fluid.
According to the forensic analysis, the cylinder failure "is consistent with environmental stress-assisted cracking of the fiberglass composite. Glass fibers failed due to the combined action of an acidic chemical environment and the stress caused by the internal pressure." "This combination of chemical attack and stress acting over several days led to the failure of the cylinder."
The Institute wishes to advise users of all composite, fiberglass-wrapped Self Contained Breathing Apparatus (SCBA) cylinders that similar cylinder failures could occur if the end-user fails to take precautions to ensure that acidic cleaning fluids or other acidic chemicals do not come into contact with such cylinders. Besides contact with acidic cleaning agents in common use, fiberglass-wrapped cylinders could be exposed to acidic chemicals during responses to fires at chemical plants, warehouses, and other hazmat responses.
Fiberglass-wrapped composite cylinders should only be used, handled, cleaned, maintained, and transported by individuals who have been made aware of the need to avoid exposing such cylinders to acidic materials.
If a fiberglass-wrapped cylinder is suspected to have come in contact with acidic chemicals, the cylinder should be immediately depressurized and removed from service. The SCBA manufacturer should then be contacted for further instructions.
Questions concerning this Users' Notice should be directed to NIOSH at the following numbers:
PHONE: |
304-285-5907 |
| FAX: | 304-285-6047 |