Breathing gas contamination
- Safety Flash
- Published on 31 January 2006
- Generated on 2 December 2024
- IMCA SF 01/06
- 2 minute read
Jump to:
A member has reported an incident involving the contamination of a diver’s breathing gas.
What happened?
CO2 contamination was found to be present in three cylinders of a diver’s breathing gas (96/4%). The discovery was made after a gas transfer to the vessel Kelley tubes during ‘routine’ testing. Subsequently, a full gas chromatographic analysis (to determine if additional contamination products were present) revealed levels of 3600 ppm CO2‚ with no other significant findings. The supplier’s gas quads were then analyzed, with readings of 850 and 110 ppm CO2‚ noted in these.
A full inspection of the gas plant and routing onboard was then made, which confirmed that there was no cross-contamination within the system. The ‘dirty gas’ was scrubbed and an investigation as to the source of the contamination was initiated.
The investigation also revealed that:
- the supplier’s quality certificate indicated a maximum allowable concentration of 300 ppm CO2. The company’s own standard is < 10 ppm for breathing gas.
- the quality standard referenced by the supplier was the UK Ministry of Defence standard 68-284 – Compressed Breathing Gases for Aircraft, Diving and Marine Life-Support Applications. This document sets a maximum limit of 5 ppm CO2 for oxygen/helium gas mixtures.
The following actions were taken:
The company has removed the suppler from its ‘approved vendor’ list and now requires independent laboratory certification for all gas. Calibration frequency for the gas analyzer and instrument limitation for detecting the lowest level of impurity is also to be studied.
IMCA Safety Flashes summarise key safety matters and incidents, allowing lessons to be more easily learnt for the benefit of the entire offshore industry.
The effectiveness of the IMCA Safety Flash system depends on the industry sharing information and so avoiding repeat incidents. Incidents are classified according to IOGP's Life Saving Rules.
All information is anonymised or sanitised, as appropriate, and warnings for graphic content included where possible.
IMCA makes every effort to ensure both the accuracy and reliability of the information shared, but is not be liable for any guidance and/or recommendation and/or statement herein contained.
The information contained in this document does not fulfil or replace any individual's or Member's legal, regulatory or other duties or obligations in respect of their operations. Individuals and Members remain solely responsible for the safe, lawful and proper conduct of their operations.
Share your safety incidents with IMCA online. Sign-up to receive Safety Flashes straight to your email.