Diving helmet locking collars
- Safety Flash
- Published on 1 January 2000
- Generated on 31 December 2025
- IMCA SF 01/00
- 1 minute read
One of our Members has brought to our attention that certain Kirby Morgan diving helmets, type KMB 601, neck dam locking collars have been subjected to pitting during oxy-arc cutting due to electrolysis.
What happened?
These particular locking collars were all made of cadmium-plated aluminium alloy.
On investigating this matter with the supplier and manufacturer, the contractor has been advised that only a small quantity of cadmium-plated aluminium alloy locking collars were manufactured. The supplier has not been able to quantify the number of such collars sold, nor identify to whom they were sold.
Because of the electrolysis action, the manufacturer has now reverted to traditional brass or stainless steel locking collars.
It is not thought that the aluminium alloy locking collars will represent a safety hazard if regularly inspected before use. However, as deterioration has been observed, the contractor involved has decided that it would be prudent to replace all their aluminium alloy locking collars.
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.