Wave Shape
Wave Shape

Rhondda Sub Aqua Club – O2 Cleaning Awareness Session

Waves Shape

With several newly qualified Sports Divers in our club in the process of depth progressing, Storm Ciara and then Storm Dennis were more than a little annoying. Scuppering our plans to get in the sea and needing a change from inland quarry diving we wanted something different to do on a weekend as a club.

When fully depth progressed and confident and competent with setting off their DSMBs etc. the icing on the cake for our Sport Divers would be a club trip to dive HMS M2, the world’s first submarine aircraft carrier sank off Portland in 1932. As she sits in 35m talk got around to planning for the dive and the optimum gas mix for them to use.

As we would be diving a mix of 32% and using partial pressure blending to fill the cylinders, a process that involves a measured pressure of oxygen being decanted into the cylinder and the cylinder then being topped up with air from the diving air compressor, there was a requirement for our cylinders to be O2 cleaned. One of our sport divers asked what was involved in O2 cleaning a cylinder and after a chat between our Diving/Training Officer and Neil Brock at Bristol Channel Diving Services a plan was hatched.

As our local dive shop Neil at Bristol Channel Diving Services has always lent his support to our club and so while Storm Jorge was battering parts of the UK several of us spent the morning in his workshop. Some club members had a genuine need to get their cylinders O2 cleaned so brought them along. They were shown how to safely empty their cylinders and how a pillar valve is removed. Then under the close supervision of Neil, the cylinders were checked for internal corrosion, dirt, and non-compatible grease that could cause a reaction with 100% oxygen. The pillar valves were taken apart for cleaning in the ultra sonic bath, dried and then reassembled with oxygen compatible o rings and grease. Neil pointed out the dirt and grease that builds up on the pillar valves. This could come into contact with oxygen during the nitrox filling process, which is why oxygen cleaning is essential to prevent unintended combustion. The pillar valves were then placed back onto the cylinders and the correctly dated oxygen clean stickers placed onto the cylinders to indicate when the next oxygen clean is required.

As with many things learning and understanding is easier when you actually see it being done in front of you. All club members who attended the session thoroughly enjoyed themselves and went away with a much better understanding of the O2 cleaning process and why it is an essential pre-requisite to filling a cylinder with nitrox when the 100% oxygen is put in first.

Visit BSAC.com