SPG Blew Off Under Pressure - Cause?

[Chavodel8en]

Not exactly the same, but I had a SPG leak (coincidentally, just down the coast at Lobos), probably due to my not tightening it enough (I installed it myself). This was what one experienced diver / equipment fixer assessed - she inspected and fixed my SPG that day.

leak was because the SPG unscrewed from the hose as he twisted the SPG to look at it. O-ring (spool) was fine. 2 wrenches and a firm, but not excessive tightening and then a check for leaks sufficed to fix his problem.

When I looked at it the SPG was partially unscrewed.

from this thread

SPG starts leaking on the surface

So I guess you can call this a near miss, bc it happened right before I was going to descend. I had even given the descend signal, when my SPG started bubbling pretty strongly. After a bit, had my buddy shut off my air, I kept my SPG high and dry and we swam back (shore dive at Pt Lobos...

scubaboard.com

 

[CD24]

That is very similar. I also hadn't considered potential damage to the first stage by shutting off the air. We turned the tank back on as we approached the shore and left it on until we were out of the water but the tank was off for about 5 minutes with the HP hose slighty underwater at the surface. Hopefully it didn't do any damage.

Makes me wonder if best practice would be to leave the tank on? The reason I had turned off was I wanted to ensure enough air to have a functioning reg in my mouth when exiting the water.

 

[runsongas]

HP leaks are relatively slow that you could have left it on possibly, it drains something like 2cf/min whereas a full blown 2nd stage LP freeflow can drain an al80 in like 4 or 5 minutes

 

[Chavodel8en]

That is very similar. I also hadn't considered potential damage to the first stage by shutting off the air. We turned the tank back on as we approached the shore and left it on until we were out of the water but the tank was off for about 5 minutes with the HP hose slighty underwater at the surface. Hopefully it didn't do any damage.

Makes me wonder if best practice would be to leave the tank on? The reason I had turned off was I wanted to ensure enough air to have a functioning reg in my mouth when exiting the water.

I turned my tank off and intentionally raised the SPG high out of the water on my swim back to shore, and I believe all was good. Not that hard to do, as I swim on my back, but maneuvering the kelp was tricky. But I just had a leak, not a completely open HP hose.

I was able to get a full dive out of that tank afterward.

 

[Fishdip]

They don't leak until they come apart. It wasn't tight. To blow off, you wouldn't have threads left in the hose end and you can see them in the picture.

You say this but I was just on a dive a few days back and a persons SPG was leaking from the same point.

 

[Tracy]

You say this but I was just on a dive a few days back and a persons SPG was leaking from the same point.

That is a spool leaking, it doesn't have anything to do with threads or unscrewing.

 

[DirtFish]

Thank you all for the replies. Sounds like the main culprit was improper torquing by Piranha Dive Manufacturing further exacerbated by me locating the boltsnap on the swivel. It's likely that the gauge had loosened and only had a couple threads holding it together before the dive.

Lessons Learned:
1) Even reputable dive shops can make mistakes -- don't assume because it came from the "factory" that all is well
2) Don't place bolt snaps on moving parts
3) Inspect equipment before each dive, including hose connections

Once you open the package it is your responsibility to check that everything is tight and safe. It is your life safety equipment. Main culprit is you not checking for yourself.
Pre dive checks should always include making sure all hoses and connections are tight.

 

[CD24]

Once you open the package it is your responsibility to check that everything is tight and safe. It is your life safety equipment. Main culprit is you not checking for yourself.
Pre dive checks should always include making sure all hoses and connections are tight.

I understand your point and agree I should have certainly inspected pre-dive, but you would also expect that if a company charges you a fee to add a hose to the SPG, they should ensure it's torqued to the proper spec. Visually, upon opening the package everything looked ok but I didn't physically put a wrench to it to ensure it was tight. I'd compare it to sending your regs in for service and then taking everything apart and reassembling when you receive it.

 

[Edward3c]

I understand your point and agree I should have certainly inspected pre-dive, but you would also expect that if a company charges you a fee to add a hose to the SPG, they should ensure it's torqued to the proper spec. Visually, upon opening the package everything looked ok but I didn't physically put a wrench to it to ensure it was tight. I'd compare it to sending your regs in for service and then taking everything apart and reassembling when you receive it.

I never get my kit serviced before a trip only afterwards. To many horror stories of poor workmanship, even from 'reputable' technicians.

 

[DirtFish]

I understand your point and agree I should have certainly inspected pre-dive, but you would also expect that if a company charges you a fee to add a hose to the SPG, they should ensure it's torqued to the proper spec. Visually, upon opening the package everything looked ok but I didn't physically put a wrench to it to ensure it was tight. I'd compare it to sending your regs in for service and then taking everything apart and reassembling when you receive it.

It's still your responsibility to make sure everything is tight prior to diving it! You should ensure it's torqued to the proper spec.
And, when my regulators arrive after being serviced I do check the cracking pressure, do a leak down test and make sure all hoses and connections are tight. I learned many years ago in Tech diving to trust no one with my life safety equipment.