2 year service interval

[dougr52]

Cleaning, re-lubricating seals and tweaking the low pressure seat adjustment is all more critical than replacing the o-rings. Of course the dynamic o-rings do wear in use, and springs do wear out over time. It is a mistake to think that o-ring elastomer shelf life is the only thing driving service interval. But a 1 year service interval is very conservative, and given how many failures occur due to mistakes that occur during servicing is of questionable benefit.

Most end users should be able to check their regulators for leaks (vacuum leaks in the second stage, and leaks of gas out), cracking pressure and intermediate pressure. Those checks should be enough to give a strong indication if service is needed or not. Assuming those checks are done pushing beyond 1 year is perfectly reasonable for all regulators. Of course the end user has to decide if they want to do those checks, or have their LDS do them. The warranty "free" parts that come with annual service also usually come with a $100-$150 labor charge. You can decide for yourself if a $100 free service is free or not.

sounds like really good advice to me.. since i am only a vacation diver, just having my lds check it out, and if no problem found not spend $100+ to fix something that AIN'T BROKE !!

 

[gsk3]

DiveRite also offers 2-year service interval to maintain warranty coverage.

 

[h90]

Most do, the reason is universal..... Flex life of o-rings.

The Society of Aerospace Engineers (SAE) issued Aerospace Recommended Practice (ARP) 5316 was issued in 1998 to supersede MIL-HDBK-695C (canceled) as the aerospace industry standard. ARP 5316 is often used as a guideline in determining useful shelf life of elastomers used in other industries.


5 years: Polyurethane (millable), SBR, Natural Rubber, Polybutadine, Polyisoprene
15 years: Nitrile, Neoprene, HNBR, Polyacrylate, Butyl
Unlimited: Ethylene Propylene, Fluorocarbon, Perfluorinated Elastomer, Silicone, Tetrafluoroethylene Propylene (Aflas®), Fluorosilicone.


Elastomer........................................... ASTM...............ARP 5316 Shelf Life
Butyl Rubber, Isobutylene Isoprene...............IIR........................15 Years.

Ethylene Propylene, EPDM or EP.....................EP.........................Unlimited

Fluorocarbon (Viton®)..................................FKM.......................Unlimited

Hydrogenated Nitrile, HNBR or HSN.................HNBR.....................15 Years

Nitrile (Buna-N or NBR)..................................NBR.......................15 Years

Polyurethane (Polyester or Polyether)...............AU / EU..................5 Years

Silicone.........................................................VMQ.......................Unlimited

Styrene Butadiene (Buna-S)............................SBR.......................5 Years

If you noticed the shelf life of Polyurethane and Buna-S are 5 years, that is just sitting around with no work load and only oxidation from air.

Once compressed, the memory and life span drop drastically. Both have been commonly used in low stress positions in the regulators to save money in mass production.

By using the 1/2 life of the weakest link it is easy to figure a safe recommendation to insure the unit performs as required.

From my experience (we sell seals)
I would add HPU (hydrolysis resistant PU) with approx. 40 years
Nitrile is usually 5 years in the brochures of the supplier.

I would also say that you can easily double it if the storage is cool, dry, dark, ozone free and half it if it is tropic climate.