Editor’s Note: This article is a follow-up to the Welding & Gases Today article “Riches in the Niches: Compressed Gas Cylinder Maintenance.”
“Doing the absolute bare minimum testing will not extend the lifespan of a cylinder,” says Jonathan Balbi, COO of Airgenics, Inc. “To keep asset bases as healthy as possible, simple and cost-effective options are available from the larger cylinder requalification companies across the country. These ‘extras’ beyond the requalification test are situationally optional but can mean the difference between replacing six percent of your asset base and two percent of your asset base.”
According to U.S. Tank and Cryogenic Equipment, Inc. National Sales Manager Alan Bustamante, the cost of a new 240 Liter, 350 PSI cryogenic vessel can be upwards of $3,000, while the cost to fully repair and refurbish a tank typically ranges from $500 – $700 depending on the requirements of that tank.
“The 50% rule prescribes that with all things being equal, if the cost to repair and refurbish is 50% or less than the cost of buying new, you should repair,” says Bustamante. “From a company image perspective, there is relatively no discernable difference between new and fully refurbished equipment.”
Adds Balbi, “I’ve seen plenty of cylinders from the 1970s up to the 2000s fail expansion tests because of obvious neglect that could have been prevented for a lot less than the cost of a new cylinder.”
So what can be done? Why should a company make investments beyond retesting and return? Because those “extras” can be the difference between having to buy a new cylinder and potentially saving money.
As discussed in part one, there are two testing options for requalifying cylinders: the hydro-test and the ultrasonic test. Both test for the same thing and Title 49 of the Code of Federal Regulations (49 CFR) subchapter C, “Hazardous Materials Regulations,” states that if a cylinder passes either of these tests and a visual inspection, it is deemed to be an authorized package and can be stamped and filled for another service cycle.
“I am a UE Level 2 operator and have personally tested 40,000 – 50,000 cylinders using ultrasonic. Newer cylinders have a pass/fail rate not dissimilar to that of hydrotesting. Same with aluminum cylinders that have not been covered in paper labels or shipping tickets,” says Balbi. “Both have advantages and disadvantages. But in terms of extending the life of a cylinder, a hydrotest is the better option.”
So how will the longer and more destructive test extend the total service of the cylinder? It goes beyond the pass/fail difference of hydrotesting vs. ultrasonic. It has to do with the options available for additional maintenance once the valve has been removed from the cylinder, something that does not happen for ultrasonic testing.
“Once the valve is out of the tank, a host of optional procedures are opened up and each one can extend cylinder life if coupled with a good in-house procedures,” says Balbi. “This does take some planning and forethought but can mean the difference between a reject asset and a good cylinder.”
He continues, “If the asset base of a company is 40,000 cylinders of mixed manufacture dates, around 5,400 cylinder per year would need to be tested to maintain an in-service asset base, with an average of 45% of cylinders being over 60 years of age. Without maintenance beyond standard testing, expect to lose around 95 cylinders per year more than with above and beyond upkeep. In dollars that can equate to more than $20,000 dollars per year on new cylinders just to make up what is lost. As compared to an entire service package, soup to nuts, on all assets in this group that would cost ¼ of that amount per year to make an older asset ‘like new.’”
In addition to having a comprehensive plan in place to sort assets as they come up for service and an inventory of cylinders that are inhouse (including a breakdown by size and gas type), there are a number of precautions that distributors can take to ensure the longest service life of their cylinder assets.
These can include:
Isolate cylinders 3‒6 months before the service date has expired. This will allow for the following benefits:
- Seamless pick-ups and deliveries with the requalification company.
- Sorting of requalification by size and need.
- Forecast of products required to allow for service changes.
- Sorting of cylinders that can be converted into an appropriate service by age and pressure.
- Forecast models for cost of requalification.
Pre-Fill Inspection Checklist
Complete a pre-fill inspection checklist to isolate problem assets that are within the service date. The checklist should include the following:
- Checking manufacture date.
- Checking most recent requalification date.
- Interpretation of information stamped into cylinder.
- Pressure rating check.
- PRD check.
- External visual inspection.
- Valve inspection.
- Hammer test.
Isolating Out-of-Service Cylinders
Most important to the prefill inspection is the communication with the filling operator and his/her direct supervisor to isolate assets that although may be in test do not meet a secondary criterion for filling. The isolation of these cylinders and need for further repair deem that they should be treated as out of service until repaired.
It is essential to have a clear marking system and isolation areas. In addition, be sure to mark out-of-service cylinders with tags (never stickers) that contain the following information:
- Out-of-service date (month/year).
- Fire damage (if applicable).
- Service change (service requested).
- External rust (strip and paint) with requested color.
- Dead ring test failure (internal issue).
- Damaged valve (repair/replace).
- Wrong/missing safety.
- Other information, as appropriate.
- Isolate cylinders by tag as well as by requirement for next delivery.
Cylinder Storage and Handling
Appropriate cylinder storage and handling are essential to the longevity of these expensive assets. Distributors must have policies in place and an infrastructure that promotes:
- Inside cylinder storage.
- Covered outside cylinder storage.
- Proper drainage of rainwater around the base of any cylinder stored outdoors.
- Avoiding exposed loose storage.
- Ensuring that all valves are closed, especially when the cylinder is empty.
- Ensuring that cylinders are not exposed to excessive heat.
- Ensuring that cylinders are properly branded for filling and gas service.
Says Balbi, “The unsure economic future of metal manufacturing as well as the turmoil in trade will make new cylinders more expensive with longer lead times for delivery. Now is the time to evaluate the age of your inventory and forecast any future needs. If planned properly, a company can maintain assets and keep them in service longer than originally anticipated, giving them a slight edge over the competition. Growing pains of purchasing new asset acquisition and shrinkage caused by asset misappropriation can be mitigated to figures that will allow for less capital investment in steel and more investments in infrastructure. All to strengthen the backbone of the company while the overreach we all sometimes commit to can be supported.”