Matheson’s Joe Barnett offers six steps to control your boneyard.

It is human nature to relax our focus on the risks involved in things we do every day. Consider the drive you took to work today.

As professionals in the compressed gas industry, we have all witnessed the same sort of relaxed focus on gas and cylinder safety. It is a good thing that in this business there are constant safety reminders coming from management, regulatory authorities, and industry associations. Conditions are much better today than in years past.

But one thing I have learned from Matheson’s Six Sigma Quality culture: there is always room for improvement.

“The old days”
Years ago in the compressed gas industry, I observed an interesting process involving the re-use of corrosive and toxic gas service cylinders. The process went something like this:

An order for a cylinder of a corrosive gas was received (for example, hydrogen chloride in a 17 liter cylinder).

Someone would go to the back dock and start looking through the stack of corrosive service cylinders for the size and type to match the order.
Once the correct cylinder in the appropriate gas service was found, the residual product was drained, and the cylinder was processed for the order.
The order was then filled and shipped.

Sometimes, as you might expect (or possibly might recall from your own experience), the cylinder valve would not open. It was not unreasonable to assume that the cylinder may have been in the stack for many years. Any number of cylinders and valves in that stack could be in the same condition.

A written procedure, if any, might have read, “If the valve does not open, set the cylinder aside, and notify your supervisor.” Does that mean that if the valve opens, the cylinder (and valve) is fit for service? Sounds humorous today, but it’s really not funny at all! Accumulating empties over time meant that cylinders could sit in corrosive gas service for a long time.

There could be literally hundreds, if not thousands, of cylinders in these inventory stacks. In this de-facto FILO (first in, last out) inventory, the oldest cylinders would be the most out of reach and occasionally would start to leak, leading to a more complex, more serious situation. Adding to the problem, cylinder draining and prep was a “time available” role. Personnel trained in cylinder draining typically were busy with other duties. We’d like to think that nobody manages their cylinder assets like this anymore. But experience tells us that there remain many abuses of best practices.

The obvious solution
The first step in improved cylinder management was a concept change from “pulling” the cylinders through the operation to “pushing” them.
Drain and process all the corrosive and toxic gas cylinders as soon as they are received. Timely “push” processing effectively minimizes the downside of corrosive gas exposure to the internal surface of the cylinder and valve.

Make cylinder draining a priority responsibility. Process corrosive and toxic empties as soon as they hit the dock. As long as there are residual corrosive gas cylinders on site, the drainer should be at his station processing cylinders.

Get serious about cylinder management
The first step is to define the scale of the problem and deploy a procedure measured against the problem. Formalize the process. Provide an inventory form to each facility within your organization and record the number of cylinders in corrosive, unknown, or toxic gas service outside the normal flow of production.
The first time inventory is formalized, you may be surprised at the large numbers. Accept only hand-counted inventory because estimates are typically understated. Get serious about finding the “boneyard” cylinders. Boneyards can be found at customer sites too. Check the most distant corner in the back lot for the best hiding places.

The problem with older cylinders
When a cylinder is set aside as empty or returned to the gas supplier, it still contains a residual amount of product; if that product is liquid, it sits in the heel of the container. In the case of a corrosive or a toxic gas, the heel has to be removed and neutralized before further processing and refilling of the cylinder. Generally this is not a problem, but there are certain events that may occur that can make it problematic:

The valve may be corroded and will not function. Cylinders have been retained at customer locations up to 40 years and longer.
The labeling and markings have faded over time, and the residual contents are now unknown.

The residual corrosive gas may disassociate and create a pressure hazard in the cylinder. Hydrogen fluoride has been known to develop extremely high pressures over time and actually rupture the container (Fig. 3). A pressure hazard is a potential problem that could become a current problem at any moment.
The product may become obsolete, and the gas company does not retain its capability to neutralize the returned heel. Certain processes are very specialized and require unique equipment and operator capabilities.

Problem cylinder remediation
Avoiding the creation of a problematic situation is one thing, but dealing with problems like those described above is quite another. What do you do with a problem cylinder?

Some remediation companies have compressed gas cylinder divisions. In one of its publications, the Compressed Gas Association (CGA) refers to these companies as Environmental Contractors. They are usually a treatment, storage and disposal (TSD) facility, which means they are permitted by regulatory agencies to process hazardous waste.

TSD facilities have developed some very interesting processes over the years to manage problem cylinders. Many specialize in the capability to sample, analyze, and identify unknown contents through the use of FTIR and mass spectrometry, combined with extensive reference libraries of spectra to enable positive identification.

Gas companies, seeking to avoid the expense of a remediation contractor, did, over the years, develop methods and still do process many of these problem cylinders. Over time, market forces prevailed, and the remediation contractors offered services back to the gas companies at pricing that was “win-win” - especially for larger projects.

Just do it
Price out your inventory with several different remediation companies. Depending on the quantity, the project may be long-term, and the overall cost may be in the millions of dollars.

An annual budget should be developed for cylinder remediation, with someone in charge of administering the process.

Develop targets, and put a monitoring program in place. For example, cut the inventory in half each year through a combination of on-site activity and off-site remediation using environmental contractors.

Tie a percentage of managers’ bonuses to cylinder remediation targets.

Monitor the inventory and report monthly to top management.

This process will work, and you will be able to proudly report that boneyard cylinders are maintained at a minimally acceptable number.

Why not zero?
You might be able to prevent cylinders from accumulating, but not everything is under your control. There will be users and customers who harbor problem cylinders for years. Zero is not realistic, but maintenance of a minimal quantity is attainable. Staying on top of it is essential.
Also, recognize that there is a cost associated with non-action:

The cost of cylinder remediation comes directly off the bottom line so there is a tendency not to spend the money.

Forward thinking companies and executives, however, recognize that there is a larger and more significant cost for inaction.

These cylinders are a risk to your employees, the environment, and the community if not promptly and properly processed. Toxic gas leaks are dangerous and soil and groundwater remediation can be very expensive.

Six steps to controlling your boneyard

  1. Always know the quantity of corrosive, unknown, or toxic gas service cylinders on site containing residual contents. If you have multiple sites, you should know, on a combined basis, your corporate risk exposure.
  2. Put someone within your company in charge of managing and reporting on this inventory, someone that has an interest in, and has demonstrated a skill set for, understanding and managing the process.
  3. Develop and financially support a plan to reduce the inventory and maintain it at a minimally acceptable level. You may also need to support your plan with personnel and equipment if you chose to remediate on site.
  4. Recognize there are multiple ways to manage this, from remediation on site to the use of environmental contractors for off-site work. A combination approach may work best within your company, e.g. 50 percent on-site remediation and 50 percent off-site to environmental contractors.
  5. Do not, under any circumstances, allow corrosive, unknown, or toxic gas inventories to accumulate within your company. Unlike bottles of fine wine, these cylinders will not get better with age. The cost of remediation will not go down over time. The unit cost of cylinder remediation has risen substantially over the last 10 years.
  6. Track and report your progress so that all within your company can take pride in a job well done, a reduction in overall risk, and a substantial improvement to your work environment.

Follow these steps and you will minimize the risks associated with an excess inventory of toxic and corrosive gas service cylinders at your facility.