“Let go of the attachment, keep the lesson.” L.J. Vanier
On February 16, 2007, a propane fire broke out at the Valero McKee Refinery in Sunray, Texas. Three workers were injured and the refinery was forced to shut down for nearly two months. The CSB investigated and determined that water settling out of a propane stream leaked through a block valve and accumulated in the low point formed by the control station. While the control station was connected to the process, it hadn’t been used for approximately 15 years. The pipe elbow upstream of the control valve was likely fractured when a period of cold weather froze the water. When the weather warmed, and the ice melted, it resulted in a release of highly pressurized liquid propane through the fractured elbow. The propane then formed a vapor cloud that traveled downwind toward the boiler house and ignited. In the aftermath, they discovered that the propane mix control station was not identified as no longer in use or as a dead-leg freeze hazard. It had been “abandoned-in-place.”
There is not a consensus in the process industries regarding abandoning equipment in place. It has its advocates due to its more cost-effective nature, and the hope that “we may use it again,” but most safety professionals argue that decommissioning equipment is a safer and much sounder option in the long run. There are others, still, who will concede that each has its place and the appropriate method depends on the situation. All that said, what is one to do?
What’s the Difference?
There are two ways to deal with equipment when it is no longer used in a process. The first method is “abandon-in-place.” This is exactly what it sounds like. The equipment is left where it is, unused, for an indeterminate amount of time, often in hopes that it will be useful to the process again in the future. Typically, no further maintenance is conducted and the equipment is left idle. The alternative to abandon-in-place is “decommissioning.” This is the more formal process for managing unused equipment. Decommissioning procedures vary from organization to organization, but most often entails decontaminating, dismantling, and disposing of the equipment. Decommissioning is, in a nutshell, the procedure for removing obsolete equipment.
It should be obvious why safety professionals prefer decommissioning to abandon-in-place: if it’s not there, it can’t fail. There are others in the industry, though, that believe there is an argument to be made for abandon-in-place.
There aren’t always enough resources to do everything that needs to be done. This finite amount of resources is often the reason abandon-in-place is a more appealing option when deciding the fate of equipment. It’s no secret that decommissioning equipment isn’t cheap. It involves decontaminating, dismantling, and disposal, as well as risk assessment at each step along the way. When a plant working with finite resources has other needs and expenditures, abandon-in-place clearly seems to be the more appealing option when decommissioning costs are taken into account. However, abandon-in-place certainly isn’t free.
Abandon-in-place doesn’t mean literal abandonment, at least it shouldn’t. If equipment is abandoned in place in the hopes that it will be utilized in the process again in the future, resources should be dedicated to the routine maintenance of the equipment. This is a viable solution if the abandonment of the equipment is short term. In a longer term, though, the costs accrue. When it is time to put the equipment back into service, there are still more costs relating to repairs and testing. Decommissioning’s upfront costs may be hard to swallow but abandon-in-place can be just as expensive in the long run.
In recent years, repurposing has been a trend on the rise. Creative individuals scour flea markets and swap meets to find pieces to refinish. Old possessions are given new life when they would have been discarded, often saving the architect money on an object they would have otherwise bought new. While this money saving method works for a piece of furniture or a decorative object, it cannot be directly applied to process equipment in the same manner.
A couch is a couch. No matter how you refinish it, it’s function and structure are generally the same. It will function as it should no matter where it’s located or what sort of furniture arrangement it is organized into. Process equipment isn’t so easily manipulated. Repurposing old equipment is a money saving solution and makes abandon-in-place the more favorable choice. However, it isn’t often that the old equipment can be repurposed with 100% certainty of functionality. When it can be, there are often significant modifications required to ensure it operates correctly in the new process. Using a glass lined vessel that was abandoned in place in a new process as a caustic holding tank may save money initially, but when the caustic erodes the glass and sends dust and shards of glass to downstream equipment, the resulting equipment damage can be a costlier fix. Instead, when equipment is decommissioned and disposed of, it paves the way for custom equipment to be installed in new processes that is specifically designed for the process.
The most important factor to consider when deciding to abandon-in-place or decommission is safety. Abandon-in-place should not mean literal abandonment, but literal abandonment is often what happens. Abandoned equipment presents hazards that may include:
- Product contamination – If piping is taken out of service and left in place without proper maintenance, block valves can leak, resulting in product contamination.
- Obstruction – Equipment left in place when new equipment is installed around it may present difficulty of access and egress around the equipment during regular maintenance, firefighting, and emergency escape.
- Leaks – Abandoned instrumentation conduits may provide a path for liquid and vapor to leak into locations where the leak may go unnoticed for an extended period. Underground conduits may even carry materials hundreds of feet from a leak location, making the leak more difficult to find.
- Releases – As was the case with the Valero Refinery, if equipment is not properly identified and maintained once it has been abandoned, a release, and subsequently, an explosion and fire are within the realm of possibilities.
This isn’t to say decommissioning is without hazards. The decommissioning process is not a routine process and deviations may occur as the procedure is carried out. However, if a thorough risk assessment is completed for each step of the process well in advance, the risks are known and mitigated when the decommissioning process is carried out. While both methods have hazards to consider, the hazards associated with decommissioning are more easily identified and mitigated, offering a safer solution for the equipment in question.
Penny Wise, Pound Foolish
While abandon-in-place may seem like the more appealing option when it’s time for budget meetings, it’s important to consider the costs of properly maintaining the abandoned equipment as well as the hazards abandoned equipment presents. Depending on the length of time the abandoned equipment is left in place, if the equipment is properly maintained, abandon-in-place can cost more than decommissioning in the long run. It’s better to be diligent and do your research than to be penny wise and pound foolish.
Frame Your Options
Even though decommissioning is the safer, preferred choice, it isn’t always feasible when working within a budget when the time comes for the equipment to be retired. However, you can prepare for future decommissions by planning in advance. If you are working on a plant modification that will leave equipment obsolete, automatically act as if the equipment will be removed. Make removal the default option by including demolition P&IDs in the work scope. Ensure that any decision to abandon-in-place is deliberate and only comes after a full safety review.
On the other hand, if you’ve considered your options and still determined that abandon-in-place is the best choice for your organization, consider policies and procedures for the maintenance of the abandoned equipment. Or, consider a dedicated storage area for abandoned equipment if the equipment can be moved. Another option is to institute a time frame for how long equipment may be abandoned in place before it is decommissioned. Establishing policies and expectations means equipment is not left forgotten to pose some threat years down the road. Pennies saved are insignificant in comparison to lives lost in a release.