Master Equipment Lists Are a Must in Commissioning
A master equipment list (MEL) is one of the highest value deliverables a commissioning professional can offer.
One of the easiest-to-create commissioning process deliverables is also one of the most valuable to the building owner/operator. I am talking about a master equipment list (MEL).
Every commissioned system consists of individual pieces of equipment, and commissioning professionals must know what they are, where they’re located, and why they’re needed. One of the first things a commissioning professional should do is make a list of systems and which equipment belongs to each. Systems are not necessarily defined by industry standards, so commissioning professionals need to define systems that make sense for each project. Sharing this information with your team ensures system boundaries are clear and that all overlaps are addressed through integration verification.
That systems list is the start to an MEL for the project. At the end of the project, it should be easy for a commissioning professional to submit a tabular list of all equipment with, at a minimum, what the equipment serves and its number, type, and location.
Additional information that may be helpful includes nameplate data like manufacturer, model number, capacity, serial number, etc.
Without an MEL, all of the pertinent information would, theoretically, be available to the owner/operator in as-built drawings and O&M manuals; however, it will be much more convenient and useful as a single document.
Future owners/operators will use the MEL on a regular basis for familiarizing new staff to the systems/equipment, populating computerized maintenance management systems, contracting outsourced preventive maintenance services, and replacing equipment and/or parts procurement.
So far this year, I’ve met two owners/operators who suffered because they did not have an MEL. One was a large industrial plant with a full-service maintenance agreement with a reputable firm. The facility engineer who was responsible for managing that contract had been in the plant for more than five years and trusted that “full-service” meant “everything.” However, the 20-plus rooftop exhaust fans were not written into the service contract.
Therefore, no one was taking care of them. During a retro-commissioning visit, we found that all exhaust fans, except those interlocked with and critical for the performance of specific process machinery, were non-functional, primarily due to broken belts.
The second owner/operator was trying to resolve uncomfortable conditions in some core areas in a new health care facility. The root cause of the problem was also exhaust fans with broken belts; however, the engineer was unaware those fans even existed.
In these two cases, and essentially in all buildings, an MEL would have been a low-cost/high-benefit document for the owner. An MEL is one of the highest value deliverables a commissioning professional can offer.