The value of commissioning
Have you ever heard an engineer or a contractor use the term “commissioning” and wondered what they were talking about? Like any profession, those in the design and construction industry have their own language. Commissioning is one of those terms we throw around often without explaining what we mean. This is unfortunate, because the concept behind commissioning is both simple and critical to performance of our buildings. So, what is commissioning? To explain, it helps to consider how buildings are designed and constructed.
There’s an advertisement making the rounds today of the design magazines that asks “Still buying building envelopes this way? (1) It features a picture of a car that’s been dismantled into it’s component parts and neatly spread across the floor – hundreds of pieces. It’s a pretty effective ad, and it highlights a fact about the design and construction industry that most people don’t think about – buildings are made of thousands of components, and it’s the job of the designers and contractors to figure out how all these disparate parts fit and function together. This is not an easy task.
Commissioning is the process of looking at one group of parts in any building – for example, the building’s Electrical system – and testing it to see if it is functioning in the way the designers intended. Electrical and HVAC systems are the most common targets for commissioning, but you can commission any system – the building skin (roof, walls and floor), plumbing systems, electrical systems etc.
You might be tempted to ask “why should I have to consider commissioning – I’ve already paid the architects and engineers to design it, and I’ve paid my contractor to build it – isn’t that enough? Depending on the complexity of your project, the answer might require careful consideration. For years, Data Center operators have understood that the testing and verification from commissioning is required for their business – even though they hire the best designers and contractors for this specialized work – because systems don’t typically start up as planned and the mission critical nature of a data center requires assurances that things will function as expected. Even if everything functioned perfectly, it’s imperative a data center operator can verify to their clients that the systems work properly. Commissioning enables them to provide that security.
In non-mission critical projects commissioning can pay dividends. Management consultant Peter Drucker said “if you can’t measure it, you can’t manage it”. Commissioning is a process that measures performance. When you commission a building’s walls and roof, part of what happens is measuring the amount of air or moisture that passes through the skin. Even though major products like windows are tested by agencies like UL for performance, that window is typically placed in a wall assembly that has multiple parts, and those parts often join with the floors or roof in ways that were not part of the standard UL test. Commissioning your building skin might include looking at those areas with thermal imaging equipment. Normally if air or moisture is leaking through the assembly it happens at these joints. A small opening in these joints might be adequate to keep out the rain, but heat, cold and moisture might be traveling through and over the life of the building, the extra cost to cover this thermal load can be significant. High performance buildings require a higher level of “fine tuning” to make them function properly. Commissioning is “tuning” your building.
Commissioning is most commonly used in conjunction with HVAC and Electrical systems. The complexity of these systems (especially HVAC) and the cost involved with these systems is why they often undergo commissioning. As a building owner, you might assume that having your consulting engineer observe the system installation during construction would be enough to insure that the system is functioning as expected. While many issues are resolved and correctly installed this way, things can be missed. For example, Fox recently completed a 50,000 SF build out for a law firm. We provided fully engineered mechanical, electrical, plumbing and fire protection documents. The building was a new high rise office tower – the law firm was the first tenant in this space. Since this project was constructed as a LEED certified interior, commissioning was required. The commissioning report found problems with a fan terminal unit’s control board, incorrect settings on other fan terminal units and improperly located CO2 sensors. These problems could not be determined through a standard inspection. They required running the system through various temperature scenario’s to detect. Without commissioning, the tenant likely would have complained temperature swings without knowing the cause.
If you have been involved with a LEED certified project, you are most likely familiar with commissioning, but it can pay big dividends on non-LEED projects also. Our office has recently been involved with multiple projects that were bid through a reverse auction process. We have found that this type of bidding, or any bidding where the mechanical and electrical subcontractors can’t be pre-selected benefits immensely from commissioning. In a low bid scenario, coordination with other trades and start-up/troubleshooting of mechanical and electrical systems is cut to the bare minimum from subcontractor bids. High performance buildings with complex systems require more than the bare minimum to function properly. It’s also good insurance for the owner to contract with a third party (no connection with the design team and the contractor) for commissioning. This way you have a neutral party insuring that both the design and installation is adequate and functioning properly.
Commissioning requires a considerable amount of testing and inspection from the commissioning agent. Prices for commissioning typically range from a dollar per square foot to $1.16 for new construction. The return on investment from improved system efficiency typically pays back in less than 4 years, however. (2)
At Fox we believe in the value of commissioning for all our projects. Musical instruments must be tuned before playing. Buildings must also be tuned to get the maximum return on investment. Commissioning is a critical step in that process!
1. Oldcastle Building Envelope, Architecture Magazine, January 2014
2. Lawrence Berkley National Labs, Building Commissioning 2009 Assessment