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Commissioning: ALL-Access Pass    

If you can’t get to it, you can’t commission it.

Whether it is for commissioning testing or periodic maintenance and repair, accessibility to mechanical, electrical, and control system components is critical for sustainable systems operation. Recently, I have been reminded of how little this seems to matter to some design and construction teams.

I guess it should not be surprising, because future accessibility really does not matter to project teams responsible for designing and installing new equipment. In general, all that matters to them is that the correct equipment is connected to the correct ductwork, piping, and wires. Also, of course, it is important that the equipment fits and can physically be installed.

Taking Responsibility

Whether or not the equipment is accessible after the project is complete really only matters to the owner and/or operators responsible for the systems following construction. There is a lot of lip service given to the importance of accessibility in design meetings and construction coordination discussions, but in most projects, there is no one who feels responsible for ensuring that accessibility is actually achieved.

This results in at least a handful of inaccessible or ridiculously-difficult-to-access pieces of equipment or control components that will need maintenance, repair, and/or replacement during the life of the building. On a commissioned project, these issues will manifest themselves during functional performance testing (if not earlier during commissioning site observations) by the inability to complete functional test steps because the commissioning professional cannot get to the equipment whose performance needs to be verified. I have seen this with devices ranging from VAV terminal unit controllers and smoke exhaust fans to makeup air unit dampers, supply duct differential pressure sensors, fancoil unit control valves, etc.

So whose responsibility is this, anyway? As with most things in building design and construction these days, the responsibility is shared by everyone on the project team starting in the design phase.

It's All About Access

The owner/operator needs to make sure that reasonable equipment accessibility is part of the owner’s project requirements (OPR). Like other OPR criteria, this needs to be defined in quantifiable, verifiable terms. “Accessible” alone is not enough to communicate the owner/operator’s expectations. For example, one design team described as “accessible” fans that required the owner to spend over $1,000 to erect scaffolding every time regular preventive maintenance needed to be performed on each fan. A powered lift was not possible due to floor loading restrictions.

The design team needs to specify accessibility in quantifiable, verifiable, and enforceable terms in the contract documents. Without this, owner/operators typically end up accepting whatever the construction team tells them is accessible. There are typically not enough teeth in the design specifications to compel the contractors to change an installation just because the owner/operator considers it inaccessible.

The construction team needs to take accessibility seriously and work closely with each other to coordinate equipment and control device locations with ductwork, piping, conduit, light fixtures, communication system devices, ceiling grids, etc., that surround the components that need to be accessed. I believe it is the general contractor’s responsibility to coordinate all of the subcontractors. However, it seems to be a default assumption that the mechanical contractor is responsible for accessibility to mechanical equipment, the electrical contractor is responsible for accessibility to electrical equipment, and so forth. This simply doesn’t work, because one subcontractor has no authority over the other subcontractors whose work might be installed later.

The commissioning professional should be responsible for observing and documenting accessibility issues as early in the construction process as possible. Often, though, problems don’t start to surface until late in construction, when most of the trades have completed their work and ceilings have started to go in.

Finally, the owner/operator and design team should be responsible for rigorously enforcing the specified accessibility requirements. As noted at the beginning of this column, the design team really does not have a vested interest in accessibility, so this responsibility is going to sit primarily on the owner/operator’s shoulders. The owner/operator needs to be assessing the commissioning professional’s concerns and firmly stating his/her intention to accept or not accept the installed conditions. With a strong specification in hand, the design team will certainly go to bat for the owner/operator if the owner/operator is unhappy. If the owner/operator is ambivalent about accessibility, it will be an uphill battle for the commissioning professional to influence any change by the construction team.

As with most things “commissioning,” the key to obtaining accessible, maintainable, sustainable systems is to define a measurable acceptance criterion early in the design phase, and then to allow the commissioning professional to shepherd that criterion through the design, construction, and acceptance phases to improve the chances of the vision being realized in the end. Next month’s column will explore some ideas on how to do this more effectively.

 

Commissioning: Getting It Right

Engineered Systems, May, 2011

by
Rebecca Ellis, PE, LEED AP, CCP, CPMP, CxA
President
Questions & Solutions Engineering
1079 Falls Curve
Chaska, MN  55318
rteesmag@QSEng.com