Written by Jenny Powell, Energy Engineer
What is Commissioning?
Many energy and sustainability programs, standards, and codes require commissioning, including LEED, ASHRAE 90.1, NGBS, IECC, IGCC, the PSEG and NYSERDA’s commercial performance-based incentive programs (see glossary below). As states embrace these codes and enforce commissioning requirements you may ask yourself: what is commissioning and why is it beneficial?
Commissioning agents provide third-party quality assurance throughout the construction process. They review design drawings and submittals, periodically inspect construction progress, witness functional performance testing of mechanical equipment, and ensure that the building staff is trained and ready to operate the equipment after it’s turned over. Commissioning agents work on behalf of the owner to ensure that the owner’s project requirements are met. Most importantly, commissioning improves construction quality and reduces maintenance and energy costs.
The benefits of commissioning are never more apparent than during a retro-commissioning project. While commissioning involves a third-party review of operation during the construction process, retro-commissioning is a third-party review of operations well after construction is complete. Some difficult retro-commissioning projects have shown us how valuable it is to resolve issues when the design intent is still clear (or clearer) – and while the construction team is still onsite!
A Few Stories…
While performing retro-commissioning at a relatively new building (less than five years old), we found that the equipment was not responding to the Building Management System. Valves weren’t modulating, dampers weren’t closing, the cooling tower was kicking on while the condenser water pumps were off – it was anarchy. We dug into the system and found that none of the control points were mapped to the front-end of the BMS! Someone had gone through all the trouble of installing controls, wiring the equipment, writing the programs, and creating the graphics but forgot to confirm that the controls were communicating with the equipment. If the project had had proper functional testing initially, this would have been caught while the controls contractor was still on board and the corrections could have been made at no additional cost to the owner.
However, because the issue had been left to linger for so long, the owner had to hire a new controls contractor to complete the project.
Another retro-commissioning project reminded us of the value of operator staff training. See the steam boiler below? The close-up is a picture of steam leaking out of the top of the boiler. The building staff believed this was standard operating procedure.
The building staff was also never shown the secondary heating hot water pumps, so it wasn’t too surprising to learn that those pumps weren’t operating. No wonder the tenants were cold! Commissioning agents make a point to verify that building staff have been trained by the contractors on all equipment before assuming responsibility in order to prevent these types of problems.
Take a look at the picture of the steam to hot water heat exchangers for the domestic hot water plant below. Notice anything wrong? Those are plate and frame heat exchangers. Most plate and frame heat exchangers are not rated for use with steam, and these were no exception. (Note that you can’t see the three inches of water covering the surrounding area!). We looked into the issue and, sure enough, the design drawings showed shell and tube heat exchangers had been specified. Had a commissioning agent been on board to review the submittals, this heat exchanger issue could have been avoided before the equipment even appeared onsite. Instead the owners had to pay for maintenance, excess steam consumption, and the eventual replacements.
ASHRAE 90.1 – The American Society of Heating, Refrigerating and Air Conditioning Engineers’ Energy Standard for Buildings except Low Rise Residential.
IECC – International Energy Conservation Code.
IGCC – International Green Construction Code.
LEED – Leadership in Energy and Environmental Design.
NGBS – National Green Building Standard.
NYSERDA – New York State Energy Research and Development Authority. NYSERDA offers a wide variety of incentives throughout New York.
PSEG – Electric and Gas Utility operating in Long Island and New Jersey. PSEG offers incentive programs to new and existing customers.
Contact us to find out which codes and standards apply to your project and what incentive programs you qualify for!