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Retrocommission for a Better Building
Want to improve your building’s performance but don’t know where to start? Use existing building commissioning (EBCx) to shine a spotlight on inefficiencies and create a list of improvement options.
Whether your building is 5 or 50 years old, chances are the property has been modified over time – changes to interior layout, shifts in occupancy, or structural alterations. These adjustments can weaken performance by slowly chipping away at energy usage, water consumption, equipment life, and occupant comfort.
“The purpose of existing building commissioning is to use a structured process to confirm that the building is operating in a manner that meets the current facility requirements,” explains Paul Levy, a certified commissioning professional with Kirlin Mechanical Services, a subsidiary of the John J. Kirlin Group.
As part of the performance investigation, EBCx also reveals no- and low-cost strategies that will help you resolve weaknesses in your building systems.
Is Your Facility Compatible?
Many owners are familiar with commissioning, a process that verifies a new building operates according to the design plans. Existing building commissioning, commonly referred to as retrocommissioning, uses a similar approach to ensure that a property’s operations support its current needs. EBCx evaluates performance regardless of the facility’s original design or whether commissioning has been performed in the past.
EBCx is compatible with virtually all building types and ages, particularly those that are older or are large consumers of energy and water. According to the EPA’s ENERGY STAR Building Upgrade Manual, facilities that experience
persistent equipment and system failures or encounter continuous complaints about occupant comfort are strong candidates. Those without obvious explanations for a low ENERGY STAR performance rating or a high energy use index can also benefit.
“Just because a building is new or uses efficient equipment doesn’t mean that it’s performing well,” stresses Alena Hutchison, an environmental protection specialist with the EPA and coordinator of the 2012 National Building Competition.
Not sure if your building could benefit? ENERGY STAR outlines these key factors that impact performance:
- Changes in room equipment or furniture that can affect heating and cooling
- Shifts in occupancy patterns or space layouts
- Equipment that is short cycling or has frequent failures
- Significant build-out projects
- HVAC and lighting controls adjusted by occupants.
Note that EBCx won’t replace the need for renovation nor can it address a significant backlog of deferred maintenance, says Mark Miller, a principal with Strategic Building Solutions and president of the Building Commissioning Association (BCA).
Tackle these projects first and then use retrocommissioning to establish a new baseline and refine operations.
Use EBCx to Your Advantage
Retrocommissioning is a valuable FM tool because it focuses on improvements that cost little to no money. Those that need funding often have paybacks of two years or less. Fixable issues typically include simultaneous heating and cooling, excess lighting, improper building pressurization, ineffective VFD settings, and broken economizers.
But these trouble areas are often hidden, overlooked, and take time to discover. It’s easy to look at a CFL and say it’s time to upgrade to an LED, but how can you decipher whether your HVAC adequately supports your operational needs? EBCx helps you tackle those tough questions.
It’s important to recognize that an energy audit is a separate undertaking from EBCx. Commissioning is a whole-building approach that reviews and tests the interactions between all systems, whereas audits are narrowly focused on energy consumption, explains Levy, who also serves on the ASHRAE committee for its Commissioning of Existing Buildings guidelines.
Energy audits are a great way to address your utility bills, but they won’t cover O&M practices, equipment life, or occupant productivity. EBCx, on the other hand, can uncover opportunities to improve water conservation, sustainability, lighting, life safety, security, and data infrastructure.
EBCx also eschews large-scale investment projects or equipment upgrades in favor of strategies that augment existing resources.
“Unlike the expensive capital retrofits that are typical with energy audits, EBCx allows owners to focus on low-cost repair and optimization opportunities,” adds Miller. PageBreak
How to Start the Process
The first step is to work with a commissioning authority (CxA) – this is not an in-house investigation you perform during spare moments. You need a dedicated individual who has the time and expertise to root around your building for inefficiencies in all system types.
To start the process on the right foot, you and your CxA should benchmark your building using a tool such as Portfolio Manager.
“Benchmarking can help you understand how your building is currently performing,” Hutchinson recommends. “It’s important to establish a baseline so you can track the improvements from retrocommissioning. You can quantify your success if you have a before and after snapshot.”
To ensure your baseline is accurate, complete scheduled preventive maintenance beforehand, Hutchinson advises. Otherwise, the process can be delayed by simple maintenance issues, such as dirty filters, worn out belts, broken dampers, or loose electrical connections.
You also need to be conscious of time. If you condense the process too much, you could be overlooking some of the savings you’re trying to find in the first place. “Commissioning is a process, not an event,” stresses Levy.
Because EBCx is a collaborative process, anticipate how much time your FM staff will need to be involved. To encourage participation and buy-in, have them work with the CxA only a few days a week to accommodate their busy schedules, Levy recommends.
“O&M staff should be actively involved throughout the testing and evaluation process because changes made after retrocommissioning will impact their operations,” Miller explains.
Owners should also consider the time of year they initiate EBCx. “If you’re commissioning your HVAC system, it’s ideal to review and test system performance in both the heating and cooling season as well as in-between periods,” Miller adds. “It’s difficult to commission a chiller in the winter when it’s not running.”
Using operating documents you provide (see sidebar), the CxA will then establish your current performance and generate a list of improvement options.
An average-sized facility may need days or a few weeks to assess the building, but the implementation phase could stretch out over months. Suggested projects aren’t generally time-intensive, but they should be completed in an order that accounts for the impact on other systems, Levy says.
“When a staged approach is adopted and performed sequentially, each stage includes changes that will affect the upgrades performed in subsequent stages,” notes the ENERGY STAR Building Upgrade Manual, “setting up the overall process for the greatest possible energy and cost savings.”
Once your improvement projects have been completed, stay on top of performance so your building won’t drift off course.
“Avoid snapbacks – you don’t want to lose the efficiencies that you’ve gained,” Hutchinson says. “To ensure that your benefits remain in place, update your policies and procedures for O&M. You also need to train the building staff on any new or revised operating guidelines.”
“You should also plan for ongoing commissioning,” Miller advises. “This can include periodic commissioning activities scheduled with the work order systems, regular performance benchmarking, and the use of automated fault detection technology.”
Facility managers who apply the EBCx process have much to gain as they root out inefficiencies, poor performance, and malfunctioning equipment. It spurs operators to refine and improve what they already have in place – the ultimate form of sustainability.
Jennie Morton firstname.lastname@example.org is associate editor of BUILDINGS.