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Lighting system retrofits are often touted as one of the lowest hanging fruits in a facility in terms of potential energy savings. After a major retrofit of the lighting system at your facility, you may be tempted to just flip the switch and call it a day. But going through the additional step of commissioning the lighting system can yield unexpected savings, or at the very least make sure the system delivers the savings it promised.
At a recent trade show for lighting specifiers, James Donson, senior engineer with kW Engineering, detailed the benefits of commissioning lighting systems. For one, very few lighting projects have an owners project requirements document (OPR), which is different than programming documents. If an OPR is not already established, the information can be captured and verified during the commissioning process.
An OPR covers:
- Who the occupants are
- What kinds of tasks are undertaken in the space
- Minimizing lamp types
- Desired level of control
- Integration goals
- Documentation goals
Commissioning covers the gaps between design intent, physical installation and operational goals. For example, Donson gave an anecdote where a design specified PIR sensors but the contractor decided to swap them out for dual criteria sensors. What the contractor failed to understand was that the facility's white noise system would trigger the sensors, which then caused the lights to operate continuously.
Here are some common issues often discovered through commissioning:
- Occupancy sensors: not put on drawings, don't have dwell schedules specified, are set to auto 100 percent on (which needlessly consumes energy as often occupants can get by on a lower setting as long as they have an option to increase levels as needed), improperly applied to space
- Daylighting: zones not indicated, sensors not on drawings, no time clock or override schedule, no sweep schedule, mismatched models
- Overly long overrides for maintenance/night cleaning
One tip Donson suggested was to request the prefunctional test results for a recent project when selecting lighting contractors. Seeing how many items failed will be the proof in the pudding for whether or not the contractor can deliver the services and systems as promised.