Lighting

Your questions answered with Michael Chow: Holistic lighting systems

Learn more about holistic lighting systems in this Q&A with Michael Chow

By Michael Chow, PE, CxA, LEED AP BD+C August 19, 2021
Courtesy: Consulting-Specifying Engineer

Get additional feedback from Michael Chow, PE, CEM, CxA, LEED AP BD+C, Principal, Metro CD Engineering LLC, Columbus, Ohio.

Codes, standards and research require lighting engineers to consider daylighting, high-quality lighting products, controls and commissioning in lighting designs to achieve a holistic design that meets the needs of the building occupants. Requirements for lighting become more complex with each edition of the energy conservation codes.

Codes and standards include ASHRAE Standard 90.1: Energy Standard for Buildings Except Low-Rise Residential Buildings, the International Energy Conservation Code and California Title 24.

When reviewing lighting drawings, is it required to ask for COMcheck?

Michael Chow: Yes, because the lighting design needs to meet the COMcheck requirements.

Are there special allowances for lighting controls within industrial areas (outdoors and indoors) including electrical rooms which contain switchgear and other power distribution equipment?

Michael Chow: NFPA 70: National Electrical Code 110.26 (D) states illumination shall be provided for all working spaces about service equipment, switchboards, switchgear, panelboards, or motor control centers installed indoors. Control by automatic means (such as occupancy sensors) shall not be permitted to control all illumination within the working space. The working space is defined in NEC Table 110.26(A)(1). The NEC requires a manual control (such as a simple light switch) to control lighting in these areas. This is to prevent the lighting in these areas from being turned off inadvertently by automatic controls. For example, if there was someone working on switchgear while energized, the automatic controls may malfunction and turn the lights making it a safety issue.

How often is tunable lighting actually used by the end user? In an open office setting, it will be difficult to make all occupants happy and can be quite a distraction.

Michael Chow: It is typically considered good practice to have the same color temperature in adjacent areas. In my experience, most owners want the color temperature for the electric lighting the same for each space, room, etc. for an entire building or floor. However, tunable lighting can have health benefits such as circadian rhythm. Tunable lighting that changes the color temperature to match the sunlight color temperature during sunrise, sunset and the periods in-between has proven to help patients heal faster in healthcare facilities.

Courtesy: Consulting-Specifying Engineer

Courtesy: Consulting-Specifying Engineer

Can lighting installed in TI spaces under a core and shell project ever be considered temporary? The lighting would be hardwired and not expected to be in place for longer than 90 days.

Michael Chow: Most TI spaces built under a core and shell have minimal lighting that usually is for code and/or security. The tenant typically changes the lighting fixtures installed under the core and shell.

Is ASHRAE/COMcheck not needed if a certain percentage of lights in a remodel are not affected?

Michael Chow: It depends on the version of ASHRAE 90.1 being used. Starting with ASHRAE 90.1-2010, if 10% of the connected lighting load in a space or area need not comply with the provisions of 90.2-2010 if the modifications do not increase the installed lighting power density. The 10% limitation is stricter that previous versions of ASHRAE 90.1-2010.

What are the control strategies for utility rooms and for restrooms?

Michael Chow: If a restroom is for a single occupant, then a dual technology (example: PIR and ultrasonic) ceiling-mounted occupancy sensor should suffice. If the restroom has multiple stalls, then multiple sensors positioned such that the sensors minor movement coverage overlap with no gaps. I recommend that you consult the sensor manufacturer or representative to ensure the designed location of the sensors will overlap. PIR is typically used to sensor someone entering a restroom and will turn the lights on. PIR cannot “see” through restroom stalls; the ultrasonic technology uses sound waves to “see” into stalls and detects movement to keep the lighting on or off.

A utility room typically is small and could have just one occupancy sensor. The sensor does not necessarily need to have more than one technology as usually occupants are not in the room long.

A larger utility room should have multiple sensors to ensure major and minor movements coverage overlap.

Are you aware that all IES lighting references have gone digital and the Handbook will no longer be published?

Michael Chow: The IES library was recently released and is online. The Handbooks have been discontinued as they were published infrequently. From the IES, “The goal was to electronically transform this large volume of information into an easy to access, easy to navigate, easy to update, and easy to customize online platform. Now all of the IES current standards are in one place, without limits, and always up-to-date…”


Michael Chow, PE, CxA, LEED AP BD+C
Author Bio: Michael Chow is the founder and President of Metro CD Engineering. He holds a BSEE from Ohio Northern University and is the current Chair of the university’s Engineering Advisory Board, a member of the Consulting-Specifying Engineer editorial advisory board and a 2009 40 Under 40 winner.