Lighting controls and ASHRAE 90

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lile001

Senior Member
Location
Midwest
I've been looking into the ASHRAE 90 energy code, which is mandatory in some jurisdictions. Under lighting, it states the following:

9.2 Mandatory Provisions
9.2.1 Lighting COntrol
9.2.1.1 Automatic Lighting Shutoff. Interior lighting in buildings larger than 5000 sq ft shall be controlled by an automatic control device to shut off building lighting in all spaces. This automatic control device shall function on either
(a) a time of day operated device ......
(b) an occupant sensor .....
(c) by occupant intervention

There are of course exceptions for emergency lights and some other situations.

Now I am taking this to mean that relay control panels are now required in commercial buildings. The "occupant intervention clause" doesn't just mean a little wall switch, it means that the occupants can turn the lights on and off but the relay panel is the device controlling the lights.

Am I reading this right? Are other people seeing relay panels installed routinely as a result of ASHRAE 90?
 

iwire

Moderator
Staff member
Location
Massachusetts
Re: Lighting controls and ASHRAE 90

Originally posted by lile001:
Are other people seeing relay panels installed routinely as a result of ASHRAE 90?
I see many of them or simply motion sensors directly operating the circuits.

I do not know if is a result of ASHRAE 90.
 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
Re: Lighting controls and ASHRAE 90

The "occupant intervention clause" does mean a little wall switch. But how that wall switch accomplishes its job is up to the designer. You could wire it such that the "off" position turns the lights off regardless of the condition of all other control devices, but that the "on" position only works if the occupant sensor sees people in the space.

A relay panel is the best way I know of to control the lights. You can wire the light switches, the occupant sensors, and any timing devices to the same relays. I have issued a few designs that use relay panels, and they seem to have been effective.
 

jtester

Senior Member
Location
Las Cruces N.M.
Re: Lighting controls and ASHRAE 90

Those requirements are consistent with the International Energy Conservation Code. In the IECC, occupant intervention is often a manual time switch that shuts itself off after a predetermined interval. In the IECC, you can use occupancy sensors and avoid the time clock scenario.

The IECC has a great document with commentary. It gives much insight into what these terms mean in practical applications. You might turn to it for help.

Jim T
 

bwyllie

Senior Member
Location
MA
Re: Lighting controls and ASHRAE 90

relay panel is not required but rather another means to accomplish the automatic turnoff.
 

lile001

Senior Member
Location
Midwest
Re: Lighting controls and ASHRAE 90

Originally posted by bwyllie:
relay panel is not required but rather another means to accomplish the automatic turnoff.
So besides motion sensors, and windup timers, what other means for automatic shutoff are available? I can see using the relay panel approach, are there other means to accomplish the intent of the code?
 

sceepe

Senior Member
Re: Lighting controls and ASHRAE 90

So besides motion sensors, and windup timers, what other means for automatic shutoff are available? I can see using the relay panel approach, are there other means to accomplish the intent of the code?
Here's an idea, run lights though a lighting contactor and let the security system switch the contactor when it is armed. No one can be in the building with the security system armed. In the morning, walk in type in security code, and boom building lights come on.

Another option, let the building's energy management system do it. A sophisticated system runs A/C differently at night. It can also turn off the lights. Owner is already paying a controls contractor to maintain the system so you have a trained person for the lighting controls. Problem with a relay switch panel system is no one knows how to program it.
 
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