Interested in Emergency Lighting Control?

Very interesting. Probably beyond the scope of the typical theatre LD or electrician operating the gear, and also beyond the abilities and scope of the building maintenance people dealing with it on a day to day basis, but good info to keep in mind for all of us.
 
That was fascinating. Having been deeply involved with 2 system renovations as well as the design of a new facility, this subject was something I became conversant in to a much less knowledgable level than the participants, but found it fascinating to learn some of the history, as well as see how complex an issue this is.

To Steve a thanks for posting.
 
Is this where I sidetrack the conversation with my note on a 90k square foot convention center wherein they faked the emergency lighting controls; as well as in the adjacent 9000 seat arena? (Wish I was joking)
 
Surely there either is (or could easily be,) in a DMX controlled house light luminaire, a control which sez "If DMX goes tro 0000, goto 10".) then place within the luminaire a double throw relay, coil powered by "normal" power, which switches power to the luminaire from "normal" to "emergency" when "normal" power fails. This relay would also disconnect the normal DMX control from the luminaire. Should normal power fail for any reason, as soon as generator power becomes available, the luminaire would go to "full on." Thougts?
 
Surely there either is (or could easily be,) in a DMX controlled house light luminaire, a control which sez "If DMX goes tro 0000, goto 10".) then place within the luminaire a double throw relay, coil powered by "normal" power, which switches power to the luminaire from "normal" to "emergency" when "normal" power fails. This relay would also disconnect the normal DMX control from the luminaire. Should normal power fail for any reason, as soon as generator power becomes available, the luminaire would go to "full on." Thougts?

I suspect its easier to have a transfer where the control sense loss of normal power than sends DMX @Full values to fixtures. My Unison dimmer pack did exactly that.
 
Surely there either is (or could easily be,) in a DMX controlled house light luminaire, a control which sez "If DMX goes tro 0000, goto 10".) then place within the luminaire a double throw relay, coil powered by "normal" power, which switches power to the luminaire from "normal" to "emergency" when "normal" power fails. This relay would also disconnect the normal DMX control from the luminaire. Should normal power fail for any reason, as soon as generator power becomes available, the luminaire would go to "full on." Thougts?

You can't really guarantee data loss in every case there might be a power loss. Consoles, network switches, and architectural lighting controllers are all likely to have battery backups in a well-designed system. You also have to allow for inputs from the fire alarm system or other emergency systems. All of those cases need a way to reliably override any other sources of control and make sure the emergency lights are doing what they're supposed to do. "Reliably" typically means a UL924 listed emergency device such as ETC's DEBC.
 
That's why I suggested "Surely there either is (or could easily be,) IN A DMX controlled house light luminaire, a control which sez "If DMX goes tro 0000, goto 10."

The luminaire itself generates the "GO TO FULL" command when the external DMX signal is not present for any reason. This command, and the luminaire's full output goes to full when emergency power appears.
 
That's why I suggested "Surely there either is (or could easily be,) IN A DMX controlled house light luminaire, a control which sez "If DMX goes tro 0000, goto 10."

The luminaire itself generates the "GO TO FULL" command when the external DMX signal is not present for any reason. This command, and the luminaire's full output goes to full when emergency power appears.

Sure, but then you're doubling the total power wiring required and also making each individual fixture more complex & expensive. It's much simpler to have the emergency fixtures get power from a single normal/emergency feed, and put all the complexity of deciding when an emergency is happening into one device rather than replicating it across many fixtures.

Also, your exact approach describes a transfer between normal and emergency power--which means each fixture needs to be UL1008 listed instead of UL924. That would add even more expense that could be avoided if the fixtures are always powered from the emergency feed and just use the normal feed for sensing a power failure (instead of actually transferring between normal and emergency power). At that point, though, you're most of the way back to my suggestion, except you still have more expensive fixtures and an extra run of normal power to each of them.
 
From the 2023 NEC:

700.24 Directly Controlled Emergency Luminaires.
Where emergency illumination is provided by one or more directly controlled emergency luminaires that, upon loss of normal power, respond to an external control input to establish the required emergency illumination level, such directly controlled emergency luminaries shall be listed for use in emergency systems. Luminaires that are energized to the required emergency illumination level by disconnection of their control input by a listed emergency lighting control device shall not be required to be listed for use in emergency systems.

and:

700.25 Branch Circuit Emergency Lighting Transfer Switch.
Emergency lighting loads supplied by branch circuits rated at not greater than 20 amperes shall be permitted to be transfer⁠red from the normal branch circuit to an emergency branch circuit using a listed branch circuit emergency lighting transfer switch. The mechanically held requirement of 700.5(C) shall not apply to listed branch circuit emergency lighting transfer switches.

ST
 
From the 2023 NEC:

700.24 Directly Controlled Emergency Luminaires.
Where emergency illumination is provided by one or more directly controlled emergency luminaires that, upon loss of normal power, respond to an external control input to establish the required emergency illumination level, such directly controlled emergency luminaries shall be listed for use in emergency systems. Luminaires that are energized to the required emergency illumination level by disconnection of their control input by a listed emergency lighting control device shall not be required to be listed for use in emergency systems.

and:

700.25 Branch Circuit Emergency Lighting Transfer Switch.
Emergency lighting loads supplied by branch circuits rated at not greater than 20 amperes shall be permitted to be transfer⁠red from the normal branch circuit to an emergency branch circuit using a listed branch circuit emergency lighting transfer switch. The mechanically held requirement of 700.5(C) shall not apply to listed branch circuit emergency lighting transfer switches.

ST
Steve, I'm suffering from Codespeak translation issues so could use some help with my home work ;)

The text in red parses to "if the control disconnection device" is Listed as ELCD, the fixtures (luminaires) can be listed for other, non-emergency use. The text would preclude luminaires and/or non-ELCD Listed controllers that autonomously decide if an emergency exists simply because they lost DMX.

Code: the fewest words to make the most difference. Not a bad thing but not always intuitive in its impact.
 
Steve, I'm suffering from Codespeak translation issues so could use some help with my home work ;)

The text in red parses to "if the control disconnection device" is Listed as ELCD, the fixtures (luminaires) can be listed for other, non-emergency use. The text would preclude luminaires and/or non-ELCD Listed controllers that autonomously decide if an emergency exists simply because they lost DMX.

Code: the fewest words to make the most difference. Not a bad thing but not always intuitive in its impact.

Thats how I read it Tim. As per Steves YT, it simplifies for the manufacturer that that there is no need to make the fixture emergency capable as the control and ELTS handle getting emergency over-ride control and power to any fixture the architect and engineers decide to use. At least thats how I understand it. Not that I'll ever do anything think with this information.
 
Steve, I'm suffering from Codespeak translation issues so could use some help with my home work ;)

The text in red parses to "if the control disconnection device" is Listed as ELCD, the fixtures (luminaires) can be listed for other, non-emergency use. The text would preclude luminaires and/or non-ELCD Listed controllers that autonomously decide if an emergency exists simply because they lost DMX.

Code: the fewest words to make the most difference. Not a bad thing but not always intuitive in its impact.
The key is that 700.24 requires a physical disconnection of the control input by a Listed ELCD, in order to exempt the luminaire itself from an emergency UL924 Listing.

ST
 
Sure, but then you're doubling the total power wiring required and also making each individual fixture more complex & expensive. It's much simpler to have the emergency fixtures get power from a single normal/emergency feed, and put all the complexity of deciding when an emergency is happening into one device rather than replicating it across many fixtures.

Also, your exact approach describes a transfer between normal and emergency power--which means each fixture needs to be UL1008 listed instead of UL924. That would add even more expense that could be avoided if the fixtures are always powered from the emergency feed and just use the normal feed for sensing a power failure (instead of actually transferring between normal and emergency power). At that point, though, you're most of the way back to my suggestion, except you still have more expensive fixtures and an extra run of normal power to each of them.
Some UL924-Listed Directly Controlled Emergency Luminaires have a "built-in ALCR". In this case, the luminaire has two power inputs:

1. Normal/Emergency power fed by an upstream transfer switch. The luminaire is always fed by this input--in both normal and emergency conditions.
2. Normal-only power sense. This is used as a sense input only. When this drops, the internal ALCR bypasses normal control. The luminaire is never fed from this input.

An example of this type of Directly Controlled Emergency Luminaire and its emergency wiring layout can be found here:

In the case above, no UL1008 Listing is required for the luminaire, because there is no transfer function. If one wanted to transfer the luminaire from a normal branch circuit to an emergency branch circuit, the weapon of choice would be a BCELTS, covered by 700.25 (see related post in this thread). Many BCELTS devices also include relay contacts for disconnection of normal control.

ST
 
Thanks, Steve! This has added much clarity. :)
 

Users who are viewing this thread

Back