EM Lighting

[mstrlucky74]

Have a job that's budgetary with a bunch of recessed 2x2's and 2x4's. How would quantify how many lights would have to be emergency lights? Thanks.

 

[USMC1302]

IMO, a design professional would have to ensure the minimum egress lighting levels were met. Photometric data should be available. As far as what those levels are, you best ask the AHJ as different codes NFPA 101, UBC, IBC have been know to be interpreted differently. Typically 1 foot candle initial average is the number I recall

 

[jeremy.zinkofsky]

Have a job that's budgetary with a bunch of recessed 2x2's and 2x4's. How would quantify how many lights would have to be emergency lights? Thanks.

Depends on which lights are for life-safety egress or optional standby.

If for life-safety, you would need to reference the architects life safety plan. The path of egress indicated on that plan needs to be illuminated to at least 1 foot-candle. Many times this is achieved by using wall pack lights rather than the light fixtures themselves. If no wall packs are used, you will need to lean on the engineer to determine which lights need to be on emergency.

Back-up powered lights that are desired but not required per life safety can be anywhere and in any amount. So you could take an arbitrary percentage for a rough order of magnitude cost.

If you are circuiting these fixtures to a generator panel and not providing battery packs within the fixtures, please note that emergency and/or life safety required lights cannot be circuited to the same panel as optional standby lights.

 

[gadfly56]

Have a job that's budgetary with a bunch of recessed 2x2's and 2x4's. How would quantify how many lights would have to be emergency lights? Thanks.

Ballasted lighting with battery backup, right? Most manufacturer's will give you a diagram or graph that gives the cone of minimum illumination for the fixture at a given height. Space the backup units to give you the required illumination along the path of egress (1 foot-candle/11 lux at the walking surface, 1008.2.1, IBC 2015).

 

[jeremy.zinkofsky]

Ballasted lighting with battery backup, right? Most manufacturer's will give you a diagram or graph that gives the cone of minimum illumination for the fixture at a given height. Space the backup units to give you the required illumination along the path of egress (1 foot-candle/11 lux at the walking surface, 1008.2.1, IBC 2015).

An engineer will need to do that calc, not the estimator or contractor. So be careful.

 

[gadfly56]

An engineer will need to do that calc, not the estimator or contractor. So be careful.

It depends on the jurisdiction as to who signs and seals what. From a technical perspective, any lighting supplier should be able to take a reflected ceiling plan and work it out for their customer. There isn't much magic sauce for an engineer to apply.

 

[jeremy.zinkofsky]

It depends on the jurisdiction as to who signs and seals what. From a technical perspective, any lighting supplier should be able to take a reflected ceiling plan and work it out for their customer. There isn't much magic sauce for an engineer to apply.

Totally agree. Just want to make sure everything is kosher from a contractual standpoint. You know how it goes. The moment you put a number on something, you own it and are ultimately the one who gets blamed.

 

[tw1156]

There isn't much magic sauce for an engineer to apply

It all depends on the project in my opinion and when dealing with emergency egress lighting as a life safety issue; it can come back to bite you if done with just placing them where one thinks they should go.

Space the backup units to give you the required illumination along the path of egress (1 foot-candle/11 lux at the walking surface, 1008.2.1, IBC 2015).

That is for normal power. Emergency power only requires an average of 1 footcandle per 1008.3.5 with max/min ratios of 40:1. In my experience, this requires photometric calculations unelss you've used the same fixture in the same scenario (ie corridor of same width, etc). For example, using an emergency egress light that says it can be spaced every 20ft for corridors of width of 5ft may not also be able to work in large auditoriums, etc.

 

[jap]

Have a job that's budgetary with a bunch of recessed 2x2's and 2x4's. How would quantify how many lights would have to be emergency lights? Thanks.

Budgetary means just that. No one has done the work needed to get hard numbers and won't until the project actually becomes serious.

I wouldn't spend too much time thinking about it for a budgetary number.

Throw in however many you feel looks right and clarify.

It'll all change once it gets to the actual design stage anyway.

JAP>

 

[gadfly56]

It all depends on the project in my opinion and when dealing with emergency egress lighting as a life safety issue; it can come back to bite you if done with just placing them where one thinks they should go.

That is for normal power. Emergency power only requires an average of 1 footcandle per 1008.3.5 with max/min ratios of 40:1. In my experience, this requires photometric calculations unelss you've used the same fixture in the same scenario (ie corridor of same width, etc). For example, using an emergency egress light that says it can be spaced every 20ft for corridors of width of 5ft may not also be able to work in large auditoriums, etc.

Fair enough. For budgetary purposes, as jap reminds us, any decent lighting supply house should be able to get you a ballpark figure (-0%, +15%). They all have access to photometric software, I'm sure.

 

[tw1156]

Good point Gadfly...definitely not worth wasting the time to send it out for a full design at this point. I overlooked his original goal and got too deep in the weeds..

 

[gadfly56]

Good point Gadfly...definitely not worth wasting the time to send it out for a full design at this point. I overlooked his original goal and got too deep in the weeds..

Gee, that hardly ever happens around here... :roll:

I confess, I'm as guilty as anyone else on the forum.