NFPA 101 - Emergency lighting for designated egress stairs 2

[Calador]

Hi,

What is performance for the emergency lighting in designated egress stairs? Is it 10.8lux or 108lux.

7.8.1.3* The floors and other walking
surfaces within an exit and within the
portions of the exit access and exit
discharge designated in 7.8.1.1 shall be
illuminated as follows:
a. During conditions of stair use, the
minimum illumination for new stairs
shall be at least 10 ft-candle (108 lux),
measured at the walking surfaces.

7.9 then talks about the emergency lighting which states a minimum of 10.8 lux.

What are your thoughts on this?

Thanks.

 

[Calador]

Oh yeah, just need to add that I am interested in finding out how to achieve the 108 lux using self contained battery packs not a central battery system.

 

[cdafd]

Cannot answer the second question

But read the main section of 7.8 and 7.9 that should answer your first question

 

[stookeyfpe]

Every manufacturer of a luminare provides a lumen output chart or graph for their equipment. Lots of equipment is available that is unit powered (see NEC Article 700) that can be used to construct a code compliant system.

 

[Calador]

Apologies for not stating my question clearly in the first place.

let me start fresh.

Section 7.8 talks about the illumination of egress routes. It doesn't state whether it is under normal or emergency (mains power failure mode). It goes on to state that stairs need to be illuminated to 108 lux.

This is easily achievable using mains powered luminaires but as soon as you switch to emergency self contained mode, the ballast factor drops the output to something in the order of 7-10%.

This is where I start to question whether the 108 lux is meant for during normal conditions (mains healthy) and is superseded by Section 7.9 when there is a mains failure.

Section 7.9 allows illumination levels of at least 10.8 lux. This is more achievable when considering using self contained emergency light fittings.

If we were to comply with section 7.8 during mains failure, we will either need a lot of these self contained emergency light fittings which are located very close to the floor (do not agree with this) OR we use a central battery system (DC-DC or DC-AC system).

So the big question is: When there is a mains failure, are we required to illuminate the stairs to 108 lux or only 10.8 lux. Please support your argument.

Thanks.

 

[Sdpaddler50]

"Please support your argument." Would you like an invoice with our support as well?

 

[DRWeig]

It's 11 lux when mains power is gone, if you're under the IBC or NFPA 101. Section 7.8 of NFPA 101 refers to normal operasion (mains power is ON). Section 7.9 refers to emergency lighting (mains power is OFF).

So, during the normal day (mains power ON), new stairs must have 10 fc (108 lux) on all walking surfaces.

The IBC is more clear, in the section on emergency egress lighting (power is OFF):1006.2 Illumination level. The means of egress illumination level shall not be less than 1 foot-candle (11 lux) at the walking surface level.

You'll need to do your lighting calculations to determine the type of battery-powered unit, the wattage, the location, and the aiming.

Best to you,

Goober Dave

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