Proper method to measure Foot Candles

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mjf

mjf

Senior Member
Location
The incredible, yet very expensive, Hudson Valley,
This is what the NYS Banking Authority has to say:

With respect to outside ATMF:
(a) A minimum illuminance of five (5) footcandles at five feet from an ATM.
(b) A minimum illuminance of two (2) footcandles in all unobstructed directions
from an ATM at 30 feet.
(c) A minimum illuminance of one (1) footcandle at 60 feet in all unobstructed
directions from an ATM, measured on a vertical plane and pointed at the
light source.
? With respect to indoor ATMF:
(a) A minimum illuminance of two (2) footcandles in all unobstructed directions
from a facility at 30 feet.
(b) A minimum illuminance of one (1) footcandle at 60 feet in all unobstructed
directions from a facility, measured on a vertical plane and pointed at the
light source.

My question is regarding the highlighted portion....do I need to measure this at grade level?

I guess I'm going to answer my own question and tell myself that I need to get my answer directly from the NYSBA inspectors.

Still interested in what the consensus on here is.
 
Smart $

Smart $

Esteemed Member
Location
Ohio
mjf said:
...

Still interested in what the consensus on here is.
Click to expand...
It says in all unobstructed directions from the facility (the ATM, I assume). Unless the ATM and customers are over 30 feet off the ground :p, illuminance at ground level is within the 30-foot radius bubble.

BTW, post #3 says outdoor while post #4 highlights an indoor requirement.
 
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mjf

mjf

Senior Member
Location
The incredible, yet very expensive, Hudson Valley,
Smart $ said:
It says in all unobstructed directions from the facility (the ATM, I assume). Unless the ATM and customers are over 30 feet off the ground :p, illuminance at ground level is within the 30-foot radius bubble.

BTW, post #3 says outdoor while post #4 highlights an indoor requirement.
Click to expand...


hahaha...I guess the "attacker" could be crawling across the parking lot!!;)

? With respect to indoor ATMF:
(a) A minimum illuminance of two (2) footcandles in all unobstructed directions
from a facility at 30 feet.

They are referring to the cubicle ATM's that are accessible 24hrs a day and talking about the OUTDOOR illumination 30 and 60 feet FROM A FACILITY:)
 
Smart $

Smart $

Esteemed Member
Location
Ohio
The specs don't say at what height. Typically when it is regarding overhead lighting, measurements are taken at grade level.
 
mjf

mjf

Senior Member
Location
The incredible, yet very expensive, Hudson Valley,
Smart $ said:
The specs don't say at what height. Typically when it is regarding overhead lighting, measurements are taken at grade level.
Click to expand...

The NYS banking authority doesn't care if it's overhead lighting, side lighting, up lighting or any other lighting we could come up with....as long as the FC are sufficient.


It's become a moot point.....Bank says today........"just add more lights" :)
 
N

Next Generation

Member
Location
Birmingham Alabama
mjf said:
The NYS banking authority doesn't care if it's overhead lighting, side lighting, up lighting or any other lighting we could come up with....as long as the FC are sufficient.


It's become a moot point.....Bank says today........"just add more lights" :)
Click to expand...

I have done work for banking locations all over the southeast doing exactly what you are doing. The directions I got was to take the FC readings at 36" above grade. I hope this helps.
 
G

GerryB

Senior Member
Location
woodbridge, ct. USA
Lumens and footcandles

Lumens and footcandles

This post got me thinking because I have a small light meter that measures lumens and i was thinking what's the difference.

  • A lumen quantifies the brightness of a light in metric measurement. The amount of light energy reflecting from the surface of a sphere one meter in diameter surrounding a candle---now the standardized "candela" international unit--equals one lumen. A low-light source, such as a nightlight, might measure 12 lumens, while a 100-watt light bulb measures 1200 lumens.
    In contrast, one footcandle of light is the measurement of the illumination which one candela provides on a surface one foot away from the source. A footcandle is a measurement of energy in non-metric terms. By converting lumens (one square meter worth of illumination) to footcandles (the illumination one foot away from the source), you are essentially measuring the same thing. The conversion formula is footcandles x 10.76=lumens.

 
Smart $

Smart $

Esteemed Member
Location
Ohio
GerryB said:
This post got me thinking because I have a small light meter that measures lumens and i was thinking what's the difference.

  • A lumen quantifies the brightness of a light in metric measurement. The amount of light energy reflecting from the surface of a sphere one meter in diameter surrounding a candle---now the standardized "candela" international unit--equals one lumen. A low-light source, such as a nightlight, might measure 12 lumens, while a 100-watt light bulb measures 1200 lumens.
    In contrast, one footcandle of light is the measurement of the illumination which one candela provides on a surface one foot away from the source. A footcandle is a measurement of energy in non-metric terms. By converting lumens (one square meter worth of illumination) to footcandles (the illumination one foot away from the source), you are essentially measuring the same thing. The conversion formula is footcandles x 10.76=lumens.
Click to expand...
Makes me wonder how it ever got to be a standard. If you ask me, they keep forgetting to specify a lit candle... :p
 
G

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
That article is so full of errors that I would say that it is even worse than the average eHow article.
You cannot convert between footcandles and lumens because they measure different things. You can convert between footcandles and lux. And that conversion factor is 10.xx.
The lumen is a measure of how much light a source produces, whether it is omnidirectional or focused, and regardless of the distance at which you measure it.
A light with an output of 100 lumens (not at all uncommon for an LED flashlight) can provide a useful amount of light within a 10 meter sphere if it is omnidirectional or a lot brighter light at 100 meters if it is tightly focused.
The lux is a measure of the intensity of the resulting light at the target. The ability of a camera to get a decent image will depend on the lux level at the target or environment it is looking at.
The lumen is a measurement of energy, while the footcandle and lux are measures of energy hitting a unit area.
A light meter measures lux.
An integrating sphere measures lumen output.

Sent from my XT1080 using Tapatalk
 
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mgookin

mgookin

Senior Member
Location
Fort Myers, FL
weressl said:
Required illumination levels are given at working plane, eg. ~3' above finished floor for most general areas.
Click to expand...

And what's the orientation of the sensor? Do you aim it straight up, towards the luminaire, facing the ATM, facing the camera, or in some other direction?
 
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