Fire Alarm Strobe Light Meter

[jcarter238]

Does anyone know if a meter exist to test the lumen output from a Fire Alarm strobe light? If so where?

[nhfire77]

http://[URL="http://www.southern-tool.com/store/Pacer_DL1076_Light_Meter.html"]

Then you can convert footcandles to candela. I don't know how.

Of course you would have to perform the test in a totally dark room.

Why do you need to? If the strobe is UL listed, then you should be able to calcuate the minimum candala output for the area. Of course odd shaped spaces are not easy but its not too hard if you have a scaled CAD drawing

[nhfire77]

Oh I misread.... Lumens?

What is that for? Is that an international requirement? I thought candela was the US standard for strobes.

[gar]

090130-1655 EST

jcarter238:

Do you need to know the peak light output or the average? I assume peak.

I do not believe the meter referenced by nhfire77 will measure peak intensity.

You could create one yourself. Use a photo diode and an oscilloscope. Calibrate with an average reading meter on a steady state source. The spectral response of the detector will be important.

.

[nhfire77]

I doubt it does peak either, I didn't think of that.

I am still wondering why its needed, isn't the product documentation enough?

[480sparky]

....Then you can convert footcandles to candela. I don't know how.. ....

You click here (http://www.unitconversion.org/illumination/foot-candles-to-candela-steradians-per-square-meter-conversion.html).

[gadfly56]

090130-1655 EST

jcarter238:

Do you need to know the peak light output or the average? I assume peak.

I do not believe the meter referenced by nhfire77 will measure peak intensity.

You could create one yourself. Use a photo diode and an oscilloscope. Calibrate with an average reading meter on a steady state source. The spectral response of the detector will be important.

.

Well, you could give it a shot. However, you would have to have some idea as to the intensity vs. time curve for the strobe and be sure that the photo diode had a much shorter response time than the rise-and-fall curve for the strobe output. Then you're talking about NIST-traceable calibration and a level of knowledge regarding photometrics that is well up in the PhD range. Not to mention that your gear, once set up, is likely to be very unportable.

I hope this is idle curiosity and not some AHJ actually expecting you to do this?

[dhalleron]

I have been doing fire alarms since the early 90's and never have found this meter you speak of. There are light meters available, but none that I know of listed for testing a fire alarm strobe. I’m sure there is a meter that UL uses when they evaluate the strobes, but I’ve never seen a manufacturer selling one for field use.

NFPA 72 even requires certain things of a sound meter that leaves out the cheap Radio Shack meter when testing the horns, but does not seem to mention requirements for testing the strobes.