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NFPA 72 ?

RJJ

RJJ

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This is an area I have struggled with for a long time for complete understanding. NFPA 72 in section A.5.8.2.1 speaks to radiant energy from a flame ..... etc. How does one determine if the best protection for a given fuel type is being provided from the detectors about to be installed. What are the best types of circuits for response within a detector and how do they vary?
 
Re: NFPA 72 ?

Rjj:

The ambient conditions and the environment expected in the area where the UV and IR detection is proposed dictates what the designer should submit. Just like the issues with Photoelectric and Ionization technology, there are limitations with these devices too and the designer needs to know exactly what conditions and environments this type of initiating device is going to be used in so the proper type can be installed based on the sensitivity rating and testing of the device being considered. And the ranges in temperatures and visual wavelength measurements expected for the deisgn scenario can be narrowed down.

You wouldn’t want a detector that responds to heavy carbon signatures where one that responds to an alcohol flame signature is needed. Wow, nice topic for a Friday ;)
 
Re: NFPA 72 ?

FM: I understand that part. How does one distinguish which component is the best for selection. Then which ones have tested to out pro form others. This seems to me to become very technical when you go in side of the detector and start to examine the unit itself. I don't like leaving it up to just the design guy. Sometimes they are wrong.
 
Re: NFPA 72 ?

When evaluating a system proposal such as this you must have (and I believe you do) a sound understanding of fire behavior associated to chemical compositions, heat release rates, thermal dynamics on compounds when ignited as associated to ambient conditions expected to mention some and far less than I can type in a response. Maybe you could PM one of the FPE's like Haz or AgeisFPE to get a readers digest version.

The detectors themselves will have listing and testing data to show what ranges and fire signatures they respond to and you would have to match that with what ambient conditions and enviornments they are intended to be installed in. At minimim, this should help in determing if the detection scheme is approporate.
 
Re: NFPA 72 ?

FM: The fire behavior part I am ok with. The ranges and listing is understood as well. I guess what I am really look for is from the approval side why one would be approved over another or which that are on the market preform better. Sorta like the Cadillac to the VW. When someone talks pumps or ice cube relays I know from experience. I would figure that not all smokes are equal even though designed for and listed for a certian performance. This understanding could be critical in a given environment.
 
Re: NFPA 72 ?

It comes down to what conditions are to be protected and the listings of the devices for the anticipated conditions and enviornments. As a reviewer, this is what I need to verify, anything beyond that is not within my span of control or scope of authority.
 
Re: NFPA 72 ?

RJJ

Can you look at it like smoke alarms for homes.

1. they have to pass the same ul testing

2. once that is done, then some makers add more bells and whistles that have nothing to do with how well they perform

????
 
Re: NFPA 72 ?

The listing is most likely not going to give you what you are asking for. You are either going to have to find someone you trust that has extensive experience designing or working with those types of detectors and these types of systems or get the information from the manufacturer of the device and compare the literature. They may have tested their device against others, however they most certainly will be prejudiced. Additionally the location of the devices in the building will most likely also affect their performance, this should be discussed in the listing if it is an issue.

I agree with FM, if they are listed for the conditions and the hazard then they should be ok.

Greg
 
Re: NFPA 72 ?

RJJ will check the section you ref.

What was explianed to me and not sure if this is the answer you are looking for.

one detector detects flame and one detector detects flicker.

are you working on a specific project are just trying to get educated
 
Re: NFPA 72 ?

RJJ

I checked the section you referenced.

Do you have a NFPA 72 handbook?? it does have a little commentary.

That is the best I can do for you.

That stuff is above my pay grade, and I rely on the experts to pick the right stuff, and if I have a question about what the experts are telling me, I ask for a tech paper.

Do not know where Haz has been lately, but he should be able to give a good one sentence explanation of what you are asking

I do know the stuff works and is neat to see it work.
 
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