Fire Alarm System Design - Contractor Talk - Professional Construction and Remodeling Forum

ABLE1 · 08-08-2008, 09:17 PM

Hey all,

I am being asked to design and install a Fire Alarm System in a new Amish
Woodworking Shop.

Now after all the "Giggles", "Say what's??" and "Gufaahaa's" this ain't no
joke.

On site there will be a generator with AC inverter and a battery bank. At
this point I do not know the amount of time for the battery capacity. In my
opinion I can't rely on that as a 24/7 power source.

I am thinking a Solar Panel with Deep Cycle battery that is sized properly
for load and time.

One of my challenges is to find a panel that will not be in constant trouble
AC Fail. I did an alarm panel years ago like this on a cabin on top of a
mountain and when I fed 12vdc to one of the AC terminals on that particular
panel it tricked the panel out of AC Fail. That panel was not a Commercial
Fire Listed and is no longer manufactured.

Anyone know of a panel today that will do similar or have any other thoughts
on this project???

Thanks for your suggestions.

Les

ABLE1 · 08-09-2008, 08:02 AM

Some more info on this project.

The generator would only be running during normal working hours. (what ever
they are)

I have not talked to the electrician for the job so I am just guessing that
during non working hours the batteries would power the Exit signs and
Emergency Lights and nothing more.

I believe that if it were not for the State Wide Building Code in Pa. this
Fire Alarm this would not be an issue. The building will be all wood
construction and is only about 30' x100' in size. With it being a wood
working shop I can only use Heat Detectors and maybe Pull Stations. Then
some synced Horn/Strobes. By the time a Heat Detectors would go off there
would be a serious fire involved and everyone will be manning the Bucket
Brigade just in time for the Strobes to start flashing.
That would be during working hours. After hours
............................ I just don't know.

Then again I could Ionization Smokes and hope that they don't use dull saw
blades when the cut wood. Lot's of variables that need to get sorted out.

I had someone suggest to just choose a panel and get Tech Support to help with the NO AC TRICK. I was hoping that someone would have already did the trick and knew what panel would work. When I did the cabin this way some years ago it was Moose Z900 and at the time it was just a simple as applying 12vdc to one AC terminal on that panel. As I learned most panels are not set up this way due to diodes being place on most panels. I am not looking forward to making board modifications to trick the AC Fail issue. But, I may have to if that is my last choice.

Thanks to all for your input. (if any)

Have a good weekend.

Les

mdshunk · 08-09-2008, 08:59 AM

In my opinion, there's only one way to do this and not run afoul of UL and other code requirements. Use a life-safety rated inverter transfer switch. Power the normal side of the inverter with the generator, and allow it to transfer to battery (though the inverter to create AC) during the off-hours. Use an inverter such as this one:
http://www.dual-lite.com/resources/inverter_selection/

ABLE1 · 08-09-2008, 10:32 AM

Quote:

Originally Posted by mdshunk

In my opinion, there's only one way to do this and not run afoul of UL and other code requirements. Use a life-safety rated inverter transfer switch. Power the normal side of the inverter with the generator, and allow it to transfer to battery (though the inverter to create AC) during the off-hours. Use an inverter such as this one:
http://www.dual-lite.com/resources/inverter_selection/

Marc,

Thanks for the input. Yes, I agree that the Dual-lite inverter may be the "cats meow" to meet "code". The application of this unit is assuming utility power being the input not a sometimes on utility.

I do have a question or three.

Have you ever installed one of these units?? In this type of application??

In my quick read of the specs, it says that it will supply(output) 115vac at rated load for a period of 90 minutes run-time. Does this mean that there is a timer that 90 minutes after power loss it then shuts down??? If that would be the case then I would think that this would not be good for this application since AC power will only be on while they are in operation. And that may be dependant upon what operation is being performed.

I may be reading this is the wrong way.

It also states that battery recharge takes 24 hours. That may also be an issue since the generator may never run for longer than maybe 8 hours a day.

Thanks again I was hoping you had a trick up your sleeve.

Les

mdshunk · 08-09-2008, 11:03 AM

That 90 minute thing is the rating at full power. Say, for instance, you pick a 1500 watt unit, it's only good for 1500 watts for 90 minutes. I'll do 750 watts for 180 minutes, for instance. Full recharge might take 24 hours, but when properly sized, you might only deplete the charge 1/16th of a full charge, so the recharge would be rather quick. In other words, you're going to have to size for a 16 hour run time and size for an 8 hour recharge. Since I think your fire alarm might only draw a watt at idle, this should be pretty easy. I think you only need to power a horn/strobe event for 60 minutes, if I'm not mistaken.

These emergency light inverters are nothing more than a life-safety rated UPS, just like you might buy for your home computer.

ABLE1 · 08-09-2008, 03:17 PM

[quote=mdshunk;477040]That 90 minute thing is the rating at full power. Say, for instance, you pick a 1500 watt unit, it's only good for 1500 watts for 90 minutes. I'll do 750 watts for 180 minutes, for instance. Full recharge might take 24 hours, but when properly sized, you might only deplete the charge 1/16th of a full charge, so the recharge would be rather quick. In other words, you're going to have to size for a 16 hour run time and size for an 8 hour recharge. Since I think your fire alarm might only draw a watt at idle, this should be pretty easy. I think you only need to power a horn/strobe event for 60 minutes, if I'm not mistaken.

These emergency light inverters are nothing more than a life-safety rated UPS, just like you might buy for your home computer.[/QUOTE

I understand. Given that the power requirements for a given fire panel is for stand by and any charging of on board batteries the load would be quite small. The requirements when in alarm would be handled by the those and not the inverter.

This is good. I will do some calculations and see what will fit. My quick assumption is that I would need to keep the power on for 72 hours as a max for a long weekend type load.

Thanks Marc, I do believe you nailed this one as well.

Good job and have a good weekend.

Les

ABLE1 · 08-10-2008, 09:41 PM

Marc,

I was looking at a Fire Panel that I might use on this project. The standby current draw is 4mA at 115vac. That calculates to .46 watts.

If I use the 400 watt unit that means it will supply power for 869.56 hours before the inverter goes dead.

That's over 5 weeks. Talk about safety factor.

I guess I will have to call and see "how much that puppy in the window" is.

Thanks again for the tip.

Les

mdshunk · 08-10-2008, 09:55 PM

Quote:

Originally Posted by ABLE1

I guess I will have to call and see "how much that puppy in the window" is.

Check with the manufacturer too, and see how quick the changeover is on the particular model you're looking at. I'd hate to see you drop some coin on one that might wink the power for a split-second, and set the ac fail on the FACP anyhow. I don't think that'll be an issue, but I felt the need to bring it up anyhow.

If you've got that much headroom on this inverter, they might want to hang something else off it too. Hard to say. At least you'll have that ability. Security system or cameras maybe.

ABLE1 · 08-10-2008, 10:12 PM

Quote:

Originally Posted by mdshunk

Check with the manufacturer too, and see how quick the changeover is on the particular model you're looking at. I'd hate to see you drop some coin on one that might wink the power for a split-second, and set the ac fail on the FACP anyhow. I don't think that'll be an issue, but I felt the need to bring it up anyhow.

If you've got that much headroom on this inverter, they might want to hang something else off it too. Hard to say. At least you'll have that ability. Security system or cameras maybe.

Marc,

Generally an AC blip makes no difference. The AC Fail will self restore.

Security System or Cameras???????

This is a Amish woodshop.

The only reason they are in need of a Fire Alarm is because the building code says so.

Thanks for the thoughts and have a good week.

Les

mdshunk · 08-10-2008, 10:22 PM

Quote:

Originally Posted by ABLE1

Security System or Cameras???????

This is a Amish woodshop.

The only reason they are in need of a Fire Alarm is because the building code says so.

Oh, .... yeah. Forgot about that part. That's sorta what caused this whole mess in the first place.