Question about smoke detectors in open ceilings

[NewOnMyOwn]

Hey guys, great forum! I usually just read but today I have a question to ask.

One of my normal accounts is a condominium building, this time they asked me to install smoke detectors in 4 basements. There is a 120Volt system in the building currently and the pipe runs right thru each basement, but they never had smoke detectors before because the basements weren't used, until now.

Piping out of the existing runs will be easy, my only concern is how many will be needed. I gave them an estimate already for 2 detectors per basement, but now I am second guessing myself.

Below you will see a link to a small diagram of the basements, they are all the same except that two of them are mirror images. In the picture you can see the beams that I drew in, those beam sits 3.5" underneath the joists.

http://tinypic.com/r/kb7i4h/6
http://tinypic.com/r/71lqhw/6

My question, will those beams and the 2 cinderblock piers underneath them section that basement off into 3 rooms? Will I need 3 smoke detectors? Or will I be alright with 2?

My plan was to just 4 point saddle 1/2" EMT under the beam where necessary and install boxes directly to the underside of the joists.

Any opinions?

Thanks a lot!

 

[NewOnMyOwn]

I don't think that image host is working properly and it won't let me edit the original post.

Hopefully this works:

Here is a picture of the beam sitting 3.5" underneath the joists:

http://imagecloset.com/tiny/911960

 

[Dennis Alwon]

First off welcome to the forum.

Now sd are not in the NEC but rather in the building code. The numbers will depend on the number of bedrooms. You would need one in each bedroom and one in any adjacent hallways. If there are no bedrooms then you only need one sd.

 

[NewOnMyOwn]

First off welcome to the forum.

Now sd are not in the NEC but rather in the building code. The numbers will depend on the number of bedrooms. You would need one in each bedroom and one in any adjacent hallways. If there are no bedrooms then you only need one sd.

Thanks for the reply!

This is just an open basement. It's a single room, but 2 beams cut thru the room and they are about 3.5" lower than the joists. These beams also have 2 piers underneath them for support. Do these beams separate the open room into individual spaces requiring separate SD's?

 

[Dennis Alwon]

Thanks for the reply!

This is just an open basement. It's a single room, but 2 beams cut thru the room and they are about 3.5" lower than the joists. These beams also have 2 piers underneath them for support. Do these beams separate the open room into individual spaces requiring separate SD's?

No, if there are no bedrooms then only one sd is required even if there were 10 non bedrooms down there.

Hope this helps.

 

[NewOnMyOwn]

No, if there are no bedrooms then only one sd is required even if there were 10 non bedrooms down there.

Hope this helps.

Oh, so only one is necessary. I see. All the other basements had 2 smokes so I was following them. But they don't have the beam lower than the joists so I thought that might be an obstacle.

Thank you very much Dennis.

 

[Fast__Eddie]

Are they Smoke Detectors or Smoke Alarms?

 

[NewOnMyOwn]

Are they Smoke Detectors or Smoke Alarms?

The building uses all Kidde i12040 Hardwire Smoke Alarms.