Heat detectors in an attic?

[ano]

They come with pretty detailed spacing requirements, like they need to be within 25 ft. of walls, and 30 - 50 ft. apart, but personally I would look around your attic and identify what could catch on fire, and focus on that.  Anything with a motor or power supply is a good candidate, especially a furnace.  I also put some around some storage areas I have in the attic.  If you have a chimney or places that might be struck by lightning, you may want to add some there too. 

 

[Desert_AIP]

I have several separate attic spaces, main house, dining room, gagrage, etc. and have these in different zones like my smokes to give me fire location information.

I also use them in my woodshop where a smoke detector won't work.

The larger spaces have several daisy chained together.
I use 18/2 firewire.