Re: Can't Mix Smoke Models....really?

mbbaker@xxxxxxxxx wrote: 
In this case, compatibility is a function of voltage *and* current.
The smoke detector consumes the same amount of energy always.  If the
voltage available to the smoke detector sags then current increases
because energy is conserved (remains constant).  P = IE.  The UL tests
take these to their logical extremes to determine the failure point.

The literal intent here is that the test only includes one make and
model at a time.  No one has paid UL to test different combinations of
devices on the same control.

I agree with you.  Two-wire smoke detectors will shunt the circuit once
they operate and who cares?  A fire has been reported!  Someone else
pointed out that this goes to liability.  If I were to mix makes and
models on the same 2-wire circuit and a tragedy were to occur, I may be
liable because I knew better than to mix makes and models on the same
circuit.

Before using common sense in this case, buy errors and ommission
insurance. 

Happy holidays,

Mike



Hi Mike:

It's amazing to me that it's taken this long for someone to address this issue. There are many installations (Vancouver not being the least of the cities represented)where "mixing" makes and models of smoke detectors occurs. It becomes more and more prevalent as the systems get older and other servicing companies get involved. What's really amazing is that a number of companies aren't aware that smoke detectors are "cross listed" to a particular control and I've seen numerous installations where properly labelled detectors (ULC, FM, UL) are "mixed in" with no thought given to compatibility. A few of our customers have gone so far as to request that we not mention it to the apartment managers if we're called in to service a particular system!! I've always responded with: "Would you compromise your own family's safety? How can you ask us to willingly compromise someone else's??" Besides which, my insurance company would have "kittens" and I quite enjoy our unblemished record (and the low premiums that go with it).
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