[Greenbuilding] Smoke detectors and EMF

[George J. Nesbitt]

I was doing some research on smoke detector last fall and here is some 
of what I came up with.

*Why* install smoke detector? because they save lives, I read several 
articles this winter about large family's perishing in fires, including 
one that took someone I knew, no working smoke detectors. I don't know 
how many people die each year in fires and how many might have survived 
it there were smoke detectors.

*Where *install smoke detectors? To pass an inspection around here you 
have to have one in every bedroom, one outside every bedroom area, and 
one on every level. I would say you should have one in almost every 
room, except maybe the bathroom and garage. One should be in the 
crawlspace or basement, one in the attic (although heat may cause a 
problem).

*What *kind of smoke detectors should you install, AC or DC? For an 
existing house, or minor renovation install DC.  Easy to install, but 
the downside is having to replace batteries. How many people die every 
year because they have smoke detectors but dead (pardon the bad pun) 
batteries? I don't know, but it is too many. They recommend you replace 
the batteries every year, whether or not they are dead yet. Major 
renovations or new houses usually require AC detectors to be installed. 
Install AC with battery back up, so when there is no power and you burn 
the house down with a fire in the open fireplace or with a ventless 
kerosene heater. These smoke detectors will be interconnected so if an 
alarm sounds in one area, they all will sound to alert you else where. 
Lithium batteries may be worth considering to cut down on dead 
batteries, having to replace them every year, and waste disposal.

*What *kind of smoke detector sensors should you install? In the old 
days (I am old enough to remember some of them) there were only 
ionization (radioactive) sensors. Then many years ago someone (Dicon) 
came out with photo sensors (non radioactive). But it turns out you 
don't want either of them, you want both! Consumers Reports recommends 
you get a detector with both sensors built in, and so do I. Ionization 
detects fast burning fires better, and photo sensors detect smoky 
smoldering fires better. Kitchens can be a problem with nusence alarms, 
so place them in adjacent (but open to) rooms, or use a photo sensor 
with a hush button.

*What *kind of alarm should the detector sound? Consumers Reports has 
looked into this, and kids don't wake to the standard screaming alarm 
(or parents). There are talking alarms that wake kids better (ionization 
sensors only, not interconnectable AC, DC wireless yes?). If you are 
deaf you need a strobe light (ionization sensors only). Some detectors 
have a light for safer egress (ionization sensors only).

*Where *should the detectors be mounted? Detectors should be mounted 
preferably on the middle of the ceiling. On slopped ceilings they should 
be near the top of the slope, but more than 4" (10cm for you *Can* *ad*d 
in metric *ian's*) below the peak and within 3' (0.9m). They should be 
mounted at least 4" (10cm **) from walls so they arnt' in a dead area 
for smoke and air flow. If mounted on the walls they should be a minimum 
of 4" (10cm) and a maximum of 12" (30.5cm) from the ceiling. They should 
be mounted where they are not subject to large airflows and heat ( 
heating supply registers), high humidity, dust (I had a collector go off 
from the cat litter box), locations below 40deg F and above 100deg F, 
near fluorescent lights.

*Beyond Smoke* detectors there are carbon monoxide and gas detectors. 
You should have a CO/gas alarm in each area that has combustion 
appliances except the garage if you park a car there (you shouldn't). 
The detector company's recommend a CO detector in each bedroom, but I 
think that outside each bedroom area would be enough. A gas alarm should 
go in each area (with or without CO) that gas is used in (crawlspace, 
basement, attic, laundry, kitchen, etc.). You can get AC and DC? 
interconnectable alarms, but not Gas CO/gas alarms.

*EMF'S* are probably low on the list of concerns with smoke/gas 
detectors, but very important if you are sensitive to them. I would go 
with the AC alarms if you are doing lots of remodeling or electrical 
work anyway, otherwise DC is ok. My understanding is EMF's are created 
when the hot and neutral are separated, twisting the wires together 
helps, and so does armored cable

*RF* radio frequency may be a more dangerous threat.



Irina Golfman wrote:
> Hello everyone,
>
> I am trying to figure out if the hard wired or battery operated 
> photo-electric smoke detectors will produce a smaller 
> Electro-Magnetic field. My concern is to create the sleeping quarters 
> that are as free from EMF as possible and it seems that a battery 
> operated smoke detector placed outside a bedroom door would be better 
> in this regard than the hard-wired detector placed inside the 
> bedroom.  I've done some poking around, including talking to "Less 
> EMF", but haven't come up with any info. Does anyone out there have 
> an opinion or a lead of information on this (other than I should stop 
> worrying about EMF...)?
>
> Thank you much,
> -------------------------------------------------
> Irina
>
>
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