ideal location for sensors

[v1rtu0s1ty]

Hey guys, I am in the final stage of drawing plans. I would like to know where some sensors such co, heat, gas, etc and would I need a gangbox for them.

1.) for CO sensor
ceiling or wall?
gang-box needed, Yes or No?

2.) for GAS sensor
ceiling or wall? I haven't seen one. Should it be near the oven backsplash? or underneath the cabinets?
gang-box needed, Yes or No?


3.) for Heat sensor
ceiling or wall? I haven't seen one. Where in the kitchen is it ideal to put?
gang-box needed, Yes or No?

Thanks guys!

Neil

 

[AutomatedOutlet]

1.) for CO sensor. ceiling or wall?
gang-box needed, Yes or No?

Wall/Ceiling - doesn't matter. CO is about the same weight as air.

Box - not needed

2.) for GAS sensor
ceiling or wall? I haven't seen one. Should it be near the oven backsplash? or underneath the cabinets?
gang-box needed, Yes or No?

Depends a little on the gas but the main thing is to locate near where you think gas might leek - no box needed.

3.) for Heat sensor
ceiling or wall? I haven't seen one. Where in the kitchen is it ideal to put?
gang-box needed, Yes or No?

Typically ceiling because heat rises. Box not needed.

 

[toymaster458]

CO Wall/Ceiling does matter! Some are made for wall installation which need to be 5' from the floor.

Gas follows the same rules as CO

Heat is always ceiling except in Attics which is about mid way.

ALLWAYS look at the installation instructions that come with the Sensor/Detector.
They will also let you know if it will mount to a box and what kind.

 

[AutomatedOutlet]

CO Wall/Ceiling does matter!

hate to disagree with you but here are some facts.

From the US Deptment of Energy:

Carbon monoxide has nearly the same density as air.
You'll notice that the manufacturer's instructions that come with the
detector don't say high or low either.

The density of a gas is proportional to the weight of a single molecule of
that gas.

So you figure relative buoyancy for yourself if you start learning a few
atomic weights:
H=1, He=4, C=12, N=14, O=16.

Add them up for the molecular weights of pure gasses:
H2 = (1+1) = 2, very light
He = (4) = 4, very light
N2 = (14+14 ) = 28, about neutral
O2 = (16+16) = 32, slightly heavy
CO2= (12+16+16)= 44, heavy
CO = (12+16) = 28, about neutral
CH4= (12+4*1) = 18, light (majority part of natural gas)
H2O= (2*1+16) = 18, light (steam)
C2H6=(2*12+6*1)= 30, about neutral (minority part of natural gas)
C3H8=(8 + 3*12)= 42, heavy (propane)
C4H10=(10+4*12)= 58, (butane)
C5H12=(12+5*12)= 70, pentane, lightest part of gasoline

For mixed gasses just take a proportionate average:
Air is 80% N2 + 20% O2 .
air = 0.8(28) + 0.2(32) = 29 (exactly neutral, by definition)

So pure carbon monoxide is actually about 3% lighter than air.
But usually it is made in modest concentrations, mixed in with the normal
combustion products: CO2, H2O. Which are always mixed with the 80% Nitrogen that never participates in burning.

Then that mixes with room air, making an even smaller concentration...

Because it travels in whatever directions your air normally circulates, which varies, it is difficult in most homes to find an advantageous position where CO
will enter or concentrate.

So we settle for any convenient position, or one associated with that
which we wish to protect.

We carry a couple of different models, some say 5 feet (because that is the level that most people breath from) but most don't specify or they say it doesn't matter.

I think that the DOE write-up above does a pretty good job explaining why it doesn't matter.

 

[AutomatedOutlet]

Here is also a typical building code talking about the location of CO sensors - note, no specific location requirements as to the height.

Location of Carbon Monoxide Detectors
(1) Where a fuel-burning appliance is installed in a suite of residential occupancy, a carbon monoxide detector shall be installed adjacent to each sleeping area in the suite.

(2) Where a fuel-burning appliance is installed in a service room that is not in a suite of residential occupancy, a carbon monoxide detector shall be installed

(a) adjacent to each sleeping area in every suite of residential occupancy that is adjacent to the service room, and

( in the service room.

(3) Where a storage garage is located in a building containing residential occupancy, a carbon monoxide detector shall be installed adjacent to the storage garage.

(4) Where a storage garage serves only the dwelling unit to which it is attached or built in, a carbon monoxide detector shall be installed adjacent to each sleeping area in the dwelling unit.

 

[toymaster458]

hate to disagree with you but here are some facts.

And back at you with some facts from the Critical Environment Technologies

What should the mounting height of the sensors be?

This depends on the density of the gas relative to air. Heavier than air gases should be detected 6 inches from the floor, than air gas sensors should be placed on or near the ceiling, and gases which have a density close to that of air should have sensors installed in the ‘breathing zone’ 4 to 6 feet from the floor. Consider accessibility for calibration when locating sensors.

 

[AutomatedOutlet]

The key is to locate them where the air flow is because it mixes with the air.

 

[v1rtu0s1ty]

Ok guys, I'm 95% finished with getting the length of each security wire from target location to the head end. These are just my estimates. I hope it's accurate.

22/2 - 1121 ft.
22/4 - 675 ft.
18/4 - 850 ft.
CAT5E - 203 ft.

However, I did not add the measurement for the one motion sensor in the second floor near hallway. I still don't see the use of the motion sensor in the second floor. The reason I say this is because I've got kids that wokes up during midnight to go to the bathroom. If I put motion sensor in the second floor, I will have to set it to night mode which also prevents the motion sensors in first floor to not function as a real motion sensor. That's how I understand a reply to my other 1 week ago thread. In case you ask, I'm going to be using ELK M1 Gold.

What do you think guys?

Please let me know so I will know if I need to change the numbers.

Thanks!

 

[v1rtu0s1ty]

1.) for CO sensor. ceiling or wall?
gang-box needed, Yes or No?

Wall/Ceiling - doesn't matter. CO is about the same weight as air.

Box - not needed

2.) for GAS sensor
ceiling or wall? I haven't seen one. Should it be near the oven backsplash? or underneath the cabinets?
gang-box needed, Yes or No?

Depends a little on the gas but the main thing is to locate near where you think gas might leek - no box needed.

3.) for Heat sensor
ceiling or wall? I haven't seen one. Where in the kitchen is it ideal to put?
gang-box needed, Yes or No?

Typically ceiling because heat rises. Box not needed.

Hi Martin,

Do you have an idea on how I will provision the wires for a window contact sensor? Here is the scenario. My house is currently being built. Technically, it's still not mine. That means, I am not allowed to drill a hole in the plastic side of a window. However, I can make a hole in the wooden frame now but I can only drill the plastic side of the window once I move in. Do you have other ideas for installing door contacts in this kind of scenario?

 

[toymaster458]

Take a lot of pictures before the drywall goes up to show where the wires are.

 

[v1rtu0s1ty]

Take a lot of pictures before the drywall goes up to show where the wires are.

Yep, I've done it already. But I will have to do it again because the pictures I have taken before doesn't have windows yet, no electricals yet, pipes. All these things will happen next week.

Do I need to worry about buying the 18/2 stranded wire now? And is 18/2 stranded just going to be used in the basement?

Thanks.