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Placement of Carbon Monoxide Detectors

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 X2015 NFPA® 720 Standard for the Installation of Carbon Monoxide (CO) Detection and Warning Equipment

If you are interested in Carbon monoxide regulation than this article is just for you.

There is a lot of misconception within the real estate industry as to where CO alarms get mounted and how many are needed in a house. So sit back and relax, I hope this clears up the air (no pun intended) for those of you who want to be a CO Pro.  We must point out that building codes are jurisdictional and you should, in a prudent manner, explore your local code that applies specifically to your area. That said, many jurisdictions refer to the NFPA720 Code book.

marc mazza inspectionsWhat is Carbon Monoxide (CO) and where does it come from?

CO also known as the “silent killer” is actually colorless, tasteless, AND odorless. Because it goes unnoticed without the use of a CO detector or metering device, anytime folks claim that they detect a smell of what they believe to be CO, they are usually referring to combustion byproducts that the human nose is able to detect. Anytime you are able to smell combustion byproducts, it’s usually an indication of an issue which should be addressed promptly.

In what ways does CO exposure affect the human?

Because it is impossible to see, taste or smell the toxic fumes, CO can kill occupants before they are aware its presence within their home. According to the Journal of the American Medical Association (JAMA), CO is the leading cause of accidental poisoning deaths in America.

LOW LEVEL EXPOSURE:

At low levels, its symptoms are similar to the flu. These symptoms differ with age and exposure but typically include headaches, dizziness, disorientation, nausea and fatigue.

ACUTE CO POISONING:

Acute CO poisoning leads to sleep and the failure of the central nervous system and heart- – leading eventually to death during sleep.

SOURCES OF CO:

Sources of CO include unvented kerosene and gas space heaters, leaking chimneys and furnaces, backdrafting from furnaces, gas water heaters, wood stoves, fireplaces, gas stoves, generators and other gasoline-powered equipment and automobile exhaust from attached garages. Incomplete oxidation during combustion in gas ranges and unvented gas or kerosene heaters may cause high concentrations of CO in indoor air. Worn or poorly adjusted and maintained combustion devices (e.g., boilers, furnaces) can be significant sources, or if the flue is improperly sized, blocked, disconnected or is leaking. Auto, truck or bus exhaust from attached garages, nearby roads or parking areas can also be a source.

 Are all houses in Southern California Required to Have CO Alarms?

As of July 1, 2011 the Carbon Monoxide Poisoning Prevention Act (Senate Bill – SB 183) requires owners of all single-family homes with an attached garage or a fossil fuel source to install carbon monoxide detectors within the home by July 1, 2011. Owners of multi-family leased or rental dwellings, such as apartment buildngs, have until January 1, 2013 to comply with the law.  So Yes, all homes are to have CO alarms installed and in good working order.

 I heard that CO is lighter than air so alarms should be installed on the ceiling or high on the wall and I’ve heard also they should be installed low to the floor because CO is heavier than air?

The fact is that CO is slightly lighter than air. Recent studies have shown little differences in CO levels based on the height of the alarm on the wall. According to healthy building science, the difference between carbon monoxide and air is so slight that CO is found to evenly distribute itself indoors. It is worth mentioning that CO indoors is usually generated from incomplete combustion (heat source) and therefore traveling in a warm air stream. This means that these CO alarms can be placed anywhere on the wall or where the manufacturer specifies hence the reason why, “according to manufacturer’s specifications” is written in the code.

The 2015 NFPA says this:

9.4.1.2* Each alarm or detector shall be located on the wall, ceiling, or other location as specified in the manufacturer’s published instructions that accompany the unit.

Should the placement of carbon monoxide (CO) detectors be influenced by CO’s weight relative to air?

Here is a scientific experiment performed by NCBI The National Center for Biotechnology Information on the effects of CO.

ABSTRACT BACKGROUND:

Numerous states and localities have recently passed legislation mandating the installation and use of residential carbon monoxide (CO) detectors/alarms. Interestingly, there seems to be confusion about the optimal placement, if any, of CO alarms inside the home.

OBJECTIVES:

It was the goal of this study to demonstrate the behavior of CO in air and to help provide a data-based recommendation for CO alarm placement.

METHODS:

CO was calculated to be slightly lighter than air. An 8-foot-tall airtight Plexiglas chamber was constructed and CO monitors placed within at the top, middle, and bottom. CO test gas (15 L, 3000 parts per million) was infused at each of the three heights in different trials and CO levels measured over time.

RESULTS:

Contrary to a significant amount of public opinion, CO did not layer on the floor, float at the middle of the chamber, or rise to the top. In each case, the levels of CO equalized throughout the test chamber. It took longer to equalize when CO was infused at the top of the chamber than the bottom, but levels always became identical with time.

CONCLUSIONS:

As would have been predicted by the Second Law of Thermodynamics, CO infused anywhere within the chamber diffused until it was of equal concentration throughout. Mixing would be even faster in the home environment, with drafts due to motion or temperature. It would be reasonable to place a residential CO alarm at any height within the room.

Credit to NCIB and the US national Library of Medicine Journal of emergency medicine Hampson NB, Courtney TG, Holm JR. J Emerg Med. 2012 Apr;42(4):478-82. doi: 10.1016/j.jemermed.2011.03.015. Epub 2011 May 4 • 1Center for Hyperbaric Medicine, Virginia Mason Medical Center, Seattle, WA 98101, USA.

 SO Where do CO alarms get installed?

CO Alarms are to be installed one on each habitable level (floor) and in the (immediate vicinity) of sleeping area within a residential application.  I was unable to find a definition in the NFPA for immediate vicinity but I’m sure most commonsensical individuals can come to the deduction it means “very close to” or in “very close proximity to”.

 What does the ICC IRC say?

Section R315.1 requires that CO alarms be located outside each separate sleeping area in the immediate vicinity of the bedrooms. The carbon monoxide alarm can be located near the smoke alarm required in the immediate area of the bedrooms by Section R314.3.

 The 2014 building code further explains;

2014 ICC IRC R315.3 Where required in existing dwellings. Where work requiring a permit occurs in existing dwellings that have attached garages or in existing dwellings within which fuel burning appliances exists, carbon monoxide alarms SHALL be provided in accordance with section R315.1  Commentary*  When any work requiring a permit is performed to existing townhouses, single-family homes or duplexes, CO alarms must be installed

 What does the NFPA 720 say?

The 2015 National Fire Protection Association says CO detectors “shall be centrally located outside of each separate sleeping area in the immediate vicinity of the bedrooms.” Additionally, each CO detector “shall be located on the wall, ceiling or other location as specified in the installation instructions….”

 Here is what the Code actually looks like:

9.4.1.1* Carbon monoxide alarms or detectors shall be installed as follows:

(1) Outside of each separate dwelling unit sleeping area in the immediate vicinity of the bedrooms

(2) On every occupiable level of a dwelling unit, including basements, excluding attics and crawl spaces

(3) Other locations where required by applicable laws, codes, or standards

 Smoke alarms are good for 10 years, how often do CO alarms have to be tested?

Gas sensors in CO alarms have a limited lifespan, generally less than 6 years. The test button on common CO alarms only tests the battery, not the CO gas censor.

Let’s take a look at what the NFPA, the Standard for the Installation of Carbon Monoxide (CO) Detection and Warning Equipment has to say about this;

In accordance with the NFPA section 8.8 Household Carbon Monoxide Detection Systems.

8.8.1 Testing of Household Carbon Monoxide Detection Systems

8.8.1.1 Household carbon monoxide detection systems shall be tested by a qualified service technician at least every 3 years.

8.8.1.2 Carbon monoxide detectors used in household carbon monoxide detection systems shall be tested in accordance with manufacturer’s published instructions.

8.8.1.3 Detectors shall be replaced when the end-of-life signal is activated, the manufacturer’s replacement date.

 Do the CO detectors have to be interconnected?

The answer to this is yes and no. According to the NFPA when you two or more CO alarms then yes they must be interconnected. As a stand-alone CO alarm, no they do not have to be interconnected.

Here is what that looks like in the 2015 NFPA;

9.6.4 Interconnection of Alarms. When two or more alarms are installed within a dwelling unit, suite of rooms, or similar area, they shall be arranged so that the operation of any alarm causes all alarms within these locations to sound.

Exception: Alarms installed in existing construction shall not be required to cause all alarms to sound.

Commentary:  The rationale for this requirement is if a CO device is activated in the basement, the occupants on the second floor on the opposite end of the home are unable to hear the audible alarm if the devices are not interconnected.

9.6.4.1 When alarms of different types are interconnected, all interconnected alarms shall produce the appropriate audible response for the phenomena being detected or remain silent. [72:29.8.2.2(5)]

 Lets see what the NFPA has to say regarding interconnection:

The 2015 NFPA defines a multipurpose alarms in this manner:

3.3.16 Multiple-Purpose Alarm. An alarm that incorporates detection capabilities for more than one hazardous condition, such as fire, fuel gas, or carbon monoxide.

9.6.3 Multiple-Purpose Alarms.

9.6.3.1 A fire alarm signal shall take precedence and be distinctively recognizable over any other signal, even when the nonfire signal is initiated first.

9.6.3.2 Distinctively different audible alarm signals shall be provided for each of the following:

(1) Fire alarms

(2) Carbon monoxide alarms

(3) Other alarms

Source Credit to http://healthybuildingscience.com

Credit to US national Library of Medicine Journal of emergency medicine Hampson NB, Courtney TG, Holm JR. J Emerg Med. 2012 Apr;42(4):478-82. doi: 10.1016/j.jemermed.2011.03.015. Epub 2011 May 4

2012-15 NFPA 720

2012-14 ICC IRC

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