Carbon monoxide detector

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A Kidde plug-in carbon monoxide detector Carbon monoxide detector 1 2018-03-01.jpg
A Kidde plug-in carbon monoxide detector

A carbon monoxide detector or CO detector is a device that detects the presence of the carbon monoxide (CO) gas to prevent carbon monoxide poisoning. In the late 1990s, Underwriters Laboratories changed the definition of a single station CO detector with a sound device to carbon monoxide (CO) alarm. This applies to all CO safety alarms that meet UL 2034 standard; [1] however for passive indicators and system devices that meet UL 2075, UL refers to these as carbon monoxide detectors. Most CO detectors use a sensor with a defined, limited lifespan, and will not work indefinitely.

Contents

CO is a colorless, tasteless, and odorless gas produced by incomplete combustion of carbon-containing materials. It is often referred to as the "silent killer" because it is virtually undetectable by humans. In a study by Underwriters Laboratories, "Sixty percent of Americans could not identify any potential signs of a CO leak in the home". [2] Elevated levels of CO can be dangerous to humans depending on the amount present and length of exposure. Smaller concentrations can be harmful over longer periods while increasing concentrations require diminishing exposure times to be harmful. [3]

Those living in all-electric homes don’t need CO detectors unless there is an attached garage with a non-electric car, or if a backup generator is used too close to your living quarters during a power outage. [4]

A First Alert smoke and carbon monoxide alarm FirstAlert Smoke and Carbon Monoxide Alarm.jpg
A First Alert smoke and carbon monoxide alarm

CO detectors are designed to measure CO levels over time and sound an alarm before dangerous levels of CO accumulate in an environment, giving people adequate warning to safely ventilate the area or evacuate. Some system-connected detectors also alert a monitoring service that can dispatch emergency services if necessary.

While CO detectors do not serve as smoke detectors and vice versa, combined smoke/CO detectors are also sold. [5] In the home, some common sources of CO include open flames, space heaters, water heaters, blocked chimneys or running a car or grill inside a garage. [6]

Installation

The devices can either be battery-operated or AC-powered (with or without a battery backup). Battery-powered devices advertise a battery lifetime of up to 10 years. The gas sensors in CO alarms have a limited life span, typically two to five years. [7] Newer models are designed to signal a need to be replaced after a set period. CO detectors all have "test" buttons like smoke detectors, but the test buttons only test the battery, electronic circuit, and buzzer, not the alarm’s ability to sense gas.

According to the carbon monoxide guidelines of the National Fire Protection Association, CO detectors should be installed in each sleeping area in a dwelling, and each detector should be located "on the wall, ceiling or other location as specified in the installation instructions that accompany the unit". [8]

CO detectors are available as stand-alone models, or system-connected devices which can be monitored remotely. [9]

Function

The primary purpose of CO detectors is to sound an alarm to warn occupants of an enclosed space of a dangerous level of carbon monoxide. The alarm should sound within 60 minutes if the concentration rises to 70 PPM, within 10 minutes at 150 PPM, in 4 minutes at 400 PPM, and immediately at 500 PPM or greater. The alarm should not sound too quickly, as brief false alarms may prompt users to disable the alarm, leaving them unprotected. [10] Some alarm devices may display the CO level. There are also measuring instruments designed to display CO concentrations down to low, non-dangerous levels, rather than detect and warn of dangerous levels.

Some detectors without UL certification have been found not to sound at the specified threshold, or to sound within seconds. [10]

In some instances, it's worth noting that a red flashing without accompanying sounds could indicate a different condition or simply inform the user about a malfunction. [11]

Wireless home safety devices are available that link carbon monoxide detectors to vibrating pillow pads, strobes, or a remote warning handset.

Several carbon monoxide detection methods are used and documented in industry specifications published by Underwriters Laboratories. Alerting methods include:

Sensors

Early designs used a chemical detector consisting of a white pad that faded to a brownish or blackish color in the presence of carbon monoxide. Such detectors are cheap but only give a visual warning. As carbon monoxide-related deaths increased during the 1990s, audible alarms became standard.

The alarm points on carbon monoxide detectors are not a simple alarm level (as in smoke detectors) but are a concentration-time function. At lower concentrations, e.g. 100 parts per million (PPM), the detector does not sound an alarm for many tens of minutes. At 400 PPM, the alarm sounds within a few minutes. This concentration-time function is intended to mimic the uptake of carbon monoxide in the body while also preventing false alarms due to brief bursts of carbon monoxide from relatively common sources such as cigarette smoke.

Four types of sensors are available, varying in cost, accuracy, and speed of response. [12] Most detectors do not have replaceable sensors.

Opto-chemical type

The detector consists of a pad of a colored chemical which changes color upon reaction with carbon monoxide. They only provide a qualitative warning of the gas, however. The main advantage of these detectors is that they are the lowest cost, but the downside is that they also offer the lowest level of protection.

One reaction used for carbon monoxide detection is potassium disulfitopalladate (II) catalytic oxidation:

As the reaction progresses, the release of palladium causes the color to change from yellow to brown to black.

Biomimetic type

A biomimetic sensor works in a fashion similar to hemoglobin which darkens in the presence of CO proportional to the amount of carbon monoxide in the surrounding environment. It uses cyclodextrins, a chromophore, and a number of metal salts. This can either be seen directly or connected to an infrared source of photons such as an IR LED and then monitored using a photodiode. Battery lifespan is usually two to three years with conventional alkaline, but a lithium battery will last the life of the product. The biotechnology-based sensors have a useful operational life of six years. These products were the first to enter the mass market, but because they cost more than other sensors they are mostly used in higher-end areas and RVs. The technology has been improved and is the most reliable technology, according to a report from Lawrence Berkeley National Laboratory. [13]

Electrochemical type

Electrochemical Carbon Monoxide sensors. Both sensors and alarms are from different companies.
Carbon Monoxide Sensor.jpg
The metal cylinder with yellow tape on it
Carbon Monoxide Sensor 2.jpg
The brown cylinder with text on it

The electrochemical detector uses the principle of a fuel cell to generate an electrical current when the gas to be detected undergoes a chemical reaction. The generated current is precisely related to the amount of carbon monoxide in the immediate environment close to the sensor. Essentially, the electrochemical cell consists of a container, two electrodes, connection wires, and an electrolyte, typically sulfuric acid. Carbon monoxide is oxidized at one electrode to carbon dioxide while oxygen is consumed at the other electrode. For carbon monoxide detection, the electrochemical cell has advantages over other technologies in that it has a highly accurate and linear output to carbon monoxide concentration, requires minimal power as it is operated at room temperature, and has a long lifetime, which typically is five years to ten years. This technology has become the dominant technology in the United States and Europe. [ citation needed ] Test buttons only indicate the operational effectiveness of the battery, circuit, and buzzer. The only way to fully test the operation of a CO alarm using an electrochemical cell is with a known source of calibrated test gas delivered in a shroud to maintain the concentration level for the test period.

Semiconductor type

Thin wires of the semiconductor tin dioxide on an insulating ceramic base provide a sensor monitored by an integrated circuit. This sensing element must be heated to approximately 400 °C for operation. Oxygen increases the resistance of the tin dioxide while carbon monoxide reduces it. The integrated circuit monitors the resistance of the sensing element. Lifespans are approximately five years and alarms need testing on installation and at least annually with a test gas.

Due to the large power demand of this sensor, it is usually powered from the mains. A battery-powered, pulsed sensor is available with a lifetime of months.

This technology is widely used in Japan and elsewhere in the Far East, with some market penetration in the USA. However, the superior performance of electrochemical cell technology is beginning to displace this technology.

Concentration readout

Although all home detectors use an audible alarm signal as the primary indicator, some versions also offer a digital readout of the CO concentration, in parts per million (PPM). Typically, they can display both the current reading and a peak reading from memory of the highest level measured over some time. These advanced models cost somewhat more but are otherwise similar to the basic models.

The models with display have the advantages of indicating levels below the alarm threshold, reporting levels that may have occurred during an absence, and assessing the degree of hazard if the alarm sounds. They may also aid emergency responders in evaluating the level of past or ongoing exposure or danger.

Portable

Portable detectors are designed for aircraft, cars and trucks. They warn vehicle occupants of any CO hazard.

CO measurement instruments

Portable meters which display CO concentration down to a few PPM are more sensitive than home safety CO detectors and correspondingly much more expensive. They are used by industrial hygienists and first responders, and for maintenance and tracing a CO leak. These devices measure low levels of CO in seconds, rather than minutes or hours like residential alarms. Like other test equipment, professional CO meters must be tested and recalibrated periodically.

Legislation

United States

In the US (As of January 2017) 32 states have enacted statutes regarding carbon monoxide detectors, and another 11 have promulgated regulations on CO detectors, [14] as well as in Washington DC and New York City. In Canada, CO alarm requirements came into effect on October 15, 2014 in Ontario, [15] there is a strong movement in Alberta to make CO detectors mandatory in all homes. [16]

More and more states are legislating for their installation as a mandatory feature. [17]

House builders in Colorado are required to install carbon monoxide detectors in new homes by a bill signed into law in March 2009. House Bill 1091 requires the installation of the detectors in new and resold homes near bedrooms as well as rented apartments and homes. It took effect on July 1, 2009. The legislation was introduced after the death of Denver investment banker Parker Lofgren and his family. Lofgren, along with his wife and children were found dead in their home near Aspen, Colorado on Nov. 27, 2008, victims of carbon-monoxide poisoning.

In New York State "Amanda's Law" (A6093A/C.367) requires one- and two-family residences that have fuel-burning appliances to have at least one carbon monoxide alarm installed on the lowest story having a sleeping area, effective February 22, 2010. Although homes built before January 1, 2008 are allowed to have battery-powered alarms, homes built after that date must have hard-wired alarms. In addition, New York State contractors must install a carbon monoxide detector when replacing a fuel-burning water heater or furnace if the home is without an alarm. The law is named for Amanda Hansen, a teenager who died from carbon monoxide poisoning from a defective boiler while at a sleepover at a friend's house. [18] [19]

Alaska House Bill 351 [ when? ] requires a carbon monoxide detector to be installed in dwelling units that contain or are serviced by a carbon-based fuel appliance or other device that produces by-products of combustion.

In July 2011, California required the installation of carbon monoxide detectors in existing single-family homes, with multifamily homes following in 2013. [20] CA Law 2015 require all new installation of smoke and CO alarms to be 10-year non-serviceable type. [21] Existing alarms may not need to be replaced for homeowners, see local codes. Required alarm locations also vary per local enforcing agencies. In Maine all rental units must have carbon monoxide detectors. In nonrental homes they are recommended but not required. [22]

Standards

North America

The Canadian Mortgage and Housing Association reports, "The standards organizations of Canada (CSA) and the United States (Underwriters Laboratories or UL) have coordinated the writing of CO standards and product testing. The standards as of 2010 prohibit showing CO levels of less than 30 PPM on digital displays. The most recent standards also require the alarm to sound at higher levels of CO than with previous editions of the standard. The reasoning behind these changes is to reduce calls to fire stations, utilities and emergency response teams when the levels of CO are not life threatening. This change will also reduce the number of calls to these agencies due to detector inaccuracy or the presence of other gases. Consequently, new alarms will not sound at CO concentrations up to 70 PPM. Note that these concentrations are significantly in excess of the Canadian health guidelines," [23] (and also in excess of US Occupational Safety and Health Administration (OSHA) Permissible exposure limits, which is 50 PPM). [24]

Related Research Articles

<span class="mw-page-title-main">Smoke detector</span> Device that detects smoke, typically as an indicator of fire

A smoke detector is a device that senses smoke, typically as an indicator of fire. Smoke detectors/Alarms are usually housed in plastic enclosures, typically shaped like a disk about 125 millimetres (5 in) in diameter and 25 millimetres (1 in) thick, but shape and size vary. Smoke can be detected either optically (photoelectric) or by physical process (ionization). Detectors may use one or both sensing methods. Sensitive alarms can be used to detect and deter smoking in banned areas. Smoke detectors in large commercial and industrial buildings are usually connected to a central fire alarm system.

<span class="mw-page-title-main">Carbon monoxide poisoning</span> Toxic effects of carbon monoxide

Carbon monoxide poisoning typically occurs from breathing in carbon monoxide (CO) at excessive levels. Symptoms are often described as "flu-like" and commonly include headache, dizziness, weakness, vomiting, chest pain, and confusion. Large exposures can result in loss of consciousness, arrhythmias, seizures, or death. The classically described "cherry red skin" rarely occurs. Long-term complications may include chronic fatigue, trouble with memory, and movement problems.

<span class="mw-page-title-main">Fire alarm notification appliance</span> Device used to signal a fire-based or other emergency

A fire alarm notification appliance is an active fire protection component of a fire alarm system. A notification appliance may use audible, visible, or other stimuli to alert the occupants of a fire or other emergency condition requiring action. Audible appliances have been in use longer than any other method of notification. Initially, all appliances were either electromechanical horns or electric bells, which would later be replaced by electronic sounders. Most of today's appliances produce sound levels between 70 and 100 decibels at 3 ft.

<span class="mw-page-title-main">Security alarm</span> System that detects unauthorised entry

A security alarm is a system designed to detect intrusions, such as unauthorized entry, into a building or other areas, such as a home or school. Security alarms protect against burglary (theft) or property damage, as well as against intruders. Examples include personal systems, neighborhood security alerts, car alarms, and prison alarms.

<span class="mw-page-title-main">Manual fire alarm activation</span> Button or lever to activate fire alarms

Manual fire alarm activation is the process of triggering a fire alarm through a call point, pull station, or other device. This usually causes the alarm to sound the evacuation signal for the relevant building or zone. Manual fire alarm activation requires human intervention, as distinct from automatic fire alarm activation such as that provided through the use of heat detectors and smoke detectors. It is, however, possible for call points/pull stations to be used in conjunction with automatic detection as part of the overall fire detection and alarm system. Systems in completed buildings tend to be wired in and include a control panel. Wireless activators are common during construction.

<span class="mw-page-title-main">Aspirating smoke detector</span> System in fire prevention

An aspirating smoke detector (ASD) is a system used in active fire protection, consisting of a central detection unit which draws air through a network of pipes to detect smoke. The sampling chamber is based on a nephelometer that detects the presence of smoke particles suspended in air by detecting the light scattered by them in the chamber. ASDs can typically detect smoke before it is visible to the naked eye.

<span class="mw-page-title-main">Heat detector</span> Type of fire alarm

A heat detector is a fire alarm device designed to respond when the convected thermal energy of a fire increases the temperature of a heat sensitive element. The thermal mass and conductivity of the element regulate the rate flow of heat into the element. All heat detectors have this thermal lag. Heat detectors have two main classifications of operation, "rate-of-rise" and "fixed temperature". The heat detector is used to help in the reduction of property damage.

<span class="mw-page-title-main">Fire alarm system</span> A system, that works using multiple devices to warn of a fire or other types of emergencies

A fire alarm system is a building system designed to detect, alert occupants, and alert emergency forces of the presence of fire, smoke, carbon monoxide, or other fire-related emergencies. Fire alarm systems are required in most commercial buildings. They may include smoke detectors, heat detectors, and manual fire alarm activation devices. All components of a fire alarm system are connected to a fire alarm control panel. Fire alarm control panels are usually found in an electrical or panel room. Fire alarm systems generally use visual and audio signalization to warn the occupants of the building. Some fire alarm systems may also disable elevators, which are unsafe to use during a fire under most circumstances.

Kidde is a brand subsidiary of Carrier Global that manufactures and distributes fire detection and suppression equipment, as well as smoke and CO alarm units. Kidde is one of America's largest manufacturers of smoke alarms and fire safety products. Kidde is headquartered in Mebane, North Carolina.

A gas detector is a device that detects the presence of gases in an area, often as part of a safety system. A gas detector can sound an alarm to operators in the area where the leak is occurring, giving them the opportunity to leave. This type of device is important because there are many gases that can be harmful to organic life, such as humans or animals.

First Alert is the retail brand of American safety equipment manufacturer BRK Brands, Inc., established in 1976 and based in Aurora, Illinois, with a production plant in Juarez, Mexico. Products sold with the brand include carbon monoxide detectors, smoke alarms, fire extinguishers, and other safety products like flashlights and fire escape ladders. First Alert supports fire safety in partnership with Safe Kids USA and The United States Fire Administration, providing smoke alarms at reduced cost to low-income families in the United States.

Electrochemical gas sensors are gas detectors that measure the concentration of a target gas by oxidizing or reducing the target gas at an electrode and measuring the resulting current.

<span class="mw-page-title-main">Breath carbon monoxide</span> Level of carbon monoxide in exhaled breath

Breath carbon monoxide is the level of carbon monoxide in a person's exhalation. It can be measured in a breath carbon monoxide test, generally by using a carbon monoxide breath monitor, such as for motivation and education for smoking cessation and also as a clinical aid in assessing carbon monoxide poisoning. The breath carbon monoxide level has been shown to have a close relationship with the level of CO in the blood known as carboxyhaemoglobin (%COHb) or "blood CO". This correlation allows for the level of CO in the blood to be indirectly measured through a breath sample.

Home safety is the awareness of risks and potential dangers in and around a home that may cause bodily harm, injury, or even death to those living there.

<span class="mw-page-title-main">Honeywell Gent</span> British manufacturer of life safety equipment

Honeywell Gent, formerly Gents' of Leicester, is a British manufacturer of life safety equipment based in Leicester, England. Established by John Thomas Gent, the company is thought to have started in 1872 however it could have been trading as early as the 1860s. The company had a workforce of several hundred at its height.

An explosive gas leak detector is a device used to detect explosive gas leaks in enclosed spaces. Typically, a local alarm will be triggered, and optionally a remote alarm may also be connected.

System Sensor is an American manufacturer of fire protection equipment. Headquartered in St. Charles, Illinois, System Sensor is a subsidiary of Honeywell International. System Sensor develops and distributes fire alarm devices such as notification appliances, fire detectors, manual initiating devices, CO detectors, and more fire protection devices for multiple markets across the globe, and for other Honeywell companies.

<span class="mw-page-title-main">Exhaust gas analyzer</span>

An exhaust gas analyser or exhaust carbon monoxide (CO) analyser is an instrument for the measurement of carbon monoxide among other gases in the exhaust, caused by an incorrect combustion, the Lambda coefficient measurement is the most common.

Workplace exposure monitoring is the monitoring of substances in a workplace that are chemical or biological hazards. It is performed in the context of workplace exposure assessment and risk assessment. Exposure monitoring analyzes hazardous substances in the air or on surfaces of a workplace, and is complementary to biomonitoring, which instead analyzes toxicants or their effects within workers.

References

  1. ↑ "Standard for Single and Multiple Station Carbon Monoxide Alarms". UL . Retrieved 2017-10-22.
  2. ↑ "UL Mobile | News". Archived from the original on 2016-03-06. Retrieved 2016-02-28.
  3. ↑ NFPA 720: Standard for the Installation of Household Carbon Monoxide (CO) Warning Equipment, 2005 Edition, Annex B Dangers of Carbon Monoxide, B.1 Carbon Monoxide, Table B.1 Symptoms of Carbon Monoxide Exposure Based on Concentration
  4. ↑ "Consumer Reports buying guide for smoke, carbon monoxide detectors".
  5. ↑ "Carbon Monoxide Detectors Buying Guide". ranky10.com. 2017-09-22. Retrieved 2017-10-22.
  6. ↑ U.S. Consumer Product Safety Commission, Carbon Monoxide Detectors Can Save Lives (CPSC Document #5010), archived from the original on 2009-04-09, retrieved 2007-07-29
  7. ↑ Sorenson, Ida (2022-04-16). "9 Reasons Why Your Carbon Monoxide Detector Went Off Then Stopped" . Retrieved 2022-10-14.
  8. ↑ NFPA 720: Standard for the Installation of Household Carbon Monoxide (CO) Warning Equipment, 2005 Edition
  9. ↑ "Top 5 Things to Know About CO," LifeSafety magazine, Fall 2006
  10. 1 2 Hope, Paul (14 March 2017). "3 Carbon Monoxide Alarms Named 'Don't Buy: Safety Risk' by Consumer Reports". Consumer Reports.
  11. ↑ Otieno, Tyron (30 October 2023). "15 Reasons Why Carbon Monoxide Detector Flashing Red But No Sound". Home Safety Point.
  12. ↑ Guide to Prevent Carbon Monoxide Poisoning , retrieved 2007-07-29
  13. ↑ Gundel, Lara A.; Michael G. Apte; Albert R. Nematollahi (1998). Carbon Monoxide Detector Technology Comparison: Response to Various Gases (PDF) (Technical report). Ernest Orlando Lawrence Berkeley National Laboratory. LBNL-40556. Retrieved 2014-01-14.
  14. ↑ "Carbon Monoxide Detector Requirements, Laws and Regulations". National Conference of State Legislatures. 2017-04-03. Retrieved 2017-10-22.
  15. ↑ "Carbon Monoxide Alarm Questions and Answers". Ministry of Community Safety and Correctional Services. Archived from the original on October 23, 2017. Retrieved 2017-10-22.
  16. ↑ Eva Ferguson (2017-01-06). "Carbon monoxide safety advocate to lobby Alberta to make detectors mandatory in Alberta". Calgary Sun. Archived from the original on 2017-10-24. Retrieved 2017-10-22.
  17. ↑ http://artclesgalore.com/article.php?id=2879%5B‍%5D
  18. ↑ "Carbon Monoxide Virtual Toolbox". Division of Homeland Security and Emergency Services. 7 November 2014.
  19. ↑ "Welcome Page". New York State Office of Fire Prevention & Control. Archived from the original on 2010-05-21.
  20. ↑ Senate Bill 183
  21. ↑ Updated Smoke Alarm Requirement (Report). 12 February 2015. California State Fire Marshal Information Bulletin 14-006. Archived (PDF) from the original on 2016-05-06.
  22. ↑ Carbon Monoxide Environmental & Occupational Health Programs.
  23. ↑ Canadian Mortgage and Housing Association Archived April 11, 2013, at the Wayback Machine
  24. ↑ "Carbon monoxide". Centers for Disease Control and Prevention (CDC). April 11, 2016. Retrieved May 10, 2016.
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