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- Published on Thursday, 06 October 2011 20:27
- by Daniel Pine
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The Health Effects of Carbon Monoxide
When we breathe air containing carbon monoxide, it is absorbedthrough the bloodstream where it displaces oxygen and bonds withthe hemoglobin in your blood. Carbon monoxide has a greateraffinity to hemoglobin than oxygen; CO bonds to hemoglobin about250 times better than oxygen. Without oxygen, vital organs, yourheart and brain become deprived and will begin to deteriorate. Tocompensate, your heart rate increases, breathing may becomedifficult and in the most serious circumstances cardiac trauma,brain damage, coma and even death will result.
Symptoms of Carbon Monoxide Poisoning
CO poisoning is difficult to diagnose because its symptoms aresimilar to illnesses such as the flu or the start of a cold.Early warning signs of carbon monoxide poisoning are:
If exposure to carbon monoxide continues, symptoms will oftenbecome worse and include severe headaches, mental confusion,vomiting, vision and hearing impairment and eventuallyunconsciousness. When CO poisoning reaches this stage, CO cancause memory loss, permanent brain damage, coma and eventuallydeath.
Progressive Symptoms of CO Poising - Time VS. Concentration
The health effects related to CO depend upon its concentration in the air and the duration of exposure. The amount of carbon monoxide in the air is measured in parts per million (ppm).
Some examples of the effect of a specific level of carbon monoxide over time are as follows:
- at 400 ppm for 1 hour, most adults will have minimal symptoms
- at 400 ppm for 2 hours, most adults will feel a slight headache, be drowsy and begin vomiting
- at 400 ppm for 4 hours, for most adults death is certain
Sources of Carbon Monoxide in the Home
Both old and new homes alike contain potential sources of CO.Older homes are susceptible because of malfunctioning appliancesand faulty ventilation. However, new homes that are energy-wiseand tightly-sealed to trap heat may be at even more risk. Gas,oil and other fuel furnaces, gas-powered appliances, fireplacesand wood stoves all require oxygen to operate efficiently. If thehome is too airtight, these devices may begin competing for theavailable oxygen. They may cause "backdrafting" whichpulls polluted or CO contaminated air back into the home.
Types of Carbon Monoxide Detection Technology
The three most common CO detection technologies availabletoday are: chem-optical (gel cell), electro-chemical andsemiconductor.
1) CHEM-OPTICAL (GEL CELL) TECHNOLOGY
Chem-optical technology alarms are also known as gel cell or biomimetic technology alarms. These alarms utilize a type of sensor that simulates hemoglobin in the blood.
Electro-chemical technology alarms are usually battery powered. This type of sensor typically has a limited lifetime of about 2 - 5 years. Some manufacturers' models will require its battery and/or sensor to be changed periodically by installing an expensive replacement. Other manufacturers' models have sealed housing that requires the entire unit to be discarded once the battery power supply is depleted.
3) SEMICONDUCTOR TECHNOLOGY
There are a variety of CO alarms that utilize semiconductor or tin dioxide technology available on the market today. Unlike alarms which utilize chem-optical or electro-chemical technology, semiconductor detectors do not require expensive replacement sensors. However, not all semiconductor CO alarms are alike. Some manufacturers utilize semiconductor sensors that are not designed to be used in a CO specific alarm and may be prone to false and/or nuisance alarms.
NADI is one of the world's largest manufacturers ofsemiconductor CO alarms. We utilize semiconductor sensors that aredesigned to detect carbon monoxide. Our alarms are stable andperform well in a multitude of environments. In addition, NADIhas developed breakthrough semiconductor technology whichconsumes even less power resulting in a sensor which allowssemiconductor reliability in a battery powered unit--the first ofits kind. Only NADI offers a wide range of semiconductor COalarms with a choice of 120 volt direct plug-in, 120 volthardwire or battery powered models and a variety of featuresincluding low level warning, back-up battery power and digital display.
How NADI Carbon Monoxide Alarms Work
NADI carbon monoxide alarms (under the brand name"American Sensors") sample the air for CO every 1 to 3minutes. When a unit detects a certain pre-programmed level ofcarbon monoxide, the alarm's microprocessor will store thisinformation and measure the CO level against time. If the COlevel is low or is present only for a short time, the alarm willignore it and burn the sensor clean (so the sensor does notaccumulate CO and cause the unit to nuisance alarm). However, ifthe CO level is high or if a low CO level remains for apre-programmed period of time, the alarm will sound an alarm.This programming effectively minimizes the occurrence of nuisancealarms.
All NADI carbon monoxide alarms are Listed by UnderwritersLaboratories Inc. UL 2034 and/or Underwriters Laboratories ofCanada.
How to Help Consumers Choose a CO Alarm
The following are considerations consumers should be advisedto take when choosing a CO alarm that will be sure to meet theirneeds.
- Consumers should consider ease of installation, the location of installation and the power source of a alarm when choosing a plug-in, battery powered or hardwire model.
- Plug-in units are designed to directly plug into a standard 120 volt electrical outlet for simple installation. This location provides easy access for both testing and resetting the alarm. In addition, the location provides both a visual and audible difference from a ceiling mounted smoke alarm which may help to eliminate confusion during an emergency alarm condition. A plug-in unit also requires no additional costs for annual battery replacement.
- Battery powered units can be easily mounted to a wall or ceiling if the consumer wishes to keep electrical outlets free, if they wish to keep the unit relatively out of sight, or if they would like to keep the alarm away from the reach of children. Some battery powered units are portable alarm that work anywhere--no installation required. These units may be mounted to a wall, left on a table top or carried while traveling. Battery powered units require battery replacement every year, similar to smoke alarms. These units will have a low battery warning signal to indicate when the batteries need replacing.
- Hardwire units are powered by wiring the unit directly into a household's AC power supply at a junction box. They should be installed by a licensed electrician according to the local electrical code. The unit can be permanently installed to prevent tampering.
- NADI offers consumers a full range of plug-in under the American Sensors brand name (models CO800, CO900, CO910, CO920), battery powered (models CO1000, CO1100) and hardwire (model CO810) carbon monoxide alarms.
- Consumers should choose a CO alarm with features (e.g. low level warning, battery back-up, digital display, etc.) that meet their needs.
- Low Level Warning - some carbon monoxide alarms sound a warning (e.g. 3 short beeps) when a low level of CO has been detected. Low levels of carbon monoxide can be hazardous over a long period of time. Low level warnings flag potential CO problems and allow consumers time to respond to them before an emergency situation arises.
- Battery Back-up - some plug-in CO alarm models have a back-up power source that allows the unit to function in the event of a main line power failure. During a power outage, people are likely to use alternate sources of power, light and heat (e.g. kerosene heaters, gas-powered portable generators and fireplaces) which may be out of tune and may produce deadly carbon monoxide gas.
- Digital Display - some CO alarms have a digital display that shows the levels of carbon monoxide in the air in parts per million. For some people, this added feature provides at-a-glance peace of mind.
- Consumers should choose an alarm that has been accuracy tested.
- NADI guarantees each of its alarms to be Triple Accuracy Tested.
- Our Triple Accuracy Testing process exposes every alarm to three separate tests during manufacturing. This testing process includes twice exposing the alarm to carbon monoxide to precisely calibrate each unit. One test is at high levels and the second is at lower levels of CO. In the third step, every alarm is tested to protect against nuisance alarms.
- This stringent method of testing and quality control helps ensure that every NADI carbon monoxide alarm will provide years of reliable, accurate protection for your family and home.
- Consumers should compare alarm warranties and note hidden operating costs.
- Consumers should select an alarm that offers a comprehensive warranty. The alarm's warranty should include its sensor. Consumers should be advised that some CO alarms require the purchase of an expensive replacement sensor and/or battery pack as an ongoing expense.
- Check that the product is Listed by Underwriters Laboratories Inc. UL 2034 and/or Underwriters Laboratories of Canada.
- Consumers should avoid any brand that does not bear the mark of Underwriters Laboratories Inc. and/or Underwriters Laboratories of Canada.
- Every NADI carbon monoxide alarm meets the stringent standards of Underwriters Laboratories Inc. and/or Underwriters Laboratories of Canada.
Where to Locate a CO Alarm
Carbon monoxide is almost identical in weight to normal airand thus will mix freely with air. For this reason alarms may beinstalled at any level in a room, from close to the floor level,to the ceiling.
If the CO alarm is to be ceiling mounted, it should beinstalled away from any existing smoke alarms in order to allowfor differentiation between a CO alarm and a smoke alarm in anemergency alarm situation.
The Consumer Product Safety Commission recommends that every home be equipped with at least one carbon monoxide alarm near the sleeping area of the home. (Because victims of CO poisoning will slip deeper into unconsciousness as their CO condition worsens, a loud alarm is necessary to wake them). For maximum protection, place one carbon monoxide alarm on every level of your home.
In homes heated by a boiler system (radiators rather thanvents), consumers should consider placing a CO alarm near thefurnace room, but about 5 feet away from the furnace itself.Locating a CO alarm directly beside a furnace would be theequivalent of locating a smoke alarm directly above an ovenrange. Under normal conditions, a furnace will emit very lowlevels of CO which will quickly dissipate and thus are notdangerous. However a malfunctioning furnace may generate a veryhigh level of CO which a nearby CO alarm will alert you to.
What to do in a CO Alarm Condition
Consumers should consult their owner's manual for a CO alarmprocedure. However, the following is a general procedure:
If a CO alarm sounds a low level warning or hazard levelalarm, consumers should push the test/reset button to silence it.
If no one in the household has any CO symptoms (headache,dizziness, nausea, fatigue) consumers should be advised to openthe doors and windows to air out their house. They should turnoff any gas, oil or other fuel powered appliances including thefurnace and call a qualified technician or their local utility toinspect and repair their home before restarting the furnace andall fuel-burning appliances.
If anyone in the household does have signs of CO poisoning,consumers should leave their home immediately and call theirlocal emergency service or 9-1-1 for help. They should do a headcount to check that all persons are accounted for once outside inthe fresh air. They should not re-enter their home until it hasbeen aired out and the problem corrected by a qualifiedtechnician or utility company.
Important Diagnostic Information Regarding CO Alarms
Sometimes after a CO alarm alarms, fire departments, utilitycompanies or HVAC installers have difficulty locating the sourceof CO. This does not necessarily mean that there has been afalse/nuisance alarm or that the unit is defective. A number offactors may combine to produce CO and these circumstances mayhave changed by the time the first responder arrives to conductan inspection.
Air pressure in a house may be influenced by one or anycombination of the following: exhaust fans running, gasappliances operating, fireplace burning, wind direction outsidethe house, exterior vents being temporarily blocked, etc. Ductsmay appear to be adequately venting when initially tested.However a certain combination of factors may cause low airpressure in the house which will lead to backdrafting of COthrough exhaust vents. A thorough test under a variety ofconditions may be required in order to locate the source ofcarbon monoxide.
Carbon Monoxide Statistics
Every year 1,700 people die from accidental carbon monoxidepoisoning in North America. Over 10,000 others are treated orhospitalized annually. Carbon monoxide is the number one sourceof accidental poisoning deaths.
A 1984 paper by The Mayo Clinic reports that actual COpoisoning figures may be significantly higher than currentstatistics indicate, as reporting and recording procedures forcarbon monoxide incidents are either not efficient ornon-existent. They report that a study done in a south-west U.S.hospital indicated that 20% of patients seeking aid for chronicflu symptoms were found to have elevated levels of carbonmonoxide.
The American Lung Association, The Lung Association (Canada),the Consumer Products Safety Commission, the American MedicalAssociation and the Consumer Health and Safety Coalition have alldeclared carbon monoxide poisoning a primary concern andencourage consumer awareness and education.
North AmericanDetectors Choice of Technology
There are three technologies commonly utilized in residentialcarbon monoxide alarms. North American Detectors Inc. (NADI) iscommitted to using those components and technologies which in itsopinion are most suitable in each circumstance based on thefollowing criteria:
A proven history of reliability,
Appropriate for the purpose intended,
Recognized by ULC, ULI or BSI as quality components.
Carbon monoxide alarms (CO alarms) currently manufactured byNADI employ semiconductor and biomimetic technology. All COalarms sold by NADI have been tested by the independentlaboratories ULI, ULC and BSI for compliance to relevantstandards and carry the mark of the testing laboratory. EveryNADI CO alarm is tested with real carbon monoxide gas in an ISO9002 factory before it is sold. NADI’s Quality Assurancegroup strictly audits the manufacturing process and ULI, ULC andBSI conduct periodic inspections.
Semiconductor sensors utilize a controlled quantity of tindioxide (SnO2) as a sensing element. The sensingmaterial is heated by a small electric heating element and carbonmonoxide gas is catalytically broken down at the surface of thesensing element. Electrons are released in this process and areabsorbed by the sensing element. This increase in chargedparticles lowers the resistance of the sensor.
In an alarm using semiconductor sensors, electronics are usedto measure the sensor resistance and from this to calculate thecarbon monoxide concentration.
Semiconductor sensors are mechanically simple and areelectronic in nature, therefore, they are very long-lived andvery reliable. Current designs demonstrate excellent immunity toother gases that may be present.
Millions of semiconductor CO alarms manufactured over the pastten years have provided historical data which demonstrates adependable sensor life of more than ten years.
Because of this positive history, the results of hundreds oftests by ULC, ULI and BSI over many years, and proven consistencyin manufacture, this is the principle technology used by NADI.
The three leading manufacturers in the world use thistechnology in their most popular models.
Biomimetic sensors utilize a material that mimics the responseof human hemoglobin to carbon monoxide. In the presence of carbonmonoxide gas, the amount of infrared light which will passthrough the sensing material declines. Alarms using this kind ofsensor use external circuitry to monitor the transmittance ofinfrared light through the sensor. The rate of change of thetransmittance is used to calculate carbon monoxide gasconcentrations.
Biomimetic sensors demonstrate acceptable immunity to othergases that may be present.
Biomimetic sensors are mechanically simple devices.
Alarms using these sensors have field demonstrated adependable sensor life in excess of three years.
Electrochemical sensors typically use platinum as a catalystand acid as an electrolyte to break down carbon monoxide gas andrelease electrons. The electrons induce a small current whichcreates a change in potential at external measurement points.Alarms utilizing this type of sensor use external circuitry tomonitor the changes in potential and use this information tocalculate the concentration of CO gas.
Electrochemical sensors are mechanically much more complexthan semiconductor sensors but can provide more accuratemeasurements of CO concentrations. Modern electrochemical sensorsdemonstrate good immunity to interferent gases.
Careful design and processing is necessary to ensure accuracyacross humidity extremes. Historically, electrochemical sensorshave been prone to leakage due to:
- Corrosion of electrical contacts
- Destruction of sealing surfaces in the body of the sensor
- Expansion of the electrolyte volume
Alarms using these sensors have not field demonstrated adependable sensor lifetime in excess of 2 years.
North American Detectors Inc. has designed several carbonmonoxide alarms using electrochemical sensors. When NADI issatisfied that this technology has an acceptable sensor lifetime,we will add electrochemical models to our extensive offering ofcarbon monoxide alarms.
Dominant Independent Testing Laboratories
Most retailers in North America and Europe require carbonmonoxide alarms to carry the labels of Underwriters LaboratoryInc. (United States), Underwriters Laboratory of Canada (Canada)and the British Standards Institute (Europe).
A brief history of these well-respected independentlaboratories are presented below. We have taken this informationdirectly from their web sites:
Underwriters’ Laboratories of Canada (ULC)
A Canadian safety, certification, testing, qualityregistration, and standards development organization dedicatedentirely to the protection of life and property,Underwriters’ Laboratories of Canada (ULC) is anon-for-profit organization headquartered in Scarborough,Ontario, Canada. With modern and fully equipped testinglaboratories, it exists for the purpose of investigating devicesand materials as to their relation to life, fire or accidenthazards, or their value in crime prevention, and to providingauthoritative information to inspection authorities.
Underwriters’ Laboratories of Canada (ULC) is accreditedby the Standards Council of Canada, under the National StandardsSystem, as a
- Certification Organization
- Testing Organization
- Quality Registration Organization (ISO 9000); and
- Standards Development Organization
ULC’s listings are accepted across Canada by inspectionauthorities and others who are concerned with the safety of lifeand property. Products and services which have been certified byULC are identified by the ULC mark (which consists of ULC in acircle) or by a ULC Certificate.
Underwriters Laboratories Inc. (UL)
Underwriters Laboratories Inc. (UL) is an independent,not-for-profit product safety testing and certificationorganization. We have tested products for public safety for morethan a century. Each year, more than 14 billion UL Marks areapplied to products worldwide.
Since our founding in 1894, we have held the undisputedreputation as the leader in U.S. product safety andcertification. Building on our household name in the UnitedStates, UL is becoming one of the most recognized, reputableconformity assessment providers in the world. Today, our servicesextend to helping companies achieve global acceptance, whether itis an electrical device, a programmable system, or acompany’s quality process.
UL has five testing laboratories in the United States andsubsidiaries in Mexico, Denmark, England, Italy, India,Singapore, Taiwan, Hong Kong and Japan. We also have numerousinternational, affiliate and representative offices, as well asfield representatives located throughout the world.
Estimated products entering the 14 billion
marketplace annually with a UL Mark
Types of products evaluated by UL more than 17,000
Manufacturers of products bearing UL more than 40,000
Laboratory and other service locations 43
UL standards for Safety published 726
Square footage of laboratory space more than 1.5 million sq.ft
Number of Staff more than 4,000
Inspection centers worldwide 190
Firms registered by UL to ISO more than 3,200
9000, QS-9000 and ISO 14001
Countries in which UL serves clients 89
British Standards Institute (BSI)
BSI was the first national standards body in the world. Thereare now more than 100 similar organizations which are members ofthe International Organization for Standardization (ISO) and theInternational Electrotechnical Commission (IEC). These bodiesproduce harmonized world standards. BSI ensures the views ofBritish industry are represented in this area.
All standards are drawn up by committees made up ofrepresentatives who have a particular interest in the subject,including manufacturers, users, research organizations,government departments and consumers. BSI staff act assecretaries to these committees and coordinate the work andproject manage the production of standards. Before and standardis published, it is made available for public comment.
NADI CommunityBased Safety Programs
NADI is a company dedicated to making your home and communitya safer place to live and work. NADI participates in manyprograms with safety organizations, retailers, fire departmentsand other safety organizations. Recently NADI developed itsinteractive Safety House™, a doll house with a resident toyDalmatian dog Safety™ and educational games included toassist educators and parents in teaching safety to children at avery early age. Another program that NADI is proud to participatein is with the Ontario Fire Marshal’s Public Fire SafetyCouncil. "This council was established in 1993, and iscomprised of representatives from the fire service, government,business, industry and the public, all of whom have a profoundconcern about fire safety. Working on an entirely voluntarybasis, the members pool their collective knowledge, expertise andresources to help shape the direction of fire safety strategiesin Ontario." To contribute to this program and increasepublic awareness, several American Sensors™ carbon monoxidealarms display the logo of this council to demonstrate itssupport of their programs like Learn Not To Burn, The ArsonPrevention Program for Children, Alarmed for Life, Risk Watch,Older & Wiser.
All CO alarms sold by North American Detectors Inc. have beentested by the independent laboratories ULI, ULC and BSI forcompliance to relevant standards and carry the mark of thetesting laboratory. Every NADI CO alarm is tested with realcarbon monoxide gas in an ISO 9002 factory before it is sold.NADI’s Quality Assurance group strictly audits themanufacturing process and ULI, ULC and BSI conduct periodicinspections.
American Sensors™ carbon monoxide alarms manufactured byNADI are sold by leading home and hardware retailers throughoutCanada and the U.S.A.
North American Detectors Inc. is a leader dedicated to theresearch, development, and distribution of a full-line of carbonmonoxide alarms, smoke alarms, explosive gas detectors, and otherHome Health and Safety products.
NADI currently has 28,883,155 common shares issued andoutstanding. Common shares trade on the CDN Over The CounterExchange under the symbol NADI. For more information pleasecontact Michele Hughes, Director Investor and CorporateRelations, (416) 496-5966.