According to a New York Times story run on September 11, 1997, "Many carbon monoxide detectors sold in hardware stores sound their alarms for no reason, or fail to sound an alarm even when high concentrations of the deadly gas are present, according to recent laboratory tests. Industry officials, prodded by the Consumer Product Safety Commission, are drafting tougher standards that may make obsolete the tens of millions currently in use."
That was two years ago. What's happening now? Let's read what Jack McNamara, Director of Industry Affairs, Bosch Security Systems, had to say in a recent issue of ISC West Show Daily FIRE/LIFE SAFETY article. (I've added occasional commentary between paragraphs in blue. The rest is pure Jack:
"Life safety measures in homes and residential facilities got a huge boost in late 2008, as a new national standard governing the installation and usage of carbon monoxide detection devices was released. The standard’s primary goal is to signiﬁantly reduce the thousands of preventable illnesses and deaths each year as a result of carbon monoxide (CO) exposure. But the new regulations surrounding CO detection also will undoubtedly spur new areas of opportunity for security and ﬁe alarm installers and manufacturers."
(This was long overdue in my opinion, but it's clear that Jack has the right goal in mind as he hones in on the preventable illnesses and deaths at stake-RM)
"Carbon monoxide poisoning, which kills more than 500 people each year and sickens 15,000, is a hidden danger in any building that uses fuel-burning appliances or other equipment. If inhaled, the odorless, colorless, invisible gas is absorbed into the bloodstream, replacing the oxygen needed by vital organs throughout the body. Exposure to CO can cause symptoms such as headaches, dizziness, and vomiting; as contact with the gas grows in length or severity, death can occur quickly."
(One point here- although these are classicly cited symptoms from the literature, here's my actual experience- unconsciousness hits you so quickly as concentrations of CO build that you're on the ground before you know it. I've seen three guys drop and had it happen to me twice, and none of us even knew we had any symptoms. It takes you out that quickly with almost no warning. That's why carbon monoxide detection equipment is critical. RM)
"Although consumer awareness of carbon monoxide poisoning has increased dramatically over the past decade, it’s estimated that only 15 percent of U.S. homes, and even fewer commercial properties, have CO detectors in use. By comparison, about 96 percent of U.S. homes have smoke detectors. Because NFPA 720-2009, the governing CO detection code from the National Fire Protection Association, was not available until late last year, many states and local jurisdictions developed their own regulations. These differed by state, county, or municipality, resulting in a piecemeal approach that caused confusion for security and ﬁre alarm dealers
operating in multiple areas."
(I believe the statistics that Jack cites here make the case beyond dispute. In talking with Norm Miller- a design engineer at Cochrane Supplies in Madison Heights, MI and one of the most gas detector savy guys I have ever known- he showed me the list of agencies, regulations and rulings he investigated before each design he develops, and it was a little much for my head. NFPA 720-2009 was a critical achievment in this regard. RM)
"The publication of NFPA 720-2009 has the potential to change many of the existing circumstances surrounding carbon monoxide detection. It will allow authorities having jurisdiction to develop their local and state codes based on the new standard. The 2009 version expands the types of facilities, such as nursing homes, schools, hotels, and other commercial establishments, where detection is required. The previous version of NFPA 720, published in 2005, addressed only dwelling units.
The New Rules
"Under the new rules, carbon monoxide detectors are now subject to the same life safety standards as smoke detectors in many respects, such as power supply and the detector’s electrical connection to an alarm system. Some major ﬁre alarm control panel manufacturers are beginning to offer panels with integrated CO and gas detection capabilities to ensure compliance for installers. Panels with combination ﬁre and gas detection capabilities have the ability to send separate signals to the central station as well as to sound separate signal patterns for ﬁe and gas. These features also satisfy the UL 9th edition of the UL864 standard, which governs all ﬁre
alarm control panels and ancillary equipment.
"Speciﬁc requirements for the placement of carbon monoxide detectors are also outlined in NFPA 720-2009. In commercial applications, a detector must be mounted on or near the ceiling in the same room as a permanently installed fuelburning appliance, as well as centrally located on every habitable level and HVAC zone in the building. For household applications, a detector should be installed outside of each separate sleeping area near the bedrooms and on every occupied level of the dwelling."
(As Dennis Patrick of the Environmental Planning Group, Ltd, observes, "What people need to be concerned with is the source. A fuel rich and improperly burning LPG or Natural Gas furnace can produce literally thousands of part per million of carbon monoxide and once it is emitted into the air it immediately starts the blending process to mix evenly with the air. People are at risk if they think they can initially predict the concentration of CO at a given point or place in the room, because the air is always moving (even in a still room) and the concentration is going to vary based on where in the room. The best place for Carbon Monoxide detectors is close and above the source, because since the Carbon Monoxide is produced from a combustion source, it is heated and as it leaks from the combustion chamber the air is also heated around the source point, together they rise and the mixing begins."
"Installation on the ceiling of a room – or at least ﬁve feet from the ﬂoor – is recommended because carbon monoxide tends to rise with warm air, particularly if the source of the deadly gas is an appliance such as a leaky forced hot air furnace. This will also ensure that the detector remains out of reach of tampering by occupants, children, and pets."
(This idea is a bit of an urban scientific myth. Parts per million mixtures of carbon monoxide have a gas density almost identical to air- and that's exactly what CO in air is- a mixture. The CO mixture in a room only rises as the air in the room rises; it doesn't rise independently. So the point is valid for ceiling placement in spite of that as the source of CO in the room is almost always from a "hot" source that will result in the mixture rising. RM)
Differentiating alarm signals
"To differentiate itself from other ﬁre alarm, trouble, or supervisory signals at the panel level, a carbon monoxide alarm signal must be distinct and 'descriptively annunciated.' The new combination ﬁre panels will also enable the signals to automatically take priority over other trouble or supervisory signals. To protect against device failure, CO detectors must also send their own trouble signals, such as a sensor failure or end of life signal, to the control panel. The CO alarm and trouble signals must also be able to be displayed by central station operators monitoring the system.
"Devices that notify occupants of a carbon monoxide alarm, such as a horn, must also conform to the new standard. For instance, audible alarms must now be a temporal 4 pattern, designed to alert occupants who are often sleeping or already experiencing the sleep-like effects of carbon monoxide exposure."