Carbon Monoxide Alarms Are Not Effective Enough
While carbon monoxide alarms are essential they must be improved to eliminate all injury and brain damage as they don’t go off soon enough.
The other big problem with our current prevention strategy is not that CO alarms are defective, it is that they are ineffective. The reason for the ineffectiveness of the alarms is the compromise that made up the UL 2034 Carbon Monoxide alarm standard. Essentially, those arguing for better alarms were drowned out by cries about false alarms. The current alarm standard aims to prevent an adult male’s COHb level from reaching 10%. That approach is regrettably flawed.
The troublesome premise of the UL 2034 Alarm standard is that it is built around the alarm resisting alarm, not actually alarming. The simple way to build an alarm is for it to go off when the CO gets to a potentially dangerous level, say 50 ppm. Instead, this standard is built around the CO remaining above an even higher level, for defined periods of time, as follows:
UL2034 Required Alarm Points·[1]:
- If the alarm is exposed to 400 ppm of CO. IT MUST ALARM BETWEEN 4 and 15 MINUTES.
- If the alarm is exposed to 15-0 ppm of CO. IT MUST ALARM BETWEEN 10 and 50 MINUTES.
- If the alarm is exposed to 70 ppm of CO. IT MUST ALARM BETWEEN 60 and 240 MINUTES.
These range tolerances are absurd. The maximum resisting times involve a magnitude of up to four times as long of exposure as the is the minimum for alarming. Four times as long means four times as much COHb, could be the difference between 10% and 40%, a near fatal level.
[1] Approximately 10% COHb exposure at levels of 10% to 95% Relative Humidity (RH).
The EU alarms have a one level alarm threshold. The UL standard must be revised.
Evidence for better carbon monoxide alarms is being provided by the CO Rearch Trust in the UK that is doing important research on the health effects of lower levels of CO exposure.
Carbon Monoxide Alarms must Detect Lower Level Exposures
Most carbon monoxide poisonings are not one time events, with lethal levels. Most CO events happen in progressively higher concentrations on successive days. The ambient air levels begin with lower levels when the appliance begins to malfunction and then increase to a point where someone get seriously ill, or an alarm is triggered. Lots of research, especially that being done in the UK, is showing serious health effects, especially in pregnant women, with much lower levels than the UL alarm standard would identify.
The advantage of lowering the standard is not only avoiding the risk of low level CO but getting the HVAC technicians out there earlier, so that they can do preventative maintenance before it is too late.
What is Wrong with Preventing the 10% COHb Goal?
First, 10% is the level where the risk factor reaches 40% for permanent brain damage. The goal should be to alarm before levels get toxic.
Second, not everyone is an adult male. Women and especially children are likely more vulnerable to carbon monoxide and they uptake it faster due to faster metabolisms. By uptake, we mean the COHb level will exceed 10% faster than it will for an adult male. Children uptake considerably faster because respiration rates are faster. A typical adult respiratory rate is 12-20 breaths per minute, while a young child’s can be between 30-60 breaths per minute. The smaller the child, the more vulnerable they are to the effects of CO and the faster their COHb levels exceed 10%.
Carbon Monoxide Alarms are not Sensitive Enough at Altitude
Finally, this standard doesn’t consider the effects of altitude. The effects of carbon monoxide are more toxic at altitude.[1] Even arguing that 9.9% was acceptable in an adult male, that goal is for an adult male at sea level. The higher the altitude, the less oxygen there is in the air. As a result, when carbon monoxide takes up 10% of the hemoglobin, there is a decreased amount of oxygen available for the brain’s metabolic needs.
It may or may not be a coincidence but the best diagnosis and treatment for carbon monoxide in the United States has historically occurred in the mountain states of Utah and Colorado.
Next: What to do if the Alarm Does Go Off?
(IMMEDIATE EVACUATION).
[1] 5. McGrath JJ. The interacting effects of altitude and carbon monoxide. In: Penney DG, editor. Carbon monoxide toxicity. Boca Raton, FL: CRC Press LLC; 2000. p. 135-156. See also: “This suggests that the high-altitude resident has a greater initial body burden of COHb and will attain the COHb level associated with the National Ambient Air Quality Standard for carbon monoxide more quickly than the sea-level resident.” Res Rep Health Eff Inst. 1989 Jul;(27):1-23. Cardiovascular effects of chronic carbon monoxide and high-altitude exposure. McGrath JJ1.