By Tom Burden
Carbon Monoxide is a silent killer on houseboats and other recreational vessels. Each year, boaters are killed or injured by carbon monoxide, and virtually all of these poisonings are preventable. We’ll discuss monitoring devices to alert you about this danger, but first, we’ll remind boaters that regular maintenance of your boat’s mechanical systems and proper operation of your boat are the best defenses against carbon monoxide.
Carbon monoxide is an odorless, tasteless, initially non-irritating gas, created by incomplete fossil fuel combustion (due to insufficient oxygen supply to allow complete oxidation to carbon dioxide) in appliances like gas-powered electrical generators, propane stoves or heaters, or your boat’s propulsion engine. Because Carbon Monoxide (CO) is lighter than propane or gasoline vapor, without smell or taste, its presence remains undetected by humans until symptoms of exposure set in.
CO results from incomplete burning of fossil fuels, so we may be exposed to it wherever engines operate (propulsion engines or gas generators) or near open flames (heaters or galley appliances). Exposure time and concentration levels determine what effect, if any, this exposure has on our bodies. Amounts over 100 parts per million are dangerous to human health. A word of caution: typical symptoms of CO exposure could easily be mistaken for seasickness because they trigger dizziness, and nausea. Unlike seasickness, a CO leak can be fatal if it goes undetected. We think this alone warrants the investment in a good CO detector.
CO is easily absorbed into the bloodstream (combining with hemoglobin 200 times more easily than oxygen) where it reduces the blood’s oxygen-carrying ability, leading to hypoxia and causing “suffocation” by the victim. Since the body can accumulate CO, the blood level can gradually increase. Remove the victim of CO exposure to a location with fresh air. Acute exposure is a medical emergency.
Here is what a person’s carboxyl level (COHb), the “parts per million” concentrations of carbon monoxide, mean to your health:
|100 ppm||.01%||Slight headache in two to three hours|
|200 ppm||.02%||Slight headache within two to three hours; loss of judgement|
|400 ppm||.04%||Frontal headache within one to two hours|
|800 ppm||.08%||Dizziness, nausea, and convulsions within 45 minutes. Insensible in two hours.|
|1,600 ppm||.16%||Headache, dizziness, and nausea within 20 minutes. Death in less than two hours.|
|3,200 ppm||.32%||Headache, dizziness and nausea in five to ten minutes. Death within 30 minutes.|
|6,400 ppm||..64%||Headache and dizziness in one to two minutes. Death in less than 20 minutes.|
|12,800 ppm||.1.28%||Death in less than three minutes.|
Take the following actions whenever you use your boat. Do not operate the vessel if any of these problems exist!
Time-weighted averaging: As of 2010 a carbon monoxide detector must meet the ANSI/UL 2034-2005 standard, and it should compute the time-weighted average of the CO concentration in the air. The time-weighted average measurement process constantly monitors all CO levels, eliminating most false alarms.
Multi-channel monitoring: This function allows detectors to sniff for fumes in different cabins. For example, the CO Sentinel CMD-4MR-RLY (Model 6818900) allows up to six detectors to be linked in series. When one detector’s alarm activates, all connected detectors will alarm to alert boat inhabitants in other locations to the presence of CO.
Sensitivity: CO alarms will sound when they measure 70 particles of carbon monoxide per one million particles of air (PPM), well before the first symptoms of overexposure set in.
Sensor mounting position: Install carbon monoxide detectors or remote sensors at or near eye level in each cabin but NOT near a hatch or porthole where water could come in contact with the device.