By TERRY PUGH
The return of the deep freeze means furnaces are working overtime, and people are advised to periodically check their outside vents to ensure they are not plugged by ice or snow.
Any blockage could potentially lead to a situation where carbon monoxide (CO) builds up inside the home, and that could have deadly consequences.
“Carbon monoxide poisonings kill an average of 300 Canadians every year,” said Warman Fire Chief Russ Austin. “It’s called ‘the silent killer’ because it’s odorless and colorless and the only way it can be detected is with a CO alarm or if people get sick.”
Austin said Warman Fire Rescue members responded to four emergencies last winter and spring involving CO poisonings. Fortunately there were no serious injuries in any of those situations because the residences had working CO alarms that alerted them to the danger early enough.
Austin said even though newer furnaces have safety features designed to prevent CO gas from building up in the event of a blockage, it’s still a good practice to knock off icicles that build up on outside furnace vents, and also to clear away snow from around those vents.
“Modern high-efficiency furnaces vent directly outside the building, usually through a side wall,” said Austin. “They are equipped with a sensor and check valve, so that if the exhaust gets plugged for any reason, then the furnace turns itself off.
“But there have been rare instances where sensors failed. So the best plan is to check around your vents when the temperature drops, and also after a heavy snowfall.”
Even older furnaces that vent through the roof can also develop CO leaks if the heat exchanger in the furnace has a crack in it. Austin recommended that homeowners should have their furnaces checked at least once a year by a qualied technician.
Austin also noted that furnaces are not the only appliances that generate CO.
“Basically anything that burns fuel produces carbon monoxide,” he said. “It’s a byproduct of combustion. And what makes it particularly dangerous is that our bodies can’t differentiate. When you breathe in CO, your body doesn’t react negatively at first. You won’t notice symptoms until it’s almost too late. The only way you’re going to know if there’s a build-up of CO is if your CO alarm goes off.”
He said every home should have CO detectors on every level of the house.
“That’s the safest way to go,” said Austin. “Some plug into the wall, some are hard-wired, and some are combination smoke and CO detectors. They’re not expensive, and they save lives.”
Martensville Fire Chief Dean Brooman echoed Austin’s warnings about the potential for carbon monoxide buildup inside homes when ice and snow block high-efficiency furnace vents.
“Back in the day, when furnaces were exhausted out the roof, there was less chance of the exhaust vent getting blocked,” said Brooman. “But, now with the high-efficiency furnaces vented out the side wall, the plastic piping can be prone to freeze up and create a blockage. CO is very harmful to your health and if it accumulates to a high level, it can cause death.”
He recommended that homeowners regularly change their furnace filters, check that their outside vents are not blocked after a major snowfall, and also to ensure they have working CO detectors on every level of their home. Smoke and CO detectors should also be replaced every seven to 10 years.
Brooman said the Martensville Fire Department responds to CO alarm calls numerous times during the year.
“We’ve had our share of more serious calls,” said Brooman. “Nothing where people had to go to the hospital, thankfully, but we have had calls where we found CO limits that required us to completely ventilate the house. On top of that, we’ve had to call in SaskEnergy to figure out the source of the CO leakage. Sometimes it’s not easy to determine where it’s coming from.”
Brooman said sometimes CO gases originate in unlikely areas.
“There have been incidents where people have been charging their car batteries,” he said. “That gives off gas, and we’ve found higher readings in garages that come from simply charging vehicle batteries.”
There are also incidents where vehicles running inside attached garages can result in CO spreading into the adjoining house.
“We’ve had calls where people accidentally hit their remote start, or they decide to warm up their car first, without opening the garage door,” he said. “In one case, a garage heater malfunction resulted in the garage filling with exhaust fumes every time the door opened.”
Brooman said another source of CO gas leakage is in older furnaces and water heaters.
“Sometimes there can be a bit of a downdraft around your older water heater, or furnace” he said. “Basically what’s happening is the appliance is not exhausting the fumes out properly. Some telltale signs on the water heater or furnace can provide a clue. We had one instance of this last spring. The SaskEnergy guy pointed it out to me. The top of the water heater in that instance was all rusted and corroded. So those are some signs you can look at to see if there’s a potential problem.”
CARBON MONOXIDE DANGER HITS HOME FOR FIRE CHIEF
Delisle Fire Chief Mike Given is thankful he took his own advice about having multiple carbon monoxide (CO) detectors in his home.
In late November, he awoke early one morning to the piercing noise of all three alarms going off simultaneously.
It saved his life and the lives of his family members.
“We dodged a bullet,” said Given. “If it can happen to a fire chief, it can happen to anyone. After the last big snowfall a week ago I woke up to the alarm going off, indicating high CO levels.
“What had happened was the amount of snow that fell completely covered up the side vent for our furnace. There are two pipes, one inside the other. One is the exhaust outlet, and the other is the cold air inlet. If they get blocked, then you have issues.”
Given said while newer high-efficiency furnaces have sensors that are supposed to automatically shut the furnace down if the vent is blocked, the furnace in his home was a 20-year-old ‘first generation’ high-efficiency furnace that lacked that type of sensor.
Consequently, the CO gas, instead of being vented outside, was sucked back into the house.
Given said he’s lived in the single-level house for five years, and has three CO alarms. The alarm closest to the furnace was triggered first.
“When we tested for CO, we got a reading of parts-per-million (PPM) in the low 70s,” said Given. “The gas sniffers our department uses have an alarm that goes off at 27 PPM, which indicates dangerously high levels. So if you’re in the low 70s, that’s deadly.”
Given said while CO gas is heavier than air, in theory it should remain close to the floor.
However, in reality, it’s always mixed with the air because every time a door opens or the furnace kicks in, air moves around and circulates throughout the house. As a result, CO gas spreads quickly.
“My advice is to have CO detectors and smoke detectors on all levels of your house,” he said. “The safest strategy is to have CO detectors at low, medium and high locations on each floor.”