Home Safety: Carbon Minoxide and the Home Part 2

The garage is a place where an all too obvious source of Carbon Mioxide, the motor vehicle is found.   But is that the most likely source of accidental CO infiltration into the building envelope?  A local landscaping company advertising their battery and solar grass cutting machines claimed that a lawnmower can be 45x more polluting than an automobile.  Cars have cataytic convertors to do some toxic gas abatement.  Lawnmowers are not equipped with these kinds of devices.  Think about a two stroke combustion engine - it can choke you in wide open spaces, so in a closed space it can be very dangerous.  But make no mistake, motor vehicles left running is still the number one form of non accidental suicide death in North Amaerica.  In even unconfined spaces, left idling with the garage door open, the car is still capable of serious health damage and even death.  

But is it the most likely killer when we know so much about its potential?  Take a look at the pictures above.  Is the car or the space heater... or any of the combustion motor tools more dangerous than the car when left running in a garage with an open door?  Take the gas power pressure washer used to clean the garage floor. How about the gas powered leaf blower used to get the leaves and dust out of the corners and stored items on the flloor?  The weed wacker or the snow blower all can get started inthe garage.  Most homes have lawn mowers that can get started in an open garage.  Any of these combustion gas enginess can have fumes migrate through garage walls and the man door.  The previous article iilustrated how disconnected door closers, frayed or missing door sweeps, missing trim, perforation on the walls, attic garage hatches, and even unpainted walls and ceilings can all allow CO gas to enter the home - and not all of these CO garage defects will be picked up by all home inspectors.  The fact that they all make noise cues us to having a home tool running that has the potential of creating a serious amount of CO gas.  So a combustion engine may not be the most serious tool for CO gas creation because some education here tells us we have something running that has a danger associated with it.

There are household tools that may be worse offenders.   These are tools or devices that are relatively silent.  Carbon Minoxide is famously referred to as the "Silent Killer."   A garage shop space heater makes relatively little noise.  This is not the most efficient way to heat liquid fossil fuels.  CO is created from incomplete combustion.  The longer the heater is on the more CO2 or carbon dioxide is formed.  This squeezes out the oxygen more and more the longer it is left running.  And when there is less oxygen avalable for burning, the CO manufactured increases.  Do you see, or hear, or smell, or taste CO gas?  No you don't.

If the space heater is a dark horse that can win the CO accidental death race it has a competitor. Gas BBQs produce flammable heat that too is not very efficient and can produce CO.  The BBQs that have smokers inside for that pulled pork, brisket, and ribs specialties produce smoldering heat are more volatile CO gas producers.  This is a more potent smoke and CO gas producer than smoke generated from a hot flame.  This tool left running for long periods of time can have disasterous results.  I have walked new home subdivisions, where people without decks are BBQing or smoking meat inside their garages, particularly during the rain. Smoke does not all dissapear into the wide open spaces.  CO gas can infiltrate the unfinished walls, the garage mandoor left open a crack, or through the new storage space in the new attic hatch left open.

What good will a second floor CO detector do in the bedroom with its door closed? Before the CO gas saturates that second floor and sets off a time delayed( that is standard in the industry to avoid false alarms) alarm the people sitting in around a kitchen or family room can all have inhaled enough CO to start CO poisoning in their bodies, or worse. 

The Ontario Buidling Code requires CO gas detectors to be on the bedroom level and if there is a bedroom by the furnace or utility room then there as well.  This is hardly adequate.  There needs to be a Carbon Minoxide detector on every level and in particular one closer to the garage man door on the inside of the house.  All of the combustion engines produce enough CO to sicken and to kill as the amount needed is very low to inflict bodily damage and even death. The silent CO  producers may be more dangerous as we do not often consider that they can produce significant CO gas amounts.  They are overlooked in home safety considerations.

We will see that there are even more hidden places where CO can be created, inside the home and even outside by a window that can kill and harm the residents.  Reliabley detecting CO is more controversal than meets the eye.  All these issues should be addressed by a home inspector when home safety is job number one.  As a home buyer you should demand that your home inspector can provide you with a CO education.

Kurt Weinberger- home inspector for EnerGREEN Home Inspection Services - serving Ktichener, Waterloo, Cambridge, Guelph, Brantord, Milton, and Mississauga and surounding areas. Your ktichernwaterloohomeinspector.ca - reached at kjweinberger@rogers.com and 519-888-0852