Timely Tips 

Fall

Carbon Monoxide - The Silent Killer

With winter approaching, windows are being sealed up and furnaces are burning off the dust and grease from the summer. That is what you smell the first time you turn on the furnace in the fall. It burns off and the smell dissipates. Now everything is in shape for the heating season. Or is it! Any time we light a fire inside a living space, there is a potential for carbon monoxide production. The new tighter houses reduce the amount of infiltration of outside air so the dangerous gasses that do get into the house are not as highly diluted . This condition results in higher concentrations and a potential for disaster.  Let's first look at what carbon monoxide is and how it effects the body.

Carbon monoxide (CO) is a chemical compound made up of one atom of carbon and one atom of oxygen. It is not the same as carbon dioxide, a relatively harmless gas we exhale and plants need to live. Carbon dioxide (CO2) is made up of one atom of carbon with 2 atoms of oxygen. Both are colorless, odorless gasses but the similarities stop there. CO is a deadly killer. When you breathe carbon monoxide (CO), it attaches itself to the red blood cells. The red blood cells are the delivery boys that pick up oxygen and deliver it to all the cells of your body. Once the CO grabs that red blood cell, it won't let go. It is very possessive too. It won't let the red blood cell go out with any oxygen molecules.  If the red cells are hooked up with that evil CO, they can't take any more deliveries of needed oxygen to the cells and the cells begin to die from lack of oxygen. The more CO you breathe, the less oxygen is delivered to the cells and more cells die. First signs might be a headache, nausea, dizziness, shortness of breath and confusion but if the condition continues, death will ensue. 

Carbon monoxide concentrations are measured in ppm, parts per million. 1ppm indicates there is one part of CO in 1,000,000 parts of sampled air. 9 ppm is the maximum indoor air quality standard. 50 ppm is the maximum concentration for exposure for 8 hours. 400 ppm will produce headaches in 1 to 2 hours and is life threatening after 3 hours. 800 ppm induces nausea and convulsions and death within 2 hours. 1,600 ppm produces nausea within 20 minutes and death within an hour and 12,800 ppm produces death within 1 to 3 minutes. These are average effects and the condition of the individual greatly effects the times. The young and elderly are more at risk as are pregnant women, anyone who is anemic or anyone with heart or lung problems. Keep in mind the effects are cumulative. Small concentrations over prolonged periods are also dangerous. So, what is a safe level and what is a desirable level aren't  the same. 0 ppm is desirable while 9 ppm is considered safe under normal conditions. That is like saying 9 ppm is safe because it will only make you a little sick. It won't kill you!

So, where does this CO come from? Any time something is burned, the by-products are carbon dioxide and water vapor. Notice that is carbon dioxide, the good guy. Under ideal conditions, CO would not be produced but under poor burning conditions, CO is produced along with the CO2. This brings up a common misconception that all heating equipment produces CO. This is not necessarily true. Properly designed and adjusted equipment will produce little or no CO. Another misconception is that a cracked heat exchanger will cause CO. The CO is caused  by a poorly adjusted furnace burner. The cracked heat exchanger will simply allow any CO produced to be brought into the home rather than up the chimney. This brings up another point. Furnace design limits the possibility of CO escaping into the conditioned air blown through the house. First the fire is contained inside a compartment inside the furnace. This compartment is called the fire box or heat exchanger. Air enters the fire box combines with the fuel and is burned. The by-products go up the flue or chimney. The air blown through the house blows around the heat exchanger and is warmed up by the heated metal. The blower is in front of the heat exchanger so it is blowing onto the heat exchanger. If there were a hole in the exchanger, this would tend to blow air into the fire area and up the chimney. 

Technical note, science class information to follow; read at your own risk: There is another physical effect taking place in the heat exchanger. This effect is called the Bernoulli effect. Any time air blows across a hole it lowers the pressure and draws the inside gas out rather than pushing itself in. This contradicts the previous paragraph to some extent. This effect will be determined by the actual characteristics of the hole and where it is located on the heat exchanger. As you  can see, there is more than one force acting on the system. Therefore, you can't rely on the pressurization around the heat exchanger to stop heat exchanger cracks from leaking potentially dangerous CO. Any apparent heat exchanger cracks are potentially dangerous.

It has been my experience that the biggest risk of CO poisoning is at the flue not at the heat exchanger. A blocked chimney will cause all the available CO to be diverted into the living space. No furnace check should be complete without a test for proper venting. Newer furnaces have blowers that blow the combustion air out. This is a good safety measure. However, if a water heater is also connected to the same flue ( which is common ) and the outside flue is blocked, the blower will blow the potentially dangerous flue gasses back out into the room at the water heater draft hood. Both vents should be checked.

Other CO producers can be fireplaces, stoves, ovens, space heaters, water heaters or any other appliance that contains fire. One particularly dangerous apparatus is an hibachi grill or charcoal grill. These fires by nature are slow burning and produce considerable CO. Wood stoves with a controlled burning wood fire also produce great quantities of CO. Cigarettes produce another fire that is a slow burning CO producer.

That should give you at least a working knowledge of the burning process and the production of the potentially lethal CO. Now, If the CO hasn't put you to sleep, this long dissertation probably has. Have a safe heating season. Monitor the CO levels in your house. Have it checked professionally at least once a year if you have an old furnace. 

Next time we will talk about Radon, another potentially dangerous gas. 

More Fall

Here it is fall again. What ever happened to summer? While summer is often the best time to do all those outdoor projects, it is also the time to go on vacation, spend some leisurely time in the yard and who wants to work on the house when it is so hot? Well, I have to agree with the logic but time waits for no man and fall and winter are fast approaching. Ready or not, it is time to think about inclement weather. Before snow flies, you better get the exterior paining completed. 

The most important thing to remember about quality painting  is proper preparation. Painting is 80% preparation and 20% painting. Depending on the surface to be painted, you need to get it ready to hold paint. Paint is only as good as the first layer. If you paint over old loose paint, the newly painted surface is going to peal off. New paint will not hold on old paint! If old paint is flaking, it needs to be removed. The more effort you put into the removal, the better the new paint job and the longer it will last.

Old paint can be removed with scraping, sanding or chemical removers. Using a pressure water sprayer can also be used. Be careful with the high pressure to prevent damage to the wood. After using a water cleaning method, the wood must be allowed to dry thoroughly.  I saw a house that had been power washed too well that had saturated the blown in insulation. The result was that the wood didn't dry out inside and the new pain ALL pealed off. It was terrible! So the word for power washing is "Caution".

Once scraped and sanded, bare wood should be primed with a quality primer designed for bare wood. Keep in mind, paint is not intended to span and fill cracks nor will it smooth a rough surface. It might look smooth when it is wet but as it dries and shrinks, it will conform to the surface below. If the surface was rough, the new paint will also be rough! The cracks and holes will still be there! The imperfections should be caulked until smooth. Only when you have a smooth primed surface, are you ready to paint! The older the house, the more the old paint layers and the more work to prepare.

Let's look at some paint characteristics. Water based paint is the most popular paint now. It covers well and clean up is easy. Older latex (water based) paint was not as durable as the oil based paint but new formulas form a good durable finish. One quality of latex paint is it's ability to pass water vapor through. Oil based paint is water proof and water vapor trapped below the surface will eventually cause the paint to blister. Blistering paint is an indication of a hidden moisture problem that should be investigated, not just scraped and painted over. Oil based stain penetrates the wood and gives it color but does not do much to protect it from sunlight and drying. I do not recommend using stain on wood siding unless it is cedar or redwood. DO NOT USE stain to protect plywood materials. It will usually result in a delaminating of the plywood that can not be repaired but must be replaced. 

Wood decks should be treated regularly. The factory treating will prevent rotting and insect infestation but it will not reduce cracking and warping. Use an oil based penetrating protector at least every three years. If the deck is in the sun, more treating will be required.

Now that I have ruined your fall, perhaps you should just wait till spring and have it sided!

Spring

Moisture Revisited:

Winter

Moisture Problems:

    Ever seen this?

Truss lift:

 

More Winter

December and January are synonymous with holidays. We are now into the winter season and cold temperatures. There might be a few days to finish up those outside projects but chances are, they will simply have to wait until spring!

Safety:

Fall

October is a month of falling leaves and changing temperatures.
It is a time to start thinking about winter and the winter needs for
the house. It is time to get those outside chores done before freezing
temperatures make it impossible.

Gutters:

Air Conditioners:

Grading around the house:

Garden hose:

Call the House Doctor for a pre-winter check up.

Prices start at $60.00

 

Top of Page

Links

Contact House Doctor

Services:

Tips:

HOME