The tighter building conundrum
By Ian McTeer
Should our industry be promising quality indoor air?
We moved to Toronto from Calgary in 1958. My father rented a nice apartment on the second floor of a low-rise building near Yonge and St. Clair. On occasion in the winter it would be necessary to open several windows quite wide because the room temperature would climb to equatorial levels. However, my fondest memories come from the Tesla-like electric shocks I was able to administer to my sister that would send her screaming into the next room. Of course, I do suppress the memories of her hitting me over the head with schoolbooks and the embarrassing self-inflicted static shocks. Suffering all of winter’s extremes seemed to be inevitable; something one took for granted. Indoor air quality was an unknown entity.
Energy Conservation Since 1973
The idea of conserving energy, especially fossil fuels, began in earnest after a political squabble in the Middle East caused the OPEC oil cartel to cut-off oil deliveries to the U.S. market starting in October 1973. Having to live on roughly 25 per cent less oil resulted in gasoline rationing, a particularly bitter pill for American gasoline-powered mobility to swallow. Since 1973, the world has been worried about “peak oil,” the notion that we are quickly running out of fossil fuel resources and must turn to more sustainable sources such as solar power. However, a crazy thing happened on the way to the fossil-fuel hell hole: fracking technology has unleashed gushers of new oil in the U.S. making it almost self-sufficient in oil once again. There is so much oil sloshing around out there that instead of $200 a barrel for oil predicted by the doomsayers, we are at $30 a barrel today. Many of the high cost oil producers are out of business; tens of thousands of Canadian oil-patch workers have lost their jobs. So, run out and buy an SUV; crank up that smart thermostat until it threatens to report you to the RCMP; put Canadian oil workers back to work! Oh wait, we can’t do that, there is another big problem called: Climate Change. It is a Google car and Passivhaus for you.
Batten Down the Hatches
For years we have been steadily tightening-up residential buildings. The R2000 program and the HOT2000 software have been around since the 1980s. The province of Ontario incorporated a performance-orientated chapter into its building code known as Part 12 in 2007. All across Canada, municipalities are just as concerned about energy efficiency as they are about building safety. Modern housing should have less conductive heat loss.
On his website, www.healthyheating.com, Robert Bean reminds us that experiencing our indoor space is a package deal he calls Indoor Environmental Quality (IEQ). IEQ consists of six metrics:
IEQ = TCQ + IAQ + ISQ + ILQ + IOQ + IVQ
TCQ = Thermal comfort quality
IAQ = Indoor air quality
ISQ = Indoor sound quality
ILQ = Indoor lighting quality
IOQ = Indoor odour quality
IVQ = Indoor vibration quality
Perhaps other than ILQ, our industry is responsible for providing the best possible base IEQ that is affordable, well suited to the application and user friendly. As we continue to fight climate change, providing an acceptable IEQ in exceptionally tight, energy efficient buildings is an enormous challenge for our industry.
Newspaper and internet articles regularly discuss IEQ going seriously wrong in Europe and North America. One recent story by Emily Hill in the British publication The Spectator, told of the “eco-home hell” that Emily and other tenants suffer due to excessive heat in the units during the spring and summer months.
“True, I’ve not turned on a radiator for two years – but in spring and summer it’s miserably, and sometimes dangerously, hot,” she said. Emily needs mechanical cooling, there is no way ventilation alone can keep her comfortable.
The State of New York Home Performance With Energy Star Program sent a note to participating contractors last December stating “recent research has revealed that a high percentage of completed projects in the Home Performance with ENERGY STAR program do not meet the savings projected during modelling.”
A report in the DutchNews.nl claims, “Modern and well-maintained central heating boilers are more likely to cause carbon monoxide poisoning than old boilers, the Dutch safety board said…in accidents involving carbon monoxide, 46 per cent are caused by heating systems, most of which are new or maintained by a professional, the board said.”
I struggle with the word “quality” as applied to indoor air because it implies a definable standard against which an HVAC contractor could possibly model a path to remediation suitable to any particular customer. However, there is no CSA standard denoting the ideal indoor environment.
My old chemistry text book says air should be roughly 78 per cent nitrogen, 21 per cent oxygen and about one per cent of trace gases, such as: hydrogen, carbon dioxide, xenon, helium, argon and others. We know that air contains many, many other gases, chemicals and particulates.
Consider the list of corrosive chemical contaminants shown in Figure 1. None of the contaminants in Figure 1 can be included in the combustion air of a furnace or boiler. Exposure to these chemicals in the air will ruin a heat exchanger in short order, never mind what they can do to one’s physiology.
I have been in thousands of homes across Canada. I said earlier that our industry must provide a “base IEQ” simply because once humans occupy a space, no two houses will be the same when it comes to what is floating around in the indoor air. People have hobbies and crafts; I have seen machine shops with metal lathes, drill presses, parts washers; motorcycles and boat motors; woodworking shops; pottery and pottery kilns; hair dressing; pet care; and home offices. I have seen piles of trash, hundreds of rotting newspapers piled up; some people still smoke various substances indoors; many people burn scented petroleum and beeswax candles; and I have encountered single family homes with several families living in them. People literally torture their HVAC systems and it could be dangerous for some people to occupy a residence tightened-up to modern building codes. It really is impossible to provide a decent IEQ with all this stuff going on.
Figure 1 Corrosive chemical contaminants
Permanent wave solutions
Chlorinated waxes and cleaners
Chlorine based swimming pool chemicals
Water softening chemicals
Deicing salts or chemicals
Cleaning solvents such as perchloroethylene
Paint, paint removers, varnish, shellac, and so on
Cements and glues
Antistatic fabric softeners for clothes dryers
Masonry acid washing materials
Air Exhausting Appliances
In the December 2015 issue of HPAC, Robert Bean’s article, “The Essential Ingredients” asked the question: how much is enough when it comes to providing proper kitchen exhaust. People love to cook, especially with gas, but cooks are oblivious to the effects of radical depressurization and simply want the fumes to disappear. Bean’s guidance on this topic is a must-read for all new installations done by professional contractors.
But kitchen exhaust has turned into a DIY project, it seems. It is sadly amusing to watch television reality renovation programs in which gas stoves, along with industrial strength range hoods, are installed into improper duct systems by renovation enthusiasts. The local home improvement store has plenty of 220 cfm range hoods in stock readily available for the DIYer to put himself at risk.
In the TSSA Fuels Edition “Update” pamphlet, Volume 8, Fall 2010, Zenon Fraczkowski (senior engineer) discussed minimum clearances to combustible material for gas or LP fired stoves: “What TSSA is finding now are very elaborate custom-designed vent hoods over gas ranges that are closer than the required 76.2 cm above the range.”
Zenon went on to point out that it is “the gas technician’s responsibility and ultimate accountability to install appliances in accordance with the code requirements and certified installation instructions.” Thus, a gas stove with a range hood can easily be a fire hazard and an IEQ nightmare at the same time. HVAC technicians beware: this is on you! Perhaps the kitchen and craft rooms should be in a separate out-building, but who is going to pay for that.
Heat Recovery Ventilators
Tight construction requires mechanical ventilation. Unless you have completed an HRAI Skilltech or community college program, you are not qualified to specify or to install a heat recovery ventilator (HRV). I bought a house built in 2005 that is fairly tight: at -27C last winter I still had 25 per cent RH in the house and struggled to keep the windows dry. The builder-installed HRV was a decent product, but was not installed properly, not commissioned properly (no evidence of balancing) and never maintained. I managed to get it going but it was replaced this summer. That replacement project was a story onto itself.
An effective air filter (MERV 11 minimum) is required in every air handling system to keep the blower wheel, secondary heat exchanger (if equipped) and evaporator coil clean. Clean components mean system efficiency is retained longer, failures are reduced and maintenance is easier. An effective filter helps overall IAQ by removing (trapping) smaller particles such as: dust, pollen, pet hair and dander and lint. Specialized filters, such as HEPA, trap particles with 99.7 per cent efficiency down to 0.3 microns. The unit I use is 99.98 per cent efficient, trapping particles down to 0.1 microns.
But remember, temperature control and humidity control are the first principles of IAQ. If your filter selection impedes airflow, then IAQ will suffer accordingly. Rob Falke, president of the National Comfort Institute says, “The pressure drop over the filter should not exceed 20 per cent of the maximum static pressure of the fan…if you choose a good quality variable speed fan rated at 1.2 in. of total external static pressure, your fan can afford 0.24 in. of pressure drop over the filter.” The problem is PSC blowers are rated at 0.5 in. in most cases (only 0.10 in. allowed) and you must check your manufacturer’s variable speed blower charts because static pressure ratings can vary widely (0.90 in. to 1.2 in. typically) depending on the model. Two other considerations:
• Many cabinet MERV 11 or better filters have a fairly high initial pressure drop. If you have got a PSC blower rated at 0.5 in. (meaning the filter should drop 0.10 in. or less) and the filter selected has an initial pressure drop of 0.26 in., that is not going to work.
• For example, when using a VS blower rated at 1.2 in., and your total system external static pressure including a 0.26 in. filter works out to 0.76 in. w.c. the VS motor is going to use more watts than expected. The operating cost will be higher, so if you told your customer the fan uses as much power as a 100 watt light bulb, you will be left with some explaining to do. Use the lowest initial pressure drop filter available, or possibly use the next largest size if the P is lower.
In The End
I haven’t even mentioned issues like asthma: the Asthma Society of Canada says more than three million Canadians have asthma which is associated with indoor allergens like dust mites, mould, ozone, volatile organic compounds, and phthalates found in some types of PVC. Then there is stuff an HRV can drag in, such as: nitrogen dioxide, sulphur dioxide, carbon monoxide, reduced sulphur compounds, ozone, and fine particulate matter or PM2.5. Nor have I talked about IEQ in commercial buildings, a place many people say makes them sick.
While the government, on one hand, may assert the right to compel private citizens into actions seemingly aimed at preserving their best interests, it is certainly another thing to legislate their behaviour at home. Governments, jolted into action by the climate change crisis, will certainly become permanent residents of the nations’ mechanical rooms. Because the homespun activities of many Canadians may no longer be suitable for tight construction, how long will it be before a smart HRV sends its owner a bill for failing to maintain key components?
Considering all the potential complications associated with living in a truly artificial environment, our industry has the responsibility to specify and to install the best possible equipment in order to provide an appropriate IEQ. Where the end user takes it from there, is something we will have to deal with as best we can.
Ian McTeer is an HVAC consultant with 35 years experience in the industry. He was most recently a field rep for Trane Canada DSO. McTeer is a refrigeration mechanic and Class 1 Gas technician.