Radon and Airtightness

first_imgYou don’t have to go very far or deep on the internet to find skeptics of the health risks that radon in homes presents. It is not easy or straightforward to calculate long-term low-level exposure hazard in homes from studies such as those on miners. But most health experts, nationally and internationally, agree that since radon mitigation is relatively easy in homes, particularly in new homes, the risk justifies the expense of radon mitigation. It gets a little more complicated for existing homes because mitigation is generally much more costly.Airtightness and radon levelsThere are five main factors that drive radon levels in homes:radon concentrations in soil gas around the home;the pressure difference between the inside of the home and the soil around it;the air exchange rate of the home;the moisture content of soil around the home (more moisture means less radon gas movement);entry pathways, their number and size.When you make a home more airtight, the good news is that you could be reducing the entry pathways and reducing the pressure differential between the soil and home. The bad news is that you are also significantly reducing the air exchange rate in the home. So, what really happens?The short answer is: it depends. One study (“Assessment of the Effects of Weatherization on Residential Radon Levels” EPA600//SR-94/002) showed inconsistent relationships between air tightness and radon levels. In my own home, air sealing and insulating throughout the home increased radon levels in the basement significantly but purposeful pressure management has kept living space radon readings consistently below 3 pCiL. There is research being conducted by Oak Ridge National Laboratory (ORNL) and the Energy Center of Wisconsin (ECW) on this topic, but results are not yet available. In general, if you look at the list of the five factors above and figure that energy efficiency upgrades affect three of the five, it is not surprising that the impact on radon levels of energy upgrades may be very case-specific.Measuring Radon LevelsQuite often you will hear that radon tests in individual homes are unnecessary because EPA radon zone maps show low levels of radon or neighbors report low levels from testing in their own homes. Unfortunately, neither the county level zone maps or what surrounding homes are experiencing says much about individual homes and their radon levels.So, with all this uncertainty, and maybe really because of it, we should be measuring radon levels in homes in which we are improving energy efficiency. You just have to test.There are quite a few options for testing radon in homes. I like to break them down into three groups: short term, long term, and continuous electronic.Short term testing is typically 2 – 7 days and either activated charcoal-based or electret ion. These are relatively inexpensive tests that you can generally get at a hardware store. The advantage of this test type is that you get quick results.Long term tests tend to be 3- 12 months and based on alpha particle tracking. Many states supply this type of test kit to homeowners. The disadvantage with this type of test is that you have to wait a long time for results. Continuous electronic monitors tend to work through an ionization chamber with readouts that give you a running average.In general, these radon tests are pretty accurate with least confidence in the short term testing because radon levels can vary pretty widely over time. I have run all three types of radon tests in my own home and I have generally found quite reasonable agreement.Radon mitigation techniquesRadon mitigation relies on two primary approaches: depressurization under the basement or first floor slab or dilution. There is a great EPA table listing radon mitigation techniques, installation costs, and operating costs. In new homes, installing a passive or active system that depressurizes the slab is only about $350; but just about any of the techniques in existing homes can run into thousands of dollars.Radon and Real EstateThis is tricky. Most states and the EPA protocol do not require radon tests as part of real estate transactions, but do require notification to potential buyers if testing has been done previously. Bit of a “don’t ask, don’t tell” policy; except that EPA has a fairly aggressive education/dissemination program to encourage radon resolution as part of real estate transactions. See the EPA “Home Buyers and Sellers Guide to Radon.”SummaryIt is certainly tempting to avoid this whole issue in the long list of tangled and vexing interactions we need to consider in green buildings. But in the long run, do enough research and testing to eliminate the concern or test after your work to determine what might need to be done. You would not think of skipping a worst-case CAZ test because you were afraid of the cost implications of combustion safety; think of radon testing in the same way. We are always trying to avoid unintended consequences of our best efforts to improve home performance. A good example of this is radon gas and air tightness levels in homes during energy retrofits. How are the two levels related and what can we do about it if they are?A bit of background on radonRadon is a colorless, odorless, tasteless gas that is radioactive. It is a byproduct of the breakdown of uranium in rock or soil. As radon radioactively degrades, it gives off alpha particles, a form of ionizing radiation. Because alpha particles are “big,” they cannot pass through even the outer layers of dead skin, so they can only cause cell damage if they are ingested, typically inhaled.Radon’s presence in homes was discovered in 1984 in Pennsylvania when a nuclear power industry worker’s dosimeter badge was maxing out, and not from his work at the nuclear plant. They eventually traced the problem back to the employee’s basement, where the concentrations of radon gas were surprisingly high.There is never a “safe” level of exposure to radiation; for radon in homes EPA has set the action level at 4 pico-curies per liter (pCiL). Background levels outdoors average about .75 pCiL, so the action level is about 5 times greater than background levels. The 4 pCiL threshold for indoor radon is based on a combination of extrapolated health risk and practical mitigation.NOTE: You might see other units of measurement for radon levels; the Canadians, for example, often use becquerels per cubic meter (Bqm-3). 4 pCiL equals about 150 Bqm-3. RELATED ARTICLES All About RadonExhaust-Only Ventilation Systems and RadonGBA Detail: Retrofit for Radon VentA Citizen’s Guide to Radonlast_img read more

The Top Two Reasons Powered Attic Ventilators Are a Waste of Money

first_img Allison Bailes of Decatur, Georgia, is a speaker, writer, energy consultant, RESNET-certified trainer, and the author of the Energy Vanguard Blog. Check out his in-depth course, Mastering Building Science at Heatspring Learning Institute, and follow him on Twitter at @EnergyVanguard. Powered attic ventilators cause problemsI’ve been in lots of attics. I’ve seen lots of powered attic ventilators, including the one in the top photo. That one was hooked up at one of the gable vents. The other seven fans in the attic were spread across the roof, and they were naturally fighting against each other. There’s no way there was enough open vent area in that attic to supply all eight of those fans.In another home, I found three powered attic ventilators in the roof. We had been called in to solve a mold problem in two of the bathrooms, and those three fans turned out to be the main problem. We turned them off and the negative pressure pulling humid outdoor air into the bathrooms has gone away. Fans in the Attic: Do They Help or Do They Hurt?Are Solar-Powered Attic Ventilators Green?Martin’s Useless Products ListGeorgia Pulls the Attic-Ventilator Plug (Sort of) The clever commentWell, I promised I’d share the wisdom of the latest commenter with you, so here it is: “OK… I’m going to say it because no one else will… Allison Bailes, you’re an ASS!! :-)”It makes me feel so much better that he used that smiley face at the end. ;~) One reason powered attic ventilators don’t helpIn my original article, I focused on makeup air. That is, I said that when you run a powered attic ventilator in a typical house, yes, it will cool the attic down. A significant amount of that cooling is likely to come from conditioned air being sucked up from the house below. Most ceilings aren’t air-sealed well, so putting a negative pressure on the attic will do that. I quoted Peter Yost in the earlier article, and in the comments, David Butler made a similar remark:“In a particular home, if a PAV truly reduces cooling costs enough to pay for itself (don’t forget to consider the energy the fan consumes), then that tells me there are issues with ceiling insulation and/or attic venting.”That’s as true today as it was three years ago when I wrote the first article. And it’s part of the reason that my state, Georgia, has banned power attic ventilators (unless they’re solar-powered, which was a concession needed to get the grid-powered fans banned). But there’s really a more fundamental reason that powered attic ventilators won’t help a lot, and for some reason, I didn’t mention that in the original article. Three years ago I wrote an article titled, Don’t Let Your Attic Suck: Power Attic Ventilators Are a Bad Idea. Nearly a hundred thousand page views and 93 comments later, it’s still generating lots of heat. I don’t know why so many people are so defensive about powered attic ventilators (PAVs), but here are a few of the things they’ve said to me in the comments:You really should do more research before you post blogs like this.Common Sense!!!! is in the building world, you really ought to check it out sometimes.I challenge you to a battle of applied knowledge in this field any day, it’s people like you who make people who need an attic fan second guess themselves out of speaking with a true professional.Oh, and let’s not forget: “You just are not getting it lady…” Last week I got another one so clever and witty I was at a loss as to how to respond. As it has mild profanity, I’ll post it at the end so you can avoid it if you’d like. With so many delicate construction types hanging around here at GBA, I try to be sensitive to your needs. ;~)center_img INFORMATION ON POWERED ATTIC VENTILATORS Effective Attic VentilationHome Energy: Drawbacks Of Powered Attic Ventilators FSEC: Performance Assessment of Photovoltaic Attic Ventilator Fans The #1 reasonHow does heat get into the attic? Well, it starts at the sun and radiates down to the rooftop. We make sure that most rooftops can soak up as much heat as possible by using asphalt shingles. They’re often dark-colored. They’re granular. And many roof surfaces are tilted toward the sun for enhanced absorption.That heat then conducts down through the roofing materials. The underside of the roof deck can get very hot — so hot you can’t keep your hand on it. At temperatures of 150°F or more, that’s a lot of heat sitting there in that plywood or OSB. Some of it will go directly into the attic air by conduction, but that’s a small amount because air isn’t a good conductor.The main way that heat gets into the attic is through radiation. That hot roof deck radiates heat down into the attic. But that radiant heat passes through the attic air and hits the solid materials. It gets absorbed by the framing, insulation, the stuff you’re storing up there, and, unfortunately, any ductwork and HVAC systems that are up there.Those materials heat up. They give up most of their heat by conducting it downwards into the house or into the ductwork and HVAC system and then into the house from there. Some of that heat gets into the air above the hot materials on the attic floor, but the attic air getting heated up is a secondary effect. See it now? Here it is: Using a fan to blow hot air out of the attic doesn’t address the radiant heat flow from the roof to the attic floor. Much of that heat then conducts downward and finds its way into the house.Trying to solve the heat gain problem in your attic by using a fan is like lying out at the beach with a fan blowing over you and thinking you’re not going to get a sunburn.† A radiant barrier would be a better way to attack this problem, but the cost-effectiveness of radiant barriers is marginal. RELATED ARTICLES Footnote:† My friend Mike Barcik gets credit for this analogy, except that when he tells it, you’re lying naked in the sun. Naturally, this being a family blog and all, I don’t talk about naked people here. (And no – that’s not me in the photo.)last_img read more

Saudi Arabia Embraces Solar Energy

first_imgThe production of solar electricity is about to get a big boost in a country sitting on some of the richest oil reserves on the planet. According to an article in The Atlantic, the Saudi Arabian government is set to get into the photovoltaics (PV) business in a big way by beginning construction of solar projects around the country and by opening a commercial-scale PV module factory of its own. Although it has since pushed back the target date, the government announced three years ago that it would have 41 gigawatts of solar capacity online by 2032, besting the output of the current No. 1 solar country in the world, Germany. It also sees an international market for the solar panels it produces as the global market for PV continues to expand.The root of the Saudi push for solar energy has nothing to do with concerns about lowering the country’s carbon footprint, the article says, and everything to do with self-preservation.With a population of just 30 million people, Saudi Arabia is the sixth largest consumer of oil in the world. The country burns about one-quarter of the oil it produces, and consumption has been rising by 7% per year, three times the rate of population growth. If the trend continues, a 2011 report predicted, domestic consumption would eat into exports in another six years, and turn the kingdom into a net importer of oil by 2038.Unless its use of oil can be trimmed, the country faces an alarming future. Great potential for solar growthOn the production side, the Saudis are planning to open a big solar panel factory near Riyadh. On the coast of the Persian Gulf, another factory will soon begin producing large quantities of polysilicon, a key raw material for PV cells, Ball reports.Saudi Arabia not only has huge oil reserves, but also some of the best solar potential on earth. Next year, two state-owned companies plan to break ground on 10 PV projects around the country.There are still many difficulties ahead, Ball says, including bureaucratic infighting that pits entrenched oil interests against the nascent renewables industry, dust and sandstorms that can blot out the sun and cut the production of electricity quickly, and a lack of public interest in conserving oil.The threat posed by unchecked consumption at home is a powerful incentive. Aramco sells oil to the Saudi Electric Company for about $4 a barrel, and with global prices now about $60 a barrel it means that the kingdom forfeits some $56 for every barrel of oil it uses at home and doesn’t send to market.More domestic oil consumption also lowers the country’s ability to keep competitors like the U.S. shale oil industry from gaining too much power.But moving to a solar future will be difficult. Skeptics think even the revised 2040 target date for the 41 GW of solar capacity is impossible.“Proving them wrong would require reshuffling an economic deck that the kingdom’s leaders have stacked for decades to favor petroleum,” Ball writes. “In that sense, Saudi Arabia’s energy challenge is a more extreme version of the one that faces the rest of the world. But if the kingdom’s leaders can find the political courage to act decisively, Saudi Arabia, of all nations, could become a model for other countries trying to shift away from oil.” Great reserves means great wasteIts huge reserves of oil make it easy for Saudi Arabia to put energy conservation on a back burner.“The government sells gasoline to consumers for about 50 cents a gallon and electricity for as little as 1 cent a kilowatt-hour, a fraction of the lowest prices in the United States,” Jeffrey Ball writes in The Atlantic. “As a result, the highways buzz with Cadillacs, Lincolns, and monster SUVs; few buildings have insulation; and people keep their home air conditioners running — often at temperatures that require sweaters — even when they go on vacation.”Air conditioning consumes about 70% of all electricity in the kingdom, much of which is produced by burning oil. Power plants are inefficient.If this trend continues, the outcome would be “cataclysmic” for the kingdom, Ball says. Oil exports underwrite the generous benefits available to Saudi citizens — not only cheap energy at home, but extensive social services (all in a country without income taxes). If oil exports decline, so does the income that pays for all of that.last_img read more

How to Be Passionate About Your Work

first_img Essential Reading! Get my first book: The Only Sale Guide You’ll Ever Need “The USA Today bestseller by the star sales speaker and author of The Sales Blog that reveals how all salespeople can attain huge sales success through strategies backed by extensive research and experience.” Buy Now If you want to do good work, it helps to be passionate about your work. There are a few ways to make it easier to be passionate about your work, even if they’re very basic ideas. First, get a good night’s sleep. Second, hydrate by drinking a big glass of water the minute you get up. Third, get a little exercise before you start working. Fourth, don’t let your Inner Critic complain about your work and recognize that billions of people would trade places with you in a heartbeat (this is gratitude, and it’s very helpful to maintaining a positive attitude).All of the things in the paragraph above will help you be more passionate about your work, but none of them are as important as this one: Make your work better.The reason you are not passionate about your work is because you are not passionate about your work. If you do anything believing it is a chore, that it is boring, and that you’d rather be doing something else, your work will reflect your beliefs, your attitude, and your state. When you don’t appreciate your work, you will not do it with passion or enthusiasm.This single question can change how you feel about your work: How do you make it better?How do you improve the outcome you are responsible for producing? If you were to change what you are doing or how you are doing it to produce a radically better result, what would you have to change?If you were to do something new, something that was going to delight your clients, your customers, or your peers, what would you need to differently? What could you do that would provide a surprise, a smile, a sense of joy? What might cause people to talk about your work?If you were to do work that was show-stopping and exceptional, how could it be boring? If you were to do more than check a box and bring your passionate engagement to your work, how different would your work feel?There are certain rewards for doing your work. There are different rewards for doing your work well. And then there are the rewards that accrue only to those who bring their best selves to their work, making it something exceptional by doing it with passion.You can be passionate about your work when you decide to make it better.last_img read more

Wimbledon 2011: Federer-Nadal to continue their rivalry for years

first_imgNick Bollettieri is a much sought after man even today. Just a month short of 80, the supreme tennis guru is at Wimbledon in a different capacity – a columnist plus expert.Tennis guru Nick BollettieriBut that has not stopped the celebrated coach from giving interviews. On Wednesday, in an exclusive chat with MAIL TODAY, Bollettieri spoke on a wide range of tennis issues.Even as tennis lovers debate who is the best men’s player and who will win the ladies singles title, Bollettieri is sure the best of the Williams sisters is not yet over. “I have no hesitation Venus and Serena can go the full distance as this is Wimbledon and they love this place so much,” he said.As one who has shaped the careers of several stars from Boris Becker to Andre Agassi and Monica Seles to Maria Sharapova, the tennis guru had one quick point to make. “When Boris used to win at Wimbledon, he would tell me he doesn’t want to leave the place till the end of the fortnight. With so much of unpredictability in women’s tennis, one Williams can still pull it off,” says Bollettieri.So where does that leave Li Na, the Chinese sensation. Bollettieri’s eyes lit up. “Li Na is indeed exciting and her win at the French Open was big. She has almost no weakness in her game and all the strokes are there in her repertoire.She is a tremendous player and loves to hit the ball on the rise,” rattled off the coach.advertisementIn between the interview, Bollettieri also takes business calls, as he runs the busiest tennis academy (NBTA) in Florida.”I have been doing so many interviews today with the London TV channels and now I have an Indian mediaman waiting for me. I am a celebrity I guess!” he said on the phone before returning for the debate on what’s the depth in men’s tennis.Bollettieri’s eyes sparkle when you talk of Federer, Sampras and Nadal. He has been a great fan of Sampras’ serve and volley style. “I mean today you have four guys at the top who can win the men’s title. Between Federer, Nadal, Djokovic and Murray, anyone can win. But you have to look at a guy like del Potro. He is big and tough,” says Bollettieri.Bollettieri says with conviction there is not going to be a change of guard in men’s tennis so soon.”Look at the way Federer has preserved himself. His serve and that backhand and his cool, everything is in place. He has a great coach in Paul Annacone who I have coached. With this kind of a technique Roger is going to be around for a long time,” says Bollettieri.So what’s that one factor which makes Federer even harder to beat. “I have no doubt in saying Federer has no off-court stuff and no night clubs to distract him. He has an excellent support and family and if he stays this way, he can win for another four years,” says Bollettieri.”The same goes for Nadal. He doesn’t hang out late, though his training methods are different. He is going to give it a 110 per cent in training come what may, and that’s even if he is returning after a break. I can tell you one thing, Nadal doesn’t burn the candle at two ends,” says the tennis guru.So who is the best? “Sampras’s serve and volley was really good.But if he was to stay back against Federer, then it would be tough to win. As for Federer, he has the serve and the fluid motions in his game. Add to that his backhand, you know it,” says Bollettieri.Still guessing?For more news on India, click here.For more news on Business, click here.For more news on Movies, click here.For more news on Sports, click here.last_img read more