Archive for January, 2012

Acrylamide in Food

Acrylamide Toxicity

  • Acrylamide has been found in certain foods, with especially high levels in potato chips, French fries, and other food products produced by high-temperature cooking
  • Food and cigarette smoke are the major sources of exposure to acrylamide
  • Acrylamide is considered to be a mutagen and a probable human carcinogen, based mainly on studies in laboratory animals

Scientists do not yet know with any certainty whether the levels of acrylamide typically found in some foods pose a health risk for humans.

  • What is acrylamide? Acrylamide is a chemical used primarily as a building block in making polyacrylamide and acrylamide copolymers. Polyacrylamide and acrylamide copolymers are used in many industrial processes, such as the production of paper, dyes, and plastics, and in the treatment of drinking water and wastewater, including sewage. They are also found in consumer products, such as caulking, food packaging, and some adhesives. Trace amounts of acrylamide generally remain in these products.

  • Is there acrylamide in food? Researchers in Europe and the United States have found acrylamide in certain foods that were heated to a temperature above 120 degrees Celsius (248 degrees Fahrenheit), but not in foods prepared below this temperature. Potato chips and French fries were found to contain higher levels of acrylamide compared with other foods. The World Health Organization (WHO) and the Food and Agriculture Organization (FAO) stated that the levels of acrylamide in foods pose a “major concern” and that more research is needed to determine the risk of dietary acrylamide exposure.
  • How does cooking produce acrylamide? Asparagine is an amino acid (a building block of proteins) that is found in many vegetables, with higher concentrations in some varieties of potatoes. When heated to high temperatures in the presence of certain sugars, asparagine can form acrylamide. High-temperature cooking methods, such as frying, baking, or broiling, have been found to produce acrylamide, while boiling and microwaving appear less likely to do so. Longer cooking times can also increase acrylamide production when the cooking temperature is above 120 degrees Celsius.
  • Is there anything in the cooking process that can be changed to lower dietary acrylamide exposure? Decreasing cooking time, blanching potatoes before frying, and postdrying (drying in a hot air oven after frying) have been shown to decrease the acrylamide content of some foods.
  • Should I change my dietAcrylamide levels in food vary widely depending on the manufacturer, the cooking time, and the method and temperature of the cooking process. The best advice at this time is to follow established dietary guidelines and eat a healthy, balanced diet that is low in fat and rich in high-fiber grains, fruits, and vegetables.
  • Are there other ways humans are exposed to acrylamide? Food and cigarette smoke are the major sources of acrylamide exposure. Exposure to acrylamide from other sources is likely to be significantly less than that from food or smoking, but scientists do not yet have a complete understanding of all sources of exposure. Acrylamide and polyacrylamide are used in some industrial and agricultural procedures, and regulations are in place to limit exposure in those settings.

  • Does acrylamide increase the risk of cancerStudies in rodent models have found that acrylamide exposure poses a risk for several types of cancer. However, the evidence from human studies is still incomplete. The National Toxicology Program (NTP) and the International Agency for Research on Cancer consider acrylamide to be a “probable human carcinogen,” based on studies in laboratory animals given acrylamide in drinking water. However, toxicology studies have shown differences in acrylamide absorption rates between humans and rodents.

A series of case-control studies have investigated the relationship between dietary intake of acrylamide and the risk of developing cancers of the oral cavity, pharynx, esophagus, larynx, large bowel, kidney, breast, and ovary. These studies generally found no excess of tumors associated with acrylamide intake. In the studies, however, not all acrylamide-containing foods were included in estimating exposures. In addition, information in case-control studies about exposures is often based on interviews (personal or through questionnaires) with the case and control subjects, and these groups may differ in the accuracy of their recall about exposures. One factor that might influence recall accuracy in cancer-related dietary studies is that diets are often altered after receiving a diagnosis of cancer.

To avoid such limitations in accurately determining acrylamide exposure, biomarkers of exposure were recently used in a Danish cohort study designed to evaluate the subsequent risk of breast cancer in postmenopausal women. Among women with higher levels of acrylamide bound to the hemoglobin in their blood, there was a statistically significant increase in risk of estrogen receptor-positive breast cancer. This finding suggests an endocrine hormone-related effect, which would be consistent with the results of a questionnaire-based cohort study in the Netherlands that found an excess of endometrial and ovarian cancer—but not of postmenopausal breast cancer—associated with higher levels of acrylamide exposure. Another cohort study from the Netherlands suggested a positive association between dietary acrylamide and the risk of renal cell cancer, but not of prostate or bladder cancer.

What are other health effects of acrylamide? High levels of acrylamide in the workplace have been shown to cause neurological damage, e.g., among workers using acrylamide polymers to clarify water in coal preparation plants.

Are acrylamide levels regulated? The U.S. Environmental Protection Agency (EPA) regulates acrylamide in drinking water. The EPA established an acceptable level of acrylamide exposure, set low enough to account for any uncertainty in the data relating acrylamide to cancer and neurotoxic effects. The U.S. Food and Drug Administration regulates the amount of residual acrylamide in a variety of materials that come in contact with food, but there are currently no guidelines governing the presence of acrylamide in food itself.

What research is needed? Although studies in rodent models suggest that acrylamide is a potential carcinogen, additional epidemiological cohort studies are needed to help determine any effects of dietary acrylamide intake on human cancer risk. It is also important to determine how acrylamide is formed during the cooking process and whether acrylamide is present in foods other than those already tested. This information will enable more accurate and comprehensive estimates of dietary exposure. Biospecimencollections in cohort studies will provide an opportunity to avoid the limitations of interview-based dietary assessments by examining biomarkers of exposure to acrylamide and its metabolites in relation to the subsequent risk of cancer.

For information about acrylamide in food from the WHO and FAO, please visit the WHO Web site at http://www.who.int/search/semantic/en/#search=acrylamide%20in%20food&sort=score%20desc&fq=%7B!noshow%3Dtrue%7Dlanguages%3Aenon the Internet.

 

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Posted by Fay B. Castro - January 23, 2012 at 6:04 pm

Categories: Chemicals, Detoxify, Health and Wellness   Tags:

Health Benefits of Flaxseed

What are the Health Benefits of Flaxseed?

Why flax? Flax is a powerhouse of disease-fighting compounds that researchers have found to prevent heart disease, protect against inflammatory disorders and certain cancers, and lower your cholesterol.

Research shows that alpha-linolenic acid (ALA), the omega-3 in flax, can help to prevent heart disease and inflammatory disorders. When consumed, ALA in flax allows nutrients to enter the body’s cells and aid in the removal of toxins which makes this fatty acid “essential to life.” But the body can’t produce ALA on its own, and it must be obtained from sources like flax.
Flax’s high content of lignans may help prevent certain cancers and its high fiber content can reduce blood cholesterol and the risk of type-2 diabetes. Flax is the best plant source of lignans which are natural antioxidants that may reduce the activity of cell-damaging free radicals, slow the aging process, and increase overall wellness. These tiny seeds provide up to 700 times more lignans than legumes or whole grains. Also, flax is an excellent source of both soluble and insoluble fiber, which ease the effects of type-2 diabetes as well as promote heart, colon, and digestive health.
An easy addition to a healthy diet Flax is an ideal ingredient added to many products on today’s grocery shelves such as breads, energy bars, cookies, crackers, and pastas. Whether it’s whole seed or milled, adding flax’s mild, nutty flavor to favorite foods makes every dish a nutritious treat.

 

Research

As the threat of heart disease, cancer, and diabetes continues to grow, we seek information about how to cure or prevent these diseases. In the following research, discover how this incredible seed could benefit the lives of you, your friends, and family.


Flax is a healthy little seed that can easily be incorporated into your busy lives. One to two tablespoons (16g) daily can be added to diets in a variety of ways. Keep reading for some helpful hints to get your daily dose.
Replace fat: Keep good fats in your recipes by substituting 3 Tbsp. of ground flaxseed for 1 Tbsp. of margarine, butter, or cooking oil.
Keep it handy: In your refrigerator, keep a handy stash of ground flax accessible in an opaque, airtight container for up to 45 days. Whole flaxseeds can be stored for up to a year! Just use a coffee or spice grinder when you need it in its milled form, which is when it offers its biggest health boost.
Simple on cereal: Sprinkle 1 to 2 Tbsp. of milled or whole flaxseed onto your morning cereal or over salads for a nutty taste.
Dress-up: Shake or stir your daily dose of flax into your salad dressing.
Shake things up: Mix milled flax into yogurt or smoothie shakes for an extra
energy boost.
Top that: Top your fruit and cottage cheese with flax for a crunchy flax punch.
A final touch: Stir it into thicker soups such as lentil or bean varieties or into pasta sauces just before serving.
In the mix: You can always mix whole or milled seeds into your favorite bread dough. Also think about mixing it into burgers, meatloaf, and fish or vegetable patties as a tasty change.
Flaximum benefits: Add whole flaxseeds to cookie dough and muffin mix or sprinkle some on your favorite bread for artisan appeal.
Getting started: When using ground flax, because of its high fiber content, add it slowly starting with about a tablespoon a day and work up to two or more per day.

Flax and Your Health

Q: What are the health benefits of flax?
A: Flax contains several disease-fighting compounds, primarily the omega-3 fatty acid, alpha-linolenic acid (ALA), fiber, and lignans. Flaxseed is one of the richest sources of ALA, a polyunsaturated fat that offers unique heart health benefits. Flax is an excellent source of both soluble and insoluble fiber, providing three grams of fiber per tablespoon. Flax also is packed full of lignans, natural cancer-preventative phytonutrients. Flax also is full of vital vitamins and minerals such as folate, vitamin E, vitamin B-6, copper, zinc, magnesium, and (dry ounce for ounce) more potassium than seven bananas. Flax has been shown to help prevent heart disease and lower its risk factors, reduce symptoms of inflammatory disorders, protect against cancer, reduce cholesterol, and even ease the effects of Type 2 diabetes. Learn more about the health benefits of flax and make it an important part of your daily diet.

Q. What is so beneficial about omega-3 fatty acids?
A. The majority of U.S. diets no longer contain the amount of omega-3 fatty acids needed for overall health and wellness. Omega-3 fatty acids correct imbalances in modern diets that lead to health problems. Today, Americans are consuming more than 10 times as many omega-6 fatty acids (another essential fatty acid family which is required by the body in moderate, not excessive, amounts) as they are omega-3 fatty acids thanks to the increase of fatty, highly processed foods in today’s diet. Eating less omega-6 and more omega-3 fats from foods like ALA-rich flax can help lower the risk of chronic diseases like heart disease, stroke, and cancer, as well as lower LDL or “bad” cholesterol. In fact, large scale studies confirm that plant-derived omega-3’s offer unique heart-healthy benefits and may be even more effective than fatty fish and fish oils in lowering the risk of some coronary diseases. Recently, scientists have discovered that flax may play an important anti-inflammatory role in reducing immune system diseases. Flax ALA has been shown to lower blood levels of a compound called C-reactive protein or CRP. Reducing this inflammatory compound appears to be as important as lowering LDL cholesterol in preventing heart attacks and strokes.

Q. What are lignans?
A. Lignans are natural antioxidants that reduce the activity of cell-damaging free radicals, slow the aging process, and increase overall wellness. Flax contains up to 800 times more lignans than other plant sources, such as whole grains and legumes. Besides acting as antioxidants, lignans are phytoestrogrens — active substances derived from plants that mimic the action of estrogen hormones in the body. Research continues to show their potential for treating menopausal symptoms without traditional drugs and reducing the risk of hormone-sensitive cancers of the breast, prostrate, and endometrium. Lignans are especially important for women as studies have shown them to decrease the risk of breast cancer, as well as minimize cancer symptoms and reduce the spread and growth of breast cancer after diagnosis. Lignans also possess powerful antioxidant and anti-inflammatory properties associated with a lower risk of artery-clogging plaques and diabetes. Lignans have also been found effective in lowering the risk of type 1 and 2 diabetes.

Q. What’s the difference between omega-3 fatty acids from flax and those found in fish oil?
A. Flax is very high in the omega-3 fat ALA (alpha-linolenic acid). This is the “essential” omega-3 fat because our bodies need it to be healthy. However, because our bodies don’t produce it, we must consume it from other sources, like flax. Other omega-3 fats, EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), found in fatty fish, are vital for health, but not “essential,” because our bodies can make them from ALA. All of these omega-3 fatty acids help decrease inflammation, which is a trigger for heart disease, diabetes, cancer, and arthritis. Flax is unique in that it also is a rich source of lignans, phytoestrogens that may reduce risk of cancer, as well as a rich source of fiber, which lowers cholesterol and maintains digestive health. Although fish doesn’t have these benefits, it is a good source of protein. Fish can contain traces of mercury, and the FDA advises women who are pregnant, nursing, or may become pregnant, as well as young children, to avoid eating certain fish.

Q: How does flax benefit athletes and sports training? 

A: Omega-3 fatty acid alpha-linolenic, ALA, an essential fatty acid found in flax, improves the metabolism of fats which is especially helpful with endurance sports, such as marathons. When a runner “hits the wall” and their glycogen stores are used up, the body begins burning fats. In this case, efficient burning of fats makes a difference in performance. ALA improves response time. Electrical impulses move from the brain to muscles across cell membranes which, as indicated earlier, are rich in ALA when consumed in the diet. Omega-3 fatty acids, such as ALA, are the most efficient fatty acids in allowing these electrical impulses to move from cell to cell. Thus, response time is improved. ALA aids in muscle repair at the cellular level. Omega-3 fatty acids present on the cell membrane significantly affect the speed and quality of tissue repair.

Q: Why is flax important to skin health?

A: Flax has a unique and healthy fatty-acid profile in the oil with 57 percent being represented by ALA, giving the seed a very favorable omega-6 to omega-3 ratio of 0.3:1. Flax therefore provides a very important source of omega-3 for skin health. Flaxseed naturally contains a very active and stable antioxidant system1 that protects its oil content of ALA. The antioxidant system in flax represents the interaction of a group of compounds working synergistically. Flaxseed contains several bioactive compounds such as lignans, phenolic acids, anthocyanin pigments, several flavonols and flavones, and phytic acid – all known to have antioxidant activity.2 These powerful antioxidants can reduce the activity of cell-damaging free radicals that are generated through oxidation in the body and thus, can help protect the skin from damage.

Flax and Food

Q: How can I add flax into my diet?
A: Flax is added to many products on today’s grocery shelves because of the omega-3 fats, lignans, and fiber found in the seed, all of which help deliver a unique and nutritious health boost that aids in overall wellness. You can find flax in a variety of foods, including snack bars, pancakes, cereals, muffins, and trail mixes. In addition, flax is often the ingredient used in omega-3 enriched products such as pastas, breads, and other dairy products. Animals are fed flax to produce omega-3 enriched eggs, poultry, and pork products. To add flax directly to your diet, sprinkle some into your morning cereal or over salads for a nutty taste. Mix some into your salad dressing or in your fruit and cottage cheese for a crunchy flax punch. Stir it into thicker soups such as lentil or bean varieties or into pasta sauces just before serving. Another option is to use it in burgers, meatloaf and fish or vegetable patties as a tasty filler. Check out our healthy recipes for more ideas!

Q: Where can I find flax?

A: Flax can be found in whole, milled, or oil forms at your local grocery store or health food store. Whole and milled flax is usually found with the packaged grains, while oil is in the refrigerated section. It is found in numerous products including snack bars, trail mixes, muffins, pancakes, cereals, waffles, breads, and pastas. Flax also is often in omega-3 enriched products, such as pastas, breads, eggs, and dairy products.

Q. Is flax organic?
A. There are a few companies that offer organically grown flax, labeling the seeds and oils with an “organic” symbol. The “organic” symbol is a mark which is earned when companies have kept chemicals away from the crop at all times. You can expect to pay a premium for organic flax. Any flax that you buy from a reputable retailer is perfectly safe to eat, organic or not.

Q. How can flax substitute for oils and eggs in cooking?
A: Flaxseed can easily replace oil or shortening in a recipe because of it’s high oil content. Just replace 1/3 c. of oil with 1 c. of milled flaxseed for a 3:1 substitution ratio. Similarly, a flaxseed mixture can be used as an egg substitute in selected recipes like pancakes, muffins and cookies. For every egg, replace with 1 tsp. of milled flax amd 3 tbsp. of water. Mix milled flaxseed and water in a small bowl and let sit for 1 to 2 minutes. The result will be a slightly gummier and chewier baked good, with a slight decrease in volume.

Learn More about Flaxseed.

         

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Posted by Fay B. Castro - January 19, 2012 at 3:14 pm

Categories: Health and Wellness   Tags:

How to Clean Vegetables

How To Make An Organic Fruit And Vegetable Wash

It’s always a good idea to thoroughly wash all your fruits and vegetables before consuming them. You never know what kinds of pesticides or dirt may still be attached to the skin.

Although washing with plain water can accomplish quite a lot, adding a natural sources of acid (namely lemon and vinegar) to the wash can provide a much better natural disinfectant.

 

Things You’ll Need:

  • 1 organic lemon (Recommended)
  • 2 tablespoons distilled white vinegar (Purchased at any Supermarket.)
  • 1 spray bottle
  • 1 cup tap water
  • Kitchen knife & chopping board

Prepare the organic lemon. You can use a normal lemon, which would be slightly cheaper, but the wash couldn’t be called “organic”, just “natural”. Regardless, both kinds of lemons will be fine for this task.

Follow these few simple steps to make your own organic and inexpensive lemon and vinegar cleaning recipe.

Step 1: Squeeze Your Lemon
Slice your lemon in half and squeeze out one tablespoon of lemon juice and pour it into your spray bottle. The lemon juice is a natural disinfectant and will leave your fruits and vegetables smelling fresh.

Step 2: Vim And Vinegar
Pour the vinegar into your spray bottle along with one cup of water. The acid in the vinegar will neutralize most pesticides. Screw on the top and shake the mixture vigorously. Spray your wash on all your fruits and vegetables then rinse with filtered water if possible.

Recommendation: You might still want to choose a spray bottle that does not contain phthalates or bisphenol: Plastics with recycling numbers 1 and 2 are acceptable choices, and number 4 or 5 should also be alright.

Below is a video on “How To Make An Organic Fruit And Vegetable Wash.”

You never know what kinds of pesticides or other toxic chemicals may still be attached to your produce. Protect your health by following some of the steps provided in Wikihow videos and throughout this website. To better health!

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Posted by Fay B. Castro - January 13, 2012 at 2:04 pm

Categories: Chemicals, Green Life, Green Solutions, Health and Wellness, Living Green, Non Toxic Products   Tags:

Lighting Efficiency Tips

Reduce Light Levels

You can often reduce light levels without reducing light quality by the following procedure:

  • Redesign visual tasks. For example, begin using a better printer with darker lettering, or install light filtering shades to reduce glare.
  • Reduce light levels where there are no visual tasks. Provide minimum light necessary for safety, security, and aesthetics.
  • Reduce light levels for visual tasks where those levels are currently excessive.

If you want to cut lighting energy consumption, while enhancing light quality, consider the following:

  • Paint and decorate using light colors.
  • Establish ambient illumination at minimum acceptable levels.
  • Provide task lighting at optimal level, depending on the difficulty of visual tasks-for example, sewing requires more light than cooking.
  • Replace lamps, ballasts, and fixtures with more efficient models.
  • Buy and use CFLs.
  • Improve light quality by reducing glare and brightness contrast.
  • Use daylight.

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Posted by Fay B. Castro - January 11, 2012 at 3:10 pm

Categories: Ecology, Global Warming Effects, Save Energy   Tags:

Lighting Efficiency

Energy Efficiency Lighting

Lighting accounts for 20% to 25% of all American energy consumption. An average household dedicates 5% to 10% of its energy budget for lighting, or commercial establishments consume 20% to 30% of their total energy use for lighting.

Electricity is usually converted into light (in residential buildings) in incandescent or fluorescent lamps.

 

Illumination

A lumen measures light output from a lamp. All lamps are rated in lumens. For example, 100-Watt  incandescent lamp produces about 1750 lumens. Dividing a lamp’s number of lumens by its watts gives efficacy-a measurement of lighting efficiency.

The distribution of light on a horizontal surface is called its illumination. Illumination is measured in footcandles. A footcandle of illumination is a lumen of light distributed over one square foot of area.

The amount of light required, measured in footcandles, varies according to the difficulty of a visual task. Ideal illumination is the minimum footcandles necessary to comfortably perform a task at the maximum practical rate of speed without eyestrain.

In the past, illumination of 100 footcandles was thought to be minimum for visual tasks in the workplace. Now, the Illuminating Engineering Society says that 30 to 50 footcandles is adequate for most home and office work. Difficult and lengthy visual task, like sewing for extended periods of time, requires 200 to 500 Footcandles. When no seeing task are performed, the lighting system needs to provide only security, safety, of visual pleasure – from 5 to 20 footcandles.

Lighting uses

Three categories of lighting by faction are ambient lighting, task lighting and accent lighting.

Ambient lighting provide security and safety, as well as lighting the tasks that occur throughout the lighted space.

Task lighting provides light at the work area. Illumination levels should be high enough for accurate task execution in task areas – not throughout the entire lighted space.

Accent lighting illuminates walls so that their brightness contrasts less with brighter areas, like ceilings and windows. Accent lighting is also used to make the space more visually comfortable.

Lighting Color

Lamps are assigned a color temperature depending on their “Coolness” or “warmness.” people perceive color of the blue-green end of the color spectrum is cool and those of the spectrum’s red end as warm. Morning light from the North is a more bluish then Southwest evening light.

Cool light sources are preferred for visual task, since they produce better contrast at the printed page, workbench, or other tasks. Warm light sources are preferred for living space, because they are more flattering to people’s skin and clothing.

Incandescent Lamps

Incandescent lamps are the oldest, most common, and most inexpensive lamps. Incandescent lights is produced by a white-hot coil of tungsten wire that glows when heated by electrical current. The type of glass enclosures surrounding this tungsten filament determines its light beam’s characteristics. Only 10% of the electricity is converted into light, the other 90% becoming heat.

Incandescent lamps have the shortest service life of the common lighting types. All incandescents are relatively inefficient compared to other lighting types. However, significant savings are possible – if you select the right incandescent lamp for his purpose.

Referred to by lighting experts as the A-type light bulb, these lamps are the most common and the most inefficient light source available. Larger wattage bulbs are more efficient than smaller wattage bulbs. Long-life bulbs, with thicker filaments and lower efficacy, are a common variant.

Fluorescent Lamps

Fluorescent lamps produce light by passing electric current through a metallic gas. The flow of electricity through the gas excites special chemicals called phosphors, causing them to glow or “fluoresce.” Fluorescent lighting is used mainly for indoor lighting. Fluorescent lighting needs controlling devices, called ballasts, the starting the circuit protection. Ballasts also consume energy.

Fluorescent lights for approximately three to four times as efficient as incandescents, and their lamp life is about ten times greater. Fluorescent lamps convert 80% of the electricity they use into light.

Compact fluorescent (CFLs) the most significant recent lighting advance for homes. They combined their efficacy of fluorescent lighting with the convenience and universality of incandescent fixtures. Recent advances in CFL designs also provide more natural color rendition and less flicker than older designs.

Recessed Fixture Issues 

Recessed light fixtures, especially cylindrical ones called “cans,”are often direct leak through the air barrier. These fixtures, when they contain incandescent bulbs, must be ventilated by holes in their shell to purge heat to from the fixture.

Installed in soffits, cathedral ceiling, and suspended ceiling, recessed light fixtures connect the conditioned space to attics or roof cavities. Not only do they exchange air between conditioned spaces and building cavities, recessed light fixtures also allow warm, moist indoor air to reach cold roof decking, causing condensation.

One remedy is to replace the fixture with a similar fluorescent fixture, which produces only a quarter of the heat and doesn’t need venting.

LIGHTING EFFICIENCY TIPS

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Posted by Fay B. Castro - January 11, 2012 at 12:18 pm

Categories: Ecology, Global Warming Effects, Save Energy   Tags:

House Insulation

Insulation Types

Insulation slows heat transmission to the buildings floors, walls and ceiling or roof. Heat transmission is the average homes leading cause of winter heat loss. Both single-family homes lost three to six times as much heat through transmission as through air leakage.

Why insulate?

When you say that insulation and resists heat transmission, we mean it resists conduction, convection, and radiation heat flow through a buildings component. In the case of a uninstall wall cavity, convection and radiation dominate heat transmission through the wall’s empty cavity. Insulation, installed in the wall cavity, forces the heat conduct from fiber to fiber and through the insulation’s tiny air pockets- a slower heat- transmission process than convection and radiation.

Insulation performs the following thermal functions:

  • Conserves energy by slowing heat transmission.
  • Enhances comfort by reducing temperature variations within the conditioned space.
  • Reduces the size of heating and cooling equipment needed by a building in direct proportion to R value.
  • Prevents wintertime condensation by improving low interior surface temperatures.

Insulation may also offer the following non-thermal benefits:

  • Adds structural strength.
  • Reduces noise and vibration.
  • Impedes air leakage and water vapor transmission.
  • Improves the building’s fire resistance.

Conductivity of Building Materials

Aluminum is the most conductive common building material. It’s thermal conductivity is more than five times greater than steel, 1000 times greater than wood, and 10,000 times greater than air. One square foot of steel, the next most conductive building material, conducts as much heat and 50 ft.² of concrete, 200 ft.² of wood, or 1000 ft.² of glass wool, assuming all are of the same thickness.

Insulation characteristics

Insulation is installed in building cavities, attached to a building’s structural frame, or attached to the building shell’s exterior surfaces.

Insulation slows heat transmission in two important ways:

1. By forcing the heat to conduct through air or some other gas. Gases are generally poor heat conductors.

2. By reducing heat radiation and air convection within cavities where it is installed.

Insulating materials are not as continuous or dense as other building materials which are heat conductors- they harbor millions of tiny air pockets within their fibers of bubbles ( in plastic foam insulation). Heat transmission proceeds slowly through insulation, having to cross this myriad of slow conducting their pockets.

If air from inside or outside the building leaks into a insulated cavity, the effectiveness of the insulation is further reduced. This reduction typically varies from 15 to 50%. Air can even flow-through fibrous insulating materials such as loosely install fiberglass. Installation’s installed density an important issue, especially in cold climates.

Wind also affects insulation performance. Wind convects heat away from the surfaces of a building. If voids and edge gaps exist, wind can push outdoor air through building cavities around the insulation or push air through insulation. These effects increase heat transmission.

Moisture Condensation:

Absorbed water decreases the R-value of insulation. Water fills the insulation’s air spaces, and conducts heat far better than air. Water and ice also can damage insulation. Wet insulation can help corrode metals and supply water to insects and microorganisms that rot organic building materials.

Air leakage is the most potent moisture carrying mechanism affecting condensation in building cavities. Vapor diffusion is water vapor traveling through permeable materials like drywall and masonry. Low-R building materials combined with water-absorbent building materials create the largest potential moisture problems.

Types of insulation:

Insulation materials are made of mineral organic materials that trap air. Plastic foams also use other gases that conduct heat more slowly than air. Mineral insulation include: mineral and glass fibers, vermiculite, and perlite. Organic insulating materials include plastic foams and cellulose.

Insulation comes in various product types: flexible materials, such as batts and blankets; rigid materials, such as foam-board; and fiberboard; sprayed on materials, such as polyurethane; and loose fill insulation, such as cellulose. Batts are narrow blankets sized to fit between wall studs, floor joists, and ceiling joists.

Fiberglass is the most popular insulation material; it is manufactured in batts, blankets, loose fill and rigid boards. Cellulose insulation is also popular for residential buildings it is manufactured as a loose- fill insulation from wood fiber on recycled paper. Plastic foam insulation is manufactured in 4-by-8 foot sheets in thicknesses from 1/4 inch to 4 inches.

Cellulose and fiberglass loose-fill insulation are good air sealers for inaccessible building cavities providing air-leakage pathways. Cellulose is superior to fiberglass because it packs tighter and has smaller fibers that are driven into small gaps during installation. However, cellulose can absorb water from leaks and high humidity. Technicians can seal areas where they can’t crawl or reach by using fill tubes to blow tightly packed insulation into the cavities.

Loose-fill insulation has particular importance to energy retrofits because of its ability to fill spaces inside closed cavities, such as walls. Sprayed insulations are often used to retrofit masonry walls, especially those with irregular surfaces.

It’s important to know each insulation materials temperature, toxicity, fire and moisture characteristics. Foam insulation can be damaged by high temperature and sunlight. Fiberglass irritates skin and lungs. Cellulose absorbs water in humid conditions. Kraft paper batt facing is flammable. And foam insulation produces toxic smoke when burned.

Fiberglass batts and blankets

Fiberglass batts and blankets are the most common and widely available, American insulation products. Mineral wool have a small market in the U.S. but it is common in Canada and popular in Europe.

Batts are most commonly installed into building cavities during construction. Batts a commonly sized to fit between framing members that are spaced on 16 inch or 24 inch centers. As a retrofit, batts are applied most often to ceilings with an attic and below the floor when there is a crawlspace.

Blown Cellulose

Blown cellulose is usually ground-up newspaper or wood wastes, treated with fire retardants. Cellulose for plowing is packed in compressed 24-to-40 pound bales.

It blows quickly and easily, achieving a high density in wall. Cellulose usually contains a lot of small fibers that tend to pack into cracks and crevices of closed building cavities, retarding airflow through these cavities. This characteristic is of cellulose is used extensively for air sealing older homes. Cellulose has better resistance to air convection than fiberglass act is commonly installed density.

Blown Fiberglass

Blown fiberglass is manufactured in two types: chopped-up batt waste and virgin short fibers. The batt waste type as long fibers and binder, so its R-value per inch is slightly lower than the virgin fibers, which are thinner and shorter. The shorter thinner fibers create smaller and more numerous air spaces.

Fiberglass for blowing is packed in compressed 24-to-40 pound bales. The compressed fiberglass requires a blowing machine with an agitator that tears it up into small pieces that travel fluidly through the blower hose.

It is easy to over-fluff fiberglass in attics, leading to low-densities and excessive air permeability. Cellulose insulation is superior to fiberglass at resisting convection as attic insulation because it blows at higher density.

 

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Posted by Fay B. Castro - January 10, 2012 at 1:33 pm

Categories: Energy Conservation, Green Solutions, Save Energy   Tags: