Posted by Nana Hinsley on Fri, Jun 25, 2010 @ 04:04 PM
According to the US EPA, Radon comes from the decay of Uranium-238 as part of the decay chain.
As the earth's crust was formed, Uranium was distributed within it. Thus radon is a natually occurring radioactive gas that is produced by the breakdown of uranium in rock, soil and water. Given the age of the earth, uranium's slowly progressing decay chain now commonly produces radon-222 . The biggest health problems are that radon is radioactive, and it is a gas. As a gas it can seep through foundations into homes (particularly basements), and accumulate into fairly high concentrations. It is drawn into homes because the air pressure inside your home is usually lower than the pressure in the soil around your home's foundation. Due to this pressure difference, your home acts like a vacuum, dragging radon in through any foundation cracks, or other openings. In the United States, radon gas in soils is the principal source of elevated radon levels in homes. Radon decay emits alpha particles, the radiation that presents the greatest hazard to lung tissue. Since radon had a very short half-life (3.8 days) that means that it emits alpha particles at a high rate. Radon is estimated to cause many thousands of lung cancer deaths each year. In fact, the Surgeon General has warned that radon is the second leading cause of lung cancer in the United States.
Please check out http://www.epa.gov/rpdweb00/understand/chain.html for more detailed information.
According to the US EPA, Radon comes from the decay of Uranium-238 as part of the decay chain.
As the earth's crust was formed, Uranium was distributed within it. Thus radon is a naturally occurring radioactive gas that is produced by the breakdown of uranium in rock, soil and water. Given the age of the earth, uranium's slowly progressing decay chain now commonly produces radon-222 . The biggest health problems are that radon is radioactive, and it is a gas. As a gas it can seep through foundations into homes (particularly basements), and accumulate into fairly high concentrations. It is drawn into homes because the air pressure inside your home is usually lower than the pressure in the soil around your home's foundation. Due to this pressure difference, your home acts like a vacuum, dragging radon in through any foundation cracks, or other openings. In the United States, radon gas in soils is the principal source of elevated radon levels in homes. Radon decay emits alpha particles, the radiation that presents the greatest hazard to lung tissue. Since radon had a very short half-life (3.8 days) that means that it emits alpha particles at a high rate. Radon is estimated to cause many thousands of lung cancer deaths each year. In fact, the Surgeon General has warned that radon is the second leading cause of lung cancer in the United States.
Please check out http://www.epa.gov/rpdweb00/understand/chain.html for more detailed information.
Posted by Lee Hinsley on Thu, Jun 17, 2010 @ 05:55 PM
Did you know that Radon is the second leading cause of lung cancer? Maybe that explains why so many who don't smoke have lung cancer! If you smoke and have radon in your home, your odds are even worse for contracting lung cancer. Radon is a cancer-causing radioactive gas. You cannot see, smell or taste radon, yet it might be found in your home. The U.S. Environmental Protection Agency (US EPA) and the Surgeon General's Office have estimated that as many as 20,000 lung cancer deaths are caused by radon each year. Radon-induced lung cancer costs the United States over $2 billion dollars per year in health care costs.
According to the US EPA, nearly 1 in 3 homes checked in seven states and on three Indian lands had screening levels over 4 pCi/L, the EPA's recommended action level for radon exposure.
A family whose home has radon levels of 4 pCi/l is exposed to approximately 35 times as much radiation as the Nuclear Regulatory Commission would allow if that family was standing next to the fence of a radioactive waste site. (25 mrem limit, 800 mrem exposure)
Another shocking statistic : An elementary school student that spends 8 hours per day and 180 days per year in a classroom with 4 pCi/l of radon will receive nearly 10 times as much radiation as the Nuclear Regulatory Commission allows at the edge of a nuclear power plant.(25 mrem limit, 200 mrem exposure) Most scientists agree that the risk of death for radon at 4 pCi/l is approximately 1 in 100. At the 4 pCi/l EPA action guideline level, radon carries approximately 1000 times the risk of death as any other EPA carcinogen. It is important to note that there are no "safe" levels of radon gas.
What can you do to stop radon gas from entering your home? Properly installed VaporBlock 20 plus will block virtually all radon gas from entering your living space whether installed underslab, in a crawl space or a basement.
Posted by Lee Hinsley on Thu, Jun 17, 2010 @ 03:40 PM
ASTM E-84 measures the flame spread and smoke index, which are considered the surface burning characteristics of a material. Depending on the numbers, materials can have classifications of Class A, B, or C according to NFPA , ANSI/NFPA No. 101, "life Safety Code" , 2006 Edition, or IBC (International Building Code), 2006 Edition, Chapter 8, Interior Finishes, Section 803, if they pass any level of this standard. The test is conducted in a fire tunnel using a 22" x 24' sample of the material. The ignition source is 7 seconds in duration, total test is 10 minutes. The flame front cannot exceed 24" during the test. Results are expressed as Flame Spread Index, and Smoke Developed Value. Following are the criteria for each level of this test, regardless of whether NFPA or IBC.
For products that pass these criteria, click here
Class A, Flame Spread 1-25, Smoke Developed Less than or equal to 450
Class B, Flame Spread 26-75, Smoke Developed Less than or equal to 450
Class C, Flame Spread 76-200, Smoke Developed Less than or equal to 450.
Please note, this test is comparable to UL 723, ANSI/NFPA No 255, and UBC No. 8-1
NFPA 701-04 Test 1 or 2 (the most recent revision of the NFPA 701) measures the mass before test, mass after test, mass loss percentage, the number of seconds of any burning drips, and the after flame of the material in seconds during and after a specified burn period at a specified flame temperature. Once the flame is extinguished the after flame in seconds is measured. 10 samples are tested, 5 in the machine direction, 5 in the cross direction (also known as warp/weft respectively). This test is a Pass/Fail test based on the following criteria. If the material fails any of the following criteria, it fails the test
Mass Loss: 40% Max Average or Average + 3 standard Deviations Max Individual
Drip Burn/Afterflame: 2 seconds Max. Avg.