Radon-Resistant Construction For New Homes

Transcription

1 Radon-Resistant Construction For New Homes

2 What Is Radon? Radon is a gas Radon Radium Uranium It is naturally occurring. It is inert and cannot be seen or smelled. It enters buildings from the soil beneath them.

3 Why Is Radon a Concern? Radon Decay Products Radon Radon Radon decays into radioactive particles known as radon decay products. These particles are easily inhaled and deposited in the lungs where they can damage sensitive lung tissue.

4 Alpha Particles Are Strong Enough To Pit Plastic Photo by Dr. J.F. Burkhart Plastic chip from passive radon test (alpha track). Magnified only 100 times. 3 months at EPA Action Level of 4 pci/l.

5 Radon Induced Lung Cancer Risk increased by both duration & concentration of exposure One dart at a time for a long time, or handfuls of darts over a short time

6 National Research Council BEIR VI: February 19, 1998 U.S. Lung Cancer Deaths/yr Smokers Non-Smokers Radon is one of the most extensively investigated human carcinogens. Radon is a...public-health problem and makes indoor radon the second leading cause of lung cancer after cigarette smoking. indoor radon should be considered as a cause of lung cancer in the general population that is amenable to reduction.

7 How Radon Compares To Other 25,000 Causes Of Death Deaths per year 20,000 15,000 10,000 5,000 Upper estimate Lower estimate 0 Drunk Driving Radon Drownings Fires/Burns Air Transportation Source: U.S. EPA s Home Buyer s and Seller s Guide (Radon: National Academy of Sciences, Non-radon: National Safety Council)

8 How Is Radon Drawn Into A Building? Vacuums created by: Exhaust systems Thermal stack effects

9 Basic Components of Passive System Junction Boxes (to power fan and warning device, if needed) Vent pipe running between sub-slab gravel and roof Sealing and caulking Polyethylene soil-gas retarder between slab and gravel Large gravel beneath slab

10 Passive System Concept for Crawl Spaces Attic Depressurization Piping System Plastic Sheet Discharge Suction point is under plastic sheet placed over exposed soil or rock Radon is collected and exhausted outdoors Seams and edges are sealed

11 Why Not Wait Until Home Is Finished? You can incorporate features that can eliminate need for fan. Sub-grade can be made more permeable during construction. Routing Routing pipe through warm chases can create natural stack effect. Vent can be hidden in chases to improve looks.

12 City Response to Radon INFORMATION: : Encourage radon testing, mitigation INCENTIVE: : Test kit sales ORDINANCES: Radon information at point of sale Building Building Code rules and inspector certification for voluntary RRNC

13 Next Step: Require RRNC? Air Quality Action Plan: consider RRNC ordinance City Council: bring RRNC ordinance for a vote as part of Building Code update

14 Process timeline Public outreach: February-March City Council Study Session: May 13 Building Code adoption: July

15 Option 1: No Change, Baseline Some builders install RRNC voluntarily. Some owners fix radon after they move in. Assuming no mitigation, expect about 472 cancers during the lifetimes of 59,000 new residents in 24,000 new dwellings with median 2.5 pci/l.

16 Option 2: Require RRNC 47% reduction from passive system would avoid about 222 lifetime cancers. Cost is about $522 per system, or about $56,000 per cancer avoided. Further reduction if owner installs fan for about $200

17 Other Options We Have Thought About Ordinance exceptions based on: First Owner Preference (quasi-voluntary) Building Location (map-based) Building Cost (keep housing affordable) These are not desirable because: Un-equal protection More costly to administer Home owner can t tell if he has a radon system based on date of construction

18 Radon Resistant New Construction Low-cost Makes Sense $350-$500 $500 per home Versus $800-$2,500 $2,500 to retrofit Simple -- uses common building materials Effective -- reduces radon levels by about 50% Other benefits include moisture control and energy savings RRNC protects families

19 Public Outreach Web site: Phone: Comment Line Outreach to affected groups Letter requesting comments Advertising, press releases

20 Thanks to National Environmental Health Association U.S. Environmental Protection Agency for presentation materials