Adding Radon Control Techniques to New Homes

Transcription

1 Adding Radon Control Techniques to New Homes Sponsored by: The North Dakota Department of Health North Dakota Association of Builders January 2012 Presented by: Doug Kladder Center for Environmental Research & Technology, Inc. Welcome Back! Doug Kladder Director Center for Environmental Research & Technology, Inc. Pass questions to facilitator Short Presentation: Resources Radon in North Dakota Inspection Elements Oops Passive vs Active Systems Installation Enhancements Costs Questions throughout Page: 1 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

2 North Dakota Department of Health Justin Otto State Radon Officer Division of Air Quality 918 E. Divide Ave, 2nd Floor Bismark, ND ph (701) Justin Otto & Doug Kladder National Radon Conference 2011 For Additional Resources: Resources (1) Log in to Online Course - Select Builder Web Casts Category Page: 2 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

3 Resources (2) Click on ND Association of Builders Webcast January 2012 Click on Login as a guest Resources (3) Page: 3 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

4 Resources (4) You now have access to the course and all the resources Show movie to colleagues, subs and employees View archive of this program Download technical documents and drawings View sample code documents What Is Radon? Radon Radon is a gas. It is naturally occurring. It cannot be seen or smelled. It enters buildings from the soil beneath them. Radium Uranium Page: 4 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

5 How Is Radon Drawn Into A Building? Vacuum Exhaust systems Thermal stack effects Radon pci/l Vacuum (pa.) Days 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. Page: 5 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

6 EPA & Surgeon General Recommend That People Not Have Exposures Above 4 pci/l On A Long-Term Basis Other Reasons Radon Can be a Concern Obstacle to resale Relocation companies Mortgage lines are now asking for radon Why didn t my builder include it??? Liability Group A Carcinogen (known to cause cancer in humans) Current lawsuit in W. VA. against national builder for several million Page: 6 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

7 Radon as a Value Added Feature Buyers are aware of it May have sold a house where mitigation was required and do not want the hassle again. Perceived benefit Indoor air quality/health Ease of resale Moisture reduction Some builders either Include in all homes, or at least as an option Radon Zone Map by County Used for determining where radon control techniques in home construction would be of the greatest benefit. Not for determining where to test! Radon entry primarily a function of source. Based on geology and survey results Expected short term radon (pci/l): Zone 1 > 4.0 Zone 2 > 2 < 4.0 Zone 3 < 2.0 Page: 7 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

8 US Geological Survey Report % 80% North Dakota Percent of Homes Greater than Surgeon General Guidance (Short-term tests) 60% U.S. Average 40% 20% 0% Walsh LaMoure Adams Bowman Dunn Ransom Stark Benson Pembina Bottineau Grand Forks Hettinger Stutsman Divide Barnes McLean Source: Air Check, January 3, 2012 Mercer Kidder McIntosh Sargent Emmons McKenzie Burke Cass Dickey Rolette Ramsey Cavalier Morton McHenry Nelson Griggs Towner Traill Golden Valley Richland Ward Williams Burleigh Mountrail Wells Sioux U.S. Counties with insufficient data excluded: Billings, Eddy, Foster, Grant, Logan, Oliver, Pierce, Renville, Sheridan, Slope, Steele Page: 8 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

9 Radon Can Be Elevated in: Low Radon Potential Homes New homes Old homes Leaky homes Homes without basements Apartment buildings Schools Offices Unless you live on house boat or in a tree house, your home or office can have elevated levels of radon! New Home Construction Techniques Page: 9 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

10 Overall Approach Key Elements Common Questions Alternatives Page: 10 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

11 Can Soils Testing Tell Me If I Need to Install a System? - NO Potential maps based on geology indoor testing recommended Radon in soil varies significantly even within a few feet Soil porosity varies Difficult factors to predict: Change in soil porosity with construction New pathways via drain lines and utility line trenches Indoor air exchange rate Can t We Just Seal The Cracks? - NO Radon can enter through very small openings. Without affecting house pressures, sealing is not a standalone technique. Page: 11 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

12 H I G H L O W HI G H L O W H I G H L O W What Areas Need to Be Treated? - Appendix F - Basement slabs Slab-on-grade Crawlspaces Enclosed patios Utility rooms Enclosed entry ways Wine cellars, storage vaults Garages? Appendix F Does not specify garages ASTM 1465 Includes Garages Page: 12 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

13 Alternate Soil Gas Collection Approaches Appendix F focuses on gravel or other undefined approaches ASTM 1465 provides alternative guidance Slabs Type I Gas Permeable Layer Larger Rock Less Perforated Pipe Radon riser 4-inch diameter soil gas collector Minimum 20 feet long Open ends Radon Riser Slab Soil gas retarder 4 inch layer washed stone #4 (1 to 1½ inch) 4-inch diameter soil gas collector Page: 13 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

14 Type I Layout Conform to footprint CVC At least 24 inches from interior footing drains* Riser Directly on pipe, or Offset to wall with non-perforated 4-inch * D.L. Kladder recommendation-assumes interior drain not used as soil gas collector Slabs Type II Gas Permeable Layer Moderate Sized Rock - Loop of Perforated Pipe Radon Riser 4-inch diameter soil gas collector Loop of perforated pipe Radon Riser Slab Soil gas retarder 4 inch layer washed stone #6 (1/2 3/4 inch) 4-inch diameter soil gas collector Page: 14 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

15 Type II Layout Conform to footprint CVC At least 24 inches from interior footing drains* Riser Directly on pipe, or Offset to wall with non-perforated * D.L. Kladder recommendation-assumes interior drain not used as soil gas collector Slabs Type III Gas Permeable Layer Rock in Trench Loop of Pipe Radon Riser 4-inch diameter soil gas collector Loop of perforated pipe Laidintrench Radon Riser Slab Soil Gas Retarder 4-inch diameter soil gas collector Trench 1 foot wide x 4 inch deep layer washed stone #4 (1 to 1½ inch) Page: 15 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

16 Riser Garage Perforated Pipe Option: Cross-Overs Grade Beam Pipe Loop Important: when passing under grade beams make sure that perforations of pipe allow drainage Make provisions for pipe to penetrate obstructions. Short lengths laid in trenches Tape ends to keep clear of debris - attach to main loop after grade beam finished Pipe sleeves in intermediate footings. Pass perforated pipe through. Perforated Pipe Option: Riser Tee and Perforated Pipe Same Diameter as Vent pipe. Sch. 40 PVC or ABS Pipe PVC or ABS Pipe Coupling or flexible boot in expansive soils Slab Corrugated, Perforated Polyethylene pipe 8 stub of 4 PVC Pipe Page: 16 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

17 Slabs Type IV Gas Permeable Layer Drain Mat No Aggregate Other than Normal Radon Riser Radon Riser Slab Soil gas retarder 12 in. x 1 in. drain mat Rectilinear loop Drain Mat (Proprietary Mat) CVC Laid on subgrade, with vapor retarder between it and bottom of slab More expensive Offset by: Easier installation No special aggregate Page: 17 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

18 Do I have to exhaustively seal the plastic under the slab? - MAYBE Difficult to do for slabs Rewire applied Causes curing problems Use dryer mix Longer finishing times and labor. A must do for crawlspaces The slab can be the critical barrier if well caulked Some jurisdictions have added this exception to App. F Easier to inspect slab integrity and caulking prior to framing Slab: ASTM 1465 Does Not Require Exhaustive Sealing of Poly Sheeting BUT Appendix F Does Plastic sheet between bottom of concrete and Gas permeable Layer Keeps concrete from entering GPL Helps bridge future slab cracks Sealing No sealing required seal provided by Ground Cover Seams overlapped 12 inches Installed as required for moisture barrier. Soil Gas Retarder Caulk Page: 18 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

19 Can I Locate the Fan Inside the Home? -- NO Fan is to be located outside of conditioned space Attic Garage Outdoors Not in crawlspace Both App. F and ASTM 1465 dictate fan to be in attic Potential leakage of fan housing Potential leakage of pressure side piping. Issues: Maintenance access Light Catwalk What if attic is conditioned space? What Size Pipe? Appendix F Allows 3 inch Success of stack effect increases with diameter. Active systems often draw more air than can be handled by 3 inch. 4 inch is recommended! Unfortunately 4 inch cannot be placed in a stud wall. Requires planning Page: 19 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

20 Can I Run The Pipe Up an Outside Wall? NOT if you want it to work without a fan! Where would the fan go if this passive system had to be activated? Answer: On the roof Passive stack requires a temperature differential to create negative pressure on subgrade. Reduced or no pressure is created if routed: In exterior wall Through garage Outdoors Other Benefits of System Moisture Reduction Soil moisture is vented through system. Reduces mold and mildew, especially when activated. Vapor Intrusion Active soil depressurization also resists entry of other soil gasses Volatile Organic Compounds Requires special design and often permitting considerations Page: 20 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

21 Why Not Build the House, Test it and Add the System If Needed? Given the high potential in this state -- odds are the home will be elevated. Almost impossible to route inside Will always need fan Cannot easily run through center for thermal stack effect. Is that what a buyer of a new expects? Pick Your System Page: 21 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

22 Inspection Items Oooops! OOOps! No Supports Discharge through low roof, near upper story window Not Vertical Page: 22 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

23 More Oops! Riser disconnected Gravel in SGC Untrapped drains into sump Riser stub waiting for gravel to enter System label and indicator behind dry wall Riser label and indicator behind vapor barrier Riser To Be Non-Perforated! What s wrong with this picture? 1. Drain pipe was used as riser 2. Hole in pipe above slab NO! Piping connected to sub-grade soil gas collector to be: Schedule 40 Rigid Non-perforated Page: 23 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

24 Bad Caulking/Sealing Wrong caulk Caulked cream over run rather than joint Should have been chipped back, then caulked Not tooled Still leaked With fan running Would not have been identified if passive system Cold joint Still leaked With fan running Would not have been identified if passive system Should cold joints be caulked? More Inadequate Sealing Nice Job - Wrong Caulk Inadequate & Wrong Caulk Broken Liner Right Caulk Inadequate Job Did not span the expansion joint Page: 24 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

25 Maintaining Membrane Integrity All trades need to be aware of care needed for membrane. May want to delay installation until at least sub-floor on. ASTM 1465 recommends concrete slab where equipment will be placed in crawlspace Hole cut in membrane for water to drain to sub grade from drain pan Post Construction Testing and System Disclosure The proposed methods are prescriptive - not performance based. Testing is better performed after occupation. The need for further reductions is decision by occupant. Disclosure should be made to occupant (and future occupant) of systems existence and need to test to verify efficacy. Page: 25 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

26 RADON COST ESTIMATE (Fort Collins) Passive: $1,270) 1. FOUNDATION OPTIONS (a) Sub-slab with gravel standard builder practice at no added cost. Typical (60% - 75%) (b) Sub-slab with gravel buyer cost option. $ VENT RISER 3-in. pipe found. thru roof, fittings, roof jack, labels, etc. $ SEALING caulk, gaskets, etc. $ FAN PREP. (Passive) permanent access, electric supply, etc. $ FAN INSTALLED (Active) passive plus operation function indicator, service light, etc. $ OTHER & Misc. Builder markup 10-20% Source: Fort Collins Studies on Effectiveness of Radon Resistant New Construction Test House With Stack Temporarily Closed Simulates what radon levels might have been if system had not been installed. Test House with Stack Open Passive Active Compare results No System - Capped Passive - Uncapped Page: 26 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

27 Fort Collins Passive Stack Study March-May 2006, ST E-Perms 30 Radon pci/l Overall 49% Reduction with Passive 40% had radon levels in excess of 4.0 pci/l -5 Cap-on, pci/l Cap-off, pci/l Guidance How Well Do Passive and Active Systems Work? Radon (pci/l) Capped Passive Active Fan Added 4.0 Guideline 0 NH2 MD1 ID1 NH5 CO5 MA4 NH4 ID3 ID4 IA2 NH1 CO3 IA3 NAHB-EPA 1994 Study Capped Uncapped Active Fan Page: 27 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

28 Other Issues with Passive to Active Approach Install Passive System Buyer Takes Possession Buyer Conducts Test Fan Installed if Elevated Owner Conducts Test Complex Buyer disappointment when system is nonfunctional in their mind Proper testing approaches Potential builder liability if levels not below guidance. Should we Consider an Active Approach Option? Active Greatest Reduction Higher Operating Cost Lower builder liability Passive Reduced cost for homes that did not necessarily need it. Page: 28 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January

29 Summary Doug Kladder Director Center for Environmental Research & Technology, Inc. Radon systems are perceived as valueadded features if done correctly. Additional Questions? Please visit website for additional resources. Contact Information Justin Otto North Dakota Department of Health: Division of Air Quality 918 E.Divide Ave, 2nd Floor Bismark, ND ph (701) Doug Kladder Center for Environmental Research and Technology Doreen Riedman, North Dakota Association of Builders 1720 Burnt Boat Drive, Suite 207 Bismarck, ND or (ND only) Radon Measurement and Mitigation Professionals: Page: 29 Copyrighted by the Center for Environmental Research and Technology, Inc ~ Revised January