Radon Control Methods for Existing and New Residential Structures

Transcription

1 Delivered at the October 2006 Meeting of the Colorado Chapter of the International Code Council Presented by: Douglas L. Kladder Center for Environmental Research & Technology, Inc. Through a grant from the Colorado Department of Public Health and Environment Colorado Department of Public Health and Environment Existing Homes What is the current practice in Colorado? What code issues may be involved? Untreated Home Draws in Radon 1

2 HIGH LOW RADON VENT Active Soil Depressurization Draws Radon Laden Soil Gas Out and Exhausts to Atmosphere FAN Existing Home What Governs Installation of Radon Mitigation Systems US EPA Radon Mitigation Standards Developed in 1994 Retired in 2006 Used by voluntary certification boards Not inspected for Colorado is not a certified state. ASTM 2121 Developed in 2005 Not currently recognized by certification programs Section 512 of the IMC Interesting! Other aspects of the code. IMC Section 512 Subslab Soil Exhaust Systems Materials: Comply with IPC sanitary drainage and vent pipe Slope 1 percent slope no traps Termination Through roof and 6 inches above roof 10 feet from opening or air intake Identification Permanently labeled within each floor 2

3 So what is going on out there? Not all systems are bad, but here are some examples of what is being provided for Colorado residents. Discharges Should Be Above Roof Discharge Discharges to be Away From Openings Discharge 3

4 Discharges Carry Moisture El Paso Cty Roof Penetrations Fan Location EPA Standards: Fans Should be Outside Living Space Leakage on positive pressure side of fan can introduce radon into o building 4

5 Piping/Vent Materials Piping is 4-inch 4 SDR35, ASTM 3034 Section 512 specifies conformance with building sanitary drainage and vent which would suggest schedule 40 DWV for above grade installation Dryer vent in Attic?? Caused Leak Through Ceiling Incomplete Systems Pipe to fan Pipe to Subgrade Nothing in between! 5

6 Unique Systems Boulder Denver Electrical Disconnects Non-rated fans Fan supports Tapping into existing circuits Licensed electrician? Permits? More Electrical Weather resistant exterior boxes Proper sealing? Low voltage Class II systems also being used. Plugged indoors and routed to fan 6

7 Labeling What should it say? How durable should it be? Where should it be? Other Issues Multi-Family Schools, Commercial Buildings Routing through structural members Through or under foundation penetrations Maintaining Fire ratings 7

8 What Does Radon Mitigation Certification Mean? Five day class (classroom or distance based) Three days on mitigation Typically half a day in field installing a system. Passage of technical exam Agreement to follow codes Experiential prerequisites None Radon class and exam passage is only prerequisite. No inspection by credentialing agency. Summary of Radon Systems in New Homes The state of Colorado estimates that 5,965 homes had radon mitigation systems installed in Were these installed per codes? Even though a jurisdiction may not have adopted a code for radon systems in new homes, there are codes that dictate how repairs or upgrades are to be performed in existing homes. Radon Control Systems in New Home/Building Construction 8

9 HIGH LOW Appendix F Radon Control Methods International Residential Code-2003 FAN 9

10 Make Provisions To Allow For System Activation Passive Active Can t We Just Seal The Cracks? Radon can enter through very small openings. Without affecting house pressures, sealing is not a stand-alone alone technique. Treating Slabs Facilitating soil gas collection Four inch layer of clean aggregate beneath slab. When gravel is incorporated for drainage or is inexpensive. Loop of perforated pipe beneath slab. When existing soils are permeable. Interconnected strips of drainage mat beneath and around interior perimeter of slab. When soil is well compacted. 10

11 Option 1: Aggregate Option Caulk Slab Footing Aggregate Fill or native soils 6-mil sheeting 4-inches 4 inches of clean aggregate Between ¼ inch and 2-inch 2 in size Soil gas retarder Minimum 6 mil poly Overlapped and extended to edges Punctures and tears to be sealed Slab joints to be caulked and sealed. Aggregate Option: Allowing for Lateral Air Flow Post and Beam Foundation with Grade Beam Riser Riser Sleeves Minimum of two grade beam penetrations. Minimum of 12 sq. inches of opening per 10 ft. of grade beam. Option 2: Perforated Pipe Riser Garage Grade Beam Pipe Loop Make provisions for pipe to penetrate obstructions. Short lengths laid in trenches Tape ends to keep clear of debris-attach to main lop after grade beam finished Pipe sleeves in intermediate footings. Pass perforated pipe through. Important: when passing under grade beams make sure that perforations of pipe allow drainage 11

12 Option 3: Mat Option Expanded View of Mat Caulk Mat Filter Fabric Minimum 1 inch high and 12 inches wide. Lay mat directly on subgrade Pour concrete over mat Installation of Mat Roll out Mat Make corners Place under re-bar Install Riser Photos: Compliments of professional Discount Supply Pour concrete on top of mat Finish Slab Stub Risers Up Before Floor-Pour Common to All Sub-Grade Systems Secure riser, so it is not tilted during concrete pour Temporarily cover end of riser to keep concrete and construction debris from entering and disabling system Short stub for vent. Secure in place. Tape over end to keep concrete out. Seal around joint after concrete cures. Connect to pipe when running vent. Label it! 12

13 Use of Water Drainage Systems as a Soil Gas Collection Methods If the sump collects water from the area inside the foundation walls, it could be considered a soil gas collection method, if an interior vent pipe is connected to it. Allowable: Aggregate completely under slab connected to sump Perforated water collection pipe connected to sump and inside of foundation wall It may be prudent to keep water drainage separate from radon system. Sealing Concrete Slabs Reduces air flow to be handled by system Improves sub-slab slab depressurization Improves moisture reduction capabilities Reduces loss of interior conditioned air The thorough sealing of the concrete slab and walls is what in some areas has precluded the requirement of a fully sealed vapor barrier beneath the slab, which can be problematic and expensive. Treating Crawl Spaces Soil gas collected beneath plastic sheet Minimum 6-mil 6 polyethylene mil cross-linked is more durable App F says seams to be overlapped For best reduction and also moisture control, seams should be sealed and plastic sealed to walls. 13

14 Multiple And Combination Foundations Separate foundation areas can be joined together. In sub-grade In house or attic Allows a single roof penetration Routing Vent Pipe Hide in chases and walls Route along side flue for maximum stack effect Allow For Condensation In Vent Pipe Cold air temperatures on outer surface of pipe Condensate Air Flow Traps will fill with water Install pipe with positive drainage back to sub-grade No Traps! 14

15 Allow For Potential Fan Installation Power Supply to Fan Attic Ceiling To Roof Penetration Fan 30 Plan for fan to be in attic or garage Cannot be inside living space or crawl space. Allow 30 inches of vertical run and 12-inches around future fan location Install duplex receptacle within 4 feet System Discharges Away from Building Openings Discharge should be high to avoid radon entering building Minimum of 10 feet above grade 10 feet from any openings of building or adjacent building which is 2 feet below discharge 10 feet from powered vents that supplies air to building. Above eave No rain cap 1/4 inch bird screen System Identification Label pipe at each level of building that it can be seen. Radon Reduction System. Label as system is installed to avoid mistaking this with plumbing system. System Label 15

16 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. Activation involves fan and performance indicator Disclosure should be made to occupant (and future occupant) of systems existence and need to test to verify efficacy. Fort Collins Experience Straight from the Horses Mouths Public Health Perspective Public Health Impact Voluntary versus Code Radon as a priority Building Official Does this fit into codes? Why modify App F? F Cost impact Consumer reaction Options Sealing unfinished areas Inspector/Plan review Reaction of industry Impact on Building Department workload Beneficial impact on building department Cost impact Who is installing. Other benefits? Why? Discussion 16

17 Brian Woodruff City of Fort Collins Environmental Planner Natural Resources Department Radon as a Health Risk Voluntary vs. Code Radon as a Priority Felix Lee City of Fort Collins Director of Community Planning and Environmental Services Does Radon Belong in the Codes? Why Modify Appendix F? Cost Impact Consumer Reaction Options Considered Sealing Unfinished Areas Michael W. Gebo City of Fort Collins Codes & Inspections Administrator Industry Reaction Impact on Building Department Beneficial Impact on Bldg Dept Cost Effectiveness Additional Benefits Does this Make Sense? 17

18 Contacts Colorado Department of Public Health and Environment Chrystine Kelley Center for Environmental Research and Technology Doug Kladder