Radon control options for new home construction William J. Angell, - - PDF document

2/5/2018 1

Radon control

• ptions for new

home construction

William J. Angell, Professor University of Minnesota June 2017 SPONSORED BY WISCONSIN DEPARTMENT OF HEALTH SERVICES

ANSI/AARST 2013. Reducing Radon in New Construction: 1 & 2 Family Dwellings and Townhouses (RRNC 2.0 standard), Hendersonville, NC: American Association of Radon Scientists and Technologists.

Also see:

Sources

Angell, WJ 2012. Radon Control in New Homes: A Meta- Analysis of 25 Years of Research, Proceeding of the 2012 International Radon Symposium, Las Vegas, NV: American Association of Radon Scientists and Technologists.

2/5/2018 2 Why is effective radon control in new homes important? What are the basic options for radon control? What are the critical components of radon control? Who should install radon control systems? Why is a performance test essential? 1 2 3 4 5

Key concepts

25,000

...far more deaths than those caused by residential fires and carbon monoxide.

Radon exposure in homes leads to

lung cancer deaths in the U.S. each year

Importance of radon control

2/5/2018 3 New homes typically have higher radon concentrations compared to older homes …especially true with air exchange rates under 0.3 ACH. Most cost-effective way to reduce radon induced lung cancer.

Importance of radon control

For 30 years, many agencies have recommended radon control in new homes.

Importance of radon control Importance of radon control

2/5/2018 4 Properly installed, radon control can reduce call-backs and liability. It tells the community that you care about resident health and safety.

Importance of radon control

2/5/2018 5

Basic options for radon control in your homes

Passive systems (without a fan)

25 year track record Specified by IRC Appendix F Depends on a 3–4” vent providing more suction than the house…a tough challenge If all details are effectively executed, there may be about a 55% reduction in indoor radon concentrations Most builder-installed systems have errors that reduce system effectiveness About 2 million systems installed 30+ years Specified in ANSI/AARST RRNC 2.0 standard Commonly uses a small wattage, in-line radon fan (14 to 40 watts) More forgiving with normal construction errors Typically, reduces indoor radon concentrations 90 to 99%…the greatest radon reduction

Basic options for radon control in your homes

Active systems (with fan)

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Critical components of radon control systems

Air-tight soil gas retarder and slab Fan or no fan Specific vent pipe type, size and routing Permeable layer under slab

Critical components of radon control systems

Permeable layer under slab under all soil contacted areas (also known as soil gas collection plenum)

OR may be geotextile drain matting In crawl spaces, a minimum of 10’ strips, 12” wide Under concrete floors, 12” wide strips placed 12–18” from perimeter Or may be a continuous loop of 4” perforated pipe placed 12–18” from perimeter and backfilled with clean aggregate Commonly, a minimum of 4” of clean aggregate with a minimum of 35% void ratio or size number 4, 5, 56,

• r 6 (ASTM C33)

2/5/2018 7

Critical components of radon control systems

A soil gas retarder must cover the top of the soil gas plenum. In crawl spaces, the retarder must cover exposed soil.

Air-tight soil gas retarder and slab

Critical components of radon control systems

Air-tight soil gas retarder and slab

Under slabs, polyethylene sheeting must be installed over the plenum

• If cross-laminated, a minimum of 3 mils

thickness

• If not cross-laminated, a minimum of 6 mils

thickness

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Critical components of radon control systems

In crawl spaces, the membrane must meet ASTM E1745 Class A, B or C

Air-tight soil gas retarder and slab

In all cases, the soil gas retarder: Must be overlapped and sealed with manufacture-recommended tape or caulk Must seal all tears and punctures with manufacture-recommended tape or caulk Must seal penetrations with ASTM C920 Class 25 or higher caulk or an equivalent method

Critical components of radon control systems

Air-tight soil gas retarder and slab (continued)

2/5/2018 9 In all cases, the soil gas retarder:

Must turn the membrane edge up the foundation wall at least 6" and continuously seal it with caulk complying with ASTM C920 Class 25 In slabs, plumbing block-outs must be filled with expanding foam, a non-shrink grout or

• ther appropriate method (If the opening is

exposed, seal with a non-shrink grout or equivalent method)

Critical components of radon control systems

Air-tight soil gas retarder and slab (continued)

Where foundation walls are concrete, the soil gas retarder must be sealed to the foundation wall or the footing Where foundation walls are masonry block, the soil gas retarder must be sealed to the foundation wall or the footing

Critical components of radon control systems

Air-tight soil gas retarder and slab (continued)

2/5/2018 10 The intersection of floors and foundation walls must be sealed with a caulk complying with ASTM C920 Class 25 or higher or equivalent Sumps in indoor floors shall have a rigid lid which must be sealed with a gasket or silicone caulk and be mechanically fastened

Critical components of radon control systems

Air-tight soil gas retarder and slab (continued)

Must be rigid, non-perforated Schedule 40 and not less than 3” ID Must have a slope towards the suction point of not less than 1/8” per foot Must prepare plastic pipe joints with a primer and solvent welded Supports for horizontal pipe shall not exceed 4’ and supports for vertical pipe must not exceed 10’ Must be labeled at each floor level and at intervals not greater than 10’ along the length of the pipe

Critical components of radon control systems

Vent pipe

2/5/2018 11 Suction points must be installed in each soil gas collection plenum as well as provided for each foundation type The bottom of the vent pipe must have not less than 2

• penings in soil gas collection

plenum (for example, a “T” fitting)

Critical components of radon control systems

Vent pipe—suction points

In an aggregate-filled soil gas plenum, the vent pipe connector must have not less than 5’ of perforated pipe extending from each opening Suction points are not permitted through sump lids Suction points must be fastened to prevent dislocation

Critical components of radon control systems

Vent pipe—suction points

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If located in an attic, access entry must not be greater than 20’ from the fan’s location Must provide space with a vertical height of at least 48” and a diameter of at least 21” in the area where radon fan will be installed An electrical boxed receptacle shall be located within 6’ of the fan (If the fan will not be a cord/plugged connected, a means for disconnect shall be in sight

• f the fan)

Critical components of radon control systems Critical components of radon control systems

Vent pipe location—provision for a fan

Must be: discharged outdoors and directed vertically upward at least 12” above the roof at the point of discharge at least 10’ above grade at the point of discharge at least 2’ above or 10’ from windows, doors, or

• ther openings into the home or adjacent homes

Critical components of radon control systems

Vent pipe—discharge

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Active soil depressurization (ASD) fan installation

Unless a pre-occupancy radon test result is less than 4 pCi/L, a radon fan must be installed The fan must be located outdoors and/or above the conditioned space Additional labeling is required on the vent pipe and within 12” of the electrical service panel (See ANSI/AARST RRNC 2.0 for specifics) The fan must be specified for use in mitigation

Critical components of radon control systems

ANSI/AARST RRNC 2.0 specifies fan sizing depending

• n the pipe diameter and total foundation area

Critical components of radon control systems

ASD fan selection

Foundation area Vent pipe Radon fan minimum rating < 1,600 ft2 50 cfm @ 0.5” WC 1,600–2,500 ft2 75 cfm @ 0.5” WC 3” diameter 1,600–2,500 ft2 50 cfm @ 0.5” WC 4” diameter > 2,500 ft2 fan must be sized by a certified

• r licensed radon mitigator

2/5/2018 14 Must be installed only on vertical pipe Must be connected to the vent pipe with flexible connectors Must be energized upon installation

Critical components of radon control systems

Fan installation

Each ASD system must have an air pressure indicator, such as a U-tube manometer, that is readily observable by occupants Upon fan start-up, the monitor air pressure must be clearly marked If the monitor is electrically activated, power must be from an unswitched circuit and, after power failure, automatically reset when power is restored

Critical components of radon control systems

Monitoring

2/5/2018 15 Sump lids must be labeled. The system label must state: installer’s name, phone number, certification or license number date of installation advisory the home should be retested for radon every 2 years

Critical components of radon control systems

Required labels

The ANSI/AARST standard specifies further labeling requirements. Must be provided to the home occupants. Package must include: description of the radon system’s operation all radon test data for the home the annual energy use of the ASD fan and the energy cost

Critical components of radon control systems

Documentation package

The ANSI/AARST standard specifies further documentation requirements.

2/5/2018 16 Systems should be installed by nationally certified radon mitigation contractors In licensing states, installation should or must be completed by a licensed radon contractor Where the foundation footprint exceeds 2,500 ft2, the ANSI/AARTS RRNC 2.0 standard requires installation by a nationally certified or state licensed radon professional

Who should install radon control systems?

The only way to determine the effectiveness of any radon control system is through radon testing The ANSI/AARST RRNC 2.0 standard requires a radon test prior to occupancy (If the test is 4 pCi/L or more, an ASD system must be installed) The RRNC 2.0 standard requires a nationally certified long- term test device to be provided to the occupant

Why is a performance test essential?

2/5/2018 17

Why is effective radon control in new homes important?

Pause recording now—answer will be revealed shortly

POP QUIZ

QUESTION 1 OF 3

• A. New homes typically have higher indoor radon

concentrations, especially those with indoor/outdoor air changes below 0.3 per hour

• B. Radon exposure in the home kills more U.S.

residents than residential fires and carbon monoxide

• C. All of the above
• D. None of the above

Why is effective radon control in new homes important? POP QUIZ

QUESTION 1 OF 3

• A. New homes typically have higher indoor radon

concentrations, especially those with indoor/outdoor air changes below 0.3 per hour

• B. Radon exposure in the home kills more U.S.

residents than residential fires and carbon monoxide

• C. All of the above
• D. None of the above

2/5/2018 18

Which radon control technique provides the greatest indoor radon reduction?

Pause recording now—answer will be revealed shortly

POP QUIZ

QUESTION 2 OF 3

• A. Active soil depressurization
• B. Heat or energy recovery ventilator
• C. Passive soil depressurization
• D. Stand-alone sealing foundation walls
• E. A and C

F. B and C

Which radon control technique provides the greatest indoor radon reduction? POP QUIZ

QUESTION 2 OF 3

• A. Active soil depressurization
• B. Heat or energy recovery ventilator
• C. Passive soil depressurization
• D. Stand-alone sealing foundation walls
• E. A and C

F. B and C

2/5/2018 19

What must be provided in a document package for a home’s occupants?

Pause recording now—answer will be revealed shortly

POP QUIZ

QUESTION 3 OF 3

• A. A description of the radon system’s operation
• B. If there is a fan, the annual energy cost to operate

the fan

• C. Radon test data for the home
• D. A and C
• E. All of the above

What must be provided in a document package for a home’s occupants? POP QUIZ

QUESTION 3 OF 3

• A. A description of the radon system’s operation
• B. If there is a fan, the annual energy cost to operate

the fan

• C. Radon test data for the home
• D. A and C
• E. All of the above