Section AF103

AF103.1 General.¶

The following construction techniques are intended to resist radon entry and prepare the building for post-construction radon mitigation, if necessary (see Figure AF103). These techniques are required in areas where designated by the jurisdiction.

AF103.2 Subfloor preparation.¶

A layer of gas-permeable material shall be placed under all concrete slabs and other floor systems that directly contact the ground and are within the walls of the living spaces of the building, to facilitate future installation of a subslab depressurization system, if needed. The gas-permeable layer shall consist of one of the following:

A uniform layer of clean aggregate, not less than 4 inches (102 mm) thick. The aggregate shall consist of material that will pass through a 2-inch (51 mm) sieve and be retained by a ¹ /4-inch (6.4 mm) sieve.
A uniform layer of sand (native or fill), not less than 4 inches (102 mm) thick, overlain by a layer or strips of geotextile drainage matting designed to allow the lateral flow of soil gases.
Other materials, systems or floor designs with demonstrated capability to permit depressurization across the entire subfloor area.

AF103.3 Soil-gas-retarder.¶

A minimum 6-mil (0.15 mm) [or 3-mil (0.075 mm) cross-laminated] polyethylene or equivalent flexible sheeting material shall be placed on top of the gas-permeable layer prior to casting the slab or placing the floor assembly to serve as a soil-gas-retarder by bridging any cracks that develop in the slab or floor assembly, and to prevent concrete from entering the void spaces in the aggregate base material. The sheeting shall cover the entire floor area with separate sections of sheeting lapped not less than 12 inches (305 mm). The sheeting shall fit closely around any pipe, wire or other penetrations of the material. Punctures or tears in the material shall be sealed or covered with additional sheeting.

AF103.4 Entry routes.¶

Potential radon entry routes shall be closed in accordance with Sections AF103.4.1 through AF103.4.10.

AF103.4.1 Floor openings. Openings around bathtubs, showers, water closets, pipes, wires or other objects that penetrate concrete slabs, or other floor assemblies, shall be filled with a polyurethane caulk or equivalent sealant applied in accordance with the manufacturer’s recommendations.

AF103.4.2 Concrete joints. Control joints, isolation joints, construction joints, and any other joints in concrete slabs or between slabs and foundation walls shall be sealed with a caulk or sealant. Gaps and joints shall be cleared of loose material and filled with polyurethane caulk or other elastomeric sealant applied in accordance with the manufacturer’s recommendations.

AF103.4.3 Condensate drains. Condensate drains shall be trapped or routed through nonperforated pipe to daylight.

AF103.4.4 Sumps. Sump pits open to soil or serving as the termination point for subslab or exterior drain tile loops shall be covered with a gasketed or otherwise sealed lid. Sumps used as the suction point in a subslab depressurization system shall have a lid designed to accommodate the vent pipe. Sumps used as a floor drain shall have a lid equipped with a trapped inlet.

AF103.4.5 Foundation walls. Hollow block masonry foundation walls shall be constructed with either a continuous course of solid masonry, one course of masonry grouted solid, or a solid concrete beam at or above finished ground surface to prevent the passage of air from the interior of the wall into the living space. Where a brick veneer or other masonry ledge is installed, the course immediately below that ledge shall be sealed. Joints, cracks or other openings around all penetrations of both exterior and interior surfaces of masonry block or wood foundation walls below the ground surface shall be filled with polyurethane caulk or equivalent sealant. Penetrations of concrete walls shall be filled.

AF103.4.6 Dampproofing. The exterior surfaces of portions of concrete and masonry block walls below the ground surface shall be dampproofed in accordance with Section R406.

AF103.4.7 Air-handling units. Air-handling units in crawl spaces shall be sealed to prevent air from being drawn into the unit.

Exception: Units with gasketed seams or units that are otherwise sealed by the manufacturer to prevent leakage.

AF103.4.8 Ducts. Ductwork passing through or beneath a slab shall be of seamless material unless the air-handling system is designed to maintain continuous positive pressure within such ducting. Joints in such ductwork shall be sealed to prevent air leakage.

Ductwork located in crawl spaces shall have seams and joints sealed by closure systems in accordance with Section M1601.4.1.

AF103.4.9 Crawl space floors. Openings around all penetrations through floors above crawl spaces shall be caulked or otherwise filled to prevent air leakage.

AF103.4.10 Crawl space access. Access doors and other openings or penetrations between basements and adjoining crawl spaces shall be closed, gasketed or otherwise filled to prevent air leakage.

AF103.5 Passive submembrane depressurization system.¶

In buildings with crawl space foundations, the following components of a passive submembrane depressurization system shall be installed during construction.

Exception: Buildings in which an approved mechanical crawl space ventilation system or other equivalent system is installed.

AF103.5.1 Ventilation. Crawl spaces shall be provided with vents to the exterior of the building. The minimum net area of ventilation openings shall comply with Section R408.1.

566 2019 CALIFORNIA RESIDENTIAL CODE

Copyright © 2019 ICC. ALL RIGHTS RESERVED. Accessed by Kevin Day (kevin.day@dgs.ca.gov), (California Building Standards Commission) Order Number #100735044 on Jul 24, 2019 03:54 PM (PDT) pursuant to License Agreement with ICC. No further reproduction or distribution authorized. Single user only, copying and networking prohibited. ANY UNAUTHORIZED REPRODUCTION OR DISTRIBUTION IS A VIOLATION OF THE FEDERAL COPYRIGHT ACT AND THE LICENSE AGREEMENT, AND SUBJECT TO CIVIL AND CRIMINAL PENALTIES THEREUNDER.

100735044

AF103.5.2 Soil-gas-retarder. The soil in crawl spaces shall be covered with a continuous layer of minimum 6mil (0.15 mm) polyethylene soil-gas-retarder. The ground cover shall be lapped not less than 12 inches (305 mm) at joints and shall extend to all foundation walls enclosing the crawl space area.

AF103.5.3 Vent pipe. A plumbing tee or other approved connection shall be inserted horizontally beneath the sheeting and connected to a 3- or 4-inch-diameter (76 or 102 mm) fitting with a vertical vent pipe installed through the sheeting. The vent pipe shall be extended up through the building floors, and terminate not less than 12 inches (305 mm) above the roof in a location not less than 10 feet (3048 mm) away from any window or other opening into the conditioned spaces of the building that is less than 2 feet (610 mm) below the exhaust point, and 10 feet (3048 mm) from any window or other opening in adjoining or adjacent buildings.

AF103.6 Passive subslab depressurization system.¶

In basement or slab-on-grade buildings, the following components of a passive subslab depressurization system shall be installed during construction.

AF103.6.1 Vent pipe. A minimum 3-inch-diameter (76 mm) ABS, PVC or equivalent gas-tight pipe shall be embedded vertically into the subslab aggregate or other permeable material before the slab is cast. A “T” fitting or equivalent method shall be used to ensure that the pipe opening remains within the subslab permeable material. Alternatively, the 3-inch (76 mm) pipe shall be inserted directly into an interior perimeter drain tile loop or through a sealed sump cover where the sump is exposed to the subslab aggregate or connected to it through a drainage system.

The pipe shall be extended up through the building floors, and terminate not less than 12 inches (305 mm) above the surface of the roof in a location not less than 10 feet (3048 mm) away from any window or other opening into the conditioned spaces of the building that is less than 2 feet (610 mm) below the exhaust point, and 10 feet (3048 mm) from any window or other opening in adjoining or adjacent buildings.

RADON CONTROL METHODS

AF103.6.2 Multiple vent pipes. In buildings where interior footings or other barriers separate the subslab aggregate or other gas-permeable material, each area shall be fitted with an individual vent pipe. Vent pipes shall connect to a single vent that terminates above the roof or each individual vent pipe shall terminate separately above the roof.

AF103.7 Vent pipe drainage.¶

Components of the radon vent pipe system shall be installed to provide positive drainage to the ground beneath the slab or soil-gas-retarder.

AF103.8 Vent pipe accessibility.¶

Radon vent pipes shall be accessible for future fan installation through an attic or other area outside the habitable space.

Exception: The radon vent pipe need not be accessible in an attic space where an approved roof-top electrical supply is provided for future use.

AF103.9 Vent pipe identification.¶

Exposed and visible interior radon vent pipes shall be identified with not less than one label on each floor and in accessible attics. The label shall read: “Radon Reduction System.”

AF103.10 Combination foundations.¶

Combination basement/crawl space or slab-on-grade/crawl space foundations shall have separate radon vent pipes installed in each type of foundation area. Each radon vent pipe shall terminate above the roof or shall be connected to a single vent that terminates above the roof.

AF103.11 Building depressurization.¶

Joints in air ducts and plenums in unconditioned spaces shall meet the requirements of Section M1601. Thermal envelope air infiltration requirements shall comply with the energy conservation provisions in Chapter 11. Fireblocking shall meet the requirements contained in Section R302.11.

AF103.12 Power source.¶

To provide for future installation of an active submembrane or subslab depressurization system, an electrical circuit terminated in an approved box shall be installed during construction in the attic or other anticipated location of vent pipe fans. An electrical supply shall be accessible in anticipated locations of system failure alarms.

100735044

RADON CONTROL METHODS

568 2019 CALIFORNIA RESIDENTIAL CODE

100735044

RADON CONTROL METHODS

		TABLE AF101(1) HIGH RADON-POTENTIAL (ZONE 1) COUNTIESa
ALABAMA Calhoun Clay Cleburne Colbert	CONNECTICUT Fairfield Middlesex New Haven New London	Morgan Moultrie Ogle Peoria Piatt	Wabash Warren Washington Wayne Wells	Trego Wallace Washington Wichita Wyandotte	Hillsdale Jackson Kalamazoo Lenawee St. Joseph	Watonwan Wilkin Winona Wright Yellow Medicine
Coosa Franklin	GEORGIA	Pike Putnam	White Whitley	KENTUCKY	Washtenaw	MISSOURI
Jackson Lauderdale Lawrence Limestone Madison Morgan Talladega	Cobb De Kalb Fulton Gwinnett IDAHO Benewah	Rock Island Sangamon Schuyler Scott Stark Stephenson Tazewell	IOWA All Counties KANSAS Atchison Barton	Adair Allen Barren Bourbon Boyle Bullitt Casey	MINNESOTA Becker Big Stone Blue Earth Brown Carver Chippewa	Andrew Atchison Buchanan Cass Clay Clinton Holt
CALIFORNIA Santa Barbara Ventura	Blaine Boise Bonner Boundary Butte	Vermilion Warren Whiteside Winnebago Woodford	Brown Cheyenne Clay Cloud Decatur	Clark Cumberland Fayette Franklin Green	Clay Cottonwood Dakota Dodge Douglas	Iron Jackson Nodaway Platte
COLORADO Adams Arapahoe Baca Bent Boulder Chaffee Cheyenne Clear Creek Crowley Custer Delta Denver	Camas Clark Clearwater Custer Elmore Fremont Gooding Idaho Kootenai Latah Lemhi Shoshone Valley	INDIANA Adams Allen Bartholomew Benton Blackford Boone Carroll Cass Clark Clinton De Kalb	Dickinson Douglas Ellis Ellsworth Finney Ford Geary Gove Graham Grant Gray Greeley Hamilton	Harrison Hart Jefferson Jessamine Lincoln Marion Mercer Metcalfe Monroe Nelson Pendleton Pulaski Robertson	Faribault Fillmore Freeborn Goodhue Grant Hennepin Houston Hubbard Jackson Kanabec Kandiyohi Kittson Lac Qui Parle	MONTANA Beaverhead Big Horn Blaine Broadwater Carbon Carter Cascade Chouteau Custer Daniels Dawson Deer Lodge
Dolores Douglas El Paso Elbert Fremont Garfield Gilpin Grand Gunnison Huerfano Jackson Jefferson Kiowa Kit Carson Lake Larimer Las Animas Lincoln Logan	ILLINOIS Adams Boone Brown Bureau Calhoun Carroll Cass Champaign Coles De Kalb De Witt Douglas Edgar Ford Fulton Greene Grundy	Decatur Delaware Elkhart Fayette Fountain Fulton Grant Hamilton Hancock Harrison Hendricks Henry Howard Huntington Jay Jennings Johnson Kosciusko LaGrange	Haskell Hodgeman Jackson Jewell Johnson Kearny Kingman Kiowa Lane Leavenworth Lincoln Logan Marion Marshall McPherson Meade Mitchell Nemaha Ness	Russell Scott Taylor Warren Woodford MAINE Androscoggin Aroostook Cumberland Franklin Hancock Kennebec Lincoln Oxford Penobscot Piscataquis Somerset York	Le Sueur Lincoln Lyon Mahnomen Marshall Martin McLeod Meeker Mower Murray Nicollet Nobles Norman Olmsted Otter Tail Pennington Pipestone Polk Pope	Fallon Fergus Flathead Gallatin Garfield Glacier Granite Hill Jefferson Judith Basin Lake Lewis and Clark Madison McCone Meagher Missoula Park Phillips Pondera
Mesa Moffat Montezuma Montrose Morgan Otero Ouray Park Phillips Pitkin	Hancock Henderson Henry Iroquois Jersey Jo Daviess Kane Kendall Knox La Salle	Lawrence Madison Marion Marshall Miami Monroe Montgomery Noble Orange Putnam	Norton Osborne Ottawa Pawnee Phillips Pottawatomie Pratt Rawlins Republic Rice	MARYLAND Baltimore Calvert Carroll Frederick Harford Howard Montgomery Washington	Ramsey Red Lake Redwood Renville Rice Rock Roseau Scott Sherburne Sibley	Powder River Powell Prairie Ravalli Richland Roosevelt Rosebud Sanders Sheridan Silver Bow
Prowers Pueblo Rio Blanco San Miguel Summit	Lee Livingston Logan Macon Marshall	Randolph Rush Scott Shelby St. Joseph	Riley Rooks Rush Saline Scott	MASS. Essex Middlesex Worcester	Stearns Steele Stevens Swift Todd	Stillwater Teton Toole Valley Wibaux
Teller Washington Weld Yuma	Mason McDonough McLean Menard Mercer	Steuben Tippecanoe Tipton Union Vermillion	Sheridan Sherman Smith Stanton Thomas	MICHIGAN Branch Calhoun Cass	Traverse Wabasha Wadena Waseca Washington	Yellowstone

(continued)

100735044

RADON CONTROL METHODS

TABLE AF101(1)—continued HIGH RADON-POTENTIAL (ZONE 1) COUNTIES ^a

NEBRASKA Adams Boone Boyd	Morris Somerset Sussex Warren	Columbiana Coshocton Crawford Darke	Lehigh Luzerne Lycoming Mifflin	Union Walworth Yankton	Fairfax Falls Church Fluvanna Frederick	Crawford Dane Dodge Door
Burt Butler Cass Cedar Clay Colfax Cuming Dakota Dixon	NEW MEXICO Bernalillo Colfax Mora Rio Arriba San Miguel Santa Fe Taos	Delaware Fairfield Fayette Franklin Greene Guernsey Hamilton Hancock Hardin	Monroe Montgomery Montour Northampton Northumberland Perry Schuylkill Snyder Sullivan	TENNESSEE Anderson Bedford Blount Bradley Claiborne Davidson Giles Grainger	Fredericksburg Giles Goochland Harrisonburg Henry Highland Lee Lexington Louisa	Fond du Lac Grant Green Green Lake Iowa Jefferson Lafayette Langlade Marathon
Dodge Douglas Fillmore Franklin Frontier Furnas Gage	NEW YORK Albany Allegany Broome Cattaraugus Cayuga	Harrison Holmes Huron Jefferson Knox Licking Logan	Susquehanna Tioga Union Venango Westmoreland Wyoming York	Greene Hamblen Hancock Hawkins Hickman Humphreys Jackson	Martinsville Montgomery Nottoway Orange Page Patrick Pittsylvania	Menominee Pepin Pierce Portage Richland Rock Shawano
Gosper Greeley Hamilton Harlan	Chautauqua Chemung Chenango Columbia	Madison Marion Mercer Miami	RHODE ISLAND Kent Washington	Jefferson Knox Lawrence Lewis	Powhatan Pulaski Radford Roanoke	St. Croix Vernon Walworth Washington
Hayes Hitchcock Hurston	Cortland Delaware Dutchess	Montgomery Morrow Muskingum	S. CAROLINA Greenville	Lincoln Loudon Marshall	Rockbridge Rockingham Russell	Waukesha Waupaca Wood
Jefferson Johnson Kearney Knox Lancaster Madison Nance Nemaha Nuckolls Otoe Pawnee Phelps Pierce	Erie Genesee Greene Livingston Madison Onondaga Ontario Orange Otsego Putnam Rensselaer Schoharie Schuyler	Perry Pickaway Pike Preble Richland Ross Seneca Shelby Stark Summit Tuscarawas Union Van Wert	S. DAKOTA Aurora Beadle Bon Homme Brookings Brown Brule Buffalo Campbell Charles Mix Clark Clay	Maury McMinn Meigs Monroe Moore Perry Roane Rutherford Smith Sullivan Trousdale Union Washington	Salem Scott Shenandoah Smyth Spotsylvania Stafford Staunton Tazewell Warren Washington Waynesboro Winchester Wythe	WYOMING Albany Big Horn Campbell Carbon Converse Crook Fremont Goshen Hot Springs Johnson Laramie
Platte Polk Red Willow	Seneca Steuben Sullivan	Warren Wayne Wyandot	Codington Corson Davison	Wayne Williamson Wilson	WASHINGTON Clark	Lincoln Natrona Niobrara
Richardson Saline Sarpy Saunders Seward Stanton Thayer Washington Wayne	Tioga Tompkins Ulster Washington Wyoming Yates N. CAROLINA Alleghany	PENNSYLVANIA Adams Allegheny Armstrong Beaver Bedford Berks Blair	Day Deuel Douglas Edmunds Faulk Grant Hamlin Hand Hanson	UTAH Carbon Duchesne Grand Piute Sanpete Sevier Uintah	Ferry Okanogan Pend Oreille Skamania Spokane Stevens W. VIRGINIA Berkeley	Park Sheridan Sublette Sweetwater Teton Uinta Washakie
Webster York NEVADA Carson City Douglas Eureka Lander Lincoln Lyon Mineral Pershing White Pine	Buncombe Cherokee Henderson Mitchell Rockingham Transylvania Watauga N. DAKOTA All Counties OHIO Adams	Bradford Bucks Butler Cameron Carbon Centre Chester Clarion Clearfield Clinton Columbia Cumberland Dauphin	Hughes Hutchinson Hyde Jerauld Kingsbury Lake Lincoln Lyman Marshall McCook McPherson Miner Minnehaha	VIRGINIA Alleghany Amelia Appomattox Augusta Bath Bland Botetourt Bristol Brunswick Buckingham Buena Vista	Brooke Grant Greenbrier Hampshire Hancock Hardy Jefferson Marshall Mercer Mineral Monongalia Monroe Morgan
NEW HAMPSHIRE Carroll	Allen Ashland Auglaize Belmont	Delaware Franklin Fulton Huntingdon	Moody Perkins Potter Roberts	Campbell Chesterfield Clarke Clifton Forge	Ohio Pendleton Pocahontas Preston
NEW JERSEY	Butler Carroll	Indiana Juniata	Sanborn Spink	Covington Craig	Summers Wetzel
Hunterdon Mercer Monmouth	Champaign Clark Clinton	Lackawanna Lancaster Lebanon	Stanley Sully Turner	Cumberland Danville Dinwiddie	WISCONSIN Buffalo

a. The EPA recommends that this county listing be supplemented with other available State and local data to further understand the radon potential of a Zone 1

area.

570 2019 CALIFORNIA RESIDENTIAL CODE

100735044

RADON CONTROL METHODS

100735044

572 2019 CALIFORNIA RESIDENTIAL CODE Copyright © 2019 ICC. ALL RIGHTS RESERVED. Accessed by Kevin Day (kevin.day@dgs.ca.gov), (California Building Standards Commission) Order Number #100735044 on Jul 24, 2019 03:54 PM (PDT) pursuant to License Agreement with ICC. No further reproduction or distribution authorized. Single user only, copying and networking prohibited. ANY UNAUTHORIZED REPRODUCTION OR DISTRIBUTION IS A VIOLATION OF THE FEDERAL COPYRIGHT ACT AND THE LICENSE AGREEMENT, AND SUBJECT TO CIVIL AND CRIMINAL PENALTIES THEREUNDER.

100735044

APPENDIX G

RESERVED

100735044

574 2019 CALIFORNIA RESIDENTIAL CODE Copyright © 2019 ICC. ALL RIGHTS RESERVED. Accessed by Kevin Day (kevin.day@dgs.ca.gov), (California Building Standards Commission) Order Number #100735044 on Jul 24, 2019 03:54 PM (PDT) pursuant to License Agreement with ICC. No further reproduction or distribution authorized. Single user only, copying and networking prohibited. ANY UNAUTHORIZED REPRODUCTION OR DISTRIBUTION IS A VIOLATION OF THE FEDERAL COPYRIGHT ACT AND THE LICENSE AGREEMENT, AND SUBJECT TO CIVIL AND CRIMINAL PENALTIES THEREUNDER.

100735044

CALIFORNIA RESIDENTIAL CODE – MATRIX ADOPTION TABLE