Accredited Environmental Technologies, Inc.         

1-800-969-6AET                           www.aetinc.biz



January is National Radon Month

Residential Properties

Radon in Schools and Childcare Facilities

Commercial Buildings

Radon Mitigation for Existing Construction

Radon Resistant New Construction



Quotes for the Month

New Beginnings

"Coming together is a beginning, staying together is progress, working together is success".
Henry Ford

"The secret to a rich life is to have more beginnings than endings".
Dave Weinbaum

"More powerful than the will to win is the courage to begin".  Unknown



  • Shorter is Better
  • Targeted is Better



  1.  Build upon AET's reputation for prompt
       response and diverse service capabilities.

  2.  Be a proactive resource to our clients focused
       on prevention.

Training in recognition and first response actions to environmental concerns will be provided by monthly newsletters.  A reference library of 18 newsletters is found on our website (www.aetinc.biz).


     Radon is a naturally occurring radioactive gas produced by the breakdown (decay) of uranium in soil, rock and water. You cannot see, taste or smell radon. Radon enters buildings through cracks in the foundation walls and floors, hollow block walls, and openings around floor drains, pipes and sump pumps. Radon is the 2nd leading cause of lung cancer in the United States (behind smoking). Smoking and radon exposure increase the risk for lung cancer 10 fold.

Residential Properties

     Radon testing prior to sale or occupancy of residential properties is a routine practice and recommended by the EPA and state radon agencies. The EPA has set an action limit of 4.0 pCi/L to fix radon problems and estimates 1 in 15 homes exceed this level. Homes in every state in the US are affected. Testing (usually a 48 hour-72 hour short term test) is performed in the "lowest lived in level" of the residence. A single test or an average of 2 simultaneous tests is performed, typically costing $150-$250 per residence.

Indoor Radon Levels Depend Upon:

  1. The amount of radon in the site soil or water (source strength)
  2. Soil porosity (e.g. the greater the porosity, the greater the radon concentration).
  3. The extent of openings in the foundation for radon gas to enter
  4. The pressure differential between the building and the surrounding soil.
  5. The buildings ventilation rate.

In general, increased rainfall and wind levels and decreased barometric pressure result in increased indoor radon levels.

Radon in Schools and Child-Care Facilities

     Radon testing in schools and other child-care facilities is not mandatory but is recommended by the EPA. Testing is performed in accordance with the EPA's Guidance Document Radon Measurements in Schools which recommends simultaneously testing "all frequently occupied rooms in contact with the ground. The EPA has found radon levels in schools can vary significantly from room-to-room. Factors affecting radon levels in schools are the concentrations of radon in the soil gas (source strength), and the permeability of the soil (gas mobility) under the school. The construction method of the school (slab-on-grade design, open-plan or pod-design, crawl space design or basement design) and the type and operation of the HVAC system can also affect radon levels. It is not uncommon for 25-50 radon tests to be conducted at a large school to evaluate radon levels (typical cost $4,000-$5,000 per school).

Commercial Buildings

     AET recommends testing in commercial buildings especially where the lowest level of the structure is below grade and occupied. Like schools, radon levels in commercial buildings can vary significantly from room-to-room. AET typically performs a baseline study consisting of 7-10 tests on the basement level and nearest occupancy locations. Worse case scenarios are employed to evaluate the impact from shafts and other building openings. Results of the baseline study are used to determine if additional testing to evaluate suspect sources and/or locations of necessary controls.

Radon Mitigation for Existing Construction

     Radon mitigation regularly involves sealing cracks and openings in the basement and installing a sub-slab suction depressurization system. This system incorporates drilling holes in the basement concrete floor and installing vent pipe(s) connected to an exhaust fan located outdoors. Diagnostic tests are performed to determine the location and effectiveness of the vent pipe/fan system. Additional points of suction for the vent pipes may be necessary where clay or other non-porous soil is found below the floor slab. The average cost of a sub-slab suction depressurization system for a home ranges from $800-$2000 depending upon the size of the basement and the number of vent pipes installed. Schools and commercial buildings may require multiple sub-slab depressurization systems to control radon gas release.

Radon-Resistant New Construction

Five basic construction features to prevent radon from entering your home or commercial building.

  1. Gravel: Place 4" layer of clean, coarse gravel below the slab/foundation. This creates an air flow layer which allows soil gases to move freely below the structure.
  2. Vapor Retarder: Place heavy duty plastic sheeting or other vapor retarder on top of the gravel to prevent soil gases from entering the slab.
  3. Vent Pipe: Install a 3" or 4" PVC pipe vertically from the gravel layer through the structure's conditioned space and exit the roof.
  4. Sealing and Caulking: Seal all openings, crack and crevices in the foundation floor and walls with polyurethane caulk to prevent radon and other soil gases from entering the structure.
  5. Exhaust Fan: Install electrical outlet near the roof level for connection to an exhaust fan to vent the vent pipe system.

For additional information regarding Radon, check out our January 2009 newsletter and white paper entitled "Radon the Hidden Killer in your Home" on our website.

When are AET's Staff Professionals like Superman?

No, we cannot fly, but we can see inside walls!

     In January, AET completed an IAQ evaluation at a certified historic bank building where building occupants complained of a musty odor smell. AET's inspection found no obvious moisture impact or visible mold. Our next step was to utilize an infrared camera to identify and trace steam lines behind walls and above ceilings in the complaint area. The IR camera confirmed a leak in a steam line above the solid basement plaster ceiling and moisture damage within the wall cavity. The client was able to remove the proper section of the ceiling, repair the steam line and optimize the steam system. Right tools, right answer, cost effective response.


Make AET your first point of contact for your environmental consulting needs in 2010. 

You cannot afford not to call (800-9696-AET) 

Alan Sutherland has been a Certified Industrial Hygienist since 1978 with over 30 years of CIH-related environmental consulting experience. He has a Masters Degree in Environmental Science from Drexel University and is the founder/owner of Accredited Environmental Technologies, Inc. (In 1984). He is uniquely trained and licensed as an Environmental Professional in both the field and laboratory. He has been the founder of two AIHA Accredited Laboratories and a mentor to six (CIHs). Mr. Sutherland is also a Certified Hazardous Material Manager. He can be reached directly at 610-891-0114 or email a.sutherland@aetinc.biz.

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