Healthy Building Science

  • HOME
  • Who We Are
    • Meet The Team
    • Position Statements
      • Healthy Paints & Coatings
      • Damp Buildings & Mold Testing
      • Water Filtration for All Building Types
    • Qualifications and Partnerships
  • What We Do
    • Residential Services
    • Environmental Testing
      • Cleaning, Verification & Coronavirus Testing
      • Air Quality Testing
      • Water Quality Testing
      • Soil Testing
      • Asbestos Testing
      • Mold Testing
      • Lead Testing
      • EMF Testing – RF Testing
      • LEED IAQ Testing
      • Silica Air Testing (OSHA)
      • Compliance Testing USP 797
    • Healthy Building Inspections
      • Cleaning, Verification & Coronavirus Testing
      • Air Quality Inspection
      • Asbestos Survey
      • Lead Inspection
      • Moisture and Mold Inspection
    • Industrial Hygiene and Compliance Testing
      • Cleaning, Verification & Coronavirus Testing
    • General Contractor
    • Process and FAQs
      • Architect FAQs
      • Building Owner FAQs
      • Property Manager FAQs
      • Human Resource Managers FAQ’s
  • Case Studies
    • Commercial – Industrial
    • Residential
    • School and Health Care Facilities
  • Blog
  • Contact Us
  • Home
  • Blog
  • Environmental Testing
  • Radiation Exposure – How much is too much?
March 25, 2023

Radiation Exposure – How much is too much?

Radiation Exposure – How much is too much?

by healthybuilding / Wednesday, 16 October 2013 / Published in Environmental Testing, Healthy Building Inspections & Testing
Quartzite radiation test

Radiation Exposure

How Much Is “Too Much”

Alex Stadtner, president of Healthy Building Science, wrote a blog in April 2012 entitled “Radioactive Granite and Quartzite – Risks from Radon” about discovering high levels of radiation in Quartzite and Granite used in residential building for items such as countertops, flooring, and bath and shower enclosures.  While that blog explained very well the risks of radiation in some common natural stone, I wanted to go into more detail about measuring radiation exposure, and what the numbers mean.

Radiation is ubiquitous.  The earth is constantly being bombarded with cosmic rays as well as other radiation (x-rays, gamma, alpha, and beta radiation).  The earth’s magnetic field does an admirable job of blocking a majority of this radiation from reaching the earth’s surface, but a small percentage makes it and sometimes we are exposed to it.  Flying at 30,000 feet in an airplane or living at high altitude can increase exposure.
Some radiation is man made, X-ray machines, MRI, Nuclear power plants, weapons, and nuclear waste for example.EPA Radiation From Granite

Some radiation comes from the natural decay of radioactive material found in the earth.  This decay creates Radon gas is some areas.  This is the radiation that can be emitted by natural stone installed in a home.

This is an excellent article from MIT about radiation exposure limits:

http://web.mit.edu/newsoffice/1994/safe-0105.html

Excerpt from the above referenced article:
“The average exposure in the United States, from natural sources of radiation (mostly cosmic radiation and radon), is 300 millirems per year at sea level. Radiation exposure is slightly higher at higher elevations-thus the exposure in Denver averages 400 millirems per year.”


The current federal occupational limit of exposure per year for an adult (the limit for a worker using radiation) is “as low as reasonably achievable; however, not to exceed 5,000 millirems” above the 300+ millirems of natural sources of radiation and any medical radiation.

Minor: 500 Millirems

The maximum permissible exposure for a person under 18 working with radiation is one-tenth the adult limit or not to exceed 500 millirems per year above the 300+ millirems of natural sources, plus medical radiation. This was established in 1957 and reviewed as recently as 1990.

Fetus: 500 Millirems Or 50 Per Month (New Rule Jan. 1, 1994)

New federal regulations went into effect New Year’s Day, establishing for the first time an exposure limit for the embryo or fetus of a pregnant woman exposed to radiation at work. The limit for the gestation period is 500 millirems, with a recommendation that the exposure of a fetus be no more than 50 millirems per month.”

So there is not so much a “safe” level as much as a maximum lifetime exposure, with monthly and yearly recommendations to keep exposure below that level.  The goal is to have your background levels well below these recommendations.

Our instruments measure millirems/hour and we usually take a 15-minute sample.  300 millirems a year equates to 0.34 mR/Hr.  Today in the office I measured background at 0.014 mR/Hr.

radiation exposure

Radioactivity Baseline

For a fetus 50 millirems per month equates to 0.069 mR/Hr.

For measuring homes and stone products, I would consider any level above 0.018 mR/Hr to be a fail (this is equal to 13 millirems per month, about 25% of the recommended max exposure for a fetus).   Levels below 0.010 may be difficult to obtain due to natural background radiation levels.  As well, any reading that is more than 150% of the background control reading is also a fail.

It is a good idea to measure your home inside and out to determine background levels, or to discover any currently installed sources prior to any renovation.  Peace of mind, or discovering a hidden source of radiation, can be the result of testing an existing home.  Basements and crawlspaces, as well as occupied spaces should be tested for Radon gas being emitted from the soil.

I would recommend testing any new natural stone products prior to purchasing and installing them.

If we are measuring natural stone, it is best to compare to the background level (a sample taken in the parking lot at least 100 feet away from any stone products) and compare to the desired stone sample.

Radiation is everywhere, and invisible and asymptomatic, but can damage cells and in the worst-case lead to cancer.  Since we all spend so much time on our homes, knowing the level of radiation in your home and being emitted by the items installed in the home, is knowledge worth having.

Tagged under: Building Material Testing, Environmental Testing, Healthy Building Materials, Soil Testing

About healthybuilding

What you can read next

Asthma and Allergy Resources – 2011
easy ways to protect your family
Free and Easy Ways to Protect Your Family Today
EMF Resources
Electromagnetic Field (EMF) Resources – 2011

Who is Healthy Building Science?

We are an environmental consulting firm based in the San Francisco Bay Area, a group of scientists working to make your indoor spaces healthier. We test your building or property to find harmful pollutants.
Healthy Building Science

Environmental Testing Services at HBS

  • Air Quality Testing
  • Water Quality Testing
  • Soil Testing
  • Asbestos Testing
  • Lead Testing
  • Mold Testing
  • RF Testing – EMF Testing
  • LEED IAQ Testing
  • Silica Air Testing (OSHA)
  • Compliance Testing USP 797
  • Environmental Testing
  • Industrial Hygiene and Compliance
  • Cleaning, Verification & Coronavirus Testing

Search HBS Blogs

Blog Categories

Archives

Sign up for our Quarterly newsletter

Subscribe to our e-mail newsletter to receive helpful updates and articles from Healthy Building Science.
SIGN UP FOR OUR QUARTERLY NEWSLETTERR

We value your privacy.
Your email is never shared or sold.

Sustainable Business Certifications

California Green Business Network

Get in Touch

To speak directly with someone;
Call (415) 785-7986

Email: [email protected]

Or click the button below, tell us a little about your project and let our environmental consultants help you create a healthier building.

New Project Inquiry

Latest From Our Blog

  • Effective Residential Drainage System’s for a Healthy Home

    A well-designed drainage system is essential to...
  • Want to Protect Your Home from Wildfire? The Secret’s not Luck – It’s Science

    It’s no secret – anyone living in Marin and Son...
  • What is ERMI Testing?

    Scientists always needed a reliable process to ...

Blog Categories

  • Business
  • Environmental Consulting
  • Environmental Testing
  • Green Building Consulting
  • Healthy Building Inspections & Testing
  • Industrial Hygiene
  • News

Locations

Mailing Address:
369-B Third St. # 521
San Rafael, CA 94901

San Francisco
201 Spear St, Suite 1100, #3226
San Francisco, CA 94105

Phone: (415) 785-7986

Email: [email protected]

  • GET SOCIAL
Healthy Building Science

© 2022 Healthy Building Science. All rights reserved.

TOP