Measuring Radon in Residential Properties What are the testing strategies for radon? Lesson 6 What are the testing strategies for radon? Connecticut Radon Measurement Training Program 2006

EPA goals Help people make decisions about radon reduction that Are timely Are simple Are cost effective Protect human health Especially against lung cancer

Importance of reliable measurement Follow EPA protocols for reliable measurement Helps property owners decide whether to mitigate May be part of price negotiations in real estate transactions What should I do to protect my family? If the mitigation system on our new home will cost $1500, will the seller reduce the asking price?

Review Length of test Short-term test Long-term test 2-90 days Provides more information about a home’s year-round average radon level Measures radon levels during brief test period Often used in real estate transactions Devices include Charcoal canisters Charcoal liquid scintillation detectors Electret ion chamber devices (short-term E-PERMs) Continuous monitors Devices include Alpha track devices Electret ion chamber devices (long-term E-PERMs)

Measuring Radon in Residential Properties What are the testing strategies for radon? Length of test Both types of test can provide accurate results Both types of test usually lead to same decisions about mitigation Image from University of Illinois Extension, “Take Action on Radon fro Healthy Homes,” http://www.takeactiononradon.uiuc.edu/reducing.html Connecticut Radon Measurement Training Program 2006

General testing process (not related to sale of a home) Step 1 Conduct a short-term test Step 2 Determine what follow-up strategy is needed Step 3 Conduct any needed follow-up test Step 4 Examine results of all tests to determine what to advise the homeowner Handout 6-1 summarizes this information

General testing strategies Step 1: Assume you have conducted a short-term test Step 2: Determine what follow-up strategy is needed Follow-up depends on the first test result 0–under 4 pCi/L (0–under 0.02 WL) 4–under 10 pCi/L (0.02–under 0.05 WL) 10 pCi/L and above (0.05 WL and above)

General testing If the first test result is 0–under 4 pCi/L You do not have to conduct a follow-up test now Advise the owner to test again in the future, especially if An unused lower level becomes used as a living space Structural changes are made Changes in the HVAC system are made

General testing If the first test result is 4 pCi/L or more, conduct a follow-up test 4–under 10 pCi/L 10 pCi/L and above

use the long-term results General testing If the first test result is 4 pCi/L or more but under 10 pCi/L Conduct a follow-up short-term test or long-term test With another short-term test, average the results of the first and follow-up tests With a long-term test, use the long-term results If the average is under 4 pCi/L, advise the owner to test again in the future If the average is 4 pCi/L or more, advise the owner to mitigate If the result is under 4 pCi/L, advise the owner to test again in the future If the result is 4 pCi/L or more, advise the owner to mitigate

General testing If the first test result is 10 pCi/L or more Conduct a follow-up short-term test Average the results of the first and follow-up tests If the average is under 4 pCi/L, advise the owner to test again in the future 4 pCi/L or more, advise the owner to mitigate

Example Step 1: Conduct a short-term test Step 2: Determine follow-up strategy Test 1 = 5.4 pCi/L Advise follow-up test Since result is under 10 pCi/L, either short-term or long-term test OK Step 3: Conduct follow-up test (short-term) Step 4: Examine results Test 2 = 3.8 pCi/L Average = 4.6 pCi/L Recommend mitigation What do you advise? You are testing for Jeri, who has no plans to sell her Simsbury home What do you advise?

Example What if Jeri had requested a long-term test as follow-up? Test 2 = 4.0 pCi/L What do you advise? Recommend mitigation You are testing for Jeri, who has no plans to sell her Simsbury home

General testing strategies Summary First test result 0–under 4 pCi/L 4–under 10 pCi/L and above No immediate follow-up Follow-up with short-term or long-term test Follow-up with short-term test

Questions? About strategies for tests that are not associated with real estate transactions

Testing associated with home sales Why are there potential problems? Time pressure Accidental violation of test conditions Possibility of tampering

Testing associated with home sales Short-term options usually preferred because of time factor Passive tests Two simultaneous tests (two tests at the same time in the same place) Two sequential tests (one test right after another in the same place) Active test One continuous monitor Handout 6-2 summarizes this information

Real estate option 1 Two simultaneous tests Conduct two short-term tests at the same time March 2010 5 6 Begin Tests 1 and 2 7 8 End Tests 1 and 2 9 Use two identical devices and methods Test in same location Place two devices 4 inches apart Run tests for at least 48 hours Return devices to lab promptly

Simultaneous test results Expect some variation between any two results Both results are under 4 pCi/L Average will be Report both results and average Recommend future retesting Both results are 4 pCi/L or more Average will be Report both results and average Recommend mitigation

Simultaneous test results Special situation One result is under 4 pCi/L and one result is 4 pCi/L or more Average may be under, at, or over 4 pCi/L Consider the difference between the two results

Simultaneous test results Special situation One result is under 4 pCi/L and one result is 4 pCi/L or more Consider the difference between the two results L = lower result H = higher result Multiply L by 2 and compare with H If H is less than L x 2, the difference is acceptable Report results and average If average is under 4 pCi/L, recommend future retesting If average is 4 pCi/L or more, recommend mitigation If H is greater than or equal to L x 2, the difference is too large Report that the results do not agree Retest See handout 6-3

Simultaneous test results Special situation example L = lower result H = higher result Example 1: L = 3.2 H = 4.2 L x 2 = 6.4 H (4.2) is less than L x 2 (6.4), so the difference is acceptable Report results and average (3.7) Example 2: L = 2.2 H = 4.6

Simultaneous test results Special situation example L = lower result H = higher result Example 1: L = 3.2 H = 4.2 L x 2 = 6.4 H (4.2) is less than L x 2 (6.4), so the difference is acceptable Report results and average (3.7) Example 2: L = 2.2 H = 4.6 L x 2 = 4.4 H (4.6) is greater than L x 2 (4.4), so the difference is too large Report disagreement of results (but not results) and retest

Simultaneous test results Summary Expect some difference between the two results Both results are under 4 pCi/L One result is under 4 pCi/L and one result is 4 pCi/L or more Both results are 4 pCi/L or more Average will be under 4 pCi/L If the higher result is twice the lower result or more, retest If the higher result is less than twice the lower, report both results and average Recommend retesting or mitigation based on average Average will be Report both results and average Recommend future retesting Report both results and average Recommend mitigation

Real estate option 2 Two sequential tests Conduct one short-term test after another First test Run the first test for at least 48 hours Return the device to the lab promptly Immediately after the first test is finished, run a follow-up test March 2010 5 6 Begin Test 1 7 8 9

Real estate option 2 Two sequential tests Follow-up test Begin immediately after first test Use identical device and method Use same units (pCi/L or WL) Place device in same location Run follow-up test for same period as first test Up to 2 hours difference allowed Run for at least 48 hours Return device to lab promptly March 2010 5 6 Begin Test 1 7 8 End Test 1 Begin Test 2 9

Sequential tests Variation in results Expect some variation between any two results Radon levels vary from day to day Moderate variation is acceptable If variation is large, consider possible causes Weather Air pressure Season Accidental disturbance of device Opening of doors or windows Tampering Lab error Moderate variation Large variation

Sequential tests Reporting results What to report Report both results Use average of two test results to determine need for mitigation When to report After second test to discourage tampering Especially if first test result is 4 pCi/L or more

Activity See scenario in handout 6-4 What did Hector do wrong? Hector, an inexperienced inspector, ran two sequential short-term tests in a home for sale in Columbia See scenario in handout 6-4 What did Hector do wrong? Revise the scenario so that Hector conducts the tests properly Consider factors that might explain differences in test results

Questions? About simultaneous tests in real estate transactions? About sequential tests in real estate transactions?

Real estate option 3 One continuous test Use any NEHA- or NRSB-listed continuous monitor or working-level monitor Use monitor that integrates and records at least every hour

Real estate option 3 One continuous test Run test for at least 48 hours Requires about 4 hours for conditions to stabilize Discard data from these 4 hours or correct them Must have at least 44 continuous (uninterrupted) hours of data for valid average If you remove any data within that period (for example, if severe weather occurs), results will not be valid

Real estate option 3 One continuous test Results 0–under 4 pCi/L 4 pCi/L or more Recommend future retesting Recommend mitigation

Questions? About continuous testing?

Summary Testing period Testing strategies Short-term (2-90 days) Long-term (91-365 days) Both provide accurate results Testing strategies General testing Testing associated with real estate transactions

Summary General testing steps Conduct short-term test Determine what follow-up strategy is needed, depending on first result 0 to under 4 pCi/L 4 to under 10 pCi/L 10 pCi/L or above Conduct any required follow-up Examine results to determine what to advise homeowner When result is under 4 pCi/L, advise future follow-up, especially if major changes are made When final result is 4 pCi/L or more, advise mitigation

Summary Real estate options Two simultaneous tests using passive devices Two sequential tests using passive devices One continuous test

Questions?

Check your understanding See handout 6-5