lesson 6
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Lesson 6. What are the testing strategies for radon?. EPA goals. Are timely Are simple Are cost effective Protect human health Especially against lung cancer. Help people make decisions about radon reduction that. Helps property owners decide whether to mitigate. - PowerPoint PPT PresentationTRANSCRIPT
Lesson 6
What are the testing strategies for radon?
Slide 6-2
EPA goals
• Are timely• Are simple• Are cost effective• Protect human
health– Especially against
lung cancer
Help people make decisions about radon reduction that
Slide 6-3
Importance of 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?
Follow EPA protocols for reliable measurement
Slide 6-4
• 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
ReviewLength of test
Short-term test
91-365 days
• Provides more information about a home’s year-round average radon level
• Devices include– Alpha track devices– Electret ion chamber devices
(long-term E-PERMs)
Long-term test
2-90 days
Slide 6-5
Length of test
• Both types of test can provide accurate results
• Both types of test usually lead to same decisions about mitigation
Slide 6-6
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
Slide 6-7
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)
Slide 6-8
General testing
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
If the first test result is0–under 4 pCi/L
You do not have to conduct a follow-up test now
Slide 6-9
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
Slide 6-10
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
Slide 6-11
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
If the average is 4 pCi/L or more, advise the owner to
mitigate
Slide 6-12
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
You are testing for Jeri, who has no plans to sell her Simsbury home
What do you advise?
What do you advise?
Slide 6-13
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
Slide 6-14
General testing strategiesSummary
First test result
0–under 4 pCi/L
4–under 10 pCi/L
10 pCi/L and above
No immediate follow-up
Follow-up with short-term or long-term test
Follow-up with short-term test
Slide 6-15
Questions?
• About strategies for tests that are not associated with real estate transactions
Slide 6-16
Testing associated with home sales
Why are there potential problems?
• Time pressure• Accidental violation
of test conditions• Possibility of
tampering
Slide 6-17
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)
– Two sequential tests (one test right after another)
• Active test– One continuous monitor
Handout 6-2 summarizes this information
Slide 6-18
Real estate option 1Two simultaneous tests
1. Use two identical devices and methods
2. Test in same location– Place two devices 4 inches apart
3. Run tests for at least 48 hours4. Return devices to lab promptly
March 2010
5
6 Begin Tests 1 and 2
78 End Tests 1
and 2
9
Conduct two short-term tests at the same time
Slide 6-19
Simultaneous test results
Both results are under 4 pCi/L
Average will be under 4 pCi/L
Report both results and averageRecommend future retesting
Both results are 4 pCi/L or more
Average will be 4 pCi/L or more
Report both results and averageRecommend mitigation
Expect some variation between any two results
Slide 6-20
Simultaneous test resultsSpecial 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
Slide 6-21
Simultaneous test resultsSpecial 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
Slide 6-22
Simultaneous test resultsSpecial situation example
L = lower result H = higher result
Example 1: L = 3.2 H = 4.2
L x 2 = 6.4H (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
Slide 6-23
Simultaneous test resultsSpecial situation example
L = lower result H = higher result
Example 1: L = 3.2 H = 4.2
L x 2 = 6.4H (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 = 4.4H (4.6) is greater than L x 2 (4.4),
so the difference is too largeReport disagreement of results and retest
Slide 6-24
Simultaneous test resultsSummary
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, retestIf the higher result is less than twice the lower, report both results and averageRecommend retesting or mitigation based on average
Average will be 4 pCi/L or more
Report both results and averageRecommend future retesting
Report both results and averageRecommend mitigation
Slide 6-25
Real estate option 2Two sequential tests
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
Conduct one short-term test after another
Slide 6-26
Real estate option 2Two 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 1Begin Test 2
9
Slide 6-27
Sequential testsVariation in results
Expect some variation between any two results
• Radon levels vary from day to day• If variation is large, consider
possible causes– Weather– Air pressure– Season– Accidental disturbance of device – Opening of doors or windows – Tampering– Lab error
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
1/5 1/6 1/7 1/8 1/9
0
1
2
3
4
5
6
1/5 1/6 1/7 1/8 1/9
Moderate variation
Large variation
Slide 6-28
Sequential testsReporting 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
Slide 6-29
Activity
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
Hector, an inexperienced inspector, ran two sequential short-term tests in a home for sale in Columbia
Slide 6-30
Questions?
• About simultaneous tests in real estate transactions?
• About sequential tests in real estate transactions?
Slide 6-31
Option 3One continuous test
• Use any NEHA- or NRSB-listed continuous monitor or working-level monitor
• Use monitor that integrates and records at least every hour
Slide 6-32
Option 3One 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
Slide 6-33
Option 3One continuous test
Results0–under 4 pCi/L
4 pCi/L or more
Recommend future
retesting
Recommend mitigation
Slide 6-34
Example of data from continuous radon monitor
Test 1: 7.7 pCi/L Sudden change may indicate tampering or severe weather
Test 2: 3.4 pCi/L
Slide 6-35
Questions?
• About continuous testing?
Slide 6-36
Summary
• Testing period– Short-term (2-90
days)– Long-term (91-365
days)– Both provide
accurate results
• Testing strategies– General testing– Testing associated
with real estate transactions
Slide 6-37
SummaryGeneral testing steps
1. Conduct short-term test2. 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
3. Conduct any required follow-up4. 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
Slide 6-38
SummaryReal estate options
1. Two simultaneous tests using passive devices
2. Two sequential tests using passive devices
3. One continuous test
Slide 6-39
Questions?
Slide 6-40
Check your understanding
• See handout 6-5