introduction to radon - ciphi ontario · engineering environmental and 1.855.pinchin pinchin.com...

Engineering Environmental and

Health & Safety Solutions 1.855.PINCHIN ■ pinchin.com

Introduction to Radon

Presented by:

Tina Manning, PMP, LEED AP.

Pinchin Environmental Ltd.

September 19, 2012

© Pinchin Environmental Ltd - All Right Reserved

© Pinchin Environmental Ltd. 1.855.PINCHIN ■ pinchin.com

What is Radon?

Naturally occurring radioactive gas

Comes from the breakdown of Uranium

Found in soils, rocks (eg. Granite, shale)

groundwater

Colorless, Odorless, and Tasteless

It can enter buildings from the soil/rocks or

groundwater beneath them

U.S EPA


Group A Carcinogen (Miner group data)

2nd leading cause of lung cancer behind smoking! (16% of all lung cancer deaths)

Health Canada estimates that approximately 3,200 lung cancer deaths are attributed to radon every year

Health Concerns


Health Concerns – Decay Products

Radon is a chemically inert but unstable atom

which undergoes radioactive decay

Breaks down into Decay/Daughter Products

(RDPs)

Radioactive decay leads to release of

ionizing radiation

U.S EPA


Uranium 238 Decay Series

Uranium decays to radium which then decays to radon

The decay rate is expressed by half-life


Radon 222 Decay Series

When radon breaks down

further into Decay/Daughter

Products (RDPs), Alpha,

beta, and gamma radiation

is emitted

Alpha emitters include radon

222, and Po 218 and Po 214

Alpha emitters are the main

concern and are very

damaging due to their

relatively large size and

speed

Radon 222

Polonium 218

Bismuth 214

Polonium 214

Lead 214

Lead 210

,

,

,

,

,


Heath Concerns – Radon Decay Products

RDPs act like solids

RDPs have a charge

Radon & RDPs inhaled,

Radon exhaled

RDPs stick to the lung

tissue


Heath Concerns – Radon Decay Products

Further breakdown in lungs leads to α

release & ionizing radiation

Damages lung tissue!

Kills cells vs. DNA strikes can cause

damage/mutations

Leads to lung cancer

Why lung cancer

not skin cancer?


Exposure Influences

Tobacco smoke

RDPs act as solids in the air and

are attracted to particles, like

tobacco smoke.

More particles in air, more RDPs

suspended and greater risk of

breathing them in

Lung Cancer Risk (Health Canada)

Smoker + high radon = 1 in 3

High radon only = 1 in 20


Exposure Influences

Ventilation

Increased fresh air dilutes radon

Increased air movement helps settle out

RDPs (plate out)

Not always feasible,

due to cold climate

Geologic Radon Potential Map

Health Canada

Survey results

from testing

14,000 homes

across Canada

~ 7% of homes

have radon

concentrations

above the

guideline


Health Canada Radon Data


Health Canada

Ontario Radon

Results (Partial)


Radon Levels in Buildings

Some known ‘hotspots’ with increased potential

for elevated radon levels.

Radon levels can vary greatly between adjacent

buildings

The ONLY! way to know what the radon levels

are in a building is to test

How Does Radon Enter Homes

and Buildings? A. Cracks in concrete slabs.

B. Spaces behind brick veneer walls that rest on uncapped hollow-block foundations.

C. Pores and cracks in concrete blocks.

D. Floor-wall joints.

E. Exposed soil, as in a sump or crawl space.

F. Weeping (drain) tile, if drained to an open sump.

G. Mortar joints.

H. Loose fitting pipe penetrations.

I. Open tops of block walls.

J. Building materials, such as brick, concrete, rock.

K. Well water (not commonly a major source).

FLOOR TO WALL JOINTS

Floor to wall joints can

be major entry points

Soil around footing is

disturbed by

construction and

permeable

Extend completely

around perimeter

Interior finishing does

not stop radon entry

Crawlspaces

Large soil surface were

suction from house is

applied

Crawlspace vents are

little help

Floor insulation is not a

radon barrier


Other Radon Entry Pathways

Water Drainage

Systems

Man made pathways

Slab Penetrations

Plumbing Block Outs

Sump Pumps


Minor Routes of Entry into Buildings

Emanation

• building materials off-gas radon (e.g.

stone, phosphogypsum wallboard)

Groundwater

• Radon dissolves in groundwater

• 10,000 pCi/L in water will add 1pCi/L in

air

• Degasses from water readily when

heated (e.g. shower, dishwasher)

Diffusion

• from soil through slab due to

concentration gradients


Radon and Building Type

Just because a building doesn’t have a

basement doesn’t mean radon cannot enter

Slab on grade buildings and buildings over

crawl spaces are also susceptible

Forces that Drive Radon into a Building

Buildings can create vacuums that will draw in radon (convective flow). 90% of radon entry attributed to this

Natural causes include thermal stack effect, wind, rain, frost, diurnal cycles

Mechanical causes include exhaust fans, windows, fireplaces, etc.

These vacuums may be very small and are referred to as air pressure differentials


Radon Guidelines CANADA Health Canada Action Level = 200 Becquerels/m3

(Bq/m3) (2007)

Occupational exposure (Mgmt of Naturally Occurring Radioactive Materials (NORM, )) 2000

UNITED STATES EPA Action Level = 4 pCi/L

(equal to 148 Bq/m³)

GLOBALLY World Health Organization

recommends 100 Bq/m3


Radon Testing

How to find out how much radon is in the air?

THE ONLY WAY TO KNOW IS TO TEST!

2 Types of testing:

Short term (typically 2 – 7 days)

Long term (minimum 91 days to 1 year).


Health Canada Measurement Guidelines

test in the lowest

occupied area of the

house (i.e. occupied

for at least 4 hours

per day

Best time to test is

during the heating

season


Health Canada Measurement Guidelines

Test in each room

occupied for 4

hours/day in the

lowest occupied

level (basement or

slab-on-grade)

Testing required on

upper floors as well


Short Term Testing

Testing is generally for 48 - 72 hrs

Closed house conditions

Lowest occupied, or occupiable level

Used for short turnaround (e.g. real estate transactions)

Provides an indication (snapshot) of radon potential

Not a basis for mitigation

Follow-up with long term testing

Grab and sniffing Samples (Diagnostic Testing)

A sample taken for a few seconds or minutes

Grab is calculated after 4 hours


Short Term Testing Provides a potential for radon levels


Example of Radon Seasonal Variations Monthly averages of pCi/L levels in Utah homes

Source – Seasonal radon variations in Utah testing results: Short term test results within 10% of the EPA

threshold (4.0 PCI/L) should be repeated in a different season- David Joseph Neville, John Douglas, 2008


Common Short Term Test Devices

CHARCOAL CANISTER Radon diffuses into charcoal

were it eventually decays into RDP

Measures gamma activity

Easy to deploy

Impacted by moisture & drafts

Over-response if air blows over or cold air

Under-response if excessive moisture, hot air ‘boils’ it off



ELECTRET ION CHAMBER (E-PERM) Voltage of electret on bottom of device is

measured before & after testing

Reported radon is a function of voltage drop &

duration of deployment

Can be used for short and long term testing



(for measuring radon or RDPs)

CONTINUOUS RADON MONITORS Radon passes through filter by

diffusion

Alphas from radon collected and RDPs are counted

Radon results calculated hourly

Lock-out/tamper resistant


SNIFF/GRAB SAMPLING DEVICES

(for measuring radon or RDPs)

Sniff Samples Sniff samples very qualitative and used for

diagnostics

Instant/direct readings

Grab Samples Also used for diagnostics but takes 4 hours

Need to pass a sufficient amount of air through cell

Sample period is too short to use a short-term measurement


Long Term Testing

Recommended by Health Canada

Testing is generally > 91 days(Health Canada does not recommend testing less than 1 month)

Test performed under normal building use

Lowest occupied (occupied by someone 4 hours per day), or occupiable level

Under normal living conditions – doesn’t inconvenience anyone

Gives a reasonable average

Guideline applies directly (i.e. can base mitigation on long term test results)


Common Long Term Test Devices

Electret Ion Chamber (E-Perm)

Alpha Track Detector Records alpha particle strike

damage on plastic sheet from radon and RDPs with the device.

Lab counts ‘alpha tracks’ on the plastic


Health Canada Mitigation Guideline

Time Frame to Remediate

Radon Concentration Recommended Remedial

Action Time

> 600 Bq/m3 In less than 1 year

200 – 600 Bq/m3 In less than 2 years

< 200 Bq/m3 No action required*


Radon Mitigation

Systems can be designed for

all types of homes & buildings

including:

Slab on grade

Crawlspaces

Basement foundations

Fairly inexpensive and all

buildings can be fixed!

SUB-SLAB DEPRESSURIZATION

Suction created in

a pit under the slab

Radon collected

and exhausted

outdoors

Most common

radon mitigation

technique

performed and

very effective


Sub-Slab Depressurization

Communication test conducted to determine best

placement for suction point and what type of fan to

use


Sub-Slab Depressurization


Sub-Membrane Depressurization

Suction created under a membrane placed over exposed soil or rock


Sump Depressurization

Vacuum is drawn from sealed sump


Modification of Air Handling Systems

When radon levels are marginally above the guideline, usage of Heat Recovery Ventilators (HRVs) can effectively reduce radon levels.

Pressurization of buildings with HVAC systems (e.g. schools) can also inhibit radon entry. Must make sure HVAC systems are balanced to avoid areas under negative pressure


LESS COMMON MITIGATION OPTIONS

Less Common

Pressurization (basement only or sub-slab)

Air-filtering Systems to reduce RDPs

Removal of Radon from Water

Aeration – water coming into building run through a small tank where air is forced through to strip out radon

Carbon Absorption – water run through carbon filled tank (carbon can become radioactive)


Testing After Radon Mitigation

Conduct follow-up sampling to

ensure radon concentration has

decreased

Retest within 2 years and every

5 years after that time or when

major renovation occurs

affecting slab/basement walls


Radon Resistant Construction

Techniques

Similar to mitigation measures

Passive systems (vs. active)

In conjunction with various measures

e.g. caulking and sealing joints/openings

Becoming more popular/standard

Purchase/rental feature


National Building Code & Radon

Allows for basic protection of all buildings

(residential and non-residential). Specific

provisions to address radon mitigation in

new residential homes and small

residential buildings

Sump pit cover required to be airtight

Caulking slab perimeter and penetrations

Granular fill under slab and polyethylene

soil gas barrier between fill and slab

Inspections

Roughed-in piping for SSD systems


WHO Facts & Trends

‘WHO Handbook on

Indoor Radon’:

“effective radon control

systems in new homes

are critical”

“Indoor radon levels are

caused by the way

homes are designed

and built”


Certification

Health Canada recognizes the National

Environmental Health Association/National

Radon Proficiency Program (NEHA-NRPP)

Health Canada has just recently adopted it’s

own certification program (C-NRPP)


Canadian Association of Radon

Scientists & Technologists (CARST)

A Canadian

association

dedicated to helping

Canadians

understand and

reduce radon gas

exposure in their

homes and

workplaces.

www.carst.ca

http://www.carst.ca/


Summary

Test for radon

Reduce elevated radon levels

Reduce your risk!


Questions?

Email : [email protected]

Toll Free: 1-888-767-3330

Direct Line (905) 363-1311

For more information or

for newsletters, please

visit www.pinchin.com

Tina Manning Email : [email protected]

Phone: (519) 682-4492 x3301

mailto:[email protected]

mailto:[email protected]

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