Radon Presentation November 2013 Overview & Building Surveyors Perspective

Kevin Sheridan MSc CEnv EurBE, FSCSI, FRICS FIBCI FCIOB MICE, FCInstCES, FBEng PEng FSPE

President AEEBC

Overview of Training Course • • • • • • • • • •

Radon history and background in Ireland Characteristics of Radon-what radon is, health risks The legislation relating to radon Radon in the workplace Radon in water Detecting/measure radon Some issues in Buying a House Radon in Buildings How to reduce radon levels in existing buildings How to protect new buildings

History of Discovery of Radon •1879- lungAcancer among Briefrate History underground miners

of Radon

•1896-Henri Becquerel discovers natural radioactivity •1924- link between radon and lung cancer suggested •1956-cause identified as radon progeny (daughters) •1984-Stanley Watras of Limerick (PA), nuclear power plant worker sets off alarm going to work

Radon • Derives from Igneous rocks • Can accumulate under the slabs and foundations where it can easily enter into the living space through construction cracks and openings. • As a gas, it can move readily through particles of soil and rock and waterRadioactivity - Unstable atoms releasing excess energy • Ionizing Radiation - energy or particles that make ion pairs during interactions with body cells • Known carcinogen

Radon • A naturally-occurring, chemically inert, cancer-causing radioactive gas that is not detectable by human senses Invisible, odorless, colorless (cannot see, smell or taste radon), • Radon gets into the air we breathe and as it decays, it gives off radiation • Smokers in high radon areas, have a higher risk of developing lung cancer. • Some scientific studies show that children may be more sensitive to radon due to their higher respiration rate and their rapidly dividing cells, more vulnerable to radiation damage? • Long latency period

Radon in Ireland 250,000 people are living in homes with cancer risk Silent Killer Radioactive particles cause changes in cells One person in Ireland dies every two days from Radon related lung cancer more than from road accidents • Long term exposure-presents late • Radon is next to smoking in Lung cancer cause • As radon is heavier than air -not normally a problem in the upper stories or high rise buildings.

• • • •

Radon in Ireland • Approximately 90% of the total annual radiation dose received by the general public is derived from natural sources. • The single largest component of this dose is that due to radon and its decay products in the indoor environment. • Radon contributes over 50% of the total radiation dose received by the Irish population

Alpha Particle Defects in tumor suppressor genes – p53

Fr Do DN u b fo e e r rm ad A le – a t ic br s t io n a l ea ra ks nd

Ionizing radiation can directly and indirectly damage DNA

At risk individuals–GSTM1 (glutathione S-transferase M1)

Why is radon harmful?

Radon daughters attach to particles in the air

Particles are inhaled via nasal and oral passages Inspired particles deposit onto respiratory tract

Radon daughters decay producing alpha radiation

Radon Exposure • Radon and Radon Decay Products (RDPs) are breathed in and the Radon is exhaled. • Because they are solid particles, RDPs remain in lung tissue and are trapped in the bronchial epithelium and emit alpha particles which strike individual lung cells and may cause physical and/or chemical damage to DNA. • Smoking multiplies the risk

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Radon Risk in Perspective • Comparative Risk Assessments by EPA (USA) and its Science Advisory Board have consistently ranked Radon among the top four Environmental risks to the Public • In 1998 Harvard Risk in Perspective, by John Graham, ranked Radon the #1 risk in the Home

Home Safety Council Risks (USA)

Why is radon harmful? • Prolonged exposure to increased concentrations known to cause lung cancer- Approx 10% of lung cancers can be linked to radon. - smokers are at an increased risk • Radon in workplaces is therefore subject to regulation

Radon in the Workplace

Radiological Protection Act, 1991 (Ionising Radiation} Order, 2000, Statutory Instrument No.125 of 2000. Workplace National Reference Level – 400Bq/m3 averaged over three months – RPII has authority to direct persons responsible for workplaces to measure Radon Levels

Radon in Workplaces in Ireland Radiological Protection Act, 1991 (Ionising Radiation} Order, 2000, Statutory Instrument No.125 of 2000. Workplace National Reference Level – 400Bq/m3 averaged over three months – RPII has authority to direct persons responsible for workplaces to measure Radon Levels

Radon in Workplaces in Ireland • Where this evaluation shows that radon remedial measures are justified, the undertaking must implement such measures as soon as practicable. • Where remedial measures are shown not to be justified or where they fail to bring levels below the Reference Level, the undertaking must apply radiation protection measures in the workplace. • Such measures might, for example, include organisation of work schedules to reduce exposure, making and keeping of exposure records, medical surveillance and controlling access to parts of the workplace where radon levels have been shown to be • high

How do levels compare internationally (WHO 2009)? 150

89 100

Mean radon concentrations OECD countries

50

0

Worldwide average 39 Bq/m3

Radon in Ireland • Average Radon level in Ireland is 89 Bq whereas UK average is about 20 Bq • 200Bq is Irish Action level • Testing using 2 alpha track detectors for 3 months • Pre tests & Post tests • Homes are poorly ventilated in Winter months

How do levels compare internationally (WHO 2009)?

This places Ireland at the upper end of the range with an average value that is over four times that of the United Kingdom and approximately twice that of Canada and the United States. National averages conceal the high regional and local variability that exists in radon concentrations

Radon in Irish Groundwater Supplies

Radon in Water Irish reference level is 1000Bq/m3 for Private Wells & 500 Bq/m3 for Public water supplies EU recommended levels are between 100 to 1000

Waterborne Radon

Primarily from groundwater sources (wells) rather than rivers Waterborne radon to air ratio 10,000 : 1

• Because of its gaseous nature, radon can move freely through porous media such as soil or water fragmented rock • Where pores are saturated with water, for example, Radon Radon Radon radon in soil and rock under the water table, diffuses into the water and is dissolved

• The dissolved radon is transported in the water and can then find its way into drinking water supplies

Radiological Protection Institute of Ireland

Radon in Domestic Water Supplies – the Problem Can result in exposure to a radiation dose both through inhalation and ingestion. Inhalation Pathway: Radon is easily released from water into the atmosphere by agitation or heating. Risk from inhalation is associated with lung cancer. Ingestion Pathway: The radiation dose received from ingesting water containing radon results in an increased dose to the stomach wall.

Wicklow Study Findings

• Pilot study of 166 houses showed that 2.4% of homes with private water supplies in County Wicklow had radon levels greater than 1,000 Bq/l • If this pattern reflects the national picture there could be between 3000 & 4000 private water supplies with comparably high levels

Radiological Protection Institute of Ireland

Radon in Water - Remediation There are three basic water treatment methods for the removal of radon: 1. 2. 3.

Decay storage Aeration Granular Activated Carbon Adsorption

All three methods are capable of over 99% efficiency.

Radon Detection & Measurement INDOOR RADON LEVELS CAN Alpha track detectors (thermoset VARY CONSIDERABLY FROM resin known commercially as CR-39a HOUR TO HOUR OR DAY TO DAY AND SO MEASUREMENTS AVERAGED OVER 3 MONTHS ARE CONSIDERED NECESSARY IN ORDER TO GIVE AN ACCURATE REPRESENTATION OF THE RADON EXPOSURE TO OCCUPANT

Radon Tracks on Etched Plastic

Active Radon Gas Detector - RAD7

Radon in Housing RPII state that 91,000 houses predicted as > 200 Bq/m3 Representing 7% of the national housing Stock around 700 of these exceeding 1,000 Bq/m3

Diagnostic Measures

Passive Radon Measurement Long term – solid state – electrostatic Short term – charcoal/electrostatic Active Radon Measurement Grab sampling Influenced by weather conditions and building usage patterns prevailing at the time of measurement

RPII The RPII provides a radon measurement service (consisting of two radon detectors) to householders at a price of €56.90 You can buy additional detectors An A1 size version of the map "Radon in Irish Dwellings" can be purchased directly from the Institute for €15? Or obtain on-line

Detector Placement is Crucial •

Place in an area where the detector will not be disturbed.

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At least 900 mm from doors or windows to the outside.

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Out of the direct flow of air from a ventilation duct.

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At least 300 mm from exterior walls.

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500 mm to 1.8m from the floor.

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At least 100 mm away from other objects horizontally or vertically above the detector.

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At least 1.2 m from heat, fireplaces and furnaces, out of direct sunlight, etc.

Where not to place detectors • Do not test in a closet, stairway, hallway, or in an enclosed area of high humidity or high air velocity. • An enclosed area may include a kitchen, bathroom, laundry room or furnace room.

Radon Radon Map

high radon area" is one in which more than 10% of houses are predicted to have radon levels in excess of the 200Bq/m3 reference level

Selling a House • The reason for considering radon at the time of purchase • Money /Value – concern over potential loss in property value • Reducing Health risks • Mitigation Measures easily installed at time of purchase • Websites raise the question of radon but do not explain risk levels • Estate Agents often avoid radon completely

Selling a House • Solicitors often more interested in having a written response than what the response says • Construction professionals often mention affected areas but do not explain what it might mean • Websites raise the question of radon but do not explain risk levels • Advice on measuring radon at the time of purchase remains unclear • Building owners should have Radon concentrations assessed when building is in use and again after remediation

Selling a House • Has the house been tested for radon ? • if yes what was the radon level? – low - then is there a problem ?? – high • have you carried out any remedial measures? • If you have carried out measures - have you re-tested the property Confirm with written evidence

Surveyors Perspective Professionalism & Competence • Range of expertise/competences • Importance of CPD -Currency of competence (up-to-date) • Committed to respect a strict Code of professional conduct with possible sanctions • Expediency versus ethical and adequate level of service • Experience/Certification for specific competences • Need for Professional judgement

Radon Consultative process- Recommendation to RPII/DoECLG • The building control process should be amended to require specific “sign off” by a • competent person regarding the installation of radon preventive measures. • It is noted that the proposed Building Control (Amendment) Regulations 2012, will result in new building certification procedures requiring sign off by competent persons on a wide range of measures. • Establish criteria that contractors must meet to be listed on Government website or to compete for Government work.

Radon Reduction & Mitigation

Pressure Differentials and Radon Entry




Buildings in general tend to have a slightly lower indoor air pressure compared to that in the ground.




This is normally sufficient to draw soil gas from the ground into the building.




Air pressure differentials between the building and outside air causes radon from the soil to be drawn into the house resulting in elevated indoor radon levels.

Radon • Pressure differences • – Stack effect • Radon gets into the air we breathe and as it decays, it gives off radiation • Radon can get into any type of building, including homes, offices, and schools • Construction standards need to be vigilantly enforced

Average Contributions From Radon Sources In U.S. Homes

n

Water < 1%

Emanation 2 - 5%

Soil Gas 85 - 90%

n

Diffusion 1 - 4% n

Radium Containing Soil

Radon from domestic water and from building materials can contribute to the indoor radon concentration in a building, The movement of soil gas into a home is the predominant entry route. These are averages - a particular home can be different!

Radon Entry • Radon enters through any opening between the building and the soil.

radon radium uranium

RADON GETS IN THROUGH: 1. Cracks in solid floors 2. Construction joints 3. Cracks in walls 4. Gaps in suspended floors 5. Gaps around service pipes 6. Cavities inside walls 7. The water supply 8. drains BUT DOESN’T GET OUT of tightly sealed homes Sources 1 Soil 2 Groundwater 3 Stone building materials

)

Radon Mitigation

View of fan located in cellar

Underfloor ventilation • Simple sealing can reduce indoor radon levels • Under floor ventilation can reduce indoor radon levels • Different methods for improving under floor ventilation • – natural ventilation • – mechanical extract ventilation • – mechanical supply ventilation

Solutions • Sealing soil gas routes into the building; • sub-floor depressurisation (or pressurisation) with passive or fan-assisted sumps to draw (or force) soil gas away from the building before it can enter; • • sub-structure ventilation; • ventilation and adjustment of the air pressure inside the building to reduce or reverse the driving force which assists the entry of soil gas • The horizontal section of pipework from the sump should run with a slight rise away from the sump (to avoid the danger of water in the pipe forming a gas trap), through an external wall where it can be turned • up and capped until needed.

Sub-slab depressurisation or sump systems • • • • • • • •

To modify the pressure gradient between the soil and the building in order to limit the entry of radon. the different types of sump systems available internally excavated sump systems – – externally excavated sump systems – passive sump systems – other types of sump system One option is draw off radon from a centrally located, (hand) excavated sump by cutting through the floor internally. Proper reinstatement of the damp-proof membrane and sealing the junction between the old and new concrete will be required. Care is needed to ensure that underfloor services such as water, central heating and electricity supplies etc. are not damaged.

Selecting the most appropriate remedial measures

Reductions achievable from different solutions

High Radon Concentration

Castle Island, Co. Kerry 50,000 Bq/m3 Highest in Europe

Risk Map not always reliable

SUBSLAB DEPRESSURIZATION SYSTEM Active. A system designed to achieve lower sub-slab air pressure relative to indoor air pressure by use of a fanpowered vent drawing air from beneath the slab.

Active Soil Depressurization •

Active Soil Depressurisation uses a fan to draw radon from beneath the house.

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All radon mitigation systems shall be designed to reduce a radon concentration in each area within the footprint of the building as low as reasonably achievable (ALARA).

Active Radon Sump • Typically drilling underneath floor from outside of the building and attaching an extractor fan • Fan draws radon from beneath the building • Fan creates a negative pressure in the subfloor and sucks the radon out & dissipates into the atmosphere

Activation of radon sump

Passive stack systems best suited to centrally located sump. High water table – ineffective sump Condensation drain

BUILDING CONTROL Amendment Regulations (2013)

Thank you Questions ??? after next speaker (later) Kevin Sheridan MSc CEnv FSCSI, FRICS FIBCI FCIOB MICE EurBE President AEEBC Acknowledgements

John O’Connor Chairman BCA Code of Practice Committee