GWASANAETHAU IECHYD A DIOGELWCH - HEALTH AND SAFETY SERVICES

Gwasanaethau Iechyd a Diogelwch – Health and Safety Services, Penbre, Lon y Coleg. LL57 2DG Tel: 01248 38-3847

Ebost: Iechydadiogelwch@bangor.ac.uk Email: healthandsafety@bangor.ac.uk Fax: 38-3259

www.hss.bangor.ac.uk

ADRODDIAD – REPORT

Radon Survey

Summary Report

September 2010

Radon Survey – Summary Report - 2010

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1. SUMMARY

Radon is a colourless, odourless gas that originates from uranium in rocks. Long term exposure to very

high levels of radon has been linked to lung cancer. The Management of Health and Safety at Work

Regulations 1999 require the assessment of health and safety risks including radon in the workplace under

certain circumstances, for example where underground workplaces exist and where premises are in a radon

affected area.

As such the University has undertaken a number of radon surveys since May 2009 to identify workplace

radon concentrations. This involved the placement of Health Protection Agency (HPA) supplied radon

monitors at a number of locations. After three months, the monitors were analysed by the HPA to compare

radon measurements against the action level of 400 Bq m3 (workplaces) and 200 Bq m

3 (residential

accommodation) designated in the Ionising Radiation Regulations (IRR) 1999.

A Preliminary Survey to identify workplaces wholly / partially underground led to radon monitors being

placed in 40 locations between May and August 2009. Two areas were identified as exceeding the action

level with a further two, although below the action level requiring further investigation because of high

room usage and limited ventilation.

However, as the readings were taken outside of the winter period, when it is felt radon concentrations are

highest, the HPA applied a ‘winter corrected’ factor. This seasonal adjustment takes account of the fact that

ventilation levels in winter are generally lower as windows are closed and buildings are warmer relative to

the ground causing increased radon seepage. As a result the University was advised to re-measure radon

levels during the winter period to obtain ‘true’ measurements.

The Second Survey involved the placement of 23 radon monitors from December 2009 – February 2010 in

the areas identified by the Preliminary Survey and the immediate surrounding areas. As a precaution, a

review of local geological maps and a post code search was also undertaken. This resulted in a Third

Survey starting two weeks after the Second Survey with 39 monitors placed across the Normal Site and

Treborth Site.

The Second Survey identified one elevated radon level of 490 Bq m3 in the George Building. However a

significant reduction in the radon levels identified as a concern during the Preliminary Survey were seen;

570 & 650 Bq m3 in Westbury Mount to 70 & 90 Bq m

3, 330 Bq m

3 in Nantlle to 120 Bq m

3 and 370 Bq m

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in Main Arts to 80 Bq m3. This highlights the risk of anomalies when measurements are ‘winter corrected’.

In addition, the Third Survey identified two areas with elevated radon levels; one a residential property

(240 Bq m3) at Treborth and the second a high usage office building (850 Bq m

3) at Normal Site. On advice

from the HPA and the RPA a Fourth Survey was undertaken by the RPA of the residential property and

office building using a Durridge Rad 7 Electronic Radon Detector. The results of the Fourth Survey have

led to the office building being vacated pending remedial works to prevent radon seepage. In addition, a

further survey is planned of the residential property during the winter period.

Elevated radon levels were reported to the Health and Safety Executive with advice also sought from the

HPA and the University’s Radiation Protection Adviser (RPA) with regards to what further action should be

taken.

2. SCOPE OF REPORT

The scope of the Preliminary Survey, funded through the Safety Executive Task Group (SEG) was to

identify the work areas across the University estate with the potential for high radon concentrations. Radon

Radon Survey – Summary Report - 2010

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measurements were then undertaken in these areas, with the findings of the Preliminary Survey directing

further surveys and action.

3. BACKGROUND

Radon is a radioactive gas which originates from uranium that occurs naturally in many rocks and soils.

Granite contains relatively high levels of uranium and granite areas of the UK, such as the South West of

England have very high radon concentrations. However, high radon areas are not restricted to the South

West and many parts of Wales are also affected (see Appendix A).

Radon can seep out of the ground and build up in houses and in-door workplaces. The highest radon

concentrations are usually found in underground spaces such as basements, caves and mines but high

concentrations can also be found in the ground floor of buildings as well.

Most radon gas breathed in is immediately exhaled and present little hazard. However, decayed products of

radon behave more like solid materials and attach themselves to atmospheric dust and water droplets which

are then breathed in, becoming lodged in the lungs and airways. Some of these decayed products emit a

particularly hazardous type of radiation know as alpha particles which can cause significant damage to cells

in the lung. Radon is now recognised to be the second largest cause of lung cancer in the UK after smoking.

Because of the hazardous nature of radon, legislation exists that requires employers to protect their

employees from exposure to radon in the workplace. The Management of Health and Safety at Work

Regulations 1999 require the assessment of health and safety risks from radon under certain circumstances.

As some areas of Wales are affected by radon and some University buildings contain work areas that are

either wholly or partially below ground, a preliminary radon assessment was carried out as a precaution.

4. METHODOLOGY

The Preliminary Survey measured radon concentrations in workplaces with the highest potential radon

exposure risk to identify if a wider ranging survey was required. It involved an examination of the

University estate, with locations either wholly or partially underground identified. Each area was

then risk rated as High, Medium and Low using the following qualitative scoring method:

Room usage (duration and numbers of occupants)

The extent to which the room is built into the ground

The level of natural or mechanical ventilation available

A total of 40 locations were selected with radon monitors, purchased from the HPA deployed between May

to August 2009. The HPA results subsequently initiated the Second and Third Surveys which involved the

placement of 62 radon monitors from December 2009 to February 2010.

The results of the Third Survey led to an immediate Fourth Survey of affected areas. This latter survey

involved use of a Durridge Rad 7 Electronic Radon Detector to take five-minute air samples throughout

the affected buildings. Each air sample was filtered, dried and analysed within the internal silicon

surface barrier detectors of the Rad 7 for radon (222Rn) and thoron (220Rn) decay progeny.

In the ‘sniffer mode’, set during the tests, the Rad 7 automatically calculated the concentration of radon

and thoron at the end of the 5 minute sampling period. Because of the very short half life of thoron (56

seconds) this radioisotope tends to only be detected very close to its source so can be used as an

indicator of where thoron (and by inference radon) is entering a room.

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5. RESULTS AND ACTIONS

The following show the results from the four surveys. All actions were undertaken in accordance with

advice from the HPA and RPA:

PRELIMINARY SURVEY

Period (3 months) May – August 2009

Number of radon monitors placed 40

Locations Main Arts, New Arts Library, College Road Houses, Music

Building, Cae Derwen, Management Centre, John Morris Jones,

JP Hall, Nantlle, Treborth, Westbury Mount, Craig Mair, Alun

Roberts, Charles Evans, Brambell, Thoday, Students’ Union,

Electronic Engineering

Results Westbury Mount 570 & 650 Bq m3

Main Arts 370 Bq m3

Nantlle 330 Bq m3

Action Information and guidance provided to staff in Westbury

Mount and Nantlle

Records kept of Westbury Mount room usage

Second Survey planned for winter period to eliminate ‘winter

correction’ of values

SECOND SURVEY

Period (3 months) December 2009 – February 2010

Number of radon monitors placed 23

Locations Main Arts, Westbury Mount, Craig Mair, Nuffield Fish

Laboratories, Ynys Faelog, Effionyd, George Building, Nantlle,

Students’ Union

Results George Building 490 Bq m3

NOTE: Measurements for the locations previously identified

with elevated levels were significantly reduced:

Westbury Mount 70 & 90 Bq m3

Main Arts 80 Bq m3

Nantlle 120 Bq m3

Action Information and guidance provided to staff in the George

Building

Access control measures implemented

Records kept of room usage

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THIRD SURVEY

Period (3 months) December 2009 – February 2010

Number of radon monitors placed 39

Locations Ardudwy, Hiraethog 1 & 2, Library, Nantlle, Dinas, Gym, Stable

Block, Wern, Rhos, Trefenai, Cilgwyn, Effionyd, George

Building, Bistro, Padarn, Meirion, Arfon & Seiriol (Halls of

Residence), Treborth (including accommodation)

Results Ardudwy 850 & 310 Bq m3

Treborth (house) 240 Bq m3

Action Information and guidance provided to staff in Ardudwy and

Treborth

Immediate Fourth Survey of Ardudwy and Treborth

undertaken by RPA

FOURTH SURVEY

Period (2 days) 18th – 19

th May 2010

Number of Readings taken using a

Durridge Rad 7 Electronic Radon

Detector

60 – Ardudwy

10 – Treborth (house)

Locations Ardudwy, Treborth (house)

Results Ardudwy 798 Bq m3 (highest)

NOTE: Ardudwy readings altered significantly throughout the

day. For example, the above reading taken at 13:26 reduced to

347 Bq m3 by 16:05. This could be attributed to the movement of

sun throughout the day, increasing / decreasing room temperature

and the opening / closing of doors increasing ventilation

Treborth

(accommodation)

69.1 Bq m3 (highest)

Action Winter survey planned of Treborth

Ardudwy vacated pending remedial works to prevent radon

seepage

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APPENDIX A – Indicative Radon affected areas across North Wales