HHSRS VERSION 2

SEPTEMBER 2004

RADIATION (RADON)

Elderly persons, lifetime exposure

Damp

Vulnerable age

Related hazards

Front elevation

HHSRS VERSION 2

Multiple locations

Yes

No

Secondary hazards

Yes

No

Radon/rating table

Radon

Likelihood

Bqm-3

1 in

Rating

score

B) Rear dining room floor

C) Front living room & spine wall

Rating

band

B

C

D

D

E

E

F

800

277

3,285

400

518

1,757

200

1,000

910

150

1,322

688

100

1,961

464

50

3,902

233

25

7,853

116

DESCRIPTION OF HAZARDS

Dwelling: 1850's 4 bedroomed detached farmhouse

A)

B)

C)

LIST OF RELEVANT MATTERS

LIKELIHOOD & OUTCOMES

A

B

C

# Secondary hazards

A

B

C

a

Timber ground floor

-

-

3

-

None

-

-

-

b

Disrepair to solid floor

3

1

-

c

Lack of DPM

3

2

2

d

Sealing around services

3

-

-

e

Ventilation rates

-

-

-

f

Open fires

-

-

-

Key

3

Seriously defective

g

Remedial measures

-

-

-

2

Defective

h

Extractor fans

-

-

-

1

Not satisfactory

i

Private water supply

-

-

-

-

Satisfactory/NA

Background: This large, two storey detached farmhouse is in a radon affected area. It is built

with random rubble stone, rendered walls and has a variety of floor constructions.

Kitchen: At the rear of the house, there is a flag stone floor to the kitchen, the flags being laid

directly onto the soil. Most of the kitchen walls show signs of rising damp.

Dining room: There is a solid concrete floor to the rear dining room and like the kitchen floor this

also shows evidence of rising damp, as do two of the walls.

Front rooms: The two ground floor front rooms have butt jointed, suspended timber floors. There

are two air-vents to the front wall, but no others, and rising damp in the spine wall.

Average likelihood, outcomes and HHSRS score for radon for persons aged 60 to 64

years in all dwellings, following lifetime exposure

HHSRS VERSION 2

SEPTEMBER 2004

HEALTH AND SAFETY RATING SYSTEM SCORES

Pre 1920 House

LIKELIHOOD

1 in

100

Low

High

Average: 10,000

Example

100

< 4200 2400 1300 750 420 240 130

75

42

24

13

7.5

4

2.5

1.5 >

Justification

OUTCOMES

Class I

Class II

Class III

Class IV

Justification

RATING

There is sufficient evidence to suggest a radon problem and subsequent measurements

show a level of over 2,000 Bqm-3, way above both the average for radon affected areas

and the recommended action level of 200 Bqm-3. Information from NRPB and other

sources (see table overleaf) indicates that this would give an annual risk of cancer of

around 1 in 100.

%

90.0

10.0

0.0

0.0

Average: 90.0

90.0

< 0.05 0.15 0.3

0.7

1.5

3

7

15

26

38 >

Av: 10.0

10.0

< 0.05 0.15 0.3

0.7

1.5

3

7

15

26

38 >

Av: 0.0

0.0

< 0.05 0.15 0.3

0.7

1.5

3

7

15

26

38 >

Av: 0.0

0.0

< 0.05 0.15 0.3

0.7

1.5

3

7

15

26

38 >

The radon level does not alter the spread of outcomes.

Score

284

Example

A B C D

Average: 91

E F G H

I

J

Score

9100

RATING SCORES AFTER IMPROVEMENT

Likelihood to

1 in

3,200

Outcomes to

90.0 10.0

0.0

0.0

%

IMPROVE

Justification

NEW RATING

Av: Nos

The installation of a radon sump under the centre of the house, close to the spine wall,

is found to reduce the radon level to just over 70 Bqm-3 and thereby the likelihood to

around 1 in 3,200 and the rating score to 284 - reducing the Band from A to E. As the

dwelling is in a high radon gas risk area, some risk remains.

Av: 91

G H

I

J

Improved

A B C D E F