© warwick university 2005 session 6 introduction to the worked examples

© Warwick University 2005

Session 6

Introduction to the worked examples


Worked Examples

• Two pages –

Page 1 describes dwelling & details of deficiencies relevant to hazard

shows stages in scoring with justification and re-scoring on the basis of suggested remedial works


Page 1 Page 2


Worked ExampleDescription


Worked Example: Damp & MouldDAMP AND MOULD GROWTH HHSRS VERSION 2

Vulnerable age Persons aged under 15 years Multiple locations NoRelated hazards Excessive Cold Secondary hazards No

A) Living room C) Second bedroom

B) KitchenRearelevation

Frontelevation

Dwelling: 1960's end-terrace, 2 bedroomed house

A)

B)

C)

LIST OF RELEVANT MATTERS

LIKELIHOOD & OUTCOMES A B C B C1 Rising damp 3 - - I Plumbing/waste pipes - -2 Penetrating damp 2 - 2 j Rain water goods - -3 Condensation 2 3 2 k Roof/sub-floor spaces - -4 Mould growth 2 1 2 l Small room sizes - -a Energy efficiency 2 2 2b Background ventilation - 3 - # Secondary hazards B Cc Extract ventilation - 3 - - None - -d Clothes drying facilities - - -e Damp proofing 3 - - Key 3 Seriously defectivef Disrepair (walls) 2 - 2 2 Defectiveg Exposed water tanks etc - - - 1 Not satisfactoryh Water using appliances - - - - Satisfactory/NA

YesYes

A

-

There is hair-line cracking to the external render generally.

-

--

DESCRIPTION OF HAZARD/S

Second bedroom: Penetrating damp and some associated mould is affecting the end wall.

Living room: Rising and some pentrating damp with associated mould growth is affectingthe external gable wall in both recesses to either side of the fireplace in the living room. Kitchen: Dampness caused mainly by condensation is affecting the whole of the frontexternal wall surrounding the window and adjacent ceiling and party wall in the small

Background: This is a two storey, two-bedroomed end of terrace house built in the late1960s of non-traditional construction on an exposed estate designed to Radburn principles.

A-

HEALTH AND SAFETY RATING SYSTEM SCORES 1946-79 House

LIKELIHOOD Low High 1 in 2

Average: 446 Example

Justification

OUTCOMES %Average: 0.0

Class I

Av: 1.0

Class II

Av: 10.0

Class III 21.5

Av: 89.0

Class IV

Justification

Example Average: 11

RATING A B C D E F G H I J

RATING SCORES AFTER IMPROVEMENT

IMPROVE Likelihood to 1 in 320 Outcomes to 0 1.0 %

Justification

Improved Av:11

NEW RATING A B C D E F G H I J

10.0 89.0

4112

2

< 4200 2400 1300 750 420 240 130 75 42 24 13 7.5 4 2.5 1.5 >

< 0.05 0.15 0.3 0.7 1.5 3 7 15 26 38 >

< 0.05 0.15 0.3 0.7 1.5 3 7 15 26 38 >

< 0.05 0.15 0.3 0.7 1.5 3 7 15 26 38 >

Score:

As well as damp, an occupant's exposure to mould growth, and associatedspores, in two of the ground floor rooms and in one of the bedrooms, willincrease the risk of a more serious outcome occurring.

Score:

Av: Nos Average likelihood, outcomes and HHSRS score for hazards from damp & mould by persons aged under 15 years in 1946-79 non-HMO and all dwellings,1997-99.

Repairing the dpc, re-rendering the external walls and providing mechanicalventilation in the kitchen would reduce the risk to close to average levels - a scoreof 15, band I. Improving the thermal efficiency of the walls would reduce thehazard further

15

0.0

77.5

21.5

1.0

The presence of dampness in two of the main rooms on the ground floor and tothe second bedroom increases the risk of a major illness being caused orexacerbated by the conditions, significantly above that for the average dampdwelling.

< 0.05 0.15 0.3 0.7 1.5 3 7 15 26 38 >

0.00.0

0.0

77.5


Worked Example: ColdEXCESS COLD HHSRS VERSION 2

Vulnerable group Persons aged 60 years or over Multiple locations NoRelated hazards Damp and Mould Growth Secondary hazards No

Front elevation

Hot water tank

Dwelling:

A)

B)


LIKELIHOOD & OUTCOMES A B # Secondary hazards Ba) Thermal insulation - 3 - None -b) Dampness -c) Settling of insulation - 3d) Type of heating provision 2 -e) Size of heating system 3 -f) Installation & maintenance 3 -g) Controls to heating system 3 -h) Amount of ventilation - Key 3 Seriously defectiveI) Ventilation controls - 2 Defectivej) Disrepair to ventilation - - 1 Not satisfactoryk) Draughts/excess ventilation - - Satisfactory/NA

YesYes

Background: The walls are of steel frame constrution, faced externally with vertical steel sheeting. Intenally the walls are finished with plasterboard supported on timber frames.

Heating: This was originally by open fires throughout. At sometime, the open fireplaces to the first floor were sealed and gas fires fitted to the two ground floor living rooms.The occupier uses portable electric heaters to supplement the gas fires.

DESCRIPTION OF HAZARDS

1950s non-traditional semi-detached house, similar to the BISF design.

A-

Insulation: The original construction included glasswool quilting hung within theexternal wall frame, and a thin (50mm) layer to the whole of the roof space. There is noinsulation to the hot water tank and the windows are single glazed.

HEALTH AND SAFETY RATING SYSTEM SCORES 1945-79 House

LIKELIHOOD Low High

Average: 400 Example

32

Justification


Class I

Av: 6.0

Class II

Av: 18.0

Class III

Class IV

Justification

Example Average: 880

RATING A B C D E F G H I J


IMPROVE Likelihood to 1 in Outcomes to 31.6 4.6 %

Justification

Improved

NEW RATING A B C D E F G H I J

Av: Nos Average likelihood, outcomes and HHSRS score for excessive cold for persons aged 60 years or more in 1964-1979 Non-HMOs and all dwellings, 1997-99.

Score

Av: 880

Score

10233

327

21.5 42.3

31.6

Av: 42.0

Installing an efficient heating system capable of heating the whole of the dwellingand providing additional thermal insulation to the external walls and the roofspace would reduce the rating around the average for dwellings of this age group(Band D).

< 0.05 0.15 0.3 0.7 1.5 3 7 15 26 38 >

< 0.05 0.15 0.3 0.7 1.5 3 7 15 26 38 >

< 0.05 0.15 0.3 0.7 1.5 3 7 15 26 38 >

< 0.05 0.15 0.3 0.7 1.5 3 7 15 26 38 >

1,000

21.5

4.6

1 in

42.3

Although the likelihood of a harmful occurrence is much higher than average,there is nothing to indicate that spread of harms will vary from the average.

The two gas fires are not capable of heating the whole of the dwelling. Theinsulation, even as original, would be considered inadequate now, and hassettled over the years to become less effective. The result is that the likelihood ofthe dwelling bein

32

< 4200 2400 1300 750 420 240 130 75 42 24 13 7.5 4 2.5 1.5 >

31.6

4.6

21.5

42.3


Worked Example: ErgonomicsPOOR ERGONOMICS HHSRS VERSION 2

Vulnerable age Persons aged 60 years or over Multiple locations NoRelated hazards Damp and mould growth, Secondary hazards No

Falls associated with bathBathroom window Vertical section

w indow catch

1950 mm

Plan of bathroom

duct

wash hand basinw indow catch

bath

Dwelling: 1 bed converted flat in 1890's house


LIKELIHOOD & OUTCOMES A # Secondary hazards Aa Position of amenity 3 - None -b Space for amenity -c Kitchen worktops -d Kitchen space -e High level storage - Key 3 Seriously defectivef Window controls 3 2 Defectiveg Electric switch/sockets - 1 Not satisfactoryh Operation of windows etc 2 - Satisfactory/NA

DESCRIPTION OF HAZARDS

Background: A large 3 storey stone built Victorian house has been converted into self-contained flats. The ground floor flat has its bathroom at the rear of the building. The bath,wash hand basin and w.c. are all located, close together, along the exter

Bathroom window: The window is set on the external face of the thick rear stone wall, and has an internal tiled sill at the back of the wash hand basin of some 450 mm in depth. The window itself comprises a fixed light with a shallow opening top hung lig

YesYes

w.c.

920 mm

HEALTH AND SAFETY RATING SYSTEM SCORES Pre 1920 converted s/c Flat

LIKELIHOOD Low High

Average: 9,074 Example

180

Justification


Class I

Av: 1.7

Class II

Av: 16.9

Class III

Av: 81.4

Class IV

Justification

Example Average: 1

RATING A B C D E F G- H I J Score


IMPROVE Likelihood to 1 in Outcomes to 0.0 2.2

Justification

NEW RATING A B C D E F G H I J Score

Av: Nos Average likelihood, outcomes and HHSRS score for hazards from poor ergonomics for persons aged 60 years or more in pre 1920 flats and all dwellings, 1997-99

< 0.05 0.15 0.3 0.7 1.5 3 7 15 26 38 >

< 0.05 0.15 0.3 0.7 1.5 3 7 15 26 38 >

< 0.05 0.15 0.3 0.7 1.5 3 7 15 26 38 >

76.3 %

21.5

76.3

Improved

1 in 180

Resiting the wash hand basin on the internal wall, on the opposite side of the soilpipe and duct, would allow easier access to the window. However, ideally thewindow should also be replaced with one having a larger opening light and lowercatch or, al

5,600

Although the likelihood is higher than average, the spread of harms is notchanged. In terms of poor ergonomics, therefore, the overall risk would berelatively low, the rating score being 52 or Band G-. In practice, a greater risk fromthis deficiency

< 0.05 0.15 0.3 0.7 1.5 3 7 15 26 38 >

52

0.0

1

21.5

< 4200 2400 1300 750 420 240 130 75 42 24 13 7.5 4 2.5 1.5 >

2.2

The catch to the top opening light is positioned just under 2 metres above thebathroom floor. This height would be just acceptable, except that to reach thecatch in this case also entails stretching over both the full sized wash hand basinand the deep

2.2

21.5

76.30

0.0


• See: www.clg.gov.uk, www.east midlandsdash.org.uk www.lacors.gov.uk

•Q. Where is the overall hazard score from the dwelling?

A. There is no single overall hazard score for the dwelling - more hazards = higher risk but cannot simply add the scores

Frequently Asked Questions

http://www.dash.org.uk/


Q. How do you deal with mixed-use accommodation, such as a flat over a shop?

A. Deal with the unit of accommodation - the sleeping, living, food preparation and bathroom accommodation AND all the common and shared areas. If the shop impacts on the unit of accommodation then take it into account. E.g. hazards such as structural stability and fire safety in the shop could well affect the accommodation unit.

FAQs


Session 7

Rating hazards - some exercises and comparison of results


• In this session you will look at a number of scenarios

• On the basis of information provided

– Consider the likelihoods and outcomes and produce a score for the hazard described; and

– note down the justification for that score (looking at both likelihood and spread of harm outcomes)

• After each hazard has been scored the results (including justifications) will be compared and discussed

Exercises


Damp and mould (1)

Front elevation

Rear elevation

Dwelling:two storey terraced house built in 1890.

There are two bedrooms in the house; there is a bathroom on the first floor and a WC in the rear addition on the ground floor. There is damp affected ceiling plaster in the rear bedroom as the result of disrepair around on the roof around the chimney stack. There is damp affected wall plaster in the WC and also some mould growth.

DESCRIPTION OF HAZARD

Rear bedroom ceiling

WC compartment


Falls on the level (20)

Dwelling: Pre-1919 terraced house.

Front elevation

There is a step at the front door with a threshold to the new uPVC door and frame. There is step up from the front hall through the door into the ground floor main hall. From the ground floor rear room there is a step down into the back addition kitchen. From the kitchen there is a step down into the back addition lobby, and a step up into the back addition shower room. The floor boarding to the kitchen is holed close to the step down. There is a step down into the rear yard at the rear door. Concrete to the rear yard is broken and uneven.


Front door (ext)

Rear door & yard

Kitchen/back addition lobby

From GF rear room


Fire (24.1)


Dwelling: First floor rear left bedsit, in a pre- 1920, three storey, terraced HMO.

Rear elevation

Partition wall

Corridor to the staircase

Staircase

Bedsit

The dwelling in common with the 21 other dwellings in the building has an electric cooker. There is a smoke detector (mains operated) linked to a hard wired alarm system – in this unit both are adjacent to the door opening. The doors to the units are half-hour fire resistant, but there are no intumescent strips. There is double door protection with a “fire door” between the door of the letting and the main escape route. There is disrepair to the lath and plaster partition walls to the letting and to the landing. The nosings to the main escape route (internal staircase) down to the ground floor are loose and worn. The second escape route is a timber staircase at the far end of the building.

Front elevation



Structural collapse and falling elements (29)

Front elevation and roof

Rear house wall

Rear (external) wall in rear bedroom

Dwelling: Pre 1920 mid-terrace house

The property is entered directly off the street. There are a number of tagged, slipped and missing slates to the front and rear house roofs. The brick arch to the ground floor rear room has dropped and there is a slight fracture to the rear wall above. A crack has appeared in the rear wall to the first floor rear room (above the window to the ground floor rear room).


Refuse storage

Sub-floor space

Vent to sub-floor space

Rat caught in groundsDESCRIPTION OF HAZARD

The block is adjacent to a railway line and a small water course , and there is a rat infestation in the area. Rats have gained access to the sub-floor space and one way appears to have been by gnawing through the plastic ventilator. The landlord has now contracted a pest control servicing company to bait the area and the sub-floor space. Refuse is stored in sacks and bins in the grounds, and is collected weekly. Much of the grounds and landscaping surrounding the flats is overgrown.

Domestic Hygiene, Pests and Refuse (15)

Dwelling: The property is a ground self-contained floor flat in a block of eight flats constructed in 1975

Front elevation


Damp and mould (1)

Dwelling:Three bedroom flat on the north west corner of the seventh floor of a twenty storey block constructed in 1969.

Living room ceiling

Kitchen wall

Second bedroom ceiling

View of of block


The ceilings in all bedrooms are affected by some mould growth although the worst affected is the second bedroom. There is also some mould growth in the living room and kitchen. The space heating is by electric storage heaters, and the windows are double glazed aluminium framed and there are no trickle vents. There are no clothes drying facilities within the block, and no balconies to the flat. There are in addition two ventilators in the kitchen walls where ventilated food storage was provided originally and which are draughty.


Wall of ground floor rear room

Front wall of front

Front bedroom window

Reveal at front bedroom window


Damp and mould (1)

Dwelling: Pre 1920 semi-detached house

Front elevation

There are two bedrooms in this house, in one there is a damp patch adjacent to the window as the result of perished pointing and cracking to the reveal fillet. On the ground floor there is rising dampness in the ground floor rear living room, in the bay wall, there is no DPC in the dwelling, and the rainwater pipe from the bay roof discharges directly into the ground


Living room wall (end wall of building)

Living room wall


Damp and mould (1)

& Excess Cold (2)

Dwelling: Fifth floor two- bedroom flat in an eight storey block of flats constructed in the 1970s

Front elevation

The flat is heated only by gas fired ducted warm air, with one outlet in the living room and another two in the hallway. There is a balcony area at each end of the living room, the single-glazed windows overlooking the balconies (east and west facing elevations) have been fitted with spinner vents. The end (north facing) wall of the sole living room is badly affected by mould. There is no heating in either bedroom but they appear to be unaffected by mould or dampness.


Ill-fitting PVCu replacement casement window in bedroom 1 Boiler in kitchen


Dwelling: Third floor two- bedroom flat in a five storey block of flats constructed pre-1920

Front elevation

The has been partly renovated, the replacement PVCu windows are generally in poor repair (in the main living room the hinge to the top hung casement is broken) and although fitted with trickle vents, these are mostly blocked with dirt or the covers are fixed shut as the opening levers are broken. Although there is central heating, the boiler has been condemned as unsafe, and there is an old open-flued gas fire in the main living.

Carbon monoxide (6.1)

Gas fire installed in bedroom 1



Dwelling: 1930’s constructed detached one bedroom bungalow with single skin brick walls

Food Safety (16)

Front elevation

Kitchen wall

Kitchen

The walls & floor are affected by dampness and in disrepair. There are no facilities for the storage of food; there is space for a refrigerator but the electrical wiring is also in poor condition; there are no fixed work surfaces; the electrical hot water heater is also in disrepair and there is no hot water; the surface of the sink is pitted and worn, and the draining board is damaged . There is an electric cooker. The only electric sockets in the kitchen are one which is part of the unit to which the cooker is connected and another adjacent to that unit

© warwick university 2005 session 6 introduction to the worked examples

Documents

damp mould warwick university

average damp dwelling

mould growthhhsrs version

class i0

class ii1

class iii21

class iv77

ground floor rooms