My partner's business just has a visit from our local Health and Safety. They allege two "Category 1 hazards", "Excess Cold" and "Excess Heat", both basically due to poor insulation. These hazards cause "unacceptable risks to the health and safety of the occupants".
But it's August in England, with temperatures here varying between 10 and 20 degrees Centigrade, and families going on camping holidays without reports of mass deaths. So what is going on here? Why do Health and Safety think there are severe risks from hot and cold?
A good starting point is this, "Housing Health and Safety Rating System Operating Guidance - Housing Act 2004 - Guidance about inspections and assessment of hazards given under Section 9 housing".
http://www.communities.gov.uk/documents/housing/pdf/142631.pdf [PDF]
The Housing Health and Safety Rating System (HHSRS or the Rating System) is the Government’s new [2006] approach to the evaluation of the potential risks to health and safety from any deficiencies identified in dwellings. The HHSRS, although not in itself a standard, has been introduced as a replacement for the Housing Fitness Standard1. This document provides guidance on the technical aspects of the HHSRS assessment in this context.
This document is readable, but quite long, so I've extracted what I think are some important parts and I'll walk you through them. First the introduction...
1.08 As the range of potential housing hazards have differing characteristics, the Rating System uses a formula to generate a numerical score which allows comparison of the full range of hazards.
1.12 The underlying principle of the HHSRS is that – Any residential premises should provide a safe and healthy environment for any potential occupier or visitor.
1.14 Some hazards, however, are necessary or unavoidable, and others are considered desirable or expected because the perceived benefits outweigh the risks. For example, electricity is hazardous but considered necessary; stairs (however well designed) are hazardous but necessary in any multi-storey dwelling. For such hazards, the design, construction and maintenance should be such as to reduce to a minimum the probability of an occurrence which could result in harm and of the potential harm that could result.
Note that word "potential". The numerical rating is not the risk to whoever lives there now, but people who might potentially do so in future - this is the first of several ways in which this system seems to inflate risks. But fortunately...
2.04 For the purposes of an assessment, a dwelling is any form of accommodation which is used for human habitation, or intended or available for such use.
If nobody will ever live here, the rules don't apply.
Let's think about harm...
Harm and Class of Harm
2.09 Harm is an adverse physical or mental effect on the health of a person.
2.10 It includes, for example, physical injury, and illness, condition, or symptom whether physical or mental. It also includes both permanent and temporary harm.
2.11 For the purposes of the HHSRS, the possible Harms that may result from an occurrence are categorised according to their perceived severity into four Classes of Harm. These are harms of sufficient severity that they will either prove fatal or require medical attention and, therefore, be recorded in hospital admissions or GP records.
You can find examples for each Class of Harm below. Now for hazards, which are things that might cause harm...
Hazard
2.12 Any risk of harm to the health or safety of an actual or potential occupier that arises from a deficiency.
2.13 In some cases, as well as being a hazard in its own right, a hazard may increase the likelihood of an occurrence of, or the severity of harm likely to result from another hazard.
Hazard Score and Rating
2.14 The Hazard Score is a numerical representation of the overall risk from a hazard. It is based on the evaluation of the likelihood of an occurrence and of the probable spread of harms that could result.
2.15 The Hazard Rating is the Band into which the Hazard Score falls.
Hazards harm people.
Likelihood
Likelihood
2.19 The probability of an occurrence that could cause harm.
2.20 For the purposes of the Housing Health and Safety Rating System, this is the probability of an occurrence during the twelve months following the assessment.
Watch out for this inflating the risk, because I think that Health and Safety officials can mis-interpret it as, "Calculate the probability,
assuming the property is occupied every day for the next 12 months". That's the only way I can explain the strange "excess cold" hazard that I mentioned at the top of this post.
This system does not seem concerned about real people, even if those living in the property now. It is really concerned with the risk to hypothetical people in a "vulnerable group"...
Vulnerable Group
2.30 A range of people for whom the risk arising from a hazard is greater than for any other age group in the population. Where there is no vulnerable group for a specific hazard, the population is taken as a whole.
2.33 The HHSRS provides a means of assessing the dwelling. It is, therefore, concerned only with those deficiencies that can be attributable solely or partly to the design, construction and/or maintenance of the dwelling ... This assessment is of the dwelling disregarding the current occupiers (if any), and based on the potential effect of any hazards on a member of the relevant vulnerable age group. This is important and means that the assessment will not be affected by a change of occupier, and that an unoccupied dwelling can be assessed.
The "vulnerable group" system inflates risk, because maybe the vulnerable group is only a small percentage of likely occupiers, yet everyone is treated as equally endangered.
How serious are hazards?
Overview of Rating Hazards
3.01 The HHSRS uses judgements made by the inspector, based on an inspection of the whole dwelling, to generate a numerical score. The information observed during the inspection should be properly and accurately recorded as this will provide evidence to justify and support the judgements which form the basis of the numerical Hazard Score.
3.02 The Rating System assessment procedure requires, for each hazard, two judgements from the inspector. These are an assessment of:
(a) the likelihood, over the next twelve months, of an occurrence that could result in harm to a member of the vulnerable group; and
(b) the range of potential outcomes from such an occurrence.
The HHSRS Formula
3.05 Three sets of figures are used to generate a Hazard Score, these are:
(a) a weighting for each Class of Harm reflecting the degree of incapacity to the victim resulting from the occurrence;
(b) the likelihood of an occurrence involving a member of a vulnerable group, expressed as a ratio; and
(c) the spread of possible harms resulting from an occurrence, expressed by percentage for each of the four Classes of Harm. ...
Class of Harm : Weighting
I Extreme : 10,000
II Severe : 1,000
III Serious : 300
IV Moderate : 10
This is an attempt to represent vastly different outcomes on a single scale, but in reality, when implemented by busy people, I expect you can ignore any hazard that doesn't cause "Extreme" or "Serious" Harm
And here's the formula to calculate the "Hazard Score". Think of a hazard; consider all the harms that it can cause; multiply each harm weighting (see above) by the chance that it will happen. Then add the scores for all harms. The system seems to slightly complicate matters by splitting this chance into the "likelyhood that a bad thing will happen" multiplied by the "likelyhood that the bad thing will do the named harm"
Figure 1 – The HHSRS Formula
S1 = 10,000 x 1/L x O1
S2 = 1,000 x 1/L x O2
S3 = 300 x 1/L x O3
S4 = 10 x 1/L x O4
Hazard Score = (S1 + S2 + S3 + S4)
Where –
L = the Likelihood of an occurrence
O = the Outcome expressed as a percentage for each Class of Harm
S = the row product for each Class of Harm.
See below for how to convert the hazard scores into "Hazard Bands", and my next post for how to convert it to "Categories".
The likelyhood numbers are a matter of judgement.
Judging the Likelihood
3.10 The inspector judges the likelihood of an occurrence over the next twelve months which could result in harm to a member of the relevant vulnerable group. For the HHSRS, the judgement is limited to the likelihood of an occurrence resulting in outcomes which would or should require some medical attention – a visit to a doctor or a hospital.
As promised, "Hazard Bands". Take your "Hazard Score" from above and look up the corresponding band.
3.26 Hazard Bands have been devised to avoid emphasis being placed on what may appear to be a precise numerical Hazard Score. These also provide a simple means for handling the potentially wide range of Scores – from under 0.2 to 1,000,00023. There are ten Hazard Bands (see Box 8), with Band J being the safest, and Band A being the most dangerous.
BOX 8 HHSRS Bands –
Band : Hazard Score Range
A : 5,000 or more
B : 2,000 to 4,999
C : 1,000 to 1,999
D : 500 to 999
E : 200 to 499
F : 100 to 199
G : 50 to 99
H : 20 to 49
I : 10 to 19
J : 9 or less
See below for how to convert the "hazard band" into "Categories".
You can skip over this next block of extracts if you like. It's really just background, but I didn't want to over-simplify this summary.
4.06 A single deficiency may contribute, to differing degrees, to more than one hazard. For example, the single deficiency of disrepair to a ceiling
could, dependent upon the nature and extent of that disrepair, lead to the following hazards:
* excessive cold (through increased heat loss);
* fire (by allowing fire and smoke to spread to other parts of the dwelling);
* lead (from old paint);
* infections from other sources (by providing means of access and harbourage for pests); and
* noise (because of an increase in noise penetration between rooms).
The contribution a single deficiency makes to each hazard will vary, perhaps from the relatively insignificant to the substantial.
4.07 Similarly, several deficiencies may contribute to the same hazard.
Assessing Hazards
4.16 First, after reviewing the deficiencies identified during the inspection which contribute to a hazard, the inspector should assess the likelihood of a member of the vulnerable age group suffering a potentially harmful occurrence in the next twelve months. Second, the inspector should judge the possible harm outcomes that could result from such an occurrence. (These two stages are described in paras 3.10-3.16 and paras 3.17- 3.22 above respectively.)
4.17 The Representative Scale Points are used to reflect the inspector’s judgements and a single numerical Hazard Score is generated by the HHSRS Formula for that hazard.
4.18 This scoring procedure should be repeated for all hazards that are considered to be worse than average – i.e. where the Hazard Scores are likely to be significantly above the average for the housing stock.
4.19 Finally, the Hazard Band for all the scored hazards should be recorded. These form the first factor in the enforcement decision-making process.
Guidance on that process is given in the Enforcement Guidance.
To convert "Hazard Scores" to "Hazard Bands", look up the score for each hazard in the following table...
BOX 9: Hazard +/- Sub-Bands
Sub Band Hazard Score
A- 5,000 – 5,400
B+ 4,600 – 5,000
B- 2,000 – 2,200
C+ 1,800 – 2,000
C- 1,000 – 1,070
D+ 930 – 1,000
D- 500 – 540
E+ 460 – 500
E- 200 – 220
F+ 180 – 200
F- 100 – 107
G+ 93 – 100
G- 50 – 54
H+ 46 – 50
H- 20 – 22
I+ 18 – 20
I- 10 – 11
J+ 9 – 10
Woo hoo! Nearly there. This document doesn't say how to convert the "Hazard Bands" to categories, so see my next blog post
Here's a recap about what inspectors do...
Scoring Hazards Schematic
Inspect the dwelling: Carry out a full inspection of the dwelling to identify all deficiencies, particularly those which could contribute to any of the 29 Hazards.
For each Hazard to be scored
Relevant Deficiencies: Review deficiencies identified which could contribute to Hazard.
Score the Hazard: Assess for this dwelling a) the likelihood range; and b) the outcome range for each Class of Harm. Taking into account national averages for particular type and age of dwelling.
Hazard Score and Band Generated
Determine Appropriate Enforcement Action: The Hazard Band is one of the factors to take into account in determining the appropriate enforcement action. On this see the Enforcement Guidance.
Finally, here are the promised examples about the Classes of Harm
ANNEX C: Examples for the Four HHSRS Classes of Harm
Class I. This class covers the most extreme harm outcomes including: Death from any cause; Lung cancer; Mesothelioma and other malignant lung tumours; Permanent paralysis below the neck; Regular severe pneumonia; Permanent loss of consciousness; 80% burn injuries.
Class II. This class covers severe harm outcomes, including: Cardio-respiratory disease; Asthma; Non-malignant respiratory diseases; Lead poisoning; Anaphylactic shock; Crytosporidiosis; Legionnaires disease; Myocardial infarction; Mild stroke; Chronic confusion; Regular severe fever; Loss of a hand or foot; Serious fractures; Serious burns; Loss of consciousness for days.
Class III. This class covers serious harm outcomes, including: Eye disorders; Rhinitis; Hypertension; Sleep disturbance; Neuro-pyschological impairment; Sick building syndrome; Regular and persistent dermatitis, including contact dermatitis; Allergy; Gastro-enteritis; Diarrhoea; Vomiting;
Chronic severe stress; Mild heart attack; Malignant but treatable skin cancer; Loss of a finger; Fractured skull and severe concussion; Serious puncture wounds to head or body; Severe burns to hands; Serious strain or sprain injuries; Regular and severe migraine.
Class IV. This Class includes moderate harm outcomes which are still significant enough to warrant medical attention. Examples are: Pleural plaques;
Occasional severe discomfort; Benign tumours; Occasional mild pneumonia; Broken finger; Slight concussion; Moderate cuts to face or body; Severe bruising to body; Regular serious coughs or colds.
ANNEX D... THE HAZARD PROFILES
A PHYSIOLOGICAL REQUIREMENTS 53
Hygrothermal Conditions 53
1 Damp and mould growth 53
2 Excess cold 59
3 Excess heat 63
Pollutants (non-microbial) 66
4 Asbestos (and MMF) 66
5 Biocides 70
6 Carbon Monoxide and fuel combustion products 72
7 Lead 78
8 Radiation 81
9 Uncombusted fuel gas 86
10 Volatile Organic Compounds 89
B PSYCHOLOGICAL REQUIREMENTS 91
Space, Security, Light and Noise 91
11 Crowding and space 91
12 Entry by intruders 95
13 Lighting 99
14 Noise 102
C PROTECTION AGAINST INFECTION 106
Hygiene, Sanitation and Water Supply 106
15 Domestic hygiene, Pests and Refuse 106
16 Food safety 111
17 Personal hygiene, Sanitation and Drainage 116
18 Water supply 123
D PROTECTION AGAINST ACCIDENTS 128
Falls 128
19 Falls associated with baths etc 128
20 Falling on level surfaces etc 132
21 Falling on stairs etc 136
22 Falling between levels 142
Electric Shocks, Fires, Burns and Scalds 146
23 Electrical hazards 146
24 Fire 150
25 Flames, hot surfaces etc 156
Collisions, Cuts and Strains 161
26 Collision and entrapment 161
27 Explosions 165
28 Position and operability of amenities etc 168
29 Structural collapse and falling elements 171
