Health and Safety
Executive / Commission
Press Releases
E096:06 02 October 2006
A large survey of every element of each gas appliance in nearly 600 homes was carried out over the summer of 2006. Experienced CORGI registered gas engineers carried out the checks along with surveys of the house and of the householder.
23% of homes were found to have a problem gas appliance installation of some kind. In 3% of all homes a situation existed where there was considered to be a very high risk to the householder of dangerous CO exposure. A further 5% were considered to have a high risk of CO exposure. Gas fires were found to be the most frequently problematic appliance. An indication was found that certain health symptoms could possibly be linked to high CO exposure.
The homes surveyed were mainly from the south and east areas of Greater London and as such do not necessarily constitute a representative sample of homes in the UK. However the sample did cover a range of housing types, ages, tenures, occupant densities, occupant ages, and socio-economic status allowing extrapolations of the results to the UK population.
The following paragraphs sum up the detailed findings of the survey.
597 homes were surveyed, 1406 appliances were checked, CP14 notices were issued for 166 individual appliances in 140 homes. Of these 166 notices, 95 referred to Immediately Dangerous (ID) appliances.
Homes surveyed had a higher proportion of terraced housing, and housing built between the wars than the national average. Flats and detached houses were underrepresented by the survey. The survey aimed to include only owner occupied homes but 10% of homes surveyed were rented. This is a lower proportion of rented accommodation than found nationally.
Half the homes were occupied by pensioners; a higher proportion than nationally. The distribution of number of occupants was very similar to the national profile. The sample was worse off than average as more people were in receipt of benefits in the sample than nationally.
Most households had British Gas as their gas supplier, but a slightly higher proportion than nationally. Average gas bills were similar to national averages. One third of homes had their gas meter located outside their property. About half of homes had had their appliances checked when they moved into their current home.
Very few had heard of the Priority Service Register scheme for free appliance checks for pensioners and other eligible persons. CO awareness was poor with 45% having received no information about the dangers of CO. The health of householders was self-reported as being generally good or ok in the majority of cases.
Almost all homes had a gas boiler, predominant brands were Ideal, Vaillant and Potterton, average age was about 7.5 years. Four fifths of homes had a gas cooker, average age of these was about 8 years old, the main brand was Cannon. Gas fires were found in less than half of all homes, with an average age of 13 years. Main brands were Valor and Robinson Willey. Only a few homes had gas water heaters.
23% of all homes were found to have at least one problem gas appliance installation. Gas fires were found to be the appliance most likely to be rated as At Risk or Immediately dangerous (28% of all gas fires.) Boilers were least likely (3% of all boilers), cookers were in between (9% of all cookers).
The following all had a higher prevalence of problem gas appliances than other options in their group:
Younger households receiving benefits had more than twice the prevalence of problem gas appliances than those receiving no benefits with at least one member over 65.
Householders reporting more health symptoms related to CO exposure were found to be more likely to have a problem gas appliance installation.
To reach a national estimate for the prevalence of problem gas appliances, the data were broken down by different categories and a weighting applied to the proportion found in this survey compared to the proportion found nationally. This resulted in finding a range of estimates from 17% - 26% of homes that could have a problem gas appliance installation. The lowest estimate was based on the age of house, the highest based on proportion of homes with pensioners.
Older appliances were found to have higher CO emissions, in general, appliances that had had no maintenance had higher CO emissions than those that did.
Questions were asked about symptoms known to be related to carbon monoxide (CO) exposure, no single symptom was reported in more than 7% of cases. A small number of people (4%) reported 2 or more symptoms.
An estimated exposure risk for households was carried out finding that 3% of homes had a “very high” risk, and a further 5% had a high risk of exposure to dangerous levels of CO. Respondents reporting 2 or more CO related health symptoms appeared linked to a likelihood of having a problem gas appliance installation and consequently a high risk of CO exposure.
By all estimates considered in this study a large proportion of homes are likely to have a problem gas appliance installation of some kind in their home (around 20%). Nearly 10% of homes were estimated to have a high or very high risk of dangerous CO exposure due to the presence of a problem gas appliance installation. A small number of people (1%) self reported health symptoms and had problem gas appliance installations that may have been linked.
In general the risk of the presence of a problem gas appliance installation to the health of householders depends on behavioural factors, how they use that appliance, and how they use available ventilation.
A problem gas appliance installation is a health risk that can be avoided with maintenance and awareness.
A small number of homes (3 of 600) were found to have life threatening situations in their homes, the identification of these and also the replacement of 5 dangerous cookers in vulnerable households can be considered an important achievement of this project.