Survey of the reliability of carbon monoxide alarms deployed in domestic homes and efficacy of use by consumers


  • This publication and the work it describes were funded by the Health and Safety Executive (HSE). Its contents, including any opinions and/or conclusions expressed, are those of the authors alone and do not necessarily reflect HSE policy.
  • This article is published with the permission of the Controller of HMSO and the Quee's Printer for Scotland.

S. Naylor

Health and Safety Laboratory Harpur Hill Buxton Derbyshire SK17 9JN UK

Tel.: +44 (0) 1298 218439

Fax: +44 (0) 1298 218840



Carbon monoxide (CO) alarms are extensively used in domestic premises in the UK to help protect against CO poisoning. Their expected lifetime has been increasing, and some current models now have a replacement period of more than 6 years under normal operation. However, concerns have been expressed as to the reliability of alarms over an extended period. In this study, 110 households with a CO alarm were surveyed, during which the alarm was uninstalled and replaced and a household survey questionnaire administered. Alarm reliability was assessed under laboratory conditions by testing conformity to the alarm condition gas tests in either the British (European) standard, BS EN 50291 for UK certified models, or the US standard, UL 2034 for US certified models. The questionnaire recorded the alarm make and model, its age, its location, whether it was correctly sited, and how often it was tested. General information on the property was also collected. Results of laboratory testing suggest that the reliability of the most common models of CO alarms used by UK consumers has improved over the last 7 years. However, findings from the household survey suggest that the way alarms are used in many homes may not maximize their ability to detect abnormal levels CO.