Papers

Prevalence of working smoke alarms in local authority inner city housing: randomised controlled trial

Diane Rowland, research fellow, ^a Carolyn DiGuiseppi, associate professor, ^b Ian Roberts, professor of epidemiology and public health, ^a Katherine Curtis, research officer, ^c Helen Roberts, professor of child health, ^c Laura Ginnelly, research fellow, ^d Mark Sculpher, professor of health economics, ^d Angela Wade, senior lecturer in medical statistics. ^e

^a Public Health Intervention Research Unit, London School of Hygiene and Tropical Medicine, London WC1B 3DP, ^b Department of Preventive Medicine and Biometrics, University of Colorado Health Sciences Center, Denver, CO 80262, USA, ^c Institute of Health Sciences, City University, London EC1A 7QN, ^d Centre for Health Economics, University of York, York YO10 5DD, ^e Centre for Paediatric Epidemiology and Biostatistics, Institute of Child Health, London WC1N 3JH

Correspondence to: I Roberts
Ian.Roberts{at}LSHTM.ac.uk

Objectives: To identify which type of smoke alarm is most likely to remain working in local authority inner city housing, and to identify an alarm tolerated in households with smokers.
Design: Randomised controlled trial.
Setting: Two local authority housing estates in inner London.
Participants: 2145 households.
Intervention: Installation of one of five types of smoke alarm (ionisation sensor with a zinc battery; ionisation sensor with a zinc battery and pause button; ionisation sensor with a lithium battery and pause button; optical sensor with a lithium battery; or optical sensor with a zinc battery).
Main outcome measure: Percentage of homes with any working alarm and percentage in which the alarm installed for this study was working after 15 months.
Results: 54.4% (1166/2145) of all households and 45.9% (465/1012) of households occupied by smokers had a working smoke alarm. Ionisation sensor, lithium battery, and there being a smoker in the household were independently associated with whether an alarm was working (adjusted odds ratios 2.24 (95% confidence interval 1.75 to 2.87), 2.20 (1.77 to 2.75), and 0.62 (0.52 to 0.74)). The most common reasons for non-function were missing battery (19%), missing alarm (17%), and battery disconnected (4%).
Conclusions: Nearly half of the alarms installed were not working when tested 15 months later. Type of alarm and power source are important determinants of whether a household had a working alarm.

What is already known on this topic Functioning smoke alarms can reduce the risk of death in the event of a house fire Many local authorities install smoke alarms in their properties Several different types of smoke alarm are available What this study adds Only half of the smoke alarms installed in local authority housing were still working 15 months later Ionising smoke alarms with long life lithium batteries were most likely to remain functioning Installing smoke alarms may not be an effective use of resources