Cellule de l’institut de veille sanitaire en région Bretagne
Agence régionale de santé de Bretagne
6, place des Colombes
35042 Rennes cedex
France, Observatoire régional de santé de Bretagne
8 D, rue Franz Heller
35706 Rennes cedex 7
12, rue du Val d’Osne
94415 Saint-Maurice cedex
- Key words: carbon monoxide, carbon monoxide poisoning
- DOI : 10.1684/ers.2011.0494
- Page(s) : 477-84
- Published in: 2011
Background: In the Morbihan district, 1,316 council flats were equipped in 2003 with a CO detector with an expected life span of 10 years. The model was a metal oxide semiconductor detector that was claimed to comply with the European standard (EN 50291).
Methods: To assess the operation of these detectors, we conducted a descriptive study among tenants, supplemented by laboratory tests of new detectors of the same model and of devices removed after 4 years of operation. During these tests, the detectors were exposed to gases with CO concentrations ranging from 33 to 330 ppm. The time until the alarm went off was compared to the European standard requirements in each test.
Results: Residents in 387 households were questioned: 19.5% [16.5-22.9] reported an alarm. The acceptance of detectors was good among tenants; however only 39.8% [35.8-44.0] had read the user manual, and relatively few knew how to respond to alarms appropriately. The incidence of the alarm days – days associated with at least one alarm – rose by a factor greater than 8 between 2004 and 2006. Symptoms consistent with CO poisoning were reported for 7.7% [3.1-18.0] of the alarm days. Alarm circumstances were partially consistent with known sources of CO exposure, and one dangerous situation was detected. None of the new detectors complied with the European standard. The test results appear to suggest that rapid sensor drift is responsible for low-level alarms and that sensor saturation may explain the alarm failures. The latter represented 18.3% of the test results of the removed devices.
Conclusions: Assessment of the performance of CO detectors before they are authorised for sale would be beneficial for public health. Providing information to the households equipped with detectors about the use of their safety device would also be useful.