DIN EN 54-26:2015-11

Carbon monoxide (CO) is a product of the incomplete combustion of carbon-based materials. CO fire detectors can react promptly to smouldering fires involving carbonaceous materials because CO does not depend solely on convection, but also moves by diffusion. CO fire detectors might be better suited to applications where other fire detection techniques are prone to false alarms, i.e. due to dust, steam and cooking vapours. The purpose of this standard is to ensure that carbon monoxide (CO) fire detectors have adequate sensitivity and reliability for use in fire detection and fire alarm systems for residential commercial and industrial premises. CO may not be produced in detectable quantities where pyrolysis of material rather than self-sustained combustion occurs (for example, overheating cables) or in the early stages of rapidly burning flaming fires (for example, liquid fuel fires). It is important that carbon monoxide fire detectors are only used where a risk assessment indicates that they are appropriate for detecting the types of fires that may occur. CO fire detectors should not be considered as a direct replacement for smoke detectors. CO fire detectors detect carbon monoxide gas rather than the smoke particulates detected by optical and ionization smoke detectors. A number of different methods for sensing CO are suitable. However, most sensors will also be influenced by other gases and phenomena. Tests have therefore been included in the test schedule to assess cross-sensitivity to substances normally present in the service environment that may affect the performance of the detector. As CO detectors are specifically well suited for the detection of incipient fires rather than flaming fires this standard only includes tests to verify performance in smouldering fires. For this purpose, test fires TF2 and TF3 from EN 54-7 have been included in the test schedule. An additional validity criterion has been added to each of these tests to make them suitable for evaluating CO fire detectors. The European Standard has been prepared by Technical Committee CEN/TC 72 "Fire detection and fire alarm systems" (secretariat: BSI, United Kingdom) and the committee responsible on the national level is Working Committee NA 031-02-01 AA "Brandmelde- und Feueralarmanlagen" ("Fire detection and fire alarm systems") of DIN Standards Committee Firefighting and Fire Protection (FNFW).