AS ISO 7240.8:2018 pdf free.Fire detection and alarm systems Part 8: Point-type fire detectors using a carbon monoxide sensor in combination with a heat sensor.
5.1.5 Measurement of CO response value
5.1.5.1 Install the specimen for which the CO response value is to be measured in a gas test chamber, as specified in Annex A, in its normal operating position, by its normal means of attachment. The orientation of the specimen, relative to the direction of gas flow, shall be the least sensitive orientation as determined in the directional dependence test (see 5.3), unless otherwise specified in the test procedure.
5.1.5.2 Purge the gas test chamber to ensure that the carbon monoxide concentration is less than 1 iil/l prior to each test.
5.1.5.3 The air velocity in the proximity of the specimen shall be (0,2 ± 0,04) rn/s during the measurement, unless otherwise specified in the test procedure.
5.1.5.4 Unless otherwise specified in the test procedure, the air temperature in the gas test chamber shall be (23 ± 5) °C and shall not vary by more than 5 K for all the measurements on a particular detector type.
5.1.5.5 Connect the specimen to its supply and monitoring equipment as specified in 5.1.3, and allow it to stabilize for a period of at least 15 mm, unless otherwise specified by the manufacturer.
5.1.5.6 For detectors whose response is rate sensitive, the manufacturer may specify a rate of increase within this range to ensure that the measured response value is representative of the static response value of the detector. The rate of increase in CO concentration shall be similar for all measurements on a particular detector type.
5.1.5.7 Introduce carbon monoxide gas at a rate of between 1 iil/l/rnin and 6 iil/l/min until the specimen has entered an alarm state. For detectors whose response is rate sensitive, the manufacturer may specify a rate of increase within this range to ensure that the measured response value is representative of the static response value of the detector.
NOTE To avoid unnecessary high levels of CO, the test can be stopped when the CO concentration reaches 100 ill/I.
5.1.5.8 The rate of increase in CO concentration shall be similar for all measurements on a particular detector type.
5.1.5.9 Record the carbon monoxide concentration at the moment the specimen gives an alarm. This shall be taken as the CO response value, S.AS ISO 7240.8 pdf download.