Can flammable and toxic gases only trigger a second-level audible and visual alarm?
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The specifications state that \"the sound pressure level of the audible and visual alarms for flammable gases and toxic gases must be no less than 75 dBa at a distance of 1 meter in front of the device, and the activation signal for the visual alarm should be based on the second-level alarm setting.\" Experts have confirmed that only a second-level drive can be used to activate such audible and visual alarms; a first-level drive is not sufficient. Is it reasonable to demand rectification? If taken literally, oxygen has only H/L level driving, so wouldn’t oxygen then not require driving the audio-visual alarm?
As required by the specifications, the audible and visual alarms for flammable gases and toxic gases must meet certain sound pressure levels, and the activation signal for alarms related to toxic gases shall be based on the second-level alarm setpoint signal. Therefore, it is reasonable for experts to recommend the use of a secondary drive for acoustic and optical alarms, in order to ensure the effectiveness and reliability of the alarms. As for oxygen, although there is only a single level of drive option, in practical situations it may still be necessary to use acoustic and optical alarms to alert people to changes in the oxygen concentration. Whether it is necessary to activate the acoustic and optical alarm depends on the actual circumstances, which need to be considered before making a decision. .
What the expert said makes sense and meets the regulatory requirements
Strip Interpretation 2.0.9: The alarm setpoints can be divided into primary alarm values and secondary alarm values. The first-level alarm value represents the upper limit alarm, which is a warning alarm ； The secondary alarm value corresponds to the high-high limit alarm; it requires immediate action once it occurs, and the interlock control of the alarm control unit must be derived from this signal. The normal level 1 alarm is driven by the built-in audible and visual alarm of the detector, while the level 2 alarm is driven by the on-site audible and visual alarm and the GDS system. What the expert said is correct.
50493-2019 5.3.1 specifies that the regional audio-visual alarm is driven by a secondary alarm