What is the alarm level for carbon monoxide detectors?

According to the national standard, for the detection of industrial carbon monoxide, there are generally two alarm settings, one is a first-level alarm, and the other is a second-level alarm. The alarm is set to 150-300ppm. Carbon monoxide alarms can be divided into household carbon monoxide alarms and industrial carbon monoxide alarms according to the direction of use, and can be divided into wall-mounted/fixed carbon monoxide alarms and portable carbon monoxide alarms according to the way of use. Different instruments can be selected according to different use requirements.