Systems and methods for robust man-down alarms

A method comprising:

• monitoring, using a motion sensor, a magnitude of motion of a man-down device;
• in an instance in which the man-down device is determined to be motionless for longer than an identified duration of time, correlating the period in which the man-down device is motionless for greater than the identified period of time with one or more other signals from one or more of the gas detector or the one or more second man-down devices, the one or more other signals being indicative of at least one of:
• an ambient temperature, an ambient gas concentration, a magnitude of motion, a smoke concentration, or a man-down alarm;
• and
• determining, based at least upon the correlating, a probability that the period in which the man-down device is motionless for greater than the identified period of time is indicative of a man-down alarm.

A man-down device comprising:

• a motion sensor configured to sense a magnitude of motion of the man-down device;
• an ambient sensor configured to sense a temperature, a gas concentration, or a smoke concentration in an ambient environment about the man-down device;
• and
• control circuitry configured for two-way communication with a central station and one or more of a gas detector or one or more second man-down devices,
• wherein the control circuitry is configured to:
• determine, based at least upon one or more signals received from the motion sensor, a period in which the man-down device is motionless for greater than an identified period of time,
• in an instance in which the man-down device is motionless for greater than the identified period of time, correlate the period in which the man-down device is motionless for greater than the identified period of time with the temperature, the gas concentration, or the smoke concentration sensed by the ambient sensor, and
• determine, based at least upon the correlating, a probability that the period in which the man-down device is motionless for greater than the identified period of time is indicative of a man-down alarm.