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Phase 1 (Yellow) Warnings

Sensors check the air quality on a frequent basis. A Phase 1 or Yellow Warning is sent to the Silvanet Cloud only if the Air Quality has significantly deteriorated within a short period of time (using a default sliding time window of 5 minutes). This means the IAQ value has significantly increased (by a value of 50) during this time, which triggers a Phase 1 alert.

Phase 1 Yellow warning

Phase 1 Yellow Warning sent to Silvanet Cloud


The sensor may not have detected a fire even though a Phase 1 alert was triggered.

The change in Air Quality (increase in IAQ) can be triggered by several events. Other environmental factors can cause a deterioration in air quality such as diesel engine fumes in the vicinity of the sensor, moving the sensor, or even the breath of someone coming close to the sensor


The sensitivity of the Phase 1 algorithm (threshold and sliding time window) can be configured remotely by Dryad’s support team. In the future, Dryad is planning to enable self-configuration by customers using the Site Management app as well as an adaptive algorithm aiming to reduce the number of Yellow Warnings over time.

Phase 1 Detection Process is as follows:

  1. Check Air Quality every 60 seconds:

    The gas sensor checks the Air Quality once every 60 seconds using an algorithm.

  2. Send data packets to Silvanet Cloud every 2 hours:

    As long as the sensor detects "Normal Air", that is, the baseline IAQ determined during calibration remains stable, it sends data packets to the Silvanet Cloud every two hours. These data packets contain air pressure, temperature and humidity readings.

  3. Deterioration of Air Quality triggers a Phase 1 Alert:

    If the Air Quality has significantly deteriorated, that is, the IAQ has increased by 50 points, within a short period of time (using a sliding window of 5 minutes), the gas sensor issues a Phase 1 alert, which is sent to the Silvanet Cloud. Clients do not receive this alert but is used internally to determine why the sensor reacted.

  4. Phase 2 Detection Process is then triggered.

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