What are calibration and drift checks for SHS detectors?

• A. Replacing detectors annually.
• B. Relying on self-calibration features with no maintenance.
• C. Drifts are acceptable if alarms trigger eventually.
• D. Regularly calibrating detectors to known test concentrations and monitoring drift of sensor readings to maintain accurate fire detection and timely release.

Answer: (D)

Calibration and drift checks keep SHS detectors accurate over time. Calibration uses known test concentrations or simulated conditions to verify that a detector’s response matches the actual hazard level, and adjustments are made so the sensor output aligns with those known values. This ensures the alarm thresholds reflect real danger and the system will release the suppressant when needed, not sooner or later than intended.

Drift checks monitor how sensor readings change as the detector ages or encounters environmental influences like temperature, humidity, or contamination. By tracking drift and establishing acceptable limits, you can intervene before performance degrades—recalibrating, cleaning, or replacing components as required. This keeps the detectors operating with reliable sensitivity and timing, which is essential for a timely and appropriate release.

Choosing to replace detectors on a fixed schedule or assuming self-calibration with no maintenance misses the ongoing need to verify and adjust performance. And relying on alarms that eventually trigger because drift occurred is unsafe, as it can delay detection and release. Calibration and drift monitoring directly support accurate fire detection and prompt, correct action by the SHS.