Stability chamber · Calibration procedure
Alarm checks
Proves that high and low temperature and RH alarms, door alarms and power-failure alarms trigger at the right limits and reach the right people.
PURPOSE
Why this is checked
Alarms are the safety net for long stability studies. If an alarm fails, an excursion could last for days unnoticed and a whole study could be lost.
Frequency
Typically every 6 months and after any change to alarm settings, software or notification lists, as defined in your SOP.
Learn how the Stability chamber worksYOU WILL NEED
Standards & tools
- Calibrated reference thermometer/hygrometer
- Calibrated stopwatch
BEFORE YOU START
Prerequisites
- Samples protected or moved if the test will push conditions outside limits
- Alarm set points and delays documented in the SOP
PROCEDURE
Step by step
- 1Record the configured alarm limits (e.g. 38 °C and 42 °C, 70% RH and 80% RH at 40 °C/75% RH) and the alarm delay.
- 2Raise or lower the condition (or simulate with a calibrator, as the SOP allows) until the alarm limit is crossed.
- 3Note the reference reading when the alarm triggers and the time from crossing the limit to the alarm.
- 4Check that the local audible/visual alarm sounds and that remote notifications (SMS, e-mail, BMS) arrive.
- 5Test door-open and power-failure alarms the same way.
- 6Return the chamber to normal and confirm conditions recover.
RECORD
Example observation table
| Alarm | Limit | Reference at trigger | Delay set | Delay observed | Notification |
|---|---|---|---|---|---|
| High temperature | 42.0 °C | 42.1 °C | 15 min | 15 min 20 s | Received |
| Low temperature | 38.0 °C | 37.9 °C | 15 min | 15 min 10 s | Received |
| High RH | 80% RH | 80.4% RH | 15 min | 15 min 30 s | Received |
| Door open | Open > 2 min | — | 2 min | 2 min 05 s | Received |
CALCULATION
How to calculate the result
Trigger error = Reference reading at alarm − Alarm limit
- High temperature limit 42.0 °C; the alarm triggered when the reference read 42.1 °C
- Trigger error = 42.1 − 42.0 = +0.1 °C, within the sensor tolerance
- Delay observed 15 min 20 s against 15 min set: alarm works as configured
ACCEPTANCE CRITERIA
Pass if
- Every alarm triggers at its limit within the sensor tolerance and after the configured delay.
- Local and remote notifications reach all people on the call-out list.
IF IT FAILS
What to do
- Treat the chamber as unmonitored: increase manual checks or move samples.
- Correct the alarm configuration or hardware and repeat the test.
- Raise a deviation and assess whether any excursions may have gone unnoticed.
MORE
Other Stability chamber calibrations
In LimsPulse · Calibration Management
LimsPulse schedules this calibration, records the result against limits, and blocks the instrument everywhere if it fails or goes overdue.