The applicable standard outlines the recovery process for a programmable high and low temperature damp heat test chamber after testing. This process should be conducted under either standard atmospheric conditions (as specified in section 5.3 of GB/T 2421-1999) or under controlled recovery conditions. According to GB/T 2423.4-2008, if controlled recovery is necessary, the test sample can either be moved to another chamber or remain in the original test chamber for recovery.
In the first scenario, the transfer time should be minimized and must not exceed 10 minutes. In the second case, the relative humidity needs to be reduced to (75 ± 2)% within one hour, followed by adjusting the temperature to the laboratory temperature with a tolerance of ±1 K for an additional hour. For larger test samples, extended transfer times may be permitted, depending on the specific requirements.
The recovery time, typically ranging from 1 to 2 hours, starts once the required recovery conditions are achieved. If the test sample has a large thermal time constant, it may require a longer period to ensure proper temperature stabilization, as mentioned in Chapter 4 of GB/T 2421-1999.
It is also important that the relevant standards specify whether any special procedures are needed to remove moisture from the surface of the test sample. After the recovery phase, the test sample should be visually inspected and tested according to the applicable specifications. Measurements should be taken immediately after the recovery period, with the most humidity-sensitive parameters measured first. Unless otherwise stated, all measurements should be completed within 30 minutes.
Proper documentation and adherence to these procedures ensure accurate and reliable test results, maintaining consistency and compliance with international standards.
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