Standard Test Conditions for High and Low Temperature Alternating Damp Heat Test Chamber
1、 Environmental condition standards
temperature range
Operating environment: The equipment should be placed in an environment with a temperature of 5 ℃ to 35 ℃ (some standards require an average temperature of ≤ 28 ℃ within 24 hours) to avoid rapid temperature changes that may affect equipment stability.
Test scope: The test chamber needs to support a temperature range of -70 ℃ to+150 ℃ (depending on the equipment specifications) to meet the requirements of extreme environmental simulation.
Humidity requirements
Operating environment humidity: ≤ 85% RH, to prevent condensation or circuit short circuits inside the equipment.
Test humidity range: 30% RH to 98% RH, supporting complex working conditions such as high temperature and high humidity (such as 85 ℃/85% RH) and low temperature and high humidity (such as 25 ℃/98% RH).
Air pressure and ventilation
Pressure range: 86kPa~106kPa, suitable for testing needs in high-altitude or low-pressure areas.
Ventilation conditions: The installation site should be well ventilated to avoid performance degradation caused by poor heat dissipation of the equipment.
Power supply and grounding
Power requirements: three-phase four wire+protective ground wire, voltage AC (380 ± 38) V, frequency (50 ± 0.5) Hz.
Grounding resistance: The grounding resistance of the protective grounding wire should be less than 4 Ω to ensure the safe operation of the equipment.
Installation and Space
Horizontal installation: The equipment should be placed on a level ground and calibrated with a spirit level to avoid vibration affecting the testing accuracy.
Interval requirement: Maintain a distance of ≥ 50cm from adjacent walls or objects to facilitate heat dissipation and maintenance.
Independent switch: An independent air or power switch should be configured to prevent interference from other devices.
2、 Performance parameter standards
Temperature and humidity control accuracy
Temperature accuracy: ± 0.5 ℃, ensuring the accuracy of test data.
Humidity accuracy: ± 2.5% RH, meeting the requirements of high-precision wet heat testing.
temperature change rate
Heating and cooling rate: 1 ℃/min to 3 ℃/min (average rate throughout the entire process), some equipment supports linear heating and cooling (such as average rate every 5 minutes).
Rapid temperature change: Some high-end equipment can reach 3 ℃/min to 25 ℃/min, meeting special testing requirements.
Temperature and humidity uniformity
Temperature uniformity: ≤± 2 ℃, ensuring no dead corners in the testing area.
Humidity uniformity: ≤± 5% RH, to avoid local humidity differences affecting the results.
wind speed control
Wind speed range: 0.5m/s to 1m/s, to prevent rapid airflow on the sample surface from causing thermal stress damage.
Fast temperature adjustment: If a higher wind speed (such as>1m/s) is required, a frequency converter or three-phase transformer needs to be installed.
3、 Testing Methods and Program Standards
Temperature change test
High temperature test: Raise the temperature from room temperature to the target temperature (such as 150 ℃), keep it constant for a specified time, and then cool down.
Low temperature test: Reduce from room temperature to the target temperature (such as -70 ℃), maintain constant temperature for the specified time, and then increase the temperature.
Temperature change rate: It should comply with the nominal rate of the equipment (such as 1 ℃/min) and record the actual change curve.
damp heat
Constant humidity and heat: Conduct a constant test for a specified time at the target temperature and humidity (such as 85 ℃/85% RH).
Alternating Damp Heat: Simulate temperature and humidity cycling changes (such as high temperature and high humidity → low temperature and low humidity → cycling) to test the weather resistance of the product.
program control
Programming ability: Supports 100 sets of programs/100 segments per set/999 cycles per segment to meet complex testing requirements.
Data recording: Real time recording of temperature and humidity curves, supporting USB download or remote monitoring.
Alarm function: It has alarm functions such as over temperature, over humidity, and water shortage to ensure testing safety.
4、 Safety and Environmental Protection Standards
Electrical safety
Insulation resistance: ≥ 1M Ω to prevent leakage risk.
Voltage withstand test: withstand 1500V/1min voltage withstand test without breakdown phenomenon.
Refrigerant management
Environmental requirements: Use environmentally friendly refrigerants such as R404A and R23, and prohibit the use of substances that damage the ozone layer (such as R12).
Recycling and disposal: Waste refrigerants need to be handed over to professional institutions for recycling to avoid environmental pollution.
noise control
Noise limit: ≤ 70dB (A), in compliance with industrial equipment noise standards.
5、 Calibration and maintenance standards
periodic calibration
Temperature and humidity sensor: calibrated once a year to ensure measurement accuracy meets standards (such as temperature ± 0.5 ℃, humidity ± 2.5% RH).
Anemometer: Calibrate every two years to ensure accurate wind speed control.
routine maintenance
Cleaning: Clean the inner and outer surfaces of the box every week, and clean the observation window every month to avoid scratches.
Drainage: Drain the accumulated water in the water tank and pipes after each test to prevent bacterial growth.
Component replacement: The humidifier should be replaced every 2000 hours, and the refrigerant should be replenished every 5 years.
6、 Comparison of international and domestic standards