Standard atmospheres for conditioning and testing of plastic specimens
This standard specifies the standard atmospheres for conditioning and testing of plastic specimens, and does not include the specific atmospheres for conditioning and testing under special conditions.
This standard was prepared with reference to the international standard ISO 291-77.
1 Terms and definitions
1.1 Conditioning: an equilibrium process in which the specimen is placed in the specified atmosphere for a certain time prior to the test so that the specimen reaches or approaches the required temperature and relative humidity.
It involves conditioning atmosphere and conditioning period.
1.2 Conditioning atmosphere: the temperature, relative humidity and air pressure specified during conditioning of specimen prior to test.
1.3 Atmosphere testing: temperature, relative humidity and air pressure where the specimen is placed during the whole test process.
2 Standard atmosphere
2.1 Standard atmospheres for conditioning and testing of plastic specimens are:
Temperature: 23°C;
Relative humidity: 50%;
Air pressure: 86-106 kPa.
2.2 If the influence of relative humidity on the properties of the specimens tested is negligible, the conditioning and testing can be carried out at 28 °C and normal humidity.
2.3 If The influence of temperature and relative humidity on the properties of the specimens tested are negligible, the conditioning and testing can be carried out at normal temperature and humidity.
Note: Normal temperature refers to 10-35 °C;
Normal humidity refers to 45%-75%.
3 Range of variation
Range of variation Temperature, °C Relative humidity, %
Normal
Smaller 23±2
23±1 45~55
48~52
Note: The range of variation of temperature and relative humidity refers to the fluctuation of temperature and relative humidity with time in the atmosphere where the specimen is located during conditioning and testing.
4 Conditioning period
The conditioning period shall be specified in relevant standards.
If not specified in the relevant standards, it shall not be less than 88 hours.
For materials that are known to quickly reach or approach equilibrium with ambient temperature and relative humidity, it may be less than 88 hours.
1 Terms and definitions
2 Standard atmosphere
3 Range of variation
4 Conditioning period
5 Tests
Additional explanation
