ISO 291:2008 pdf download.Plastics - Standard atmospheres for conditioning and testing
I Scope
This International Standard sets out specifications relating to the conditioning and testing of all plastics and all types of test specimen at constant atmospheric conditions.
Special atmospheres applicable to a particular test or material or simulating a particular climatic environment are not included in this International Standard.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 62, Plastics — Determination of water absorption
3 Terms and definitions
For the purposes of this document, the following terms and detinitions apply.
3.1 standard atmosphere
preferred constant atmosphere for which specific air temperature and humidity values, as well as limit ranges for atmospheric pressure and air-circulation velocity, are specified, the air not having any significant additional constituents and the atmosphere not being subject to any significant additional radiation influences
NOTE 1 Standard atmospheres permit a defined state to be attained and maintained for samples or specimens.
NOTE 2 Standard atmospheres correspond to the average atmospheric conditions in laboratories and can be established in conditioning (controlled atmosphere) cabinets, chambers or rooms.
3.2 conditioning atmosphere
constant atmosphere in which a sample or test specimen is kept before being subjected to a test
3.3 test atmosphere
constant atmosphere to which a sample or test specimen is exposed throughout a test
3.4 conditioning
one or more operations intended to bring a sample or test specimen into a state of equilibrium with regard to temperature and humidity
3.5 conditioning procedure
combination of the conditioning atmosphere and the period of conditioning
3.6 ambient temperature
environmental conditions corresponding to the usual atmospheric conditions in laboratories with uncontrolled temperature and humidity
NOTE
The phrase“at ambient temperature" refers to an environment the air temperature of which lies within a specified range, no consideration being given to relative humidity, atmospheric pressure or air-circulation velocity. In general, the air-temperature range extends from 18 °C to 28 °C and is stated as“at an ambient temperature of 18 °C to 28 °C”.
4 Principle
If a test specimen is exposed to a specific conditioning atmosphere or temperature, then a reproducible state of temperature and/or of moisture equilibrium is reached between the test specimen and the conditioning atmosphere or temperature.
It is not the intent of this International Standard to define procedures specifying how to determine sensitivity to moisture.
Some materials may have special conditioning requirements. Follow the relevant International Standards.ISO 291 pdf download.