Normal climate

from Wikipedia, the free encyclopedia

As normal climate (also referred to as standard climate or standard climate ), DIN  EN ISO 139 defines the area with controlled relative humidity and temperature in which textiles are adjusted and tested, or DIN EN ISO 291, which is used for conditioning and testing all plastics and types of For test specimens, the preferred constant climate applies, for which certain values ​​of air temperature and air humidity, but also limit values ​​of air pressure and air speed are specified.

Since many textile fibers , but also other materials, are hygroscopic , they absorb moisture from the environment and change their physical properties in the process. The humidity of the air depends on the temperature. Even the testing and measuring equipment is influenced to a certain extent by climatic conditions. In order to obtain comparable and reproducible test results, the internationally defined normal climates as test climates must be observed for all test rooms of the materials affected by the standards. Because of its great importance for the proper testing of textiles, DIN 53801-1 (= DVM 3801-1) was introduced as the forerunner of today's DIN EN ISO 139 standard.

The normal climate for conditioning and testing must have a temperature of 20.0 ° C and a relative humidity of 65.0% for textile tests, which is also indicated in the short form as 20/65. An agreement between the parties involved is necessary for the use of alternative, but not equivalent, normal climates. This must be documented in the test report. The alternative standard climate is the specific standard climate with a temperature of 23.0 ° C and a relative humidity of 50.0% and the tropical normal climate with a temperature of 27.0 ° C and a relative humidity of 65.0%. Both for the normal climate and for the alternative standard climates, the limit deviations for the temperature are ± 2 ° C and for the relative humidity ± 4%. The adjustment of the textiles to the test climate before the test can be regarded as complete if there is no further change in mass of 0.25% after two successive weighings (2 h apart). The display time depends on the type of fiber (minimum duration e.g. for polyester or polypropylene 2 hours, for cotton 6 hours and for wool 8 hours) and the type of presentation (minimum duration e.g. for fiber flocks 12 hours and strands, bobbins as well as sheet material samples 24 H).

The normal climate for testing plastics is an air temperature of 23 ° C and a relative humidity of 50% for non-tropical countries, and 27 ° C and 65% for tropical countries . This information is valid for an air pressure between 86 kPa and 106 kPa and an air speed of ≤ 1 m / s. The limit deviations in both standard climates are ± 1 ° C for the air temperature and ± 5% (class 1) or ± 2 ° C and ± 10% (class 2) for the relative humidity.

Even Paper Materials showing a hygroscopic behavior, so they also need an adequate climate undergo prior to testing. As for the later physical tests, a normal climate with an air temperature of 23 ° C and a relative humidity of 50% is preferred for the conditioning.The limit deviations are ± 1 ° C and ± 2%. The adjustment of the sample to the test climate is considered to be completed when the change in mass is less than 0.25% within one hour. The orientation for air conditioning is 4 hours for light-weight papers, 5 to 8 hours for heavy papers and 1 to 3 days for cardboard.

The testing of wood and wood-based materials is given a normal climate with an air temperature of 20 ° C and a relative humidity of 65%.

Individual evidence

  1. ↑ Anton Schenek: Lexicon of yarns and twisted threads: Properties and production of textile threads ., Deutscher Fachverlag, Frankfurt am Main 2006, ISBN 3-87150-810-1 , p. 338.
  2. ↑ Anton Schenek: natural fiber lexicon . Deutscher Fachverlag, Frankfurt am Main 2001, ISBN 3871506389 , p. 150
  3. ↑ DIN EN ISO 139, October 2011 edition: Textiles - normal climates for sample preparation and testing, p. 5.
  4. ↑ DIN EN ISO 291, August 2008 edition :: Plastics - normal climates for conditioning and testing, p. 4.
  5. ↑ Thomas Gries, Dieter Veit, Burkhardt Wulfhorst: Textile manufacturing processes - An introduction . 2nd, revised and expanded edition. Carl Hanser Verlag, Munich 2014, ISBN 978-3-446-44057-9 , p. 346.
  6. ↑ Ralf-Dieter Reumann (Ed.): Test methods in textile and clothing technology . Springer, 2000, ISBN 3540661476 , ISBN 9783540661474 , p. 13.
  7. ↑ DIN EN ISO 139, October 2011 edition: Textiles - normal climates for sample preparation and testing, p. 2.
  8. ↑ DIN EN ISO 139, October 2011 edition: Textiles - normal climates for sample preparation and testing, p. 6.
  9. ↑ DIN EN ISO 139, October 2011 edition: Textiles - normal climates for sample preparation and testing, p. 7.
  10. ↑ Ralf-Dieter Reumann (Ed.): Test methods in textile and clothing technology . Springer, 2000, ISBN 3540661476 , ISBN 9783540661474 , p. 25.
  11. ↑ DIN EN ISO 291, August 2008 edition: Plastics - normal climates for conditioning and testing, p. 6.
  12. ↑ Jürgen Blechschmidt (Ed.): Pocket book of paper technology . Fachbuchverlag Leipzig in Carl Hanser Verlag, Munich 2010, ISBN 978-3-446-41967-4
  13. ↑ Andreas Hänsel: Wood and Wood-Based Materials: Examination - Structure - Properties (basic knowledge for wood engineers) . Verlag Logos, Berlin, 2014, ISBN 3832536973 , p. 21