Cotton testing has to be done under specific climate conditions, which are given in the according standard practices (as ASTM 1776 or ISO 139). Particularly in countries with tropical conditions, it is very difficult and energy-intensive to maintain the required temperature level of 21°C, although temperature shows, compared to the influence of the relative humidity, a low impact on cotton test results - as long as the relative humidity is kept constant. Therefore the ITMF International Committee on Cotton Testing Methods (ICCTM) discussed during its meeting in Bremen, Germany on March 18, 2014, about the influence of temperature on the test results for cotton.

Whereas it is well known that the relative humidity shows a strong influence on cotton test results, the influence of the temperature is not as clear. The conclusions of the committee were:

a) Research should be done to check, if with a different temperature level (e.g. 24°C or even 27°C) the same test result level and the same accuracy of results can be achieved. Furthermore it has to be investigated, how the respective relative humidity has to be adapted – presumably on a level that results in the same moisture content of the cotton fibres as the currently given standard conditions (21°C / 65% relative humidity). At this stage, USDA-AMS, CSIRO in Australia and the Bremen Fibre Institute in Germany promised to investigate on this.

b) The allowed tolerance for temperature variations (1°C in ASTM 1776 or 2°C in ISO 139) should definitely not be widened, as this shows, with given constant total water content of the air, a direct impact on the relative humidity.

The results will be discussed at the next ICCTM meeting, which will take place in Bremen in March 2016.