HVI Guideline Updated

The ITMF International Committee on Cotton Testing Methods (ICCTM) approved updates to the Guideline for Standardized Instrument Testing of Cotton during its meeting in Bremen, Germany on March 18, 2014. The Guideline is a joint effort by the International Cotton Advisory Committee (ICAC) Task Force on Commercial Standardization of Instrument Testing of Cotton (CSITC) and the ICCTM.

The Guideline provides specific instruction on the conditioning of cotton samples, operation of instruments and instrument testing laboratories and the handling of data in the evaluation of the quality of cotton fiber. The purpose of the Guideline is to assure standardized testing procedures so as to ensure results that are accurate, precise and repeatable and are thus useable by the cotton and cotton textile value chains in both the marketing and use of cotton fiber.

The major changes approved at the ICCTM meeting in Bremen included updates to the basic ASTM reference documents, a recommendation that climate data in each laboratory be averaged over a maximum 5 to15 minute interval, cautionary guidance in the use of rapid conditioning equipment, requirements for the continuous identification of samples handled within laboratories, requirements regarding calibration material, information on within-instrument and inter-instrument variations, information about participation in CSITC Round Trials and recommendations regarding the handling of data by laboratories.

The new version of the Guideline will be available at www.ITMF.org and www.CSITC.org  from April 07 on. It will be translated into Arabic, Chinese, English, French, Portuguese, Russian and Spanish.

Is a modification of the temperature level in cotton testing laboratories suitable?

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.