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Laboratories for Cotton fibers classification

The physical features of the Cotton yarns and fibers are easily influenced by their amount of moisture content (MC%) and by room conditioning to the reference samples which must be kept constant within the tolerance limits, therefore the equilibrium is defined constant climate or standard atmosphere to be applied for a period of time not less than 24 hours approved before, during and after the tests.

About conditioning and analyses on Cotton the reference Standard is the ASTM D-1776-15, 2015, "Practice for conditioning and testing textiles. ASTM International, West Conshohocken, PA, www.astm.org", that indicates as thermo-hygrometric reference values:

Temperature:	21 ± 1°C (70 ± 2°F);
Relative humidity:	65 ± 2%

The allowable limits for humidity control are fixed at ± 2%, thus the most important point.
This statement shows the notable importance not only to achieve the value of the 65%, but also keeping it inside the prescribed limits.
It is admittable to add compensations for slight variations on the absolute value of humidity, if the reading value of RH% remains under a stable control, for example, upon 63% or below 67%, but it is definetely wrong to apply any compensations on continuous fluctuations to RH% value.

The conditioned laboratory for cotton classingfying must be always to be conditioned to the reference values for 24/24 h and 7/7 days during cotton preparation and testing.

Climatic conditions in the laboratory must be controlled inside tolerances, alternatively all test running with HVI, CCS and alternative test equipements can't operate properly.

Monitor and collect records of temperature and humidity continuously with probes or dataloggers independent from those of air handling unit in order to compare periodical trend graphs.
Probes need to have a periodical calibration from Accreditation Institute that issues a Calibration certificate.

For Cotton testing it's possible to calculate an average value for thermo-hygrometric records with sampling rate of 5 to 10 minutes. The scope to avoid variations responsible for most of the errors of measurement on cotton fiber as well as drifts over long time periods.

In order to keep the laboratory within the tolerance limits the structural improvement of a conditioned laboratory insulation is needed to exclude the influence of distrubing elements as heat, instruments radiation, solar radiations and fumes coming from the external environments and reducing their influencial impact.

S.T.A. Branca Idealair offers supply and installation of:

BRANCA CLIMATIC UNIT

To have a fullfilment of all Standard requisites and to reach and obtain a constant laboratory Standard Atmosphere conditions within tolerance limits, the precision air conditioning unit known as BRANCA CLIMATIC UNIT is the best solution. These units are able to manage the following climatic parameters close-control:

Room Temperature:	20°C ± 0,5°C
RH%:	65% ± 2%
Spatial temperature gradient:	≤ 0,3 °C/m;
Temporal temperature gradient:	≤ 0,3 ° C/h	1 ° C/day
Inlet air speed:	≤ 0,15 m/s

Get more information and technical details about direct expansion units selecting the air volume to be conditioned (m³):

Get more information and technical details about cooled water units selecting the air volume to be conditioned (m³)::

For samples relatively wet or dry, Branca Idealair includes in the installation drawing an air lock realized for the samples set on the dry side without the use of driers and heaters. The relative humidity inside the air lock will be maintained at constant values closed to those required inside the laboratory, but with wider tolerances as requested by ASTM D5867.

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