TEXTILE LABORATORIES

After a long experience in Textile laboratory applications, Branca Idealair approaches new developments and projects of Accreditated Textile Testing Laboratories arranging the installation of Branca Climatic Units

These precision air conditioning units are able to assure a daily constant climatic control guaranteeing a perfect conditions of uniformity at every point of the conditioned testing areas foreseen for the preparation of samples and in order to improve test repeatability and reproducibility.

The most accurate quality control on physical and mechanical properties for Textile products has to be considered the Keyword of the Modern Textile Industry that has to reach the highest scopes of Quality for their products in a competitive market. The tests and analyses on textiles must be performed in environmentally controlled rooms, thus obtaining results more precise, influencial and evaluable.

 Before subjecting any textile material under a laboratory examination, samples need to be collected and prepared to a suitable conditioning equilibrium and after that placed inside a conditioned room at a Standard Atmosphere for a standard period of time according to material characteristics and to the specific tests in compliance to the Standard.

For Textile laboratories, the norm ISO 139 defines the Standard Atmosphere that has to be at a reference temperature of 20 °C and a Relative Humidity of 65%. The norm defines also the tolerance limits for thermo-hygrometric variations:

• Room temperature: 20 ± 2°C
• Room Relative Humidity: 65 ± 4%

Laboratory thermo-hygrometric records must be collected periodically with a continuous data recording system or datalogger keeping under control the previous acceptable limits upper cited. The monitor of room conditions should be analyzed by independent probes from those used for air conditioning control (ISO 139 par. 5.2); these probes must be compatible in terms of measure accuracy to the requested parameters and below their measure uncertainties must be lower than tolerances requested by the norm.

In other Textile applications it includes a complementary Standard Atmosphere defined by a Temperature of 23°C and an RH% of 50%.

The Standard ISO 139 describes that the temperature spatial variations inside a Textile laboratory must be kept inside these specified tolerances and should be checked periodically through a overall mapping of the laboratory with a accreditated psychrometer; in order to obtain spatial variations not to exceed over tolerances it is essential to have an air conditioning system able to convey the inlet air into the laboratory at a very low speed inferior to 0,15 m/s.

At International level, the British Standards BS 4194: 1967 describes two types of tolerances inside a Textile laboratory fixing the constant Temperature at 20°C and the constant Relative humidity at 65%:

TOLERANCE TYPE 1

TOLERANCE TYPE 2

For the American Standards, the norm ASTM D123-58 indicates the terms of Standard Atmosphere for textile materials is set at:

All the Standards on textile materials define admitted ranges of Temperature(°C) and RH (%) inside the testing laboratories, but they highlight too that the air conditioning systems, that have to maintain these acceptable limits, must operate with a closer variable control on Temperature too.

The temperature variations (in equal amount of water vapour) generate variations in the RH (%) too, particularly when the heating and cooling performances causes the decrease of the RH% .

Example: A Textile laboratory requires a Temperature of 20°C and RH of 65% to perform the strenght test on universal testing machines, but the ambient conditions are not stable and all tests results have a statistical trend graph deviations. Then, what could be the reason of getting unstable conditions?

A Temperature variation of ± 1°C leads to a RH% variation of ± 4%, then it is absolutely necessary to obtain a reduction of temperature flunctuations the closest as possible instead of managing range control as prescribed by the regulations. It is also essential that an air conditioning system controls closely temperature and RH% with a suitable logic in order to get positive results of temperature and RH% within tolerances.

S.T.A. Branca Idealair offers two options in relation to the needs of the Customer:

Solution “A”: 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: