Conditioning and procedures of Climatic Textiles Testing

Before proceeding with a climatic test, it is extremely important to understand the scope of the test to be performed and the kind of material to be tested. After making sure of that, there are some precautions to have in mind and the settings of the climate chamber to be set.

In this specific case, we will focus on a climatic textiles testing.

Given the type of material, you should take into account, before starting the climate test, that we cannot run it before making sure that we are matching with an official procedure.

The ISO 139 standard regulates weathering textiles testing and clothing material.

It specificates that samples should be put in a normal environment (Standard Atmosphere) for a fixed time, according to the type of textile to be tested.

Climatic textiles test conditions

Before proceeding with a climatic textiles test, there are some conditions that the ISO 139 reference standard establishes, in order to have reliable final test results.

The standard lays down climatic conditions and the limits under which the sample must be tested. Often, textile testing laboratories perform part of the test with unreliable equipment.

The FDM climatic chambers, are designed to perform these tests all in only one environment.

The textile material weathering testing is completed within the climatic chamber. So it is not necessary to move the sample several times, risking to lose the final report reliability.

Standard Atmosphere

The Standard Atmosphere means fixing starting climate conditions under which the textile sample is exposed before proceeding with the actual test.

The environmental temperature to be set on the climatic chamber must be 20° C, while the relative humidity must be 65%.

The period of sample exposition to the standard atmosphere, is determinate the weather resistance in according to material type and is defined by the reference standard

Variation limits

During the testing process, the environment where the samples will be tested must not deviate from the ISO 139:2005 limits.

In fact, the temperature can vary to a maximum of ± 2°C, while the relative humidity to a maximum of ± 4%.

These two limits can be directly set from the chamber’s controller, that constantly monitors the two parameters, also thanks to sensitive temperature and humidity probes.

Final result tolerances

Even in case the test procedure is followed step by step, there will always be external agents that will affect test results.

According to the BRITISH STANDARDS – specifically the BS4194: 1967 norm – a climate textiles test allows two types of tolerances:

Tolerance 1. Temperature ± 2 ° C, Relative humidity ± 5%

Tolerance 2. Temperature ± 1 ° C, Relative humidity ± 2%

It differs in type of test that will be performed.

Climatic Chamber Requirements

Now you can focus on the main component: the climatic test chamber. There are three main factors to keep in mind:

⦁ temperature variation rate

⦁ internal dimensions of the chamber

⦁ product to be tested

Temperature variation rate

The first thing to consider with any test chamber is the temperature, in particular the available temperature range and the temperature variation rate.

A standard chamber varies from -25 °C to +70 °C but the most performing ones can reach a wider temperature range.

The temperature variation rate is a fundamental parameter for a successful test. This value proves the performances and reliability of a climatic chamber and should not exceed ± 0.2/0.3 °C.

FDM test chambers are way more than performing, with an internal temperature variation of just ± 0.1 °C.

The internal dimensions of the chamber

You should also consider the internal dimensions of the chamber, which is among the most commonly overlooked factors.

In order to obtain accurate results, the chamber must have sufficient airflow in relation to the overall dimensions of the tested samples.

It is always a good idea to buy a slightly bigger test chamber than you think may be enough for your tests.

The product to be tested

Also the type of material to be tested will determine what kind of chamber to choose.

FDM guides customers in choosing the right climate chamber, according to the required test.


Please note that the chamber must be correctly calibrated in order to provide accurate results.

Climatic Textile Testing Procedure

First of all, check the ambient temperature where the climatic chamber is located, and check if the operating temperature match the data declared by the manufacturer.

Prepare and check the calibration of the temperature and humidity recording probes (usually it is performed at least once a year).

Place the samples so that the air has access to all surfaces. Distribute the textyle surfaces, only one layer per shelf.

Begin the preconditioning procedure (the Standard Atmosphere). Usually a sufficient time for preconditioning is reached after four hours at 20 °C and at 65% relative humidity.

Unless otherwise specified, yarns, threads and similar materials have to be displayed in skein form.

The tests will take up to eight hours for the animal or viscous fibers and only two hours for the fibers with a recovery of less than 5% with a humidity of 65%.

Heavy fibers take more time.

If a fabric contains more than one type of fiber, then you should take into account a longer conditioning time (find the component that takes longer to condition and run the test in that period).

Final test report

Last step is preparing your test report.

The test report includes all processes, materials and procedures of the tests. It shows the conditions from each phase, so that you can understand why a material reacted in a certain way and make your inferences.

In general, the report should include:

  1. subdivision of the tested material
  2. equipment used
  3. test conditions
  4. procedure
  5. results
  6. critical results
  7. final observations