The ISO 3005 standard is used to measure the dimensional change of knitted and woven fabrics after its exposure to saturated steam, without the involvement of any mechanical pressure or wetting. The difference between the initial measurement and the after steaming measurement is represented in the form of a percentage, which is called the shrinkage percent due to steam.
ISO 3005 Steaming Test
Objectives
The ISO 3005 shrinkage test to steaming is specifically designed for knitted and woven fabrics that are sensitive to thermal energy, such as wool. These fabrics may undergo shrinkage or expansion during wet processing, finishing, steaming or dry cleaning.
The main purpose of the ISO 3005 standard is to measure the dimensional change of knitted fabric after its exposure to saturated steam, without the involvement of any mechanical pressure or wetting.
This standard focuses only on shrinkage due to steam; it does not address other parameters. To perform this test, we will cut the fabric specimen 300 mm × 50 mm, and then place it into the controlled environmental conditions for preconditioning up to 4 – 8 hours, before steaming.
We will mark the point 250 mm apart from the center of the specimen in warp and weft directions. After that, the fabric is passed through saturated steam and then again placed for cooling. Now we will take the measurements for dimensional changes in percentage.
Why Steam-Induced Shrinkage Matters in Fabric Performance?
Why Steam-Induced Shrinkage Matters in Fabric Performance?Steam-induced shrinkage is an important factor because in the textile manufacturing process and in the real world, the fabric has to face steam in different methods, such as finishing, ironing, and laundering.
So, in such cases, the steam-induced shrinkage can change the garment’s dimensions. If a fabric does not shrink on washing, then it’s not the guarantee that it will retain its dimensions after steaming.
Because steam has heat and moisture content, which can release the yarn’s internal tension that is created during spinning, weaving, knitting or pre-heat setting, the relaxation of yarn causes a reduction in the fabric’s length or width.
The measurement of steam-induced shrinkage helps the textile manufacturers to control this issue by applying special finishes and mechanical treatments.
ISO 3005:1978 standard gives the guidance on measuring the shrinkage of fabrics induced by steam without any mechanical pressure.
Step by Step Process of ISO 3005 Testing
Specimen Cutting, Marking, and Conditioning
The fabric specimen is cut within the size of (300 L × 50 W) mm, and it must be cut at least 150 mm away from the selvedges. It helps avoid distractions caused by edge effects. After that, the specimen is marked on both sides, warp and weft, commonly 250 mm apart from the center of the specimen.
These dimensions will be measured again after the steaming, and then we will note the change in dimensions. For ISO 3005 testing, specimens must be conditioned before steaming to get accurate results.
Specimens for ISO 3005 testing must be cut in a standardized manner to ensure consistent, comparable results.
Importance of Baseline Measurements and Atmospheric Control
All shrinkage tests depend heavily on the measurements before and after the test. So, the baseline measurement is the main point of this test, which confirms the dimensional change in the fabric specimen.
Similarly, in the ISO 3005 test, the 300 × 50 mm fabric specimen is initially marked, then conditioned, and finally passed through saturated steam to measure the dimensional change in the fabric due solely to steam.
The difference between the initial measurement and the after steaming measurement is represented in the form of a percentage, which is called the shrinkage percent due to steam.
ISO 3005 Steam Treatment
ISO 3005 Steam TreatmentPrinciple of the Free Steam Exposure
After cutting and measuring the fabric specimens, we will place these specimens on a fine wire frame or net support separately. Now we will put these sample assemblies into the steam chamber.
The steam is produced at a constant rate in the tester, approximately 70 g/min, and it flows inside the chamber from the specimen’s back side to the front side.
According to the ISO 3005 test, in the dimensional change tester for steaming, we will only focus on the dimensional changes in the fabric specimen after steaming; there is no application of vacuum or mechanical pressure inside the tester.
In this way, the ISO 3005 standard excludes the effects of felting, consolidation, pressing, or ironing. After removing the specimens from the steaming tester, we will keep the specimens on the frame until they cool to avoid sudden cooling-related distractions.
The frame will keep the specimen in a stretched position and will not allow the specimen to undergo uneven shrinkage due to variation in room temperature. As the sample cools, we will take the measurements again to calculate the shrinkage percentage due to the steaming effect.
Timing, Repetition and Measurement Procedures in Real Lab Work
In practice, for the determination of dimensional changes in a woven fabric specimen induced by steam, we may give three successive steam exposures to ensure uniform steam action. Test completes after steaming, cooling and re-measurement of dimensional changes.
We can calculate the shrinkage percentage due to steam action through the following formula.
Dimensional Change (%) = Final length – Initial length × 100
Initial length
After steaming, the final length is usually shorter than the initial length, so a negative value indicates the shrinkage percentage. Sometimes, its final length may increase due to expansion, but it happens in rare cases due to the expansion of internal yarns.
To get reliable results, we will check 04 specimens from the warp side and 4 specimens from the weft side, to determine the potential anisotropy in shrinkage behavior.
Conclusion
The ISO 3005 shrinkage test to steaming is specifically designed for knitted and woven fabrics that are sensitive to thermal energy, such as wool. These fabrics may undergo shrinkage or expansion during wet processing, finishing, steaming or dry cleaning.
This standard focuses only on shrinkage due to steam; it does not address other parameters. In ISO 3005 test, the fabric specimen 300 × 50 mm fabric specimen is initially marked, then conditioned before steaming and after that it passed through saturated steam to measure the dimensional change in fabric just only due to steam.