AATCC 127 Hydrostatic Pressure Head Test is applied to the textile to determine the fabric’s water repellency. This test is done under specified pressure to determine the hydrostatic limit of the fabric.
What is Hydrostatic Head Testing?
“Hydrostatic Head testing is done to evaluate the fabric’s water resistance capability under specific water pressure.” This test is known as AATCC 127.
What is the purpose of the AATCC 127 Test?
AATCC 127 result is used to check whether the fabric is waterproof.
For example, tourists take tents in mountain areas. If the tent’s water resistance is good, then it can survive heavy rain, and people can stay inside safely. Otherwise, in case of leakage, the tent fails to prevent the tourists in the camping from raining.
How does AATCC 127 relate to fabric performance?
Hydrostatic head test relates to fabric performance in the following ways:
1. Water Proofness
It measures the fabric’s resistance to water. It gives the value to how much water pressure your fabric can withstand without leaking.
2. Water Resistance Time
It examines the fabric retention time with water and how much time the specimen can withstand under water pressure.
3. Fabric Durability to water
This test shows the durability of fabric when water is used under pressure.
4. Seams Integrity
It helps to estimate the strength of seams and stitching in wet conditions.
5. Coating Material Effectiveness
It gives an idea about the efficiency and effectiveness of coating material to make fabric water-repellent.
6. Material Selection
This test helps us to choose the best materials to withstand the worst environmental conditions.
Importance of hydrostatic head testing in quality control
According to the AATCC 127 test method, hydrostatic test equipment determines textile water repellency.
“Hydrostatic Head testing is the main parameter to check the fabric quality under worse rainy environmental conditions. It helps to understand the behavior of garments when they are in contact with water under a certain pressure.”
Units of Measurement
The water column height of the hydrostatic tester is measured in mm, cm, or inches. The pressure of water that applies to the textile sample is taken in Pa and KPa.
Hydrostatic Head Test Procedure
Hydrostatic Head Test Equipment and Material
Suppose we are taking AATCC 127 Hydrostatic Head Tester YG (B) 812Q equipment by Darong Company China.
This Equipment has these major parts for performing the test.
1) Hydrostatic Head Tester
There is a sealed head for clamping the specimen tightly during the test when water pressure is applied. Hydrostatic Head Tester may be manual or automatic and is operated by the button. It depends on your choice and machine model.
2) Fresh Distilled Water
Freshly Distilled water of grade 3 should be used for this test. We need to use water that meets the requirement of ISO 3696.
Why is it important to use Grade 3 water or follow ISO 3696?
Water temperature affects the hydrostatic values. If the water temperature is slightly high, hydrostatic values would be reduced.
The water and room temperature should be 20 + 2 OR 25 + 2.
3) Direct pressurizing
AATCC 127 Hydrostatic Head Tester YG (B) 812Q has the direct pressurizing option.
The water column is uplifted by just clicking on the direct pressurizing button. Here, pressure can be increased or decreased by just putting the desired value.
Otherwise, manual instruments must attach an air compressor to an instrument to give uplift pressure for water. That air compressor has a manual gauge bar to change the pressure.
Relevant Standards
Woven Fabric
- GB/T4744 (China national standard drafting enterprise)
- FZ/T01004
- AATCC 208* + AATCC 127 2018
- JIS L1099 + JIS L 1092
- DIN 53886
- JIS L1092
- BS7209
- EN ISO 811
Non – Woven Fabric
- NWSP 080.6R0
- EN ISO 9073-16
- ISO 1420
- BS EN ISO 811:2018
AATCC 127 Test method step-by-step
Here is a complete step-by-step guide on how to perform AATCC test method 127.
Sample Preparation
1. Cut fabric sample in square shape 180 mm × 180 mm. It can be circular, but its width and height should be a minimum of 180mm.
2. The sample should be straight and wrinkle-free. There should be no crease or fold on it.
Mounting
1. Place the sample under the clamping head. There would be water under the sample. Place carefully and try to straighten the sample without bending or folding.
2. Ensure the sample is clamping tightly. There should be no leakage at the ends of the clamping head.
Testing
Here is the answer: how do you calculate Hydrostatic Head Pressure?
1. Turn on the power switch of hydrostatic head tester YG(B)812Q
2. Click Add Water; press the pause button when the water is full
3. Click Testing Method and Function, choose direct pressurizing
Hydrostatic Head Tester Testing Method and Function4. Now, the testing interface will be open. Here press set
5. Set testing parameters, raise rate 6KPa/min and click confirm
Hydrostatic Head Tester Pressure Rise to 6KPa6. After setting testing parameters, take a testing sample
7. Sample size should be 180 mm × 180 mm
Hydrostatic Head Tester Sample Size8. Put the sample in the Head Tester under the clamp and press Down
9. Back to zero. Press start
10. Wait until 03 water seepage appears on the sample surface
Hydrostatic Head Tester Sample Water Seepage11. Press stop, we get the 1st hydrostatic head rating on the screen
12. Similarly, take five samples and perform this test repeatedly to take the average value
13. The final average value would be the result of the hydrostatic pressure resistance of a sample
Ensuring compliance with AATCC 127
1. Equipment should be cleaned and calibrated before testing
2. Use freshly distilled water grade 3 to avoid any contamination on the sample during testing
3. Water and room temperature should be maintained around 20 + 2 or 25 + 2
4. Repeat the sample testing 3 to 5 times, and then take the average value to get more accurate results.
5. Follow lab standard operating procedures for safety.
Factors Affecting Results
Fabric Properties
Fabric properties directly depend upon the water resistance. Thick, dense, and tight weave fabrics tend to resist water more.
Temperature
If water or room temperature is high, water penetration would be easy, and hydrostatic values would be reduced. Ensure the water and room temperature 20 + 2
If the temperature is too low, then water penetration will be harder and hydrostatic values will be increased.
Humidity
High humidity can affect the water absorption. So, the humidity level should be controlled.
Interpreting Test Results
The average value of 5 tests would be considered the final result of the fabric hydrostatic pressure head. It’s a good way to show all the table readings, representing the test trend and accuracy.
Understanding the Meaning of Test Results
Data from 5 repeated tests clearly shows how fabric behaves under water pressure. Finally, we can summarize the test result using lab remarks.
How to Ensure Consistent and Reliable Results
Calibrated Equipment, following SOPs, controlling environmental conditions, being a responsible operator, and repeated sampling to take average values help get consistent and reliable results.
Common Issues and Trouble Shootings
1. Leakage of water is a common issue. It can be removed by tightening the head correctly and checking the water seals.
2. Temperature and humidity affect the test results. This issue can be resolved by controlling the lab’s environmental conditions.
3. Fabric sample preparation errors can lead to disturbing the values. The sample should be prepared carefully. It should be clean, straight, and not contaminated or folded.
Tips for Accurate and Repeatable Testing
1. Calibrated Equipment
2. Controlled environmental conditions
3. Proper fabric sample preparation
4. Use fresh distilled water
5. Gradually raise the water column pressure
6. Take the average of at least five tests
Importance of Proper Maintenance and Calibration of Equipment
Proper Maintenance and Calibration of Equipment enhances the equipment life, gives accurate results, and reduces the chance of errors. It also reduces the repair factor for Equipment.
Application of Fabric Hydrostatic Head Pressure Tester
Hydrostatic Head Pressure Tester is widely used in various industries to check the fabric’s resistance to water.
1. It is usually used in Textile and Apparel, Industrial Fabrics, Medical and Healthcare, and Outdoor and Sports Equipment industries.
2. It tests the filtration and separation material, geosynthetics, and construction material.
3. Departments of Research and Development, Quality Control and Assurance, Material Selection and Development, Product Design and Optimization also used this Equipment
Conclusion
“AATCC 127 Hydrostatic pressure is the main test to check the fabric quality under worse rainy environmental conditions. It helps to understand the behavior of garments when in contact with water with a certain pressure.”
FAQs
1) What is Hydrostatic Pressure Head Testing?
Hydrostatic Head testing evaluates the fabric’s water resistance capability under specific pressure.
2) What is the AATCC 127 test?
AATCC 127 test is used to check whether the fabric is waterproof.
3) What is hydrostatic head meaning?
It means how much water pressure a fabric can hold without leaking. It is examined by water column height, which is measured in mm.
4) What are the main parts of a hydrostatic head tester?
The main parts of the Equipment are the hydrostatic head and water pressure column.
5) What is the common issue during hydrostatic head testing?
Leakage of water is a common issue. It can be removed by tightening the head correctly and checking the water seals.
6) How much hydrostatic head is used for fabrics?
Usually, a waterproof jacket has a hydrostatic head 1000mm. For tents, a 4000mm hydrostatic head is considered. A 20000 hydrostatic head is applied to marine fabrics.
Related Resources
AATCC 127 Hydrostatic Head Tester YG(B)812Q