Textile Notes related to fiber, yarn, fabric knowledge, spinning, weaving, processing, projects, knitting, Indian Traditional Textiles and denim manufacturing
Monday, 1 October 2012
Fabric Losses during Spreading
What is FPT ( Fabric Package/Performance Test) and GPT ( Garment Package/Performance Test)
What is FPT and GPT in Garment and Fabric Testing?
In garment manufacturing, the product is not judged only by how it looks at the time of shipment. A garment may look perfect on the inspection table, but the real test begins when the customer starts using and washing it. This is where FPT and GPT become important.
FPT means Fabric Package Test or Fabric Performance Test. It checks whether the fabric is suitable for garment production. GPT means Garment Package Test or Garment Performance Test. It checks whether the finished garment will perform satisfactorily after washing and use.
FPT asks: “Is this fabric technically fit for production?”
GPT asks: “Will the finished garment behave properly after customer use?”
Why are FPT and GPT Required?
In apparel production, many problems are not visible in the beginning. A fabric may shrink after washing. A seam may open. A dark colour may bleed. A print may fade. A button may come off. A zipper may not move freely after wash. These failures may not be noticed during normal visual inspection, but they can lead to customer complaints, returns and brand damage.
FPT and GPT are therefore preventive tests. They help the buyer, manufacturer and merchandiser identify risk before bulk production or before shipment.
What is GPT: Garment Package / Performance Test?
GPT is performed on finished garments. The main purpose is to check how the garment performs after washing as per the care label. The test tries to simulate the way a customer will wash and use the garment at home.
Generally, three identical garments are required for GPT:
- One garment for dimensional stability — to check shrinkage or growth after washing.
- One garment for appearance evaluation — to observe change in look, handle, pilling, puckering, twisting or other defects.
- One garment for seam slippage and seam strength — to check whether seams remain secure after washing and stress.
For button pull testing, a mock placket or mock patti may be prepared with buttons attached to it. This helps test button attachment strength without depending only on the garment sample.
Important Points Checked in GPT
- Dimensional stability: Does the garment shrink or grow after washing?
- Appearance after wash: Does the garment still look acceptable?
- Puckering: Are seams or panels showing unwanted wrinkling?
- Pilling: Are small fibre balls appearing on the surface?
- Seam strength: Are seams strong enough for normal use?
- Seam slippage: Are yarns slipping near the seam?
- Zipper movement: Does the zipper still move freely?
- Button attachment: Are buttons securely attached?
- Colour change: Has the garment faded after washing?
- Staining: Has colour transferred to other parts or adjacent fabrics?
GPT is not only a laboratory formality. It tells whether the customer will receive a garment that remains wearable and presentable after washing.
How Many Washes are Done in GPT?
The number of washes depends on the buyer’s requirement, product type and market. In many cases, GPT may be done after one wash or after three washes.
A general industry observation is that some buyers require testing after one wash, while others may ask for three washes. The important point is that the washing method should follow the care label and the buyer’s approved test protocol.
For example, if the care label says machine wash at 40°C, the garment should be tested according to that instruction. If the garment is labelled dry clean only, the test route will be different.
What is FPT: Fabric Package / Performance Test?
FPT is performed on fabric before or during the approval stage. It helps decide whether the fabric is technically suitable for making garments. If the fabric itself is weak, unstable or colourfastness is poor, then the finished garment will also carry those risks.
Usually, around 3 metres of fabric may be required for a complete fabric testing package, although the exact requirement depends on the laboratory and buyer protocol.
Common Tests Included in FPT
| Test | What it Checks | Why it Matters |
|---|---|---|
| Yarn Count | Fineness or coarseness of yarn used in the fabric | Helps confirm whether the fabric matches the approved specification |
| Construction | Ends per inch and picks per inch, or loop structure in knits | Affects weight, strength, cover, handle and appearance |
| GSM | Grams per square metre | Indicates fabric weight and helps check consistency |
| Fibre Composition | Actual fibre content such as cotton, polyester, viscose, silk, wool etc. | Important for labelling, costing, performance and legal compliance |
| Tensile Strength | Resistance of fabric to breaking under pulling force | Important for durability and end-use performance |
| Tear Strength | Resistance to continuation of a tear | Important for garments exposed to stress, abrasion or snagging |
| Colourfastness to Washing | Colour change and staining during washing | Prevents customer complaints related to bleeding and fading |
| Colourfastness to Rubbing | Colour transfer during dry and wet rubbing | Important for dark colours, denim, prints and contrast garments |
| Colourfastness to Perspiration | Effect of acidic and alkaline perspiration on colour | Important for garments worn close to the body |
| Colourfastness to Water | Colour bleeding or staining when fabric is exposed to water | Important for wet handling, washing and rainy conditions |
| Shrinkage | Dimensional change after washing or processing | Critical for garment fit and size stability |
FPT vs GPT: The Main Difference
| Point | FPT | GPT |
|---|---|---|
| Full Form | Fabric Package / Performance Test | Garment Package / Performance Test |
| Stage | Before or during fabric approval | After garment is made |
| Sample | Fabric length, often around 3 metres depending on lab requirement | Finished garments, usually multiple identical pieces |
| Main Focus | Fabric properties | Finished garment behaviour |
| Typical Tests | GSM, construction, fibre content, strength, colourfastness, shrinkage | Shrinkage, appearance, seam strength, seam slippage, button pull, zipper movement |
| Purpose | To approve fabric for production | To approve garment performance before shipment |
Why FPT Alone is Not Enough
A fabric may pass all fabric tests and still create a problem in garment form. This happens because garment performance depends not only on fabric, but also on pattern, sewing thread, seam type, fusing, trims, washing method and finishing.
For example, a fabric may have acceptable shrinkage as a flat fabric, but the finished garment may still twist, pucker or lose shape after washing. This is why GPT is necessary even after FPT approval.
Why GPT Alone is Also Not Enough
If only GPT is done, the problem may be identified too late. By the time the garment is ready, cutting, stitching and finishing costs have already been incurred. If the garment fails at this stage, the loss is much higher.
FPT helps catch fabric-related risks early. GPT confirms whether the garment as a complete product is acceptable.
FPT should be used as an early warning system. GPT should be used as the final confirmation of product performance.
Common Mistakes in Understanding FPT and GPT
- Mistake 1: Thinking that FPT and GPT are the same. They are related, but not the same.
- Mistake 2: Doing GPT only for export orders. Domestic customers also wash and use garments.
- Mistake 3: Ignoring care label conditions during testing.
- Mistake 4: Treating lab testing as paperwork instead of risk control.
- Mistake 5: Not comparing the tested garment with the original unwashed garment.
- Mistake 6: Forgetting trims such as buttons, zippers, fusing and elastic.
Practical Checklist for Merchandisers
Before approving fabric or garments, a merchandiser should ask:
- Has the fabric test report been received and reviewed?
- Is the fabric construction matching the approved specification?
- Is the GSM within tolerance?
- Is fibre composition matching the claim?
- Are colourfastness results acceptable for the garment end use?
- Is shrinkage within buyer tolerance?
- Has the garment been washed according to the care label?
- Is the garment appearance acceptable after wash?
- Are seams, buttons, zippers and trims performing properly?
- Has the report been approved before bulk shipment?
Conclusion
FPT and GPT are two important testing stages in apparel quality control. FPT checks the fabric before it becomes a garment. GPT checks the finished garment after washing and use simulation. Together, they help reduce production risk, customer complaints and product failure.
For a merchandiser, buyer or quality professional, the key lesson is simple: do not look at testing as a formality. Testing is a way of predicting customer experience before the customer actually uses the product.
Research Findings Related to FPT and GPT
The terms FPT and GPT are commonly used in the apparel industry, but research papers usually discuss the individual performance areas covered under these tests, such as shrinkage, dimensional stability, seam strength, colourfastness, pilling, tensile strength and garment durability.
The following research findings help us understand why Fabric Performance Testing and Garment Performance Testing are important in practical apparel quality control.
| Research Area / Article | One Important Finding | Relevance to FPT / GPT |
|---|---|---|
|
Physical garment durability Guo et al., “A framework for measuring physical garment durability” |
Garment durability is difficult to measure through one simple test because real-life garment use involves washing, wearing, rubbing, stretching and repeated handling. | This supports the need for GPT, because the finished garment should be tested as a complete product, not only as a fabric sample. |
|
Garment failure causes Cooper et al., “Garment failure causes and solutions” |
Common reasons for garment failure include pilling and colour fading, both of which affect the customer’s perception of quality. | This supports including appearance change, pilling and colour change checks in GPT, and colourfastness checks in FPT. |
|
Seam performance of knitted fabrics Bansal, Sikka and Choudhary, “Seam performance of knitted fabrics based on seam strength and seam efficiency” |
Seam strength depends on fabric type, seam angle, needle size and construction. Cotton and cotton/lycra knitted fabrics showed lower seam strength than polyester/cotton fabrics. | This is directly relevant to GPT, because a garment may fail at the seam even when the fabric itself appears acceptable. |
|
Dimensional stability after domestic washing Longurova et al., “The effect of fabric structure parameters on dimensional stability after domestic washing” |
In 100% cotton woven fabrics, shrinkage occurred after domestic washing, and shrinkage was influenced by fabric structure, cover factor and weave factor. | This is relevant to both FPT and GPT. FPT helps predict fabric shrinkage, while GPT confirms whether the finished garment still maintains fit after washing. |
|
Seam strength prediction in denim jeans Manzoor et al., “Machine learning prediction model for seam strength of five-pocket denim jeans” |
Seam strength in denim jeans was strongly influenced by thread count, stitch density, fabric weight and seam type. | This supports GPT because garment durability depends not only on fabric, but also on stitching parameters and seam construction. |
FPT should not be treated as only GSM, fibre content and construction testing. It should also help predict shrinkage, colourfastness, strength and fabric stability. GPT goes one step further by checking whether the complete garment system — fabric, seam, thread, trims and washing — will perform satisfactorily for the customer.
General Disclaimer
This article is intended for educational and general textile understanding only. Testing requirements, sample size, wash cycles, acceptance criteria and test methods may vary by buyer, product category, country, laboratory and applicable standards. For commercial approval, always refer to the latest buyer manual, applicable ISO/AATCC/ASTM/BIS standards and accredited laboratory reports.