Complete Guide to Stitch Types
Classification ISO 4915 and the ASCS System
Clear communication ensures product quality and consistency. To referring stitches in particular, you can use two international standard systems: the ISO 4915 standard and the ABC Seams Code System (ASCS).
While both aim to facilitate technical communication, they differ in structure, scope, and application. So… what exactly is each system? Can they be used together? Which one is best for a tech pack?
This question is common among designers, technicians, educators, and development teams. In this article, we’ll explain—using real-life examples—how each system works, when to use them together, and how to avoid costly miscommunications with your supplier or workshop.
ASCS & ISO 4915
What they are, how they relate, and when to use each.
What is the ASCS system?
The ASCS system is an international seam classification system developed to communicate design details in a visual, practical, and consistent way. It is particularly useful in communication between design, development, and manufacturing teams—especially through tech packs.
Each ASCS code identifies a seam type and the stitch(es) required to construct it.
This classification clearly conveys the visual structure of the seam, including stitches, without delving into more technical aspects like the exact stitch formation method.
Examples of stitch types in ASCS: flat, chain, overlock, cover stitch, zigzag
Best used for: technical design, prototyping, visual documentation, multidisciplinary teams.
What is ISO 4915?
ISO 4915 is an international standard first published in 1981 by the International Organization for Standardization (ISO). Its goal was to standardize stitch types globally in response to growing globalization in the textile industry and inconsistencies in stitch terminology and quality control.
This standard classifies stitches by their formation method (how threads interlock and which machinery is used), organized into six main classes.
Best used for: industrial machinery sourcing, high-performance garment QC, audits, certifications.
ASCS vs ISO 4915: What's the difference?
Can they be used together? Yes—and here's the trick.
In most cases, ASCS is sufficient to communicate clearly what seam and stitch type is needed. However, if the exact stitch formation is critical (e.g. for stretch, strength, or removability), it’s wise to complement it with ISO 4915.
“If stitch behaviour is key to the garment’s performance, combining ASCS + ISO 4915 ensures maximum clarity.”
Practical Examples
Example 1: Woven Blouse
- Requirement: clean, simple side seam
- ASCS: C010-1 (French seam with lock stitch)
- ISO 4915: ISO 301 – It is not necessary to specify since this is the default for woven garments.
Example 2: Tech Leggings
- Requirement: elasticity, skin-friendly seams, tear resistance
- ASCS: C120-7 (FS) (Flat seam with four-needle flatlock stitch)
- ISO 4915: Complement with stitch ISO 607 to specify stitch method and performance level.
When should ISO 4915 be included?
- For technical or performance fabrics (e.g. elite sportswear, PPE, corsetry)
- When specific strength or stretch behavior is required
- For industrial sewing machine sourcing or sales
- For audits or technical certifications
Conclusion
Both ISO 4915 and ASCS play vital roles in stitch standardization. Understanding how and when to use each system helps:
- Ensure clear communication with suppliers and workshops
- Prevent costly production errors
- Guarantee consistency, function, and quality in every garment
Summary Chart: When to Use Each System
The key isn’t choosing one over the other, but using the right system at the right time. Both are allies for technical clarity and garment excellence.
Looking for visual references for your tech packs?
Explore ASCS diagrams and codes here
Consulted and Related Sources
- https://www.iso.org/about-us.html
- https://www.astm.org/ABOUT/overview.html
- https://en.wikipedia.org/wiki/International_Organization_for_Standardization
- https://www.iso.org/standard/42918.html
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