· Seekingtex Technical Team · Technical · 1 min read
Understanding UPF 50+ Sun Protection Fabric Standards
A technical guide to UPF ratings, testing methods, and what to look for when selecting sun protection fabrics.
Ultraviolet Protection Factor (UPF) is the standard measurement for sun-protective textiles. A UPF 50+ rating indicates that the fabric blocks 98% of harmful UV radiation, allowing only 1/50th of UV rays to pass through. This is the highest classification in most international standards including UV Standard 801, ASTM D6603, and AS/NZS 4399.
How UPF Testing Works
UPF testing involves measuring UV transmission through fabric samples using spectrophotometry. Key factors affecting UPF rating include:
- Fiber type: Polyester and nylon naturally absorb more UV than cotton
- Fabric construction: Tighter weaves provide higher protection
- Color: Darker colors typically absorb more UV
- Finishes: UV-absorbing chemical treatments can enhance protection
- Stretch and wetness: Both can reduce effective UPF
Seekingtex UPF 50+ Certification
All Seekingtex sun protection fabrics carry UV Standard 801 certification, the most rigorous international standard for UV-protective textiles. Unlike some standards that test only new, dry fabric, UV Standard 801 tests fabrics under real-world conditions including stretched, wet, and aged states.
For brands developing sun-protective clothing, selecting certified UPF 50+ fabric ensures your products deliver the protection your customers expect and the compliance your quality team requires.
