Measuring the cover and shade protection factors of synthetic shadecloth

Importance of the Topic

Exposure to solar ultraviolet radiation poses health and material risks. Synthetic shadecloth is widely used in horticulture and as architectural shading to reduce UV exposure. Reliable measurement of its protective performance is essential for human safety, plant growth, and compliance with industry standards.

Study Objectives and Overview

This application note demonstrates a spectrophotometric method for evaluating the cover factor and UV–visible transmission of synthetic shadecloth. Two fabric constructions—a woven green sample and a knitted white sample—were assessed and classified according to the Australian standard AS 4174-1994.

Methodology and Equipment

Instrumentation and software:

• Cary 1/3E UV-Vis spectrophotometer
• Labsphere DRA-CA-30 integrating sphere accessory
• Schott UG 11 ultraviolet filter
• Shadecloth Easy Menu software

Cover factor measurement at 350 nm involved:

1. Zeroing the spectrophotometer with the UG 11 filter.
2. Measuring percent transmission (%T) of five sample replicates, rotating each by 90° for two readings each.
3. Calculating cover factor as 100 minus the average %T.

UV–visible transmission testing from 290 to 770 nm used ten replicates per sample. The software computed:

• Shade factor (100 minus average %T).
• Average UVR transmission (290–400 nm) and percent UV block.
• Average PAR transmission (400–700 nm) relevant to plant growth.

Main Results and Discussion

The woven green sample achieved a cover factor of approximately 87%, a shade factor of 83%, blocked around 89% of UVR, and transmitted 18% of PAR, earning an extra-heavy classification. The knitted white sample showed a cover factor near 51%, shade factor of 41%, UV block of 51%, and PAR transmission of 63%, corresponding to a light category. These findings align with AS 4174 cover factor and color code ranges. The Shadecloth Easy Menu software generated real-time spectral scans and detailed reports, streamlining compliance verification with a reference mesh standard.

Benefits and Practical Applications

Accurate shadecloth evaluation enables:

• Selection of appropriate protective fabrics for nurseries, livestock shelters, public pools, and parks.
• Quality assurance and compliance with national standards.
• Optimization of plant microclimates by balancing UV protection and photosynthetically active radiation.

Future Trends and Potential Applications

Emerging developments may include advanced spectral mapping, smart fabrics with dynamic shading properties, nano-coatings for enhanced UV blocking, and expanded standards to cover diverse environmental conditions.

Conclusion

The described UV–Vis spectrophotometric approach, combined with integrating sphere technology and dedicated software, provides a robust, user-friendly solution for measuring cover factor, UV block, and PAR transmission. This method supports both product development and routine quality control of synthetic shadecloth.

Reference

• Pailthorpe M.T. and Auer P.D. On the %UV shade provided by shade cloth, Australasian Textiles, 11(6):35 (1991).
• Australian Standard AS 4174-1994, Synthetic shadecloth, Appendices A and B.