What is ‘Shade Factor’ ?
Shade Factor relates to the performance of shadecloth that reflects or absorbs visible and invisible light in the 290nm to 770nm range of the spectrum. Essentially, this is the shade that we can see underneath shadecloth installations on a sunny day.
For example, black has a higher shade factor than yellow. This means that the black shadecloth stops more of the visible light than yellow.
Why is this important?
This allows designers to choose an appropriate level of shade for different applications. Whether this may be a high level of shade for an outdoor play area or a lesser level of shade for plants in a garden centre.
Shade factor may not necessarily relate to Ultra Violet Radiation (UVR) Block. For example a shadecloth that offers a shade factor of 77 may offer a UVR block of 93%. That is, visible light is still allowed to pass through the fabric but the fabric still absorbs an amount of UVR (see Tech Questions – What is UV Block?)
What is ‘Av. % Transmission’ then?
Average Percentage Transmission is the amount of incident visible and invisible light in the 290nm to 770nm range of the spectrum that actually passes through the material of the shade cloth.
What is ‘Cover Factor’?
Cover factor is a scientific measurement of the percentage area of the fabric covered by the yarns and fibre. In other words, the test establishes cover factor by recording a specific amount of light that passes through the gaps in the fabric. The cover factor depends on the construction of the fabric incorporating; yarn density, the type of weave and the profile of the yarn. Cover factor is not a measure of the fabric weight. Nor is it based on fabric weight. A light-weight fabric can still have a high cover factor.
According to the Australian Standard AS 4174 – 1994 Synthetic Shadecloth, cover factor is primarily used to classify the shade cloth into three categories heavy, medium and light.
Does the Cover Factor vary between different brands and types shadecloth?
Yes. This heavily depends on the type of construction and colour of the fabric. Cover factor should be considered with the other test data recorded according to the Australian Standard for Synthetic Shadecloth AS 4174-1994.