System Description

NYSAN EXTERNAL ROLLER SHADES MOTORIZED

As with venetian blinds, fabric roller shade systems can be retracted when not required. They provide less light and solar control than a venetian blind, however, the extent of the performance being dependent upon the fabric used.

A wide range of fabrics is available, the most effective ones being manufactured from PVC coated fiber glass yarn. These fabrics are specifically produced for external use and are:

• Color fast to light
• Resistant to the elements (rain, temperature variations, direct sunlight etc.)
• Dimensionally stable
• Rot resistant

Additionally, the fabrics (in particular due to the fiber glass yarn) have good fire properties and can meet many international standards, including M1 (France), B1 (Germany) and ASTM E84-97A Class A (USA).

The performance of a fabric is measured in a number of ways, including:

• Transparency or openness factor (OF)
• Visible Transmittance (Tv)
• Shading Coefficient (Sc)
• Solar transmittance (Ts)
• Solar reflectance (Rs), and
• Solar absorptance (As)

Considering each of these:

The Openness factor (OF) measures the proportion of holes in the fabric and is independent of the color of the fabric. This factor gives an indication of the degree of visibility through the fabric – a low OF indicates that the fabric has a very close weave.

The Visible Transmittance (Tv) measures the percentage of visible light coming through a fabric. A low figure indicates an efficient fabric which provides a high level of light control. Tv is dependent upon color – the lighter the fabric the higher the level of Tv, for the same fabric weave and openness factor.

The Shading Coefficient (Sc) measure the efficiency of the fabric in combination with the glazing. Further details are given in the section on Effectiveness of shading systems.

The Solar Properties (Ts, Rs and As) measure the solar performance of the fabric:
Ts is the amount of solar energy transmitted through the fabricRs is the amount of solar energy reflected by the fabric, andAs is the amount of solar energy absorbed by the fabric.Ts + Rs + As is always equal to 100%.

The solar properties of a fabric will vary significantly dependent upon color. Considering a box-weave fabric called Natté 450, the solar performance by color is as follows:

Installed externally, dark fabrics are therefore more effective as the solar transmittance is lower and as a result the shading coefficient is lower. Additionally, as the light transmittance is lower, glare control will be greater and visibility through the fabric will in fact be greater.

The appropriate type of fabric shading system will be dependent upon the specific project requirements. Gravity drop roller shades, drop arm awnings and markisolettes are all designed for vertical glazing, whereas façade awnings can be installed on either vertical or inclined glazing or a combination of the two. Drop arm awnings and markisolettes can allow for outward opening windows whilst still providing protection – this is not possible with gravity drop roller shades and façade awnings.

In all cases, the external fabric shading system will comprise the following elements:

• Headrail to protect the motor and the fabric in the raised position
• Roller tube incorporating the motor and onto which the fabric shade is attached. The roller tube runs in bearings which are mounted onto the end caps of the headrail
• Bottom rail
• Side guides. These can be manufactured from perlon or PVC coated stainless steel, or alternatively from extruded aluminum.
• Brackets to fix both the headrail and the side guides to the façade.

For additional information contact Nysan at 403.204.8675