There are three things, which can affect the final outcome of an installation.
1) Fiber Content
2) Weave
3) Weight

FIBER CONTENT: The long-term stability of an installation will be greatly affected by the fiber content of the fabric chosen. Fabrics which are made of or are a blend with rayon, viscose or nylon should almost never be used in any type of stretch installation. They are all hydrophilic (readily absorb moisture from the atmosphere). This will cause sagging and rippling. Neither rayon nor viscose has a memory, which means that they will sag and never tighten up again without being re-stretched, which can happen repeatedly. Nylon will sag then tighten back up, but when it sags it becomes very apparent. If it is re-stretched it will still tighten up and may shrink so it is to short. Certain other fabrics have these qualities, but the affect is not apparent, in other words they have enough stretch and self-healing properties that the change in moisture content does not become visibly apparent.

Three important things to do that will help avoid problems such as these are:

1. Advise your customer if they have made a bad fabric selection.
   
2. Never install the fabric until the space has been enclosed, is weather-tight and the ambient temperature and humidity levels are near those to be used during final occupancy.
   
3. If in doubt, get a large sample from the fabric manufacturer and put up a sam- ple panel for a week to see the results.

WEAVE: There are three basic weaves used in the construction of fabrics; plain, twill and satin.

Plain: Each warp yarn passes over and then under the weft yarns. This results in no particular surface pattern or texture, making plain weaves ideal for printed fabrics. Plain weaves wear well but tend to wrinkle.

Twill: Each warp yarn passes over then under the weft yarns as in plain weave, but the sequence is started slightly higher (or lower) on each successive yarn. A diagonal pattern is created.

Satin: Each yarn floats over at least four yarns creating a smooth, lustrous sur face. Of the three types of weaves, satin is the most suspect. The weave of satin creates a fabric, which will not stretch on the weft. Therefore, it is not self heal- ing. If something touches it or leans against it the result is a dimple in the finish which has to be brushed out. Satin woven fabrics are also usually very thin, requiring a knit or pellon backing.

WEIGHT: The weight of the fabric can affect an installation in two ways. If a fabric is too thin it may be transparent, allowing the mounting system and core to telegraph through the fabric. A thin fabric also may not properly secure in the locking jaws of the plastic extrusion. We recommend the use of a knit backing, acrylic backing or stretching a liner fabric before hand, depending on the circumstances. If the fabric is also a satin weave, then the best solution will be a knit backing, as the backing will also give the fabric some dimensional stability. If acoustics are a concern, then we recommend against an acrylic backing as it will block the absorption of some of the sound.

When gathering information about specific fabrics from suppliers, pertinent questions to be asked are:

• Fiber content - including percentages.
• Flame spread and Smoke developed ratings, does the fabric have a Class A or Class 1 rating?
  
• Fabric width.
  
• Is the fabric backed or unbacked? - If backed, with what and can it be ordered unbacked?
  
• Is there a minimum order?
  
• Are there any pattern repeats? - vertical, horizontal.
  
• What is the availability? - most suppliers will put a temporary reserve on the fabric.
  
• Pricing based on bolt yardage - how large are the bolts? (Bolts are usually 50- 60 yards)
  
• Pricing based on cut yardage. (Less than bolts)

BACKINGS: There are three types of backings that are useful for increasing the dimensional stability or the opacity of a fabric.

Knit: Usually cotton, open weave, is good for adding stability and opacity It is necessary to specify a flame resistant backing when ordering. Is very good for backing silks.

Pellon: A nonwoven textile made of natural or man-made fibers bonded together by heat and chemicals. Good for adding stability and opacity.

Acrylic Latex: Latex is applied to the back of the fabric. Good for adding stability. It is usually clear, so it does not affect opacity. Will reduce the amount of sound that passes through the fabric. Many fabrics used for direct apply installa- tions have this backing applied as part of the manufacturing process.

LINERS: Useful with fabrics lacking opacity. Are installed as a separate operation prior to the installation of the finish fabric. Cottons & polyesters - can be purchased with a flame-resistant treatment applied and in widths up to 108 inches.
(Sources: Maharam and Dazian)

FLAMMABILITY: All fabrics should have a Class A or Class 1 flame spread and smoke
developed ratings. This can be achieved in two manners:

1. The fabric will be inherently flameproof:
   
   a. Trevira polyester
   b. Nylon (although not advised for a stretch installation)
   c. Wool
   
   
2. The fabric can be treated with a flame-resistant treatment.
   
   Polymer treatment: Applied through an immersion process and then set with heat. Will cause shrinkage thus requiring up to an additional 5% more fabric than is needed for the project. In some fabrics, there can be a noticeable change in color or stiffness. Will wash out if the fabric is dry cleaned more than 20 times.
   
   Saline treatment: Is less expensive than polymer treatments. Can have a cor- rosive effect on metal. May have a tendency to leach out, discoloring the treated fabric. May increase the fabric's tendency to absorb moisture. If spotted with water, may form white salt rings.

STAIN-RESISTANT TREATMENTS: Will make most fabrics resistant to oil and water based stains. Spray applied during the manufacturing process. Can also be applied in the field after the fabric has been installed. Usually will not effect flame-resistant treatments. Can be easily removed. Are odorless, harmless, and do not effect the Hand of the fabric.
1. Teflon by Du Pont
2. Scotchguard by 3M

GLOSSARY:

HAND: A fabric's tactile qualities, e.g., softness, firmness, drapability, and resiliency.

HYDROPHILIC FIBERS: Fibers that absorb moisture readily, such as rayon.

HYDROPHOBIC FIBERS: Fibers which are normally non absorptive and repel moisture, such as polyester.

OPACITY: The quality or state of being opaque (transparent)(impervious to the passage of light).

THERMOPLASTIC: Plastics that become soft when heated and can be remolded repeatedly without affecting the properties of the plastic.

WARP: Yarns that run lengthwise and parallel to the selvage in woven fabrics.

WEFT: Yarns that run from selvage to selvage at right angles to the warp in woven fabric.

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REFERENCE MATERIALS:

A Dictionary of Textile Terms
Dan River Inc.
1325 Avenue of the Americas
New York, NY 10019
(212) 554-5555

Specifying Interiors Item #JWY 61
Construction Specifications Institute
601 Madison Street
Alexandria, VA. 22314-1791
(703) 684-0465

Fabric For Interiors: A Guide for Architects, Designers, & Consumers
Jack Lenor Larsen
41 East 11th Street
New York, NY 10003-4685
(212) 674-3993

Davison's Textile Blue Book
Davison Publishing Co.
PO Box 12215
Gastonia, NC. 28053
(704) 864-5406

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