A niche no more: engineers, interior designers, and architects now use fabric duct systems for air distribution in a variety of facilities. By outlining relevant applications, design parameters, sizing and installation tips and more, our monthly puzzle author spells out the fabric solution for moving air up, down, or across a space

Engineered Systems, Jan, 2005 by Steve Liescheidt

Although the term "duct" is used with fabric air distribution systems, they are actually classified as an "air distribution device" by Underwriters Laboratories and as a "fabric air dispersion product" by the International Code Council (ICC). In this regard, fabric air distribution is performing as a replacement for the supply air devices in a space and the exposed ductwork that these air devices are mounted on.

Applications that require noncondensing duct surfaces, or those requiring lightweight material installations in facilities with lightweight roof construction or non-denting materials of construction are just a few of the applications that have found solutions with fabric duct systems.

ADVANTAGES TO USING FABRIC DUCT

Some of the advantages to using fabric duct systems are that they:

* May be less expensive to install than other air distribution systems;

* May be installed in less time than other air distribution systems;

* Are flexible and not subject to denting;

* May provide more even air distribution than traditional grilles and diffusers;

* Are colorful and aesthetically pleasing;

* Are easily cleaned with minimal system or process downtime;

* Are essentially self-balancing;

* Are easily shipped in boxes;

* Provide lower shipping and handling cost due to less weight;

* Provide quiet air delivery;

* Have multiple fabric material options to fit essentially any application;

* Come in a variety of shapes and sizes with optional fittings;

* Provide draft-free air distribution;

* Are not subject to condensation on the "duct" surface;

* Have some manufacturers' certification as "green" product for LEED[TM] certified facility designs;

* Are a soft fabric that provides an additional acoustical absorptive surface in the space;

* May be used for spot cooling;

* Can handle a wide range of pressures;

* May be used in VAV as well as constant volume systems.

INSTALLATIONS/APPLICATIONS

The use of fabric duct systems is generally limited to exposed applications and not allowed by code for concealed applications. However, there may be some areas such as crawl spaces and other nonoccupied concealed spaces where fabric air distribution systems may be allowed. Consult the local building code AHJ in these applications.

FOOD PROCESSING AND MANUFACTURING

Several types of food processing industries could be considered good candidates for fabric duct installations. Some examples of successful installations include such industries as meat packing, dairies, canneries, candy factories, beverage producers, etc. The fabric ducts can be used in both the production and storage areas. One of the key benefits of using fabric ducts in food processing facilities is the ease of cleaning the fabric duct as compared to traditional sheet metal duct. When properly designed and installed, the fabric duct can be cleaned faster and allow for shorter production downtimes during the cleaning periods. Any large open facility where ventilation is needed is a good candidate for fabric air distribution. Providing forced supply air as opposed to using exhaust fans may often be a more effective way to provide proper ventilation in these types of large spaces.

NATATORIUMS / GYMNASIUMS

Fabric ducts have found a major market in buildings with enclosed pools and natatoriums. These spaces have high humidity and chlorine in the air that can cause corrosion in some steel duct installations. Fabric ducts can offer a cost-effective, noncondensing, corrosion-proof solution to these air distribution challenges.

Gymnasiums have also become very popular places for fabric ducts. Fabric ducts don't dent when a ball is kicked into the duct. Fabric ducts provide a soft material to help absorb noise from the yelling and screaming in a gymnasium during a sporting event. Fabric ducts can be used to provide custom colors, logos, or advertising in a fun yet functional way. Fabric ducts are lightweight compared to steel ducts and thereby don't impose as much weight on the structure. Fabric ducts can be installed quickly in existing facilities where ventilation needs to be added or improved.

AUDITORIUMS / SPORTS ARENAS / CONVENTION CENTERS

Public facilities like major auditoriums, arenas, indoor stadiums, and convention centers generally need low initial first cost construction methods when tax dollars are on the line. Fabric duct can answer this challenge.

LARGE PUBLIC SPACES

Large public spaces like casinos, concert/music halls, museums, and convention center meeting rooms typically require air distribution from high ceilings. Fabric air distribution systems can accomplish this in a manner that is not only effective for air distribution but also adds another dimension to the interior design of the space. Signage and advertising can be provided on the fabric ducts to help inform the public of areas of interest while in these facilities.

Likewise, facilities like hospitals and places of worship have spaces that architects attempt to make aesthetically pleasing. The use of fabric ducts provides a softer look, provides a quiet method of air distribution, and provides good air coverage in the space.