Room to grow
October 1, 2007
The average hotel guest probably doesn’t notice it, but fabric ductwork for heating, ventilating and air-conditioning systems is one of the quickest emerging trends in the hospitality construction industry.
Fabric duct, which already commands an estimated 10 percent market share of ductwork in all open-ceiling architecture uses, is increasingly specified at many hotels and in accompanying health clubs, indoor pools, restaurants, convention rooms and common areas.
In the skyrocketing trend of resorts that include indoor water parks, fabric duct has become especially popular. The Kalahari water park resort in Sandusky, Ohio, uses fabric ductwork to distribute air evenly without the chilly drafts sometimes caused by metal ductwork.
Fabric duct is also used in other areas of the hotel, such as arcades, retail spaces and other non-pool areas. In addition to reduced maintenance costs, the construction expenses for the fabric duct were about 20 percent less than if metal ductwork has been used.
Aquatic environments such as indoor pools and water parks are particularly hard on building materials because of the corrosive mixture of humidity and pool chemicals. Metal duct is subject to condensation and often requires protective epoxy coatings and double-insulated walls, which can raise installation, material and maintenance costs.
ReasonsBesides reduced material, installation and maintenance costs, some hotel complexes are using fabric duct for different reasons. At the 10,000-square-foot Mountainside Athletic Club at the Bear Mountain Westin Hotel complex in Victoria, British Columbia, architect Zeigler Partnership Architects and Stantec Consulting wanted an upscale HVAC look that complemented the $3.1 million club’s upscale appearance. The streamlined appearance of premium fabric duct, which has nearly invisible linear diffusers instead of protruding registers and ribbed surfaces of spiral metal duct, was preferred to match the lodgelike club’s slate, wood and natural stone decor.
HVAC designer, Tom Wilson, a principal at Stantec, also specified fabric duct for its linear diffuser functions, which provides a low-airflow velocity. In most athletic clubs, the mechanical engineers specify spiral metal ductwork with larger diffusers. But the drafty, high airflow velocity of these spot diffusers produce a chilling effect on perspiring patrons, especially at the cool 65°F temperature most health clubs prefer.
Specifically, Mountainside’s fabric duct has L-Vents, which include up to 1-inch-diameter perforations factory-designed into a linear pattern the entire length of the duct. With several porosities available, Wilson also chose a material that’s designed to allow 15 percent of the air to flow through the fabric and the remaining 85 percent distributed evenly via the L-Vents. The accomplished air-distribution goal in each room is unnoticeable airflow with no chilling effects or drafts on exercising patrons.
HumidityEven air distribution was important for patrons as well as the glass-and-steel atrium above the pool and spa at the Bolero, a resort in Wildwood, N.J. Fabric duct is strategically placed near the glass to assure dry, warm air from the dehumidifier is spread evenly to eliminate condensation that might impair the panoramic view of the New Jersey shore. In addition, the architect helped make clear vision possible by specifying glass with dividers outside rather than inside that could block airflow to all parts of the glass.
Another fabric duct advantage is its weight, which is approximately 90 percent lighter than metal duct. This can mean lower construction costs because the building isn’t required to support as much of a load. This was the case at the Wilderness Resort in the Wisconsin Dells, Wis., long one of America’s top water park destinations.
One of the country’s largest water-themed resorts, it includes a 68,000-square-foot water park. An expansive, lightweight translucent roof allows the facility to offer tanning even during Wisconsin’s harsh winters.
Fabric duct also saved more than $230,000 in HVAC installation and material costs, according to officials with Kilgust Mechanical Inc. of Madison, Wis., which acted as the design-build mechanical contractor. The fabric duct cut installation time by at least 50 percent for this fast-track project that required transforming an outdoor pool into an indoor facility in time for the winter season.
VersatileBesides weight, fabric duct offers many advantages in design versatility. Choices abound with different “throws,” the distance the air can be distributed; fabric porosity and the amount of air allowed to flow through the fabric; colors; and even shapes, such as the popular half-round “D-shape,” which is mostly used in areas with low clearance, such as suspended ceilings.
The Wilderness added silk-screened advertisements onto its fabric duct. With the many restaurants in the Wisconsin Dells area, the Wilderness put black-lettered logos of the resort’s own spa and three restaurants on the ductwork.
Logos and restaurant names are just the beginning, however. Some fabric duct is now being offered in patterns and custom colors for interior design coordination. For example, some camping equipment retailers have used camouflage patterns. Who knows what architects and interior designers will conceive in the future once they know exposed ductwork plays an important part of any building’s interiors?
The fabric duct industry is also continually designing and adding many new accessories. For example, in response to requests for better balancing, manufacturers are now offering airflow adjusters that are easily zippered into the duct and can be adjusted on-site.
To improve indoor air quality, manufacturers have developed a flexible final filter that zippers in the first section - allowing easy replacement by maintenance crews. This adds even greater air purification beyond the conventional filters of HVAC mechanical equipment. Besides filters, fabric duct offers easy cleaning. Fabric duct can be disassembled in just minutes, commercially laundered, and reassembled by in-house maintenance people.
As more architects discover the aesthetics of fabric duct and consulting engineers realize the obvious functional and cost-saving benefits it offers over metal duct, many expect the category to grow in the hotel industry during the next 10 years.
This article was supplied by Dubuque, Iowa-based DuctSox Corp.