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Different types of duct support hangers are used to secure heating and air conditioning ducts to surrounding walls or ceilings. Installers fasten each duct support to the ceiling using a bolt, screw, or other fastener, then secure the duct within the support hanger. Some ducts simply rest inside of the support, while others include integral hangers for easy installation. Duct supports must be installed at carefully chosen intervals to ensure adequate support and reduce the risk of failure.
Installers can choose from three basic varieties of duct support, depending on the application at hand. Trapeze hangers support the duct on three sides, and typically consist of a metal strut supported by two vertical rods. The strut may be lined with neoprene or some other type of foam to protect the duct from damage and reduce noise and vibration.
Strap hangers are basic strips of metal that wrap around the duct, allowing installers to secure ducts to a wall or ceiling. Single-rod straps wrap all the way around the duct, with a threaded metal rod used to anchor the strap to the ceiling. Double-rod straps consist of two separate metal straps that each wrap halfway around the duct. A threaded metal rod supports the hanger at each point where the straps intersect.
Steel cables represent the simplest type of duct support hanger. Installers fasten a metal cable to the ceiling, then loop the cable around the duct every few feet along its length. Many fabric or plastic ducts include built-in steel cable hangers.
Builders and engineers must consider a number of factors when comparing duct support options. They must choose among steel, plastic, and other materials based on the needs of the application. For example, galvanized duct supports may be required in moisture-prone areas, while thermoplastic units may hold up better against some chemicals in an industrial setting. The material's ability to resist fire and high temperatures should also be taken into account.
Each duct support must be sized carefully based on the size, shape, and weight of each duct. Engineers also consider the force created by air flow through the system, as well as any external factors that may add force to the hangers. The length and width of each hanger depends on total load as well as the design and construction of the wall or ceiling. Finally, some duct hangers are also designed to provide easy access for maintenance and removal over time as needed.
I got a job once doing the demolition work inside of a big old factory. I was basically hired to tear down everything, walls, ceilings, toilets and especially ducts. They wanted the placed gutted so that they could do a complete rehab.
I remember that I was working with a partner and we got the goofy idea of rigging up a swing off of one of the really high up ducts. We figured that once we put our body weight on it it would fall right down (hopefully not on top of us).
After we finally got the rope in place my buddy took a big running start and proceeded to swing all over the factory. That duct
had incredible supports because it held both of our body weights as we swung on that thing all day. It eventually took 5 r 6 of us to pull it down. That part was a pain in the neck but swinging on it was a lot of fun. I was almost sad to see it come down
This article mentions the most common kinds of duct support, but there are a number of building that have designed their own custom supports.
The reason they do this is that exposed ducts are a common feature of interior design. When treated artfully they can provide striking blocks of color and form to interior spaces. Part of the design process involves creating custom supports that match the design scheme in play elsewhere.
These custom supports can range from the spare and simple to the outrageous but their variety is amazing. A clever architect and designer will make the most of these features rather than relying on what is easiest or cheapest to get.
I've been doing HVAC work for a long time but I will never forget something that I saw in an old factory I serviced right at the start of my career.
The maintenance man took me down to the basement where the boiler was. he said they had been having problems for a few weeks. When I went down there and started poking around I noticed that all of the ducts were held up by colorful plastic Mardi Gras beads. They were pretty old and dusty by the time I saw them but they were still unmistakeable.
I asked the maintenance man who had rigged it up that way and he just shrugged. He didn't seem to think it was particularly unusual. I have seen some jobs rigged up in goofy ways but never anything like that. Its like they went out of their way to be weird.
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