Purpose- What is the functional objective of the awning: shading, weather protection, identification, or aesthetics?
Style, Configuration, Color- most awnings and canopies of fabric are stretched over and secured to a fixed metal frame that is secured by laces, staples or screws. These frames may be welded, bolted or otherwise connected. Other awnings and canopies that consist of individual fabric panels can be stapled to a groove in the face of an extruded aluminum, fixed-frame element. Still other awnings and canopies consist of rollers and lateral arms that can be retracted manually or automatically.
Size and Fit- The size of an awning is determined by its length, width and projection from the building to which it is attached. Other aspects of size include clear height, rise of roof and post or rafter spacing. These features are usually important to those involved in the planning and review process.
The fit of an awning is determined by the interfacing of its frame with other connecting structures. In the case of a building, it is important to coordinate the appropriate parts of the awning frame with structural members in the building so that loads are transmitted properly.
Economy- The economy most directly affects customers and awning contractors. It is clear that an awning system should not have to meet the same code requirements as a high-rise building. However, in most cases, a code does strictly apply. In rare cases when it is not expressly required, there is still a moral and legal obligation to install an awning that can withstand any unforeseeable loads. (more on loads)
To develop an economical awning system, the designer must understand how to arrange, size and connect structural members so that the foreseeable loads will be transmitted to its supports while incorporating safety factors, without over engineering the system.
Safety: Egress and Fire- Except in rare cases, this is not a significant issue with modern awning and canopy systems. In most cases, frame materials are non-combustible, and fabrics are flame retardant. However, this point should be ascertained whenever appropriate, such as for enclosed walkway canopies and enclosed patio canopies.
The answer is not necessarily to require fire doors and sprinklers for these systems. But the building official does have the right to design systems that provide an open, safe and quick exit to the outside
Stability- The average designer may have a concept of how beams and posts work structurally. But to design a safe structure, one must fully understand stability issues. A structure comprised of simple beams mounted on the top of simple posts is inherently unstable. This, means that the structure is susceptible to falling down because of the number, arrangement and, method of connection of the members.
Common post and beam structures, such as pole barns, are rendered stable by the addition of siding, roofing, "X"- bracing and fixed cantilevered footings.
Fabric has no in-plane stiffness; therefore, it does not replace, in an awning or canopy, the function that siding or roofing performs as in a pole barn. This in-plane stiffness, which is instrumental to the development of stability, can usually be supplied by triangulation of structure members.
Anchorage more information on Anchorage
•Strength- After a stable configuration has been established for an awning design frame, members should be chosen for strength consistent with the amount and type of stress imposed on them. The most common types of stress are tension, compression, bending and shear.
A common misconception about awnings is that they are safe as long as they don’t fall down. All code and engineering standards have long required that a safe design use members that 1.67 to 2 times stronger than the yield strength required to satisfy the actual design stress. The yield strength is the strength at which the material no longer fully recovers to its original shape when load is removed; the yield strength is usually significantly lower than the ultimate strength. Thus, it can be immediately recognized that a "safe" structure is stressed well below its breaking strength when it is exposed to its maximum design load.
•Drainage and Ponding- Provisions must be made to drain water off an awning or canopy. Fundamentally, this involves establishing a steep enough pitch, properly spaced bows or rafters, as well as maintaining a taut fabric, so that draining water or melting snow cannot cause the fabric to sag and collect water on the surface. Lack of proper attention to this detail can result in potentially large gravity forces on the frame and anchors.
Graphics- The overall success of a commercial awning may hinge on the design of its graphics. Local codes and ordinances may dictate the size and other characteristics of this feature.
Fixed vs. Moveable- A Fixed awning’s frame cannot be deployed from a stowed position and vise versa. A moveable awning can be stowed against the building to which it is attached. The standard lateral arm/ retractable awnings and horizontal bow awnings are examples of a moveable awning.1
"Have had a lot of compliments on the awning. It really dresses up a plain building. Keeps it much cooler."
-Michigan Implement
The benefits of awnings go far beyond aesthetic appeal. Awnings can enhance the look of an ordinary home or business through adding shape, dimension and color. They offer energy saving benefits as well as protect furniture, floors and carpets from fading caused by harsh sunrays.
You can actually feel the energy saving benefits. In a typical home, more energy is lost through glass doors and windows than through any other construction element. In fact, on a hot day, more energy comes through one square foot of glass than through an entire insulated wall. Solar radiation through glass is responsible for approximately 20 percent of the loan on an air conditioner. Window films and lightly tinted glass effectively reduce heat gain, as well as glare. Properly designed awnings accomplish the same purpose and substantially increase energy saved over the film and tinted glass alternatives. In studies by the American Society of Heating and Air conditioning engineers, during the period of the day when the sun shines directly on southern facing windows, a fabric awning reduces heat gain by 55 to 65 percent. For western exposure, the reduction in heat gain is 72 to 77 percent.
If you are considering an addition to your home, a canopy over your deck or patio offers a long-term solution to needed space at a lower cost. Your deck will be shaded from the hot sun rays as well as provide outdoor protection during a rainy day for your entire family.
Style-
It’s important to select a style that will accommodate how much the sun penetrates the windows. For northern and southern exposure, sides may need to be added to the awnings for additional protection. For eastern and western facing windows, less protection is necessary. Seasons will also make a difference. In order to take advantage of the suns warmth, some awnings are designed to roll up and out of the way. Further, frames can be designed to accommodate casement windows.
more information on frame styles
Venting-
The awning design creates more air circulation to dissipate heat build up. Select a shape that best suits the windows being protected, as well as the orientation of the windows.
Color-
When Choosing an Awning with a low head clearance, (for instance on a patio umbrella), remember that lighter colors do not trap heat as much as dark colors do.
Design Considerations for Awnings:
