Stacks are the point which the captured/cleaned air exits the building. Like the other parts that make up a corrosive ventilation system, they are engineered for the customer's application. We fabricate different types of stacks for each job and take into consideration such things as stack velocity, maintenance and use, and environmental considerations. Some types of stacks we build are no loss stacks, velocity stacks, backdraft stacks, and rain caps. Usually, stacks are made from PVC, but we can build them from CPVC, Polypro or other materials.
Each type of stack has pros and cons depending on the application. Rain caps are the most basic type of stack and consist of an inverted cone suspended over the outlet. They are the least expensive type of stack, but they return the exhausted air downward possibly directing air onto the roof of a building or other equipment. A no loss stack, is fabricated as a tube within a tube configuration separated by thin fins. Because rain and snow don’t fall straight down, it hits the outside tube and runs out through the gap between the tubes. Our engineers determine the proper lengths and diameters to ensure proper operation. You can learn more about the types of stacks we manufacture on our resources page.
The stacks pictured here are very tall to ensure that their discharge is above the roofline of the building. Chicago Plastic Systems designs and installs the proper supports for all the stacks we build.
These are called backdraft stacks. Inside the larger top section is a kind of flapper that rests against a seat when the fan isn't running to prevent rain and snow from entering the stack. When the fan is turned on, the air forces the flaps up for air to escape.
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