Commercial Ventilation Fans

By Author: Oleg Tchetchel
Total Articles: 50
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Almost every building has some type of ventilators to vent hot or contaminated air from the structure. As a rule, this equipment is inadequate for anything more than safeguarding the health of the occupants. In some cases, it does an inadequate job of this. To do a satisfactory job of eliminating excessively hot air, it is usually essential to have powered wall and/or roof exhausters. These fans should also help to control air pressure within the building whether it be negative or positive pressure. The most effective way to incorporate wall or roof exhausters into a system will be discussed below. A large number of buildings use exhaust fans and/or power roof ventilators to exhaust fumes, smoke, dust or other contaminants unavoidable in the operation of the business. As a result, these buildings are frequently under a severe negative pressure. This condition can create problems in many areas of operation. Examples are: (1) reduced efficiency of exhaust systems that are working against each other; (2) down drafts in flues, that may extinguish pilot lights and cause explosions and tire; (3) severe drafts around windows, doors ...
... and other locutions when air seeks to enter the structure. The solution to problems of this kind is usually found in the use of supply fans or "make-up" air ventilators. During the hot weather period, these fans become a valuable source of fresh, cooler, outside air to replace the superheated air being exhausted. If they arc correctly sized and coordinated with the exhaust fans, an effective ventilation system may be achieved.

A work stoppage or strike may occur if the problem of personnel discomfort is unresolved. The benefits from a solution to such a situation are enormous. In plants where there is a high density of employees and many manual operations involved, an improvement in the environment can produce substantial benefits in terms of increased production, reduced errors, and a decline in complaints and absenteeism among employees. In other circumstances, the attentiveness of an audience or student group may be a factor that spells success or failure for the project. There is a CB Blower Fan case history where a high ambient temperature had actually reduced the capacity of a big power turbine. To obtain rated performance by the machine, an improvement in the room ventilation and cooling system was necessary. When this was accomplished, the plant management was amazed to find an equivalent improvement in the efficiency of the employees who were required to work in this same environment with the machine.

If the exhaust and supply air requirements of a building have been carefully engineered and installed, and there continues to be a high instance of worker discomfort, the problem usually relates to the matter of air circulation. Typical examples of worker discomfort are found in areas where exhaust fans are roof mounted and air supply is through windows and wall openings. Air flow is generally from the window opening to the nearest roof exhauster. The cooling effect on the individuals in the area is negligible. To be effective, air flow must be at or near floor level. In this way, occupants obtain maximum benefit from the fresh, cooler air; they receive the added comfort of air circulation over their bodies and they are not adversely affected by the superheated air being exhausted from the building.

A carefully engineered ventilation and cooling system frequently combines several methods of air movement to accomplish the desired results. Exhaust fans, power roof ventilators, supply fans, make-up air units and air circulators may all be utilized. CBC Canada Fan sales engineers with experience and training in the selection and use of this equipment can be consulted for advice in the design of the system and installation of its components. System components, practical limitations and common consideration involved in the design of an American Coolair Breeze Conditioning System are discussed in the following sections.

For additional information please refer to http://www.cbblower.com/coolair.html

Oleg Chechel
Ventilation Equipment Designer
olegsystems@olegsystems.com
CB Blower Co.
http://www.cbblower.com/custserv.html
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