Commuters do not often think of disaster scenarios when they travel through transportation tunnels, but the engineers behind the scenes are acutely aware of just what can go wrong when the proper safety precautions aren’t in place. Whether it’s a tunnel for vehicular traffic, subways, or a train, tunnel dampers are essential for maintaining life safety in the event of an emergency.
In this last installment in our General Industrial Ventilation series, we discuss an industrial building with a Natural Supply/Natural Exhaust ventilation system.
Natural supply/natural exhaust is the simplest but also the most misunderstood method used to ventilate an industrial building.
Everyone knows that warm air rises and this is the driving principle behind this method: create an opening in the side of the building, and then create an opening in the roof of the building, and then the fresh outside air just naturally flows into the building and the warmer inside air just naturally flows out the top of the building.
This month, we cover perhaps the most common method for ventilating an industrial building: natural supply/powered forced exhaust.
Simply, powered exhaust fans are mounted on the roof of the building. The powered roof exhaust fans create a negative pressure condition within the building which allows for the natural draft of fresh outside supply air through any opening around the building perimeter.
Large open loading dock doors, overhead crane doors, or perimeter louvers all provide a way to get fresh outside supply air into the building. Typically, these exterior openings are sized so that the pressure drop vs airflow is very low in order to allow roof exhaust fans to operate very effectively and exhaust large volumes of air.
Last month, we covered powered forced supply/powered forced exhaust in our first installation in the general industrial ventilation series. This month, we are looking at a powered forced supply/natural exhaust ventilation system, which uses motorized supply fans and natural exhaust vents (often called gravity vents).
Typically, supply fans are mounted in the perimeter wall of the building about 8 to 10 feet above the floor with a diverter to force the air back down to the floor level. Natural exhaust vents are mounted in the roof of the building. Natural exhaust vents can take the form of a hood style ventilator, a continuous ridgeline vent, or a low profile thermal vent. The type of vent you choose will depend on what works best to allow a low pressure drop and high volume flow of air out of the building while at the same time preventing rain or snow from entering the building.
An industrial building with a powered forced supply/powered forced exhaust ventilation system uses both motorized supply fans and motorized exhaust fans.
Supply fans are mounted in the perimeter wall of the building about 8 to 10 feet above the floor with a diverter to force the air back down to the floor level. Exhaust fans are mounted in the roof of the building.
This is an extremely effective way of generating airflow toward the center of the building for personnel comfort cooling. Roof exhaust fans are located in strategic areas above high heat generating processes. Fresh air is forced to the areas of highest heat by supply fans and the roof exhaust fans extract the heat. When combined with column-mounted fans, the fresh outside air can be kept moving through critical work areas hundreds of feet away from the wall supply fans. For winter ventilation, direct heated air make-up units can be used (or incorporated into several supply fans) in order to add heat to the work area. The system can be designed to provide either a positive pressure or a negative pressure within the building. Fresh air can be provided through supply fans fitted with filters to maintain interior building cleanliness as required for food processing or where high outside dust conditions exist.
General industrial ventilation refers to the practice of applying ventilation equipment (fans, louvers, gravity vents, heaters) in order to create an environment within an enclosed industrial building which is conducive to employee comfort, productive work, and process efficiency.
Air curtains are a great way to seal off an entryway to separate two different environments. For example, you might want to keep hot air out and air conditioned air in. Or you might simply want to keep bugs and debris out of a work area. Air curtains, also known as air doors, create an air seal to prevent the environments from mixing.
Topics: General Ventilation
A well-functioning industrial ventilation system is more than just supply and exhaust fans. Sure, it all starts with exhausting stale air out and bringing outside air in, but there are ways you can optimize your system and keep your equipment working better and longer, and your employees more comfortably. Depending on your specific situation, you may need any combination of the following pieces of equipment.
We’ve been designing ventilation systems with air filters for many, many decades. In this time, we’ve come to realize that sometimes a customer might expect air filters to actually filter out sound as well as particulates. It seems like a logical conclusion, but it’s actually pretty far from the truth. Here are some thorough answers to some of your most common questions.
Unfortunately, we find ourselves in a downturn situation today that mirrors what we experienced in the mid-1980’s. The big difference, however, is that the offshore drilling rigs* of today are much more expensive and technologically complicated. Since we posted the article Best Practices for Dehumidification of a Mobile Offshore Drilling Rig Lay-up back in September 2014, the response has been overwhelming.