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Large commercial facilities present unique challenges when it comes to temperature management. Air stratification, process heat and circulation issues can contribute to lowered productivity and even unsafe conditions for workers and/or inventory. The following tips will address some of the most common temperature-control problems found in large manufacturing plants and the best methods for solving them.
Because hot air rises and cool air falls, the temperature in any given room will always tend to be warmer near the ceiling. This phenomenon is noticeable even in small rooms. However, in very large, open spaces such as a warehouse, the effect intensifies. It’s not uncommon for the floor-to-ceiling temperature differential in a room with a 40-foot ceiling to reach 30 degrees or more.
In winter, the problem is obvious: Heated air gets trapped where it is not needed, while building occupants shiver below. In summer, it might seem advantageous for the air near the floor to be cooler in such a space, but that’s not the case. In reality, the large stagnant mass of hot air overhead tends to cause the entire building to overheat. Occupants are left sweating, uncomfortable or in danger of heat exhaustion. If the air conditioning kicks into overdrive, workers must cope with air that’s too cold for comfort. Regardless of the season, the situation results in poor working conditions, lowered productivity and high utility bills.
Air flow is key to proper destratification. Large ceiling fans are particularly effective at mixing and circulating the air in a large space. Not only does the mix of air become more uniform, but the steady flow produces a gentle, evaporative cooling effect that can make the space feel up to 10 degrees cooler.
Where the hot air near the top of a building has a means to escape, the same phenomenon of rising warmth gives rise to the stack effect. This refers to rising columns of air forming in a plant, similar to what happens in a chimney.
Stack effect creates negative pressure in the plant and can lead to a number of problems such as excessive energy loss, infiltration of unwanted substances like dust or cigarette smoke, dangerous backdrafting of combustion appliances, and reduced efficiency of air-handling equipment.
Helpful measures to combat stack effect include revolving doors, air sealing and strategic air flow control throughout the plant.
Where temperature differentials exist, so does the possibility of condensation. Condensation happens when warm air hits a surface cool enough to reduce it to the dew point, allowing the water in the air to collect on the surface.
Condensation can cause many problems within a plant. Excessive moisture buildup leads to rust and corrosion, and facilitates the growth of mold and other harmful biological agents. When this occurs on a concrete floor, it is called sweating slab syndrome. This condition can be especially dangerous in a warehouse situation where the condensation results in slick floors. Handrails can also become slippery if condensation is allowed to persist.
Condensation issues can be resolved by correcting the air flow and/or dehumidifying the space. Commercial dehumidifiers can help reduce air moisture levels enough to prevent condensation in some cases. Fans are another good solution for many buildings, as they have both an evaporative and temperature-mitigating effect.
Most temperature-control problems in large facilities are intimately connected with air flow. While it is tempting for workers to simply adjust the thermostat, this approach does not always result in the desired effect. In fact, it can create damaging or dangerous situations. If you are struggling with these or other unresolved temperature issues in your plant, consider having a heating, ventilation and air conditioning (HVAC) expert or building performance professional inspect your facility and recommend specific air-flow solutions for your site.
Nikki Heinkel is the marketing manager for Go Fan Yourself, a company that manufactures high-volume, low-speed fans for spaces in need of an energy-efficient air-movement solution, such as warehousing, manufacturing, agricultural and commercial facilities.