A slippery mess
John Rock Inc. of Coatesville, Pa., goes through 250,000 ft of green hardwood and 9,000 lbs of nails to create 20,000 pallets every shift. Greenwood hardwood is between 30% to 45% moisture, which was causing condensation within the facility.
“At our old facility, the floor was so rough and beat up, it didn’t matter if it was wet, there was still lots of traction,” said Penn Cooper, business development and purchasing manager. “Here, we spent a lot of money to make sure we had a very smooth floor so we could move efficiently. We created a huge skating rink issue, just because it was wet. People were getting hurt.”
On top of the slip-and-fall risk, the moisture also allowed mold to flourish on the newly constructed wooden pallets. Both issues were addressed by the addition of air movement from six 24-ft diameter, low-speed fans used to thoroughly mix the air.
The result is only a slight temperature difference from floor to ceiling and reduced opportunity for condensation to form. Rather than using dozens of small fans to blow directly on the ends of the pallet rows, the 24-ft diameter overhead fans efficiently and effectively circulate air throughout the space.
Product integrity case in point
Kentucky-based Owensboro Brick & Tile manufactures 35 million bricks annually, running its kilns at 1,950 F. The staging area holds 300,000 to 400,000 bricks at a time as they dry before going into the kiln. “We have to get a certain percentage of moisture out of the brick before we can fire it,” said Mark Sexton, plant manager. As one set of bricks would come out the kiln, the steam would keep the area hot and perpetually wet, preventing a thorough drying. The four 16-ft diameter, low-speed fans were installed to increase the air speed in the drying area, helping to evaporate the moisture from the green bricks waiting to be fired, while also dissipating heat and moisture from the steaming bricks exiting the kiln.
“These fans are helping to remove the moisture from the brick,” Sexton said. “So it’s actually letting me run our kilns a little faster to get more product out, because the bricks are drier.”
All buildings, regardless of age, are susceptible to deficiencies in indoor environmental quality (IEQ). New and renovated construction are prey to tighter building envelopes that can reduce ventilation system effectiveness, and humidity and moisture buildup can cause unforeseen effects for building occupants in regard to bacteria and mold growth.
Large-diameter, low-speed fans play a significant role in improving IEQ by turning the air in the space over several times per hour, ensuring good air distribution. This increased air circulation allows for more constant, uniform temperatures that help inhibit mold growth.
WestWind Logistics in Omaha, Neb., washes and then stacks up to 50,000 wooden pallets to dry before putting them back into service. Any pallet that sprouts mold must be rewashed, costing time and money. Unfortunately, the warm, humid warehouse was the perfect environment for mold, and wood is among mold’s favorite places to set up shop.
“If the pallets sit here too long, they mold. At one point, we had 4,000 pallets in the warehouse, and over half of them got moldy,” said Vincent Hoy, facility manager. “We have to rewash anything that has mold on it or touching it, so that’s two days of work lost.”
The air movement from the two 20-ft-diameter, low-speed fans that were installed disturb the thin sheet of stagnant air surrounding each pallet, helping to prevent the establishment of mold by speeding up the drying process on surfaces on which mold can form. “About 95% of the stock we put under the fans never molds,” Hoy said. “We put everything we wash and sort under the fans—that’s the premium real estate.”
Whereas most warehouse-style facilities don’t have air conditioning, they do employ heating systems in the winter months. On the human front, adequate IEQ is typically a concern between 3 and 72 in. from the floor, which is considered the occupant breathing zone. When using a traditional HVAC system in the winter, only about 80% of the fresh air brought into a space reaches the designated occupant level, which means the system must compensate for the lost air to create a space that complies with ASHRAE Standard 62.1-2007, Ventilation for Acceptable Indoor Air Quality.
The addition of large-diameter, low-speed fans to circulate the air down to the occupant level not only helps to keep IEQ levels in check but reduces reliance on the HVAC system altogether. This air circulation also compensates for the insufficient mixing of the supply air and room air, and the natural buoyancy of the hotter air allows it to remain at the ceiling level.
Airing on the side of safety and comfort
Fortunately, there is a middle ground between surrendering to the expense of air conditioning and suffering a continual loss of profits due to comfort-related problems. According to the Center for the Built Environment, temperature and air quality are two of the most important factors when considering productivity.
At the forefront, using large-diameter, low-speed fans is cost effective both in terms of worker productivity and reduced operating costs. Ideally, worker comfort leads to safer working conditions as employees can spend more energy on the task at hand without experiencing heat discomfort or exhaustion. This in turn results in increased worker productivity, positively affecting the bottom line, considering fewer days are missed due to illness and accidents.
Following that same agenda, businesses are able to keep workers comfortable in a far more energy-efficient manner, reducing operating costs and dependence on expensive heating and cooling systems.