Mechanics working in a shop sized to fit the massive on- and off-road heavy equipment that keeps Luck Stone’s rock quarry products on the move were struggling to stay comfortable year-round. In the winter, all the heat rose to the top of the 30-ft ceiling, leaving technicians shivering below, particularly when the four large bay doors were opened to move equipment. The temperature differential between the floor and a second-story loft was as high as 9 °F.
“We were basically heating the rooftop of the shop,” says Mark Endries, project manager at Luck Stone in Richmond, Virginia. “We tried several different things to bring that heat down here and provide comfort, with limited success.” Typical small ceiling fans didn’t make any difference in the tall space, and Luck Stone needed a bigger solution.
“We recognized we needed a way to improve the comfort level of the mechanics working in the shop, while being operationally efficient and environmentally conscious, too,” says Endries.
Maintaining comfortable conditions in a shop sized to fit heavy equipment that keeps quarries’ products can be an expensive task. But a familiar concept can be put to work in these facilities to increase technicians’ comfort and reduce their shops’ energy usage in every season.
High-volume, low-speed (HVLS) fans produce a column-shaped jet of air roughly equal to the diameter of the fan. As this jet strikes the floor it spreads out in all directions, displacing the stagnant air and setting up a convection-type circulation pattern. Air from the floor level is moved out toward the walls or obstructions and then moves up back into the fan to be recirculated. This air movement works to improve year round comfort and can drastically reduce energy costs.
According to the Center for the Built Environment, adequate ventilation and air circulation are key components to maintaining the narrow range of environmental conditions at which people are most productive. Human thermal comfort, as defined by ASHRAE Standard 55-2010 Thermal Environmental Conditions for Human Occupancy, requires the proper balance of four environmental factors: temperature, thermal radiation, humidity, and air speed, along with activity level and clothing. Both winter and summer conditions greatly affect worker comfort in any industry.
Efficient heating is often difficult in large spaces like warehouses. Luck Stone’s struggle to heat the shop was taking a toll on the employees and the company’s bottom line. In some climates, inefficient heat can lead to safety concerns, as workers subjected to excessively cold temperatures can suffer losses in dexterity. Additional clothing required to cope with the cold might also put them at risk for entanglement or other perils. Some workers might need additional breaks to warm back up, cutting into productivity.
In the winter, stratification occurs because the hot air from a heater is approximately 5-7% lighter than cool air in a space and tends to rise to the ceiling. In the winter, HVLS fans can be used for destratification by gently pushing the warm air trapped at the ceiling down to occupant level, creating a more uniform temperature throughout the space without creating a draft. In addition to providing comfort to occupants, destratifying the air in a space has the added benefit of allowing for a lower thermostat setpoint, which results in significant cost savings from reduced energy consumption.
“Even though the thermostat setpoint remains the same in the winter, the heating system does not have to work as hard to maintain the given setpoint,” says Christian Taber, LEED AP and a member of the engineering team at Big Ass Fans. “By reducing the amount of heat trapped at the ceiling, it’s similar to turning the thermostat down 5-7 °F.”
In addition to providing winter heat recirculation, the fan from Big Ass Fans also works all summer. During cooling seasons the fan speed can be increased, so that faster-moving air working in concert with the body’s natural cooling process produces a cooling effect of up to 10 °F.
When temperature and humidity levels rise, the body’s natural ability to cool itself decreases. OSHA standards indicate temperatures of 100.4 °F and above are dangerous for workers, while air temperatures that exceed 95 °F significantly increase the heat load on the body, explains Taber.
Discomfort issues have a negative impact on productivity and the bottom line. Elevated temperatures can affect the potential for both mental and physical work. Hot working conditions can affect worker morale, absenteeism, turnover, quality of workmanship, and the frequency of both accidents and grievances.
At Luck Stone, the fan is used to keep employees comfortable on hot days, as well as cool. The single overhead fan replaced several noisy floor fans on the shop floor.
“Taking out the floor fans cleared up some space and got cords out of the way,” says Endries. “Our people used to take breaks to get water or cool off in front of the floor fans, and I think our productivity may have been a little off because of them needing to cool down.”
The fan keeps Luck Stone’s technicians comfortable year-round and has become standard equipment in the shop, says Endries. “In the winter the Big Ass Fans fan pushes down the warm air at the ceiling very effectively, and in the summertime it creates a breeze. That fan runs every day that we’re working.”