Controlling Climate and Managing Heat Stress

HVLS fans, fabric diffusers, and curtain walls provide temperature control solutions.

• By Andy Olson
• Jun 01, 2019

Rising temperatures. E-commerce growth. Escalating consumer expectations. The heat is on this summer—specifically on workers in storage warehouses and 3PLs.

Hot in-plant temperatures can negatively impact employee productivity and create health hazards. Due to the large, cavernous layouts of these types of facilities, and the ever-shrinking delivery times that today’s online shoppers expect, it’s difficult for warehouse workers to "keep their cool," especially during June, July, and August.

While there is no one way to address this climate challenge, there are a variety of products facility managers can implement to improve working conditions for employees. Keeping workers comfortable with high-volume, low-speed (HVLS) fans, fabric diffuser systems, and fabric curtain walls can increase their productivity and maintain their well-being. Before taking an in-depth look at these solutions, let's look at some of the signs workers exhibit that will tip off facility managers that they need to control their indoor climate more effectively.

Signs of Heat Stress
Workers who appear lethargic might not just be lazy. They might be experiencing a form of heat stress. This not only hampers productivity; heat stress can lead to potentially dangerous mistakes that harm others. If not addressed right away, heat stress can result in a hospital visit or even death.

Workers will begin to lose concentration and perform erratically when experiencing heat fatigue. Some will even show symptoms with heat rash. These are the first warning signs. In these cases, workers should take a break and drink water or a sports drink to replenish electrolytes, which is important when excessive sweating occurs.

Heat exhaustion, heat syncope (fainting), and heat stroke are among the most serious types of heat stress disorders. Heat syncope usually happens because of a pooling of blood in the lower extremities and dilated vessels of the skin, leading to low blood pressure and sudden unconsciousness. Heat exhaustion can occur on its own or as a prelude to fainting. Common symptoms are similar to heat fatigue but can include diarrhea, nausea, and disorientation.

Heat stroke is the most serious heat stress disorder. It occurs when the body's systems of temperature regulation fail and body temperatures rise to potentially fatal levels. It can be marked by an absence of sweating, as well as confusion, fainting, and/or convulsions. Hospitalization is a must for anyone who suffers a heat stroke.

Addressing Heat Stroke
If multiple workers experience heat stress symptoms on a regular basis, there is reason for action. As mentioned earlier, providing rest and hydration breaks is a first step. However, there are various ways to enhance the work environment with in-plant solutions that make it easier to deliver cool air and manage temperature. Some of these facility upgrades include using HVLS fans to circulate air, fabric diffusers to distribute air more effectively, and industrial curtain walls to create easily controllable temperature zones.

While adding air conditioning is the best-case scenario, it isn't always practical due to cost considerations and building configurations. With or without air-conditioning, facilities dealing with heat stress challenges will find relief from HVLS fans. Although smaller, floor-mounted fans can be helpful in limited spaces, their high wind speed and noise levels may cause problems. They also use a relatively high amount of electricity. HVLS fans, on the other hand, use relatively little energy and provide a gentle, quiet breeze that is very comforting to workers. In fact, some HVLS fans use gearless motors that run with virtually undetectable noise.

According to the U.S. Department of Health and Human Services paper "Workers in Hot Environments," a 2-3 mph air speed creates an evaporative cooling sensation of 7-11 degrees F. To put this in perspective, the effective temperature of an 84-degree warehouse environment can be dropped to 73 degrees by adding a fan moving air at 3 mph.

A single HVLS fan can move large volumes of air up to 22,000 square feet and replace as many as 20 floor fans. By mixing air, HVLS fans also help air-conditioning systems work more efficiently, allowing them to be operated at a set point up to 5 degrees lower.

There are a number of factors to consider when deciding how and where to use HVLS fans. They include obstructions such as pallet racks, machinery, and product staging; personnel work areas; and overall building layout. HVLS fans that are 24 feet in diameter can move air further down rack aisles and over obstructions. Smaller diameter fans in the 8- to 12-foot range can be most effective in specific work areas or where installation space is limited.

For even more environmental and energy control, as many as 24 HVLS fans can be linked into a single network that can be easily managed with one device. This can greatly reduce maintenance challenges in facilities that have ambient sunlight or temperature-effecting operations (such as loading docks) in one part of the building, but not another.

That controller allows for independent speed adjustments, scheduled start/stop times, and the ability to start/stop based on preset temperature settings. It also ensures that fans are running only when they need to, reducing energy use.

An optional Ethernet port allows the system to be accessed via a remote device so they can be controlled via smartphone or other mobile device. Additionally, they can be programmed into a building management system (BMS) and connected to other infrastructure equipment such as exhaust fans. A "fire stop" option is also available, in which the BMS will automatically turn off the HVLS fans and activate sprinklers in the event of a fire.

Efficient Air Distribution with Fabric Ductwork and Diffuser System
While metal duct systems have been used to distribute air in buildings for decades, fabric dispersion systems are becoming more prevalent. They are used in a variety of industries that require precise air flow. The main benefits of fabric systems when compared to traditional metal counterparts is that they are custom designed for the application to provide even airflow throughout the space. Additionally, a fabric system has lower material, installation, and lifetime ownership costs.

Similar to how HVLS fans can lower the perceived temperature in specific areas, fabric dispersion systems provide targeted, precise, efficient air flow throughout the length of their run. Fabric diffusers use various methods to achieve this uniformity, including air porous fabrics, linear vents, nozzles, and orifices. Any of these methods will be more effective than standard metal ductwork that uses localized diffusers spaced many feet apart, creating hot and cold spots along the length of the system.

The various types of fabric dispersion products allow facility managers to specify the performance requirements that will best serve their environments. One of the most significant benefits of fabric ducts is their complete customization for each application. Whether it's providing the exact temperature for food products or helping to cool off workers in a 3PL, fabric diffusers help ensure maximum environmental control.

Fabric ducts are fairly easy to install. Because they're significantly lighter and more flexible than their metal counterparts, installation is usually faster, there's less of a load on the ceiling structure, and setup costs are lower. It's because of these reasons that they're also easy to reconfigure in a facility if needs change.

Manage Temperature Zones with Curtain Walls
Large warehouses and storage facilities are designed to provide the maximum amount of space for storing products. However, this often results in large spaces that are extremely difficult to cool down. Creating smaller spaces can be a cost-effective way to manage temperatures.

By using fabric curtain walls, facility managers can easily create compartmentalized spaces for specific processes or employee comfort and safety. Creating temperature-controlled zones makes it possible to be much more efficient with HVAC expenditures, instead of heating or cooling unnecessarily large areas. Because of their modular design, industrial curtain walls can easily be reconfigured if a space needs to be enlarged or reduced or the shape of the footprint needs to change. They are also durable enough to withstand contact from machinery and can provide up to 40 degrees Fahrenheit of temperature separation.

Insulated curtain walls with vinyl-covered surfaces are ideal in separating two different temperature zones, as humidity can be a concern. Their surface is waterproof and the insulation inhibits the transfer of heat away from the outer surface, keeping the outer surface temperature above the dew point of the exterior air so there is no condensation.

Fabric curtain walls can be easily installed, trimmed to fit around conduit, piping, or ductwork, and anchored to the floor to withstand pressure differential. Depending on the application, a curtain wall can be suspended from the room ceiling or they can hang from a stand-alone framework. They are available as stationary and sliding applications and can be fitted with strip curtains, personnel doors, or high-speed industrial doors.

Don't Stress the Heat
Facility managers who feel the heat this summer or observe heat stress in their employees might have to make some facility upgrades. Not only can the heat create inefficiencies, it can generate dangerous situations. Creating a more comfortable and healthier workplace is possible through the right system of products. Whether it's the gentle cooling of HVLS fans, the directional air supplied by fabric diffusers, or creating smaller temperatures zones with fabric curtain walls, facility managers have options to make their facility more efficient and safer.

This article originally appeared in the June 2019 issue of Occupational Health & Safety.