Impactable Dock Doors: Helping protect warehouses and increasing worker safety

May 25, 2015

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All photos courtesy Assa Abloy Entrance Systems

By Steve Kalbfleisch
When it comes to specifying the doors for a loading dock project, safety statistics are a dramatic way to help people understand the important connection between choosing the right materials and equipment and the ultimate return on investment (ROI).

According to the latest data from the Association of Workers’ Compensation Boards of Canada (AWCBC), there were more than 340,500 accepted work-related injuries/illnesses recorded in 2013. The Canadian Centre for Occupational Health and Safety (CCOHS) reports that of these, approximately 60,000 workers in Canada are injured each year due to slip-and-fall accidents alone. This number represents nearly 18 per cent of ‘time-loss’ injuries accepted by workers compensation boards or commissions across the country that can cost companies billions annually.

One of the easiest ways to avoid slips and falls in work environments, such as a warehouse facility, is by trying to control (or better, eliminate) the hazards. Many of these threats can simply be avoided by selecting the proper loading dock doors.

Role of dock doors
Impactable doors can be a solution for controlling several work-related risks. Of paramount importance is the door’s tight perimeter brush and loop weather seals that eliminate water and air infiltration as well as light gaps. Such seals are attached to the impactable door panels themselves instead of the door jamb. This keeps the seals out of harm’s way to ensure consistently dry work surfaces around the inside of the door.

Impactable dock doors, unlike their standard overhead counterparts, are not only designed to seal out moisture, but can also stand up to the rigours of everyday use, including impacts from forklifts. Impactable doors ride along unconventional V-groove tracks and use retractable plungers. When a door is hit, the panel offers no resistance and is knocked out of its track undamaged. A quick pull on the panel resets it in place and the door is then easily placed back into operation.

Further, since door and track damage are some of the leading causes of broken seals and gaps on doors that can lead to moisture buildup on the warehouse floor, many models feature an impactable track running the entire length of the opening. This protects against impact damage from forklifts, masts, and materials without sustaining any damage or exposing the facility to gaps that can let in the rain, snow, condensation, or ice.

To further protect impactable doors from permanent damage, their interior skin is made of a tough polycarbonate material that resists impacts from forklifts and other heavy equipment. Additionally, varying thicknesses of available interior foam insulation between the door panel skins help to absorb impacts as well as provide increased energy efficiency depending on the insulation thickness and associated R-value.

Workplace injuries
When considering workplace falls, most people immediately think of accidents from a height, yet statistics suggest roughly two-thirds happen on same-level surfaces and result from slips and trips, according to both the CCOHS as well as the Workplace Safety and Insurance Board (WSIB) Ontario.

While keeping people from harm is obviously the priority, a loss of productivity is often a side effect of worker injury. On average, workers who are injured as a result of a slip-and-fall accident spend more days away from work than those hurt by other causes. For example, the WSIB estimates the average slip, trip, or fall in the workplace costs employers in Ontario $2000 in direct costs and an additional $20,000 in indirect costs. Industries of particular interest when it comes to determining the allocation percentages for these injuries include warehouse, wholesale/retail, and manufacturing spheres, which together account for the greatest proportion of injuries resulting from same-level falls—more than 60 percent.

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Impactable doors that also take wind loads into account can still protect against forklift impacts. Heavy-duty retractable plungers allow the door’s panels to release and then snap back into position without damage to the door or track.

Safety in warehouses and manufacturing facilities in Canada is regulated by standards developed by the Government of Canada’s Labour Program, as well as CCOHS. The main focus of these entities is to prevent work-related injuries and illnesses through continuous monitoring and inspections of facilities and modifications to applicable standards.

Loading dock locations are an important area to consider when specifying safe materials in a warehouse. There can be up to hundreds of doorways along the typical loading dock—these openings can permit moisture to enter the area and mix with dirt, debris, and oil, creating a dangerously slick surface.

Many companies are realizing warehouse safety begins with planning and prevention on the dock and inside the warehouse during the design, construction, or retrofitting of a facility. With this in mind, there is no better place to start than with the warehouse doors separating the inside of the facility and employees from a host of potential hazards.

Dock doors can be easily damaged by forklift traffic and products on tight, busy docks as workers try to manoeuvre materials into and out of trailers. Due to their unique track, panel, plunger, and weather seal design, impactable dock doors can prevent gaps from forming between the door panels when they are hit, and reduce the amount of elements and moisture that can enter a facility.

Wet floor surfaces
Wet floor surfaces are a particular area of concern regarding slip-and-fall injuries. CCOHS guidelines recommend employers retain an effective housekeeping program ensuring work area floor surfaces are kept as dry as possible. Areas that cannot be cleaned continuously should have some form of anti-slip flooring in place as an added safety measure.

Impactable dock doors allow them to stand up to the abuse experienced on the dock. When a forklift or other object collides with the door, the impact causes the plungers to retract, allowing the door to release from the opening, thus preventing panel damage. After the door is knocked out from the track, a light pull on the handles resets the door, putting it back in operation quickly without damage. This, as well as weather seals being attached to the door panels themselves rather than the door jambs, helps to keep floors dry and safe, and ensures employers remain in compliance with CCOHS guidelines. Additionally, because the weather seals are attached to the door panels, the seal cannot be easily damaged—this, in turn, lowers total cost of ownership.

Since door and track damage are some of the leading causes of broken seals and gaps on traditional doors that can cause moisture to build up on the warehouse floor, impactable doors also feature an impactable track. These tracks can run the entire length of the door opening to protect against potential damage from impacts from forklifts, masts, and materials without sustaining any damage or exposing the facility to gaps that can let in rain, snow, condensation, or ice that could otherwise be disastrous for both pedestrian and forklift traffic.

Weather as a major contributor to safety risks
Slips and falls are not the only types of risks with which loading dock doors need to contend. Environment Canada emphasizes significant differences in its regional geography and seasonal conditions create risk for a wide range of hazardous weather conditions that can affect dock doors, including ice storms and blizzards, tornadoes, and hurricanes. On average, there are about 80 tornadoes reported annually across Canada according to Environment Canada, but the total number of tornadoes occurring annually nationwide could actually be closer to 230.

Canada’s Maritime coastlines and low-lying inland areas are susceptible to high-wind events associated with hurricanes and tropical storms and the potential devastation they cause when wind speeds can range from approximately 180 to 240 km/h (110 to 150 mph). Even if an area has been spared from dealing with these disasters in the past, building owners should be prepared for whatever nature blows their way.

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An impactable door with an optional clear vision panel that runs the full width of the dock door provides outside visibility without sacrificing a facility’s energy efficiency or security.

Canada and its Atlantic waters are threatened by an average of six tropical storms a year, according to Environment Canada. Given the devastation caused by gale- to hurricane-force winds, and the driving rain that often accompany these events, investing in proper planning is critical.

Due to the potential sheer size of hurricanes, Canada’s interior is not invulnerable to such events. One of Mother Nature’s most recent devastating storms impacted interior Canada in 2012 when Hurricane Sandy made landfall in New Jersey. The hurricane system then tracked northwest into Ontario and southern Québec with extremely high wind gusts. Sarnia, Ont., was particularly hard hit a result of strong north winds off Lake Huron.

Of particular concern are commercial operations, especially warehouses and distribution facilities that find themselves increasingly exposed to danger and injuries as a result of numerous overhead doors and 24-hour operation. The potential for billions of dollars in damage and injuries to personnel when a hurricane makes landfall, or a tornado touches down, is motivation enough to storm-proof operations during construction.

Having a door that can withstand high winds is crucial to a building’s survival and employee safety. About half of the damage to a distribution centre’s contents, and injuries sustained by employees during these events, is a result of the dock doors being ripped from their tracks and off the walls.

Moreover, the door is the only moving part one must consider on the building’s structure. Most other components—such as the walls or roof—are securely fastened into the building materials. In the parts of the country that could potentially experience devastating storms, commercial buildings must have doors that stand up to the pounding wind and flying debris, yet do what they are supposed to routinely do—open and close to efficiently handle truck traffic on the loading dock.

Whenever commercial building owners are unaware of the importance of proactively designing and building to reduce damage to their facilities and the disruption to schedules, insurance companies, and, consequently, the code-writers for provincial and local governments, will remind them.

The role of building protector
Do high-wind events and the potential for extensive property damage provide companies with an option to help reduce losses and business interruptions? How can warehouses and other facilities protect assets from these storms?

Wind loads are the pressures exerted on a structure (and the components comprising it) due to wind. They are assumed to act both toward (i.e. positive pressure) and away (i.e. negative pressure) from a building’s surface. Stepping into this role as a building protector are wind load-rated, impactable loading dock doors, already designed to stand up to impacts on the inside of the building. Now, these doors are available in wind load-rated designs to even meet the highest of requirements for resistance to forces and impacts outside the building.

Impactable dock doors were introduced to address the common damage and downtime issues associated with traditional metal overhead doors used in distribution centres and warehouses. Traditionally, these openings are similar to a standard garage door, and hardly built to take a hit from a forklift, much less withstand hurricane force winds.

The widely accepted use of impactable dock doors has enabled distribution centres, manufacturing plants, and other commercial facilities to address the common damage and downtime issues that come with forklift impacts, saving considerable damage, energy loss, and reducing operating costs.

With an impactable door protecting against forklift impacts inside the facility, a logical next step was to enable them to stand up to high-wind events and flying debris from hurricanes, tropical storms, or tornados that can injure employees on the docks and in other areas of a facility.

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Some impactable doors include slide locks and pins that offer enhanced security during high-wind events.

The features of these wind-load doors are similar to those on standard impactable doors mentioned earlier that can help prevent moisture infiltration and subsequently slips and falls, with an extra layer of protection. They include:

The damage-resistant panels with polycarbonate skin also guard against damage from flying debris and materials, as well as provide a layer of ultraviolet (UV) protection from the sun’s harmful rays that can weaken the door panels.

The high-density impactable tracks mounted flush to the jambs are another part of these wind-load-rated impactable assemblies, which enable the door to remain attached to the wall. Unlike standard door tracks, the high-density tracks fight off the most abusive forklift impacts on the inside, while providing the necessary strength to withstand negative and positive wind pressures on the outside during a storm.

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Impactable dock doors are designed to provide optimal energy efficiency at a lower total cost of ownership; they offer the potential to help facilities realize substantial energy savings and reduced maintenance costs.

With regard to wind storms, negative wind pressures are a particular issue with overhead doors in general. To combat these forces, wind load-rated impactable doors have multiple slide-locks mounted securely to a steel plate on the panels. As a storm approaches, the crew can engage the slide locks into holes along the height of the guide track and secure with a pin attached to the tracks. This is an extremely important consideration in facilities that have a large number of these doors with limited time and resources to prepare for a high-wind event. As a way to combat these high-wind events, rigorous testing establishes whether a door design meets static air pressure resistance.

Canadian Standards Association (CSA) Group works with manufacturers and key industry associations to develop and maintain harmonized standards that help meet the needs of the North American market. It tests requirements per the American National Standards Institute/Door and Access Systems Manufactures Association (ANSI/DASMA) 108, Standard Method for Testing Sectional Garage Doors and Rolling Doors: Determination of Structural Performance Under Uniform Static Air Pressure Difference, or ASTM E330, Standard Test Method for Structural Performance of Exterior Windows, Doors, Skylights, and Curtain Walls by Uniform Static Air Pressure Difference.

Though static air pressure (positive and negative) is one issue (measured in lb/sf or Pascals), some localities require door testing to determine the ability to resist penetration of airborne debris. The testing involves hundreds of simulated wind gusts and impacts from a 2×4 stud shot from a cannon at 15.24 m (50 ft) per second.

Essentially, testing has determined these impactable door designs meet even the most stringent building codes, such as those enacted by the state of Florida after Hurricane Andrew in 1992.

The same door panels, which stand up to the forceful impact of speeding forklifts carrying heavy loads, were able to pass the wind gust and projectile tests and still provide coverage for the doorway. To provide additional assurance to overcome these forces, there is a flexible tubular frame reinforced with a steel angle inside the panels.

Warehouses and other facilities throughout Canada face the potential of damage in varying degrees, ranging from extreme weather events to normal wear and tear of everyday operation. However, innovative and stringently-tested impactable doors can help distribution and warehouse facilities of all sizes reduce worker slip-and-fall injuries, realize reduced property damage from extreme weather, and maintain a more secure loading dock, minimizing disruption of the supply chain.

Kalbfleisch_Steve_photo (2)[6]Steve Kalbfleisch has almost 25 years of experience in loading dock equipment sales and service. He currently serves as Canadian sales director of industrial door and docking solutions for Assa Abloy Entrance Systems in Mississauga, Ont. Kalbfleisch can be contacted by e-mail at

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