Reinventing The 'Danger' Zone

Loading docks play an often overlooked role in the supply chain. By treating the dock as part of a Material Transfer Zone, companies can improve speed-to-market—and avoid accidents.

When is a loading dock not just a dock? The answer is now—because an efficient, productive loading dock provides a competitive advantage in supply chain logistics, which many agree is industry's new profit frontier. The fact is that businesses today can no longer think of the dock in isolation. Instead, companies will benefit by treating the dock as a part of a Material Transfer Zone (MTZ) that plays a critical role when working to improve speed-to-market.

The MTZ can be thought of as a valve that regulates the rate at which goods flow in and out of a facility. In this context, an efficient, productive loading dock becomes a competitive necessity. When everything flows smoothly, delays are avoided, accident potential is minimized, product damage is prevented, schedules are met and customers are satisfied.

The MTZ reaches from the drive approach well into the shipping/receiving/staging area. In the past, many simply thought of this area as the loading dock. However, the MTZ has evolved to become much more. As such, it presents facility managers with challenges and opportunities.

Complex Interactions Abound

In the world of supply chain logistics, profitability is largely achieved through efficiencies. The drive for supply chain efficiency increases the importance of the MTZ. Yet at the same time, the challenges associated with the MTZ have never been greater. In other words, the seemingly simple process of moving material between plant floor and inbound or outbound vehicles is not what it appears. Instead, it involves complex interplay concerning:

  • Flow of trucks in and around the facility and loading dock approach;
  • Material handling vehicles;
  • Widely varied tractor/trailer types;
  • Loads and load configurations;
  • Loading dock door openings;
  • Loading dock equipment selection; and
  • Safety initiatives.

The number of factors that affect the MTZ continues to expand. These issues are further complicated by management schemes and various supply chain productivity trends.

Trucking is one area that is profoundly impacted by recent trends. Within the trucking industry, physical changes in trailers increasingly affect receiving and shipping efficiency. The overriding trend is toward larger trailer dimensions. To maximize interior space, trailer walls have also become thinner. Many dry trailers have as much as 101 inches of clear width inside.

Some trailer manufacturers have also introduced low-profile tires to squeeze out more cube space within the trailer. This allows the box to be six to eight inches higher while overall trailer height remains the same. Additionally, increasing numbers of trailers use air suspensions that are designed to minimize cargo damage and increase trailer life. This causes bed heights to fluctuate by several inches at the dock as loads are added or removed and as lift trucks move in and out.

Challenges Of Reconfigured Loads

As trailer dimensions have increased, shippers have reconfigured loads to take advantage of increased payload space.

In particular, 102-inch-wide trailers enable 48-inch-by-40-inch Grocery Manufacturer Association (GMA) pallets to be pinwheeled (turned 90 degrees) to increase the payload. If pallets are stacked two high and double pinwheeled (meaning two pinwheeled rows side by side) the total payload can increase by as many as 12 pallets.

Trailer widths aside, some shippers have opted for full-width loads to achieve fewer lift truck cycles and save time. Full-width loads may also travel on wood or plastic pallets, depending on the situation, or even specially designed racks.

Changes in trucks, trailers and loads can boost shipping efficiencies. Yet, they also create bottlenecks at the MTZ.

Mismatches Clog The Valve

Many existing loading docks are undersized or ill equipped to handle today's larger loads and wide range of trailer designs. Additionally, many new dock designs rely on outdated rules of thumb for dock height, dock leveler size and capacity, door opening size and dock-door sealing configurations. The result is a mismatch at the dock, which translates into a clogged valve in the supply chain.

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