High-speed doors maximize high-ceiling design for cold storage

by Katie Daniel | January 16, 2018 3:46 pm

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by Michael F. Watkins
The changes taking place in cold-storage operations over the past 20 years have called for new approaches in the traffic doors enabling access to these low-temperature rooms.

Visit any major city that goes back to the turn of the last century and one can spot buildings that used to distribute frozen and chilled food products, but have been converted into condos or offices. Some of these structures now stand as empty hulks in depressed areas of town, while a number of others have been torn down.

Multistory storage facilities were built as cost of land in big cities was high, but these spaces faced operational challenges. Product had to be moved into and removed from the building using freight elevators and involved the laborious handling of individual boxes of chilled food. Clearly, this was not an efficient approach.

This changed when America began expanding into the suburbs. The interstates that took people out to rural areas also enabled cold-storage distribution centers to no longer depend on rail service. These businesses were now able to leave the ‘big city’ and spread out in a single-story suburban building because land—at that time—was far cheaper than at the edge of downtown. These larger-footprint buildings also made it easier and faster to store and retrieve product for shipment. Meanwhile, improvements were made in both material-handling techniques and equipment to meet increasing demand.

One example of these changes was the 10-story Fulton Market Cold Storage Company Building, just west of downtown Chicago in the meatpacking district. As one blogger observed, before the 90-year-old building’s dramatic renovation to office suites in 2013, the building went through an epic refrigerator defrost, which was chronicled in a series of eerie pho[2]tos.[3] The owners vacated the building not only due to its age, but also because the inefficient process of moving product from floor to floor greatly cut into profits (The company is now serving its customers from a modern, single-story building in the suburb of Lyons.). (For more information, visit www.ediblegeography.com/defrost-prior-to-consumption[4].)

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The trend in cold-storage facility height also began to change at the turn of the last century. A growing number of these third-party warehouses and rooms serving food processing plants are now going higher again, but not with multiple floors. Rather, cold storage is being done in one giant-sized room. Taller high-speed doors are enabling these facilities to meet customer and operational demands.

For cold-storage operation management and owners, when considering facility capacity, cubic feet have become more important than square feet. (For more, visit www.anccold.com/blog/cold-storage-construction-cost[6].) Now, the average height for cold-storage facilities is 11 to 12 m (36 to 40 ft) when compared to the 6-m (20-ft) height in the 1900s.

Raising the roof
These roofs are rising for a variety of reasons.

Decreased real estate costs
Rising land costs have caught up in the suburbs. Higher ceilings mean reduced square footage for a lower investment in real estate.

Increased capacity
Real-estate developer Jones Lang LaSalle cites a finding by HPA Architects that there is an opportunity to increase the pallet capacity of a building footprint by 12 to 25 percent by utilizing an 11-m (36-ft) clear height versus the old 10-m (32-ft) standard. (Visit cscmpaz.org/wp-content/uploads/2015/09/JLL_Industrial_Dist_Facilities-white-paper-April-2013.pdf[7] for more information.) For example, in a 10-m clear height building, the study shows an occupant can stack 1626-mm (64-in.) pallets—these make up approximately 50 percent of the market—five loads high. With an 11-m height, that load number can increase to six high for a 20 percent increase in pallet positions.

Reduced heat loss
Modern Material Handling relates that high-density storage creates not only a smaller area to cool, but also an environment that better minimizes heat loss. (Read the article, “Best practices for managing a cold storage warehouse.”[8]) A smaller footprint, for instance, translates into a smaller roof.

“Since the roof is one of the places in an operation where air can escape, it literally pays to keep the area as small as possible,” says Bill Leber, director of business development for the automation solutions company Swisslog.

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Faster material handling
The smaller footprint means shorter aisles in the cold-storage room to store and retrieve product with the help of high-mast forklifts.

A growing number of cold-storage facilities are investing in online automated storage and retrieval systems for high-volume material handling. They are considering these automated systems because labor is either high-cost or difficult to find or at times both.

To maximize their value and economic effectiveness, the higher the volume these systems can manage, the greater the payback they can achieve. Consequently, these systems need to be housed in taller cold-storage facilities.

However, volume is key. Most facilities still employ a fleet of forklifts to move products. But these are not just any kind of industrial trucks. They have a high mast enabling the forklifts to reach the highest shelf, and then retract to a lowered height for traversing the warehouse floor and finally passing through the facility’s doorways.

Reduced downtime
As high-ceiling cold-storage spaces become increasingly common, the doors allowing access to the rooms play a significant role in the full utilization of the facilities. The building’s smaller footprint means there is less linear wall space, so these rooms have fewer doorways. With minimal access points, if a doorway is inaccessible, it creates a huge issue for facilities.

An example is pizza-maker Palermo’s Pizza. Just a few years after building and moving into a new facility in Milwaukee’s Menomonee Valley industrial corridor, demand for its product increased and the company needed more space. Rather than relocate to an area farther from its workforce, Palermo’s added 5946-m² (64,000 sf) to its existing operation, including a 12-m (40-ft) high ceiling in the freezer storage room. Since the facility is in the heart of the city, this addition made sense as it minimized land usage.

The higher ceiling in essence created a smaller footprint and meant less aisle distance to cover for faster access to the product. However, there are also fewer doorways—just five in this case. Downtime of any of these doors would be a costly slowdown for the operation.

According to Palermo’s facilities engineer Steve Daniels, “Our guys are going back and forth through that freezer all day long, taking raw materials to the line. If we cannot keep that flow going, we are shut down.”

High-mast forklifts—requiring 5.5 m (18 ft) of clearance—can go through these doorways hundreds of times a day. The extreme cold and the demands of meeting short deadlines force drivers to move quickly.

A slow-opening door could be a target for forklifts because drivers can misjudge whether or not a doorway is clear; they might clip the door’s bottom as it rolls up. Drivers are watching the floor as they access a doorway and are not looking up. Losing even one doorway due to a vehicle collision could severely impact the company’s tight schedules and strain its customer relationships.

However, fast doors make collisions with their panels nearly impossible. The fastest doors can provide a clear doorway in less than two seconds, allowing unimpeded traffic access for even the tightest approaches.

In the rare case of a door getting hit, most high-speed models have a breakaway/fast reset feature that gets the door back in operation in just seconds. Consequently, door repair crews—a common sight in many operations—seldom have to pay a visit except for an occasional tune-up, also saving repair costs.

Additionally, when it comes to routine door maintenance, advanced electronics in the high-speed door controller enable operational adjustments to be made at floor level, a real benefit when doors are 5.5 m tall. This means the man-lift stays parked.

These electronics systems offer total digital control and self-diagnostics to minimize maintenance surprises, too. The AC drive enables soft starts and stops, while providing smooth motion at the door’s high speeds for a longer component life. These doors can further reduce maintenance by eliminating coil cords, usually attached to the bottom bar. Instead, wireless communication with the controller—wherever it is mounted—continually tracks door operation and provides greater safety.

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Faster traffic flow
Every second counts in a busy operation where doorways are accessed hundreds of times or more each day. Since a high-speed door can be opened and accessed in only seconds, even for doorways upwards of 5.5 m tall, it can save hundreds of accumulated man-hours a year, which is otherwise, spent waiting for the door to open. This speed allows for better utilization of both human resources and investment in equipment.

The McCook, Illinois, facility of Golden State Foods (GSF) has a considerable volume of product to handle and disperse to hundreds of locations, with each of its clients ordering more than 100 inventory items daily. Based on its volume, this 24/7 food-service operation generates 10,000 to 15,000 cycles per month. Inventory for each account cycles every six days; turns in the cooler happen twice a day. In the freezer, inventory turns every day and a half.

Door speed is key to product flow in these instances. With doors operating at a rapid speed—an average of more than 2540 mm (100 in.) per second, the 5-m (16-ft) door panels open fully in less than two seconds. In an operation like this, extra seconds can add to days of wasted time over the course of a year.

Sustainability
For cold-storage operations, the temperature differential between the freezer room and the chilled dock can be around 22 C (40 F). A high doorway typically has about 15 m² (160 sf) of exposure area. The exchange of air between the cold- and dry-storage rooms as well as the loading dock can result in a significant loss of mass airflow.

Low-temperature, high-speed doors reduce air infiltration with fabric panels covering the doorway. Some models even feature insulated panels providing additional R-value.

Recent research has found high-speed models can more than compensate for any of the doors’ insulation deficiencies. Further, when a door is cycled more than 55 times a day, a high-speed saves more energy than a standard one.

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In a busy facility, 55 cycles can occur in a matter of few hours. At this kind of doorway, energy loss is greater through convection than conduction (Figure 1).

When closed, a high-speed door does an excellent job of sealing the doorway along the entire perimeter. Along the sides of the panel, guides envelop the edges to stop energy from escaping the room. Combined with a floor-hugging gasket and brush gaskets along the header, cold air is contained.

For Palermo’s operation, with freezer storage near production, there are both sustainability and productivity concerns. Daniels notes that with their freezer at – 22 C (– 15 F), “every time the door opens, I lose refrigerated cold air to my production space.”

While Daniels cannot share quantifiable figures on energy savings from high-speed doors, he says there is a change in his compressor usage.

Ensuring product quality
The advantage of cold-storage rooms that use automated storage and retrieval systems (AS/AR) is that there are no forklifts crossing the threshold. However, powered industrial trucks are still needed to traverse the area, carrying product from the room to the loading dock doorway. Moreover, these automation systems can be cost-prohibitive for many operations.

Preferred Freezer Services (PFS) has a 28,316-m³ (10 million-cf) facility in Elizabeth, New Jersey, which utilizes 12 insulated high-speed doors for entry into their automated, lights-out freezer. Combining the use of high-speed doors and dehumidification system on the dock, PFS is seeing a significant reduction on the load to the refrigeration system and more comfortable working conditions on the dock. This setup also ensures minimal exposure to dock temperatures and keeps the product frozen solid.

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The high-speed, high-cycle doors ensure the doorway is not a pinch-point. As a result, the facility is capable of taking in more than 1000 pallets per day and handling 2000 stock-keeping units (SKUs) for multiple clients, keeping this vast freezer area full and active.

The coordination between the automated system and forklift drivers on the dock is up-to-the-second and in real-time. The warehouse management system (WMS) communicates with each forklift by way of an on-board computer. Once the driver picks up a pallet at the receiving door, the WMS receives notification.

The system alerts the freezer crane that a load is on its way. By the time the forklift reaches the doorway, the crane is ready. The door rapidly opens, enabling the crane to quickly pick up the pallet and retreat into the freezer. The entire hand-off is complete and the door is closed again in under two seconds, minimizing product exposure on the warmer dock.

There is also a safety consideration. The insulated panel’s heat transfer barrier on the door prevents itself from becoming a condenser. This means moisture will not form on the panel surface and then drip on the floor. Wet floors or ice on floors are a slip hazard for personnel and can cause injuries.

Conclusion
Doors are the one kinetic element of a building. In the case of cold-storage facilities, the choice of doors can determine the operation’s ability to meet schedules, budgets, and profit targets.

The once growing frozen food market stood at “$22 billion in 2016, almost identical to the four years prior,” according to an article in Food Manufacturing[13]. In the face of nearly flat market conditions, efficient frozen food-handling/processing facilities call for even tighter operations. Advancements in high-speed door design and integration into cold-storage facilities will enable the industry to continue meeting the demands of retail customers and maximize profit throughout the supply and distribution channel.

FABRIC VS SOLID PANEL HIGH-SPEED DOORS

For years, cold-storage facilities were faced with a choice: install a solid panel door to prevent heat transmission from the room; or cover the doorway with a fabric roll-up door that delivers high-speed and minimizes infiltration. While the solid panel doors did a great job of offering insulation as thick as the freezer room walls, its lumbering speed slowed down traffic and was a target for forklifts. On the other hand, fabric roll-up doors are ideal for 24/7 operations, but for locations running two shifts and taking breaks during the holidays, the freezer system had to work harder during those periods to keep the room at freezing. Recent advances in door design now offer some options. The fabric curtain on roll-up doors can be insulated and manufacturers are making the seal around the doorway even more secure. Solid panel door speed is now over 3048 mm (120 in.) per second for bi-parting models, minimizing the amount of cold air escaping to the dock and the invasion of warmer air. As for the problem of forklift collisions, these doors have impact-resistant panels and can be easily aligned and reset to get back into operation. The main determining factor is available wall space for the solid panel doors. Nevertheless, both styles can handle taller doorways and keep up with traffic as well as the demands of 24/7 operating schedules.

Michael F. Watkins is vice president of marketing at Rytec High Performance Doors, a manufacturer of high-speed doors for industrial, commercial, food and beverage, and controlled-temperature environments. Watkins has consulted to the communications, industrial and durable goods industries and has held management positions in marketing, business development, and new product development. He can be reached at mwatkins@rytecdoors.com[14].

Source URL: https://www.constructionspecifier.com/high-speed-doors-maximize-high-ceiling-design-cold-storage/

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