Efficient Distribution

Warehouses may look a lot alike from the outside, but M/E/P engineers familiar with this type of facility know that the same is not true of the infrastructure. Warehouse owners all have unique needs and requirements. And while there may be ideal types of building systems for these facilities, what is desired often conflicts with what is practical in terms of size and cost.

By Scott Siddens, Senior Editor March 1, 2004

Warehouses may look a lot alike from the outside, but M/E/P engineers familiar with this type of facility know that the same is not true of the infrastructure. Warehouse owners all have unique needs and requirements. And while there may be ideal types of building systems for these facilities, what is desired often conflicts with what is practical in terms of size and cost.

One A/E firm that has logged much time designing and managing the construction of warehouse/distribution centers is Chicago-based A. Epstein & Sons Intl. A look at one of the firm’s recent projects—the expansion of the Albertson’s Grocery Distribution Center in suburban Chicago—offers a good example of the meticulous planning and design that goes into such facilities.

The big picture

Epstein provided full architectural, engineering and construction management services for the 156,000 sq.-ft. expansion of this dry grocery distribution center. Firm officials are quick to point out that a distribution facility of this magnitude is not just a warehouse. “In terms of the warehouse function, there are both ambient- and cold-storage functions,” explains Charles Dierker, P.E., an Epstein vice president. “But there are also all the administrative and support functions, such as office and maintenance areas, fueling areas and even truck washing bays.”

But while the varied functions of these facilities present many different challenges for M/E/P engineers, the storage facilities are the bread and butter, so to speak, of grocery distribution facilities. And it is innovation in storage and handling equipment that is most affecting the way engineers are designing the infrastructure for these buildings.

Up, not out

Warehouse owners are discovering that they need to build up, not out. High-rack storage systems are becoming popular for efficient use of space. These automated systems store product on a complex system of shelves and conveyors. With the use of high-racking comes a need for higher ceilings, and this, in turn, can create challenges for designers.

Lighting is an obvious example that comes to mind. With the clear height of storage facilities almost double what it used to be, there is the issue of how to effectively light the various levels of activity. Moreover, tall forklifts, cherry pickers and other material-handling equipment are easily tall enough to take out the lights.

While many warehouses are using either metal-halide or compact fluorescents, one alternative, according to Byron Byraiah, P.E., electrical engineer with SLL/Leo A. Daly, is a bi-level dimming system for high-pressure sodium (HPS) fixtures. Byraiah recently adopted this approach in a West Coast distribution center project for another large grocery chain.

For the Albertson’s project, however, engineers found that T5-HO fluorescents with mixed-tube fixtures would work just fine. In order to protect the high-bay lighting, fixtures are mounted in the ceiling no lower than the joists, which form a protected shell around them.

And for cost savings, like almost all distribution facilities nowadays, the Albertson’s center is equipped with zoned lighting systems and locally situated motion sensors. “There’s only one day of the entire year that this facility doesn’t function,” says Dierker. With that much power being consumed in this 24/7 facility, keeping the lighting bills down is a must. “Motion sensors in the rack aisles are very important in this respect. And with a zone system, lighting in areas of the facility that are not being utilized at a particular time can be completely deactivated,” he says.

Fighting fire from above

Taller clear spaces in these facilities also have implications for fire-protection strategies. One commonly used system these days is the early-suppression, fast-response (ESFR) system. ESFR and large-orifice sprinkler systems are mainly being used in coolers and freezers of up to 25 ft. ceiling heights, though some suggest that use in storage areas of up to 35 to 40 ft. is possible.

At the Albertson’s facility, however, engineers decided to go against the grain. “ESFR is the preference,” says Dierker. “But we decided the Albertson’s facility was above the range where it would be effective.”

Dierker points out that some of Albertson’s distribution centers do use ESFR systems, but those facilities don’t have the exceptional ceiling height of the suburban Chicago center. He also argues that ESFR systems don’t really help with some of the highly flammable materials that are stored in a dry-grocery distribution center. “We decided to go with in-rack sprinklers, despite the possibility of forklifts jostling and damaging sprinkler heads,” he says.

But even though the ceiling wasn’t the right place for fire sprinklers and smoke detectors, it was ideal for refrigeration plants and electrical runs.

Penthouse refrigeration

On the subject of ceiling height, Epstein designers decided to make optimal use of the roof. For example, locating refrigeration units in the roof would benefit the owner in many ways. First, it helped to streamline the construction process. By locating refrigeration units and piping outside the main building space, other trades could begin and work simultaneously with the refrigeration installers. But more importantly, maintenance work on the units can be performed from the outside, without disrupting daily operations. And there’s a major benefit to maintenance personnel themselves: They don’t have to go through -10

Electrical distribution, too, is in the ceiling. “The distances are great in these facilities,” says John Coogan, senior construction manager at Epstein. “The need to keep the voltage up for as long as possible means that substations must be in close proximity.”

Coogan explains that, typically, running the electrical distribution below grade is the most economical method, but overhead distribution, though sometimes slightly more expensive, is a necessity.

“At the Alberston’s distribution center, we used a conduit-and-wiring system that uses aluminum conduit in spaces at less than 40

The electrical distribution configuration is conveniently located close to the refrigeration plant. And the way in which building automation works with refrigeration is invaluable, as well. “The building automation system is especially handy for facility managers to control refrigeration. They can do it from their homes via the Internet,” says Dierker.

Innovations in engineered building systems and equipment, such as flexible, high-intensity lighting and ESFR sprinkler systems, are keeping pace with the changing needs and scale of these distribution centers. In the future, the issues of life-cycle costing and energy efficiency will be of increasing concern. Cost is always the issue. For this reason, in designing the Albertson’s facility expansion, designers carefully weighed the pros and cons of different technologies. Sometimes, practical wins out over ideal.

More Than Just A Warehouse

Warehouses and distribution centers pose unique challenges, but one thing that the outside observer often forgets is that a distribution center is more than just a warehouse. Chicago-based A. Epstein & Sons Intl. provided a complete range of architectural and engineering design services on a recently opened 215,000-sq.-ft. food bank and training center for the Greater Chicago Food Depository (GCFD), a not-for-profit food distribution center working to feed the hungry throughout the Chicago area.

The facility consists of two-story office space, warehouse space with both -10also provides a community teaching kitchen with classrooms and multi-use areas. In short, this isn’t just a warehouse.

Raising the Roof

When company officials decided to expand the Albertson’s Grocery Distribution Center in Melrose Park, Ill., they decided to build up, not out. After all, raising the roof by 20 ft. would essentially triple their warehouse space.

But raising a 630,000-sq.-ft. roof presented some daunting challenges—not the least of which was how to keep the facility in operation during the renovation. It wasn’t accomplished overnight. In fact, the roof raising was phased over two and a half years in five sequential lifts. The distribution center was able to maintain full operation throughout the project in areas adjacent to the lifts, while keeping employees, material-handling equipment and stored product safe. Also, during this time, a conveyor and 48-station palletization system was installed, fed by two high-speed sorters and six 3-ft.-high modules.

Raising the roof had significant implications for M/E/P design. In a facility that now reached 38 ft. high—55 ft. at the roof peak—and with high-rack storage and tall handling equipment, layout of lighting fixtures, fire sprinkler heads and overhead electrical and HVAC had to be planned very carefully.