Much of the plumbing and wiring was completed in advance on this Safeway processing system. Fully functional operator interface panels also were available for training well in advance of start-up.
“Classic recalls have occurred when listeria or other contaminants have migrated into a process area with dust from a construction area,” says Redmond, noting that construction workers can help the cause with training in food plant sanitation. He recalls a complicated project at a Brewster Cheese plant in which product flow had to be reversed. “We had to put an addition on the back of the line so that we could create a void at the front,” he said.
Getting as much of the work and construction done off the plant premises not only protects against the upheaval of such contaminants but provides an opportunity to see that piping, electrical and equipment function properly before they are put to the test within the plant itself.
Shambaugh says the amount of pre-fabrication of systems has jumped two to three times over the past five years. Assembly in a pre-fab shop is almost always quicker, easier and more effective. It may often cut 50 to 60 hours of plant installation in half.
“Installing unitized equipment on a skid definitely helps,” says Safeway’s Barrow. “You can assemble the equipment for the hot water sets to your process equipment, for instance. You can also pre-wire and do the pre-plumbing, to an extent, before you get into the plant. It definitely helps.”
A lot of companies dismiss the notion of major pre-assembly of equipment and process systems before they have thought the idea through. “They think, ‘Oh, my doors or (dock ports) are too small. We can’t do that,’ ” says Shambaugh. “You have to think outside the box. Perhaps knock out a wall. It’s not that hard to do. And you may miss only a few hours of production instead of days or weeks.”
One of Shambaugh’s most recent projects involves installation of a new ammonia refrigeration engine room at a Smith Dairy plant in Orrville, Ohio. “We can’t shut down the plant for more than one day, so we are re-doing the whole engine room and bringing it into the plant in two pre-fabricated 40-ft. sections,” says Shambaugh. “It’s a whole room on wheels, basically.”
To save space, the Smith plant is also positioning its condensing units on the roof. Those, too, will be assembled off premises and brought to the roof on skids. Piping and the refrigeration-control interface also will be assembled off site. “They will miss only a few hours of production instead of days or a week,” says Shambaugh.
Off-site assembly can solve critical problems months before final installation, notes a site project manager for a dairy processor, who asked not to be identified. “Pre-fabbed, pre-built, pre-engineered and on a skid -- you can solve a lot of problems and keep downtime to a bare minimum that way,” he says, noting that his latest project required only two short shutdowns — one for parts and valves and a second for equipment installation. “Done this way, it becomes a changeover more than a big plant project.”
Every plant project today includes some sort of plan for energy savings or efficiencies, even if that means little more than scheduling production to take advantage of running during off-peak hours.
This pre-fabbed dairy system was engineered, built and put on skids for months before final installation. "It becomes more like a changeover than a renovation when executed this way," according to the project manager.
Renovation projects provide occasions to review plant practices concurrently with physical improvements. Digital control systems open energy control strategies to processors, helping to reduce energy cost and making the plant more reliable as well. The open architecture of today’s systems makes more systems compatible as well.
Water cleanup has become a target area for energy savings. Drying out a wash-down area takes significant energy. One simple approach to reducing that energy requirement is to plan to use less water during the clean up. Less water in means less energy required to take it out.
“Companies are no longer just plugging into an electrical grid either,” says Redmond. “Some are looking at solar power to preheat feed water.”
Refrigeration is a key energy issue for food plants, and one that had undergone huge changes in recent years because of environmental considerations of some refrigerants, says Peter Comeau, president of Refrigeration Engineering and Contracting Co. (www.reccousa.com), Woburn, Mass.
Note to QA
A Top 10 U.S. food company has applied the Process Safety Management (PSM) template for ammonia refrigeration safety to renovation and construction scenarios in operating food plants.
“Plant personnel must go through a checklist dealing with key elements to separate activities,” says Chris Harmon of Hixson Architects & Engineers, Cincinnati. “That list includes how to maintain refrigeration temperatures and traffic control of personnel and materials — how to get old materials out and new materials in — without affecting production flow or exposing product to contaminants.”
Harmon stresses that the key to maintaining product safety and integrity during renovation activities is to “make it a team effort,” involving all parties involved with the renovation and plant production.
Quality assurance should also do increased sampling around construction areas to make certain that product passes the test.
Comeau sees many more plants looking to – or returning to – ammonia-based refrigeration systems. One reason is the inherent advantage in using a natural refrigerant. “They are very efficient, and they won’t be regulated away like R-502 (CFC), R-22 (HCFC) or R-12 (CFC),” he says. (Production of R-22 will slow in 2008 and will be eliminated by 2020.) There’s a cost factor, too. “When they were phasing out R-12, it went from a dollar a pound to $20 per pound. That was dramatic.”
He recommends that plants with refrigeration systems operating on R-22 develop contingency plans to use alternate refrigerants.
“If you don’t want ammonia, try R-507,” Comeau adds. “It’s a new refrigerant, and the price is getting competitive.” So far, plants that have installed systems that use R-507 are working well, he reports.
Replacing refrigeration systems requires very rapid turnaround since product safety and quality are often at risk during this period. Sometimes the new system has to be built side-by-side with the old system to facilitate a quick switch. Multiple systems may be replaced in sequence.
When Recco converted an ammonia refrigeration system to all glycol, Comeau was uncomfortable with the ammonia piping. His solution was to put in a parallel piping system that tied into the central system. “We had glycol available on five floors,” he recalls with pride.
Piping is always an issue when renovating older facilities. “The pipes of 30 years ago were not made to today’s standards,” says Comeau. Addressing the deterioration of steel piping or hot gas defrost lines can be an important aspect of a plant renovation. Non-destructive testing methods will help determine if pipe walls have thinned.
“Typically, the pipes are insulated with urethane,” says Comeau. “The vapor barrier breaks down and the vapor passes through the insulation and hits the piping. Mix the condensation, the water and steel with the temperature cycles, and you have a corrosion situation.”
Gel-coated piping can be a very effective defense against corrosion, he notes. Some paints and primers work, as well.
Motorized valves offer greater efficiency and reliability. They can quiet banging and shaking pipes and enhance the effective life of the valve as well. “They will also smooth out your plant operation, stabilizing compressor usage,” says Comeau. “Your compressor stays in one position throughout the daily cycle of the plant. You get no surges with motorized valves. It makes a dramatic difference.”
That’s what can happen when your plant has a plan.