July/August 2010
Stormwater, safety, climate, and noise are a few reasons why yards enclose or cover their shredders, though these yards are still the exception rather than the rule.
By Theodore Fischer
About 280 shredders operate in North America, and maybe a dozen of them are within walled structures or under a roof. More are under construction, but it's a trickle rather than a tidal wave. That's in stark contrast to Europe and Japan, where enclosed shredders are fairly common, says Jim Schwartz of Metso Texas Shredder (San Antonio). The difference may have to do with geography: "You see them more in Europe because of tighter quarters," he suggests. In other words, when shredders are in a more densely populated area, "people don't want to look at the damned things."
He might have a point. Some of these companies say they constructed their shredder enclosures to respond to—or get ahead of—community concerns about noise, aesthetics, stormwater runoff, and more. "It's a wonderful thing from an environmental standpoint because indoor shredding eliminates, among other things, stormwater [concerns]," says Bill Baumgartner of W.Z. Baumgartner & Associates (Franklin, Tenn.), an environmental engineering firm. "But I look at shredders from a, 'How can I keep them operating without complaints or environmental questions?' standpoint, and from that standpoint indoor shredding has some pluses and some minuses."
Why Indoors?
One reason scrap companies enclose their shredders is because they had to: Local permit-granting authorities made that a condition of their installing or replacing a shredder at that facility. What do the governing bodies object to? "The very existence of it," says Baumgartner. "They sometimes just don't want them, for whatever reason."
The potential for noise, dust, stormwater contaminants, and an unsightly appearance lead but don't conclude the list of reasons regulatory bodies object to shredders, Baumgartner says. "If the zoning board—or whatever decision group you're dealing with—is wavering and [enclosing the shredder] will make the difference in getting them to move forward, that might be something shredder companies would offer" to get an agreement.
Northern Metal Recycling's state-of-the-art enclosed shredder is on the banks of the Mississippi River a few miles north of downtown Minneapolis. Constructed after years of wrangling with state and local authorities, the LEED-designed metal enclosure houses both the shredder and the downstream separation equipment, with the infeed conveyor outside the building. Camden Iron & Metal (Camden, N.J.) faced similar community concerns when it applied for permission to relocate its metal-shredding operation from an outdoor site near the Philadelphia airport to an indoor facility along the Delaware River in Eddystone, Pa. "Being in a building takes care of a lot of the issues people are concerned about," said Joseph Balzano Jr., president of Camden Iron & Metal, to the Philadelphia Inquirer. (At press time, county authorities had approved Camden's plan, and the company—which is changing its name to Eastern Iron & Metal Recycling--was awaiting borough council approval.) SA Recycling (Anaheim, Calif.) has entirely covered two of its shredders to comply with new Southern California regulations on the emission of volatile organic compounds, says the company's CEO, George Adams. The structure will have a system to capture and filter any steam and dust the shredder produces.
Some scrap companies are moving to enclose their shredders because they think that's what regulators soon will require. That was one factor that motivated Upstate Shredding (Owego, N.Y.) to enclose almost all parts of its shredding system. So far the company has constructed a roof over its infeed stock piles and a large building to house its downstream separation system and shredder residue. Still to come are buildings for ferrous and nonferrous shred and a 65-foot-tall building around a new 10,000-hp shredder. "We didn't have to do it, but I think it's coming down the pipeline that we will have to do it," says Upstate President Adam Weitsman. "So while it's a good time in the shredder business, we wanted to do it now." And, he points out, such capital improvements can qualify for accelerated depreciation under current tax laws, "but you don't know if the tax laws will change in the future."
Other companies have partially or fully enclosed their shredders due to safety concerns. A specific danger point is the top of the infeed system, where the scrap enters the shredder box through the feed rollers, says SA Recycling's Adams. "There are millions of pieces of steel going through there, and there's the opportunity for steel to hit something" and bounce out under the infeed rollers through the infeed chute, becoming a high-speed missile. The scrap "will find amazing ways to get out," he says, and covering the top and sides of the infeed rollers can keep such incidents from killing someone.
Over the past 25 years, the SA facilities have experienced several accidents and near-accidents caused by flying scrap, Adams says, and they have added more barriers around the shredder each time. In 1985, one piece of scrap flew out of a shredder and became embedded in a worker's hard hat, which almost certainly saved that man's life. A wall and a half-roof over a new shredder did not entirely solve the problem: Another piece of scrap flew out, went through the cab of a crane, and landed between the crane operator's legs.
"When we built our new shredder in 2004, we completely enclosed the whole shredder, all the way over the top," with rubber flaps on the sides of the infeed rollers, Adams said. That worked until a rubber flap came loose during a shift one day. "A piece of steel came out through that side, flew 562 feet through the air, went right through the roof of my lunchroom, and hit a table in the back of the room. … It's just pure luck there was nobody there at the time." Now that shredder has rubber shielding around the infeed area and a second layer of rubber flaps hanging off the edges of the roof. All four SA shredders have roofs over the infeed area and flaps around them so they're fully enclosed, and some of them have roofs over the entire shredder.
Newell Recycling of San Antonio has seen the worst that flying scrap can do. In the late 1990s, a worker on the picking line was struck and killed by a piece of scrap that flew out of the shredder, says Buck Nichols, the company's vice president. Newell has since surrounded its shredder with two-story-high metal walls that are about 5 feet away from the shredder on each side.
In at least one case, the building came first, the shredder second. In 2008, Recycle West Virginia installed a 4,500-hp shredder in a historic building on the 14-acre former site of the Virginian Railway manufacturing and repair yard in Princeton, W.Va. "I didn't want to tear down these buildings," explained Recycle West Virginia owner Tom Bishop at a meeting of local businesspeople. "This was an indoor scrapyard already in place."
Nor was indoor shredding a new idea to Hutcherson Metals (Halls, Tenn.). "In the late '70s to early '80s, H.O. Forgy was probably one of the first people to operate a shredder inside," says owner Wiley Hutcherson. "He went out of business, and we bought the property" where that shredder operated in Jackson, Tenn. Though Forgy's shredder had been removed and put into service elsewhere, in May 1992 Hutcherson installed an electric-powered 80/104 Texas Shredder in a new building that's 100 feet wide, 300 feet long, and 50 feet high. The system is designed so that conveyors can load the processed material into railcars either inside or outside of the building. The company's Halls, Tenn., yard already had an outdoor shredder of the same design, though it runs on propane or natural gas, not electricity. In 1997, Hutcherson added one more 80/104 Texas Shredder, this one powered by diesel—and he enclosed it in a building that's 10 feet taller than the one in Jackson. Hutcherson says he uses the Jackson shredder and the outdoor Halls shredder for day-to-day production and the indoor Halls shredder for special projects.
Benefits of Buildings
So what problems can enclosures address? Start with noise. There's no doubt that shredders are noisy, Baumgartner says. "When you've got moving equipment, moving belts, machines rotating at 500 or 600 rpm driven by a 2,000-hp engine, you've got some serious machinery in place there." Placing a shredder indoors helps stifle noise, though shredder manufacturers note there are other approaches to this problem. Some yards have sound barrier walls strategically placed around parts of the facility. Shredder design also can help. "We usually use thicker plates for the chutes, so it makes less noise when the scrap is bouncing on the plates," says Christian Nevarez, an engineer at The Shredder Co. (El Paso, Texas). Just keep in mind that the enclosure doesn't protect those inside it from shredder noise. Facilities should evaluate noise levels and provide hearing protection as needed.
As mentioned, building a roof over a shredder also can reduce stormwater contamination problems. At the Upstate yard, the trucks unload under a roof, so stormwater does not touch the unprocessed material, Weitsman says, nor does it touch the shredder residue. In about 45 days the ferrous and nonferrous will be covered, and after that, the shredder itself. When stormwater "doesn't hit the scrap material, it's not counting as process water, it's just counting as basic water," he explains. The 13-acre facility is entirely concrete-surfaced, and the company is installing a full stormwater treatment plant. "The whole point is to be a wholly 'green' certified facility, with no stormwater leaving the facility that's unprocessed," he says.
Stormwater was the primary reason Weitsman chose to cover his shredder, but "customer happiness" was not far behind. For this facility, located just west of Binghamton, N.Y., and just north of the Pennsylvania border, unloading scrap under a roof means that "customers don't have to be in the snow, they're not getting rained on," he says. At the other end of the climate spectrum, "we have shredders in Saudi Arabia where you have picking conveyors, but people there can't work 10 or 12 or 16 hours under the sun," Nevarez says. "That's one advantage of an indoor facility, that you can work more efficiently due to better climate." Tom Bishop Jr. of Recycle West Virginia echoes those sentiments. "You don't get rained on, it's cooler in the summer, it's warmer in the winter, that makes it easier on the employees."
Weitsman also believes sheltering his shredder can increase productivity and efficiency. "There are lights on top of the building, so we can run later at night and keep our shredder plant open 24 hours a day," he says.
Design Options
In most cases, purpose-built structures for shredders are metal buildings that contain most of the shredder plant. "Normally, the infeed conveyor starts outside and goes inside, and in many cases the stacking conveyor—where the final product is—is outside again," Schwartz says. Though some of the structures housing shredders also encompass the infeed conveyors and the infeed and output material, most do not. "You need a lot of room and a lot of height to stockpile a few thousand tons of material," Schwartz says.
At Recycle West Virginia, the 100- by-558-foot restored steel building contains the shredder and the downstream separation equipment: three eddy-current separators, two induction sorting systems, and a 1,700-foot conveyor system. Outside the building are the feed piles and cranes, the infeed conveyor, the operator tower above it, and the cyclone.
CFF Recycling (Houston) operates a shredder is in a metal building manufactured by the firm ilg (Industrielärmschutz) and marketed by Metso. These "plant capsules" consist of galvanized casings with noise-absorbing sliding doors that facilitate cleaning and maintenance. The buildings can incorporate custom-built noise-protection housings integrated with crane equipment with capacities of up to 10 mt, with splinter-protection mesh to prevent the escape of tiny metal particles. The plant capsules run from $350,000 for a small shredder to $750,000 for a megashredder—that's without the roof, which is how they're most often installed, says Tim Conway, vice president of business development for Metso Recycling North America. Upstate Shredding's structures are from Vulcraft Group, a subsidiary of Nucor, which is an Upstate customer. They're constructed of steel beams with galvanized siding.
The SA Recycling yards use a variety of different roofing materials over their shredder infeed areas, from solid steel to a double-layer of chain link mesh, Adams says.
Inside Knowledge
For operators contemplating indoor shredding, Metso's Schwartz has three pieces of advice. "First, isolate the shredder itself from the rest of the building, because there are occasional explosions," he says. That can be the unfortunate result when something that is not supposed to enter a shredder—a compressed-gas cylinder, paint container, or automobile that has not been fully drained of gasoline, for example—gets into the shredder box. He advises placing the shredder in a building of its own. If that's not possible, use concrete barriers to separate the shredder from the people working downstream, he adds. Nevarez seconds that advice. Even without an explosion, the problem of projectile scrap makes it wise to "have the shredder itself enclosed inside the enclosed building." Upstate will have an opening in the roof of its building above the shredder box, Weitsman says, "because if you get an explosion, it would blow the roof of the building off."
Next, Schwartz says, place the operator in a remote location near, but not inside, the shredder building. "It can be anywhere from just outside the building to anywhere in the yard," he says. Though historically the operator has been positioned above the shredder "looking down the feed chute," there's no need for that with today's technology, he points out. "It's still done out of inertia, but with all the cameras—and, in particular, the infrared cameras—there's really no good reason to put him there." That said, several yards with enclosed shredders still have the operator tower right above the shredder box and infeed rollers.
Third, leave yourself plenty of headroom. "The clearance must be very high, a minimum of 60 feet, because you have to get a crane in there," Schwartz says. "A few have been built with the crane already inside, then they put the roof on afterwards, which I don't think is as good as having a much higher clearance—80 or 90 feet. But of course that costs more money." A roof that can be removed or opened is helpful for maintenance, says SA Recycling's Adams.
Along the same lines, Tom Bishop Jr. advises leaving plenty of space around the shredder for equipment to maneuver safely, with "no closed-in spaces, no tight spots where you couldn't clean up if you make a mess." Recycle West Virginia designed the installation of its shredder with "nice, wide aisles" for Bobcat skid-steers to get around it, and it added scrap steel guards around anything that might get damaged if bumped. Upstate has added 10-foot to 12-foot concrete bollards around the support beams of each building. Weitsman admits that was an afterthought—a piece of equipment struck and bent a beam just a few weeks after one building was finished.
Keep maintenance in mind as well. At Newell in San Antonio, doors in the walls slide open about 25 feet so workers can change the rotors and liners and do other work on the shredder, Nichols says.
Gimme Shelter?
Although zoning boards might continue to force shredders under cover, Bill Baumgartner doesn't believe indoor shredding will become prevalent in the United States any time soon. "One reason I don't think we'll see it as a trend is that there just can't be that many more shredders built," he says, especially in densely developed areas. "Most folks don't go out and try to buy a piece of property [for a shredder] in some urban downtown when they can get land out in a soybean field a lot cheaper, and usually encounter less opposition."
But Metso's Schwartz thinks partially or fully enclosed shredders will become more prevalent, primarily because he expects U.S. environmental agencies to further regulate shredders' "fugitive emissions," including VOCs. It will be very difficult to meet the future standards without enclosing the shredder somehow, he says, so a metal frame and rubber flaps around the shredder, plus a system to control the emissions, will become more common. (The United States is "uncharacteristically" far ahead of the Europeans on the regulation of fugitive emissions, he notes.) "All this means more cost, of course, but it appears that it's going to become necessary."
Upstate's Weitsman, who plans to spend $4.5 million on the enclosures and other upgrades to his yard, also remains enthusiastic about—or at least resigned to—an indoor shredding future. He also predicts that "tough regulations are coming down the pipeline.
I would suggest that people don't wait until they get forced to do it," he says. "Do it ahead of time, and you can spread the money out a lot better." •
Theodore Fischer is a writer based in Silver Spring, Md.
Stormwater, safety, climate, and noise are a few reasons why yards enclose or cover their shredders, though these yards are still the exception rather than the rule.