“Better Things for Better Living ... Through Chemistry” was a long-time DuPont slogan, and a number of regional and national chemical firms are trying to prove its validity by training their sights on food and beverage manufacturers’ special flooring needs and developing a wide range of polymer and resin-based coatings to meet them.
Of course, no single cement coating could be expected to measure up to the demands of all types of manufacturers, or even the varying conditions in a single plant. But two resin classes-epoxy and cementitious urethane-have emerged as the best fit for most areas. Cost advantages over traditional flooring, as well as speed of installation and low-VOC and odor levels that minimize disruptions to normal production, have helped make epoxy and urethane the materials of choice for many. But while project engineers and architects give the new-age resins high performance marks, they caution that improper preparation and installation can lead to delamination and early failure. “Know thy installer” is the first commandment when selecting a flooring system, regardless of the material used.
“The products today are really quite good,” says Steve Deal, senior architect at POWER Engineers Inc., Haley, ID. “The failures, particularly with the seamless resins, reside in the lack of proper preparation of the substrate. If there was better supervision to ensure installation instructions were followed to a tee, there wouldn’t be an issue. But it doesn’t happen, and you have failures six months down the road, followed by fingerpointing.”
Anecdotally, Mike Folmer of Hixson Inc. cites a Cincinnati manufacturer that refuses to even consider one particular material for floor covering. The same manufacturer operates a plant in another state; however, and plant managers there don’t hesitate to use the verboten-in-Ohio material. The reason? Confidence in the installer. “Preparation is the key,” says Folmer, vice president and senior project architect.
Impatience works against preparation, and a weekend timeframe for a floor installation is a luxurious pace by today’s standards. With new construction, few manufacturers are willing to wait 28 days for the concrete substrate to cure. Consequently, chemists have responded with base-coat formulations that can be applied to green concrete. One example is Corro-Cure, an epoxy primer that can be applied within 24 hours, according to Hugh McVey, a principal in Corro-Shield International Inc., Rosemont, IL. The coating cures in 18 hours.
Regardless of how well the resinous material is formulated, or how appropriate the covering is for the application, improper surface preparation and installation will lead to early floor failure. Sherwin-Williams Protective & Marine Coatings developed a certification program through the Society for Protective Coatings a few years ago, augmenting a contractor training program the company inherited from General Polymers. Preparation, substrate essentials and material application are covered, according to John Durig, market director-food & beverage at Cleveland-based Sherwin-Williams. The coatings firm wrote the certification program, and the first eight instructors were Sherwin-Williams employees, he adds.
“We’re selling an outcome and an expectation of performance, not a bucket of resin-based materials,” adds Durig. “We have an obligation to ensure it is going in properly. We do that with a warranty, and we won’t provide a labor and material warranty with a contractor we’re not confident in.”
Other suppliers are taking a more direct route toward quality assurance. “We’re the only global player that makes the product, specifies the solution and installs the floor,” says Mike Jewell, vice president-marketing at Maple Shade, NJ-based Stonhard Inc. The company produces hundreds of formulations and various textures of epoxy and urethane coatings, depending on the application. But if the substrate isn’t clean and dry, none will perform as desired. “If the substrate is contaminated, the floor will fail,” which is why Stonhard also is a contractor, explains Jewell.
Keith Kwasny, founder and president of SaniCrete in Farmington Hills, MI, directed work crews that painted buildings and applied wall coverings for a decade before he began focusing on food and beverage facility floors and walls. Six years ago, Kwasny began manufacturing his own polymer coatings, and he now deploys eight crews across the country to apply them. “You can’t just buy my product and slap it down,” he says. By offering turnkey flooring solutions, SaniCrete can be price competitive with the largest floor coatings suppliers, he says.
Seamless appealInstallation is an issue with acid-resistant brick and other alternatives to resinous compounds, as well, points out Kwasny. Besides the lower cost, “polymer is slowly catching up in terms of performance,” he says, “and speed of installation is the key criterion today. If it used to take two days, now [facilities] want it done in one.”
Epoxy finishes are available from SaniCrete, but urethane concrete is becoming the polymer of choice in many food plants, he says, because of its chemical resistance and ability to handle thermal shock. To boost urethane concrete’s durability, Kwasny’s firm created a cementitious urethane containing stainless steel fibers, in a ratio of 1 lb. of steel to 52 lbs. of urethane compound. The fibers perform much the same as rebar or wire mesh in concrete, strengthening the chemical bond and making the topping crack resistant. Rust proofing is an added benefit: Oxidized metal weakens concrete and causes corrosion in polymers (though the phenomenon is referred to as degradation). A zinc coating would also curtail rusting, but “food processors didn’t want to talk to us if it wasn’t stainless,” Kwasny states.
At least half the installations using Sika Corp.’s materials involve urethane cement, estimates Brad Weil, marketing & technical director at the Lyndhurst, NJ firm, and virtually all “the harshest environments” in food production use those coatings. “Urethane cement can last 10-20 years,” he says, assuming it is properly maintained and appropriate for the use. Thicknesses range from 3/16 to 1/4 in., whereas three coats of epoxy might measure 0.050 in.
Sika personnel are not directly involved in the installation, but the firm offers annual training for contractors and has altered formulations to make it easier for them to be applied correctly. “If the material is easier to work with and cures slower, contractors prefer it,” says Weil.
From a food safety perspective, seamless floor covering has obvious appeal, particularly in food production areas subject to high-pressure washdown. A monolithic floor protects the porous concrete substrate from moisture, food acids and corrosive sugars and salts. It also eliminates the need for grout, removing a potential harborage for dirt and bacteria, chemical companies state.
Methyl methacrylate, polyurethane, polyester and a variety of other coatings are also used on industrial floors, but issues have surfaced in food and beverage applications. Generally speaking, the industry has settled on epoxy and cementitious urethane for seamless floors, with urethane mortar the material of choice for the most challenging conditions.
“Because of the thermal cycles in food and beverage, cementitious urethane has become the standard,” maintains John Crowley, vice president of Garon Products Inc., Wall, NJ. Whether it’s troweled down or applied as a 3/16 in., self-leveling urethane cement or aggregate medium, “you’re cutting two days from any project” with urethane mortar, Crowley says. His firm recently developed a cementitious urethane with a gloss finish, a more cleanable surface than a matte finish, he says.
Given the industry’s focus on food safety, cleanability is an important consideration in flooring selection. Just as there are tradeoffs in material selection, manufacturers seek a balance between cost, durability, food safety and worker safety. A glass floor would be the ultimate cleanable surface, but it would be a disaster in terms of traction (not to mention durability). A recent Liberty Mutual Research Institute for Safety report highlights a sharp increase in Worker’s Compensation costs due to trips and falls. Over a 10-year period, the cost of workplace injuries resulting in at least five days of missed work because of falls on the same level increased 36.7 percent to $7.7 billion. Falls to a lower level cost $6.2 billion, a 33.5 percent increase. If indirect costs are included, the total economic cost of workplace falls may exceed $48 billion, according to Ted Courtney, director of Liberty Mutual’s Center for Injury Epidemiology.
Plant safety programs focusing on ergonomic issues have helped slash the incidence and cost of repetitive motion injuries, but slips and falls do not receive the same attention, Courtney points out. A Liberty study found that slip-resistant footwear could cut slips and falls in half. Other studies focusing on the coefficient of friction (COF) of floors in food service kitchens have concluded that high-friction floors can reduce slips by a factor of 2.5 times, compared to low-COF surfaces. The good news is that most flooring suppliers use measurement tools to provide COF values; the bad news is the absence of standardized values, making it difficult to compare one supplier’s floors to another’s.
Injuries sustained on platforms or mezzanines are categorized as either falls on the same level or falls to a lower level. Diamond-plate surfaces on elevated floors are factors in both types of falls. A high COF is critical on platforms, particularly when grease or water is present. Cement coatings are inappropriate over a steel substrate, though spray-on epoxies and fiberglass panels often are applied. “Fiberglass always chips, epoxy always peels or flakes,” states Sterling Larson, director-engineering at M.G. Newell Corp., Louisville, KY. “We’re seeing more people committing to stainless steel plate with a shallow tread.”
A former corporate engineer at Nestlé USA, Larson specified stainless steel plate from Detroit-based SlipNOT Metal Floors, “and it stood up well.” He often recommends it for platforms and decking for Newell food clients, in part because it can be welded onto the framework, eliminating any harborage areas. Attaching fiberglass to a frame requires fasteners.
Aluminum or galvanized steel can be used to create SlipNOT’s metal flooring, but 304 stainless is the median used at food factories, according to Glenn Dusek, sales representative. Plate is fed into a machine where it is heated to approximately 2,800°F. A molten metal alloy binds to the plate under pressure of 4,000 psi, creating a cross-hatched matrix with a variance of 0.020 in. from high to low point.
Old school optionsPolymer scientists haven’t cornered the market on flooring innovation; new options and enhancements to the tried and true are becoming available. A cement and granite composite developed for Danish pork plants impresses Tom Boll, director-project development at Jacksonville, FL’s Stellar. “It’s virtually indestructible once it’s laid,” says Boll. “It’s very difficult to repair, but if it’s installed properly, that’s not an issue.”
The non-slip, blood- and fatty acid-resistant material is installed domestically by Margia Floors Inc., New Orleans, LA. A 1.3-in. bottom layer is applied over roughened concrete, with a 0.7-in. top layer of granite and concrete providing an impervious, non-slip surface that is compressed with rollers and then dehydrated. One of the earliest US installations was at the Armour-Ekrich Meats plant in Junction City, KS.
FDA recently gave its approval to vitrified ceramic tiles with extremely low porosity and greater resiliency than quarry tiles. Specialty clays baked at very high temperatures produce dense, 3/4-in. thick tiles, about half the thickness of acid brick. Special grout is required, cautions Corro-Shield’s McVey, because the tiles expand much less than brick. “In this case, hardness helps.”
A handful of firms have produced vitrified tiles for European food plants for a quarter-century, but the manufacturers are just beginning to establish US beachheads, according to Shawn Hamilton, managing director of Montgomery, MN-based Kagetec. The German firm installs almost 1 million sq.ft. of the tile annually, though the US installed base “is almost nothing.” Because Kagetec’s tiles are “fully vitrified,” water absorption is less than 0.05 percent, about one-hundredth the rate of brick.
A 4x8-in. rectangular tile might produce a “lipper” when laid over a sloped floor. Vitrified tiles usually are 5-in. hexagons. “The hexagonal shapes allow us to go around contours without a point sticking up,” notes Hamilton. “Once installed, it’s almost indestructible.”
Highly polished concrete is a successful flooring choice in retail, and the treatment is being used in USDA-inspected food facilities, as well. Celebration Foods (“The science and art of mass production,” Food Engineering, April 2009) used the technique on its ice cream cake manufacturing facility’s 43,000-sq.-ft. production floor. Grinding with progressively finer grit polishers produced an easily cleaned surface; a sealer made the surface impervious to water and lactic acid.
“Cleanability is great, and it doesn’t peel, unlike some of the other systems,” reports Bob Palczewski, director of engineering at the New Britain, CT winner of the 2009 Plant of the Year award.
“But if you don’t do the prep work right, you’re dead,” Palczewski cautions. The company also incurs the ongoing expense of slip-resistant rubber boots to minimize the risk of worker slips and falls. “Everything is a trade-off,” he allows, but after two years’ use, no cracks or other performance issues have surfaced. “We can always coat it with urethane,” he adds.
However, resinous coatings cannot be applied to polished concrete until the silicate densifier is removed, cautions Will Hier, president of Integrated Industrial Services Inc., Syracuse, NY. “You can’t just shot-blast that off,” he says. “It’s going to take time and money.” His firm applies a multi-step grinding process to polish concrete, using resin-bond diamonds from 100 to 3,000 grit. The technique started on the West Coast and has migrated east, reaching the East Coast in the last five to10 years.
For many food manufacturers, acid-resistant brick remains the gold standard. “If you want a bullet-proof floor, that’s the way to go,” believes POWER Engineers’ Deal. For durability and functionality, brick is best, adds Hixson’s Folmer. With brick, grout and mortar used to be the weak links, but those are being improved. Plus, harder sealants that protect the bricks’ edges while handling thermal shock are coming into the market, Folmer points out.
Bugs be goneBugs be gone
For several years, suppliers of antimicrobial compounds have promoted their products as food safety additives for floors and other surfaces, but acceptance is mixed. Agion Inc., which manufactures a silver ion additive, made a push into flooring a few years ago, but only Sherwin-Williams offers Agion’s product as an option in one of its resinous coatings. Sherwin-Williams also offers the bactericide DM-50.
Perhaps one in five of Stonhard’s food clients requests an antimicrobial additive, estimates Jewell, usually because someone has encouraged them to do so, “but it’s not insurance. The role of any polymeric surface is to provide a dense, impervious surface that can be cleaned. Antimicrobials are passive defenses. Companies with very good cleaning regimens don’t see the value.”
SaniCrete’s Kwasny echoes the sentiment. The antibacterial Triclosan can be added to his coatings, but “if you have a good sanitation program, a good, nonporous, crack-free floor is going to do the job,” he says, adding that interest in antimicrobials appears to be waning.
Sika offers silver ion for wall coatings but not for floors. “We get much more interest in antimicrobials from schools and hospitals than from food and beverage plants,” says Weil. “It’s very expensive.”
Antimicrobials might be appropriate for surfaces in remote areas of the plant, suggests Hixson’s Folmer, but critical areas are washed “at least once a day,” making the long-term kill from these aids moot. Still, “if corporate leaders decide, ‘we’re going to use it,’” antimicrobials are part of every coating, Sherwin-Williams’ Durig notes.
Sanitation and hygiene requirements have increased dramatically with additional scrutiny from the Food Safety and Inspection Service (FSIS) division of USDA, says Keith Pfaff, engineered linings director with Blome International, located in O’Fallon, MO. Building on existing polyurethane technology, Blome’s third generation polyurethane-urea technology product, THERMCRETE, features antimicrobial technology with a very low modulus of elasticity. Coupled with an increase in compressive strength, the system provides improved impact and abrasion resistance.
The polyurethane-urea formulation has a coefficient of thermal expansion close to that of concrete, says Pfaff, giving the material thermal shock resistance. The third generation polyurethane-urea formulation has a significantly higher solids content reducing shrinkage while increasing flexibility. Other benefits of this technology include: non-toxic, no-odor, improved color stability, cold environment application, high degree of moisture tolerance, greater lifetime expectancy, fast application and quick setting with no primers or sealers required, and bonds well to substrates unsuitable for previous formulations.
Making the callConditions of use and amount of abuse dictate what type of flooring should be used. Epoxy can be the best option for packaging rooms, cafeterias and other worker-welfare areas. But what is needed in a slaughterhouse is probably overkill in a bakery.
Length of expected service is another variable. “With monolithic floors, you’re lucky if you get five to seven years’ use,” points out Folmer. But if a product line’s long-term prospects are iffy, or the plant may be reconfigured and require different drainage patterns, five years might be ample. “Cost is a big issue, and what you spend depends on the longevity you want,” he adds. “If you want 20 to 30 years, you should use brick or tile.”
Even the best material will fail if it is not properly maintained, cautions Stellar’s Boll. “Whether it’s brick, granite or whatever, floor maintenance and joint maintenance need to be addressed.” If flooring isn’t installed and maintained properly, plant owners will find themselves going through the selection process again, much sooner than expected.
Floors that go heave-ho
Discretion and client confidentiality prohibit naming names, but Johnny Johnson gets weekly calls from companies experiencing problems with their freezer floors. And by and large, the cracked floors and heaving cement could have been avoided with a diligent maintenance program.
If the temperature of subsoil below a freezer’s sub-slab dips below 32°F, moisture in the soil will freeze and form an ice lens, a miniature glacier resembling a flying saucer. Instead of flying through space, it pushes upwards, buckling and heaving the concrete floor above and affecting pallet racks and even building columns and roof members. Although monitoring the performance of glycol heating loops, electric heating cables or vent-tube systems with sensors or thermo couples can ensure that subsoil remains above the freezing point, enough companies neglect maintenance to keep Johnson and professionals like him busy.
The vice president of field services for Jacksonville, FL-based Stellar recalls the food freezer where concrete had heaved 18 inches and sections had been closed off by the time he was called. To keep refrigerant costs in line, the customer’s former maintenance manager had filled the glycol lines with water. “Now they had a $150,000 problem,” sighs Johnson. Another food freezer was imperiled when sensors were severed “because they were in the way” when racking was repositioned, he grimaces. A meat company followed conventional wisdom and didn’t bother with any safeguards because operating temperatures were above 0°F, only to experience frost heaving after 20 years.
Most of the failed heating systems he encounters involve clogged vent tubes. Regardless of what heating system is used, the key to prevention is monitoring soil temperatures. “Installing sensors is a relatively inexpensive thing to do,” Johnson notes. Once installed, pay attention to the feedback they provide on soil temperatures and heating system performance. An ounce of preventative maintenance is worth a pound of uneven floor grade.
Food & Beverage Industry Flooring Suppliers
Atlas Mineral and Chemicals Inc.
1227 Valley Rd., P.O. Box 38
Mertztown, PA 19539
BASF Construction Chemicals-Building Systems
889 Valley Park Dr., Shakopee, MN 55379
Blome International Inc.
1450 Hoff Industrial Dr., O’Fallon, MO 63366
300 Edwards St., Madison, OH 44057
750 Patrick Place, Brownsburg, IN 46112
Corro-Shield International Inc.
7059 Barry St., Rosemont, IL 60018
Crossfield Products Corp.
3000 E. Harcourt St.
Rancho Dominguez, CA 90221
Fortified Systems Inc.
126 Eisenhower Ln. N.
Lombard, IL 60148
Garon Products Inc.
P.O. Box 1924, Wall, NJ 07719
Integrated Industrial Services Inc.
6169 Eastern Ave., Syracuse, NY 13211
Kagetec Industrial Flooring Systems
309 Elm Ave. SW, Montgomery, MN 56069
24535 Hallwood Court
Farmington Hills, MI 48335
Sherwin-Williams Protective & Marine Coatings
101 Prospect Ave.
Cleveland, OH 44115
Sika Industrial Flooring
Division of Sika Corp.
201 Polito Ave., Lyndhurst, NJ 07071
SlipNOT Metal Safety Flooring
2545 Beaufait St., Detroit, MI 48207
One Park Ave., Maple Shade, NJ 08052
Surface Solutions Inc.
5689 W. 73rd St.
Indianapolis, IN 46278
Tnemec Co. Inc.
P.O. Box 165770, Kansas City, MO 64116
West Coast Industrial Flooring
3765 Omec Circle
Rancho Cordova, CA 95742