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Flooring systems
The Effects of Composition and Application




                                             1610 East Morehead Suite 200 Charlotte, NC 28203
Flooring systems The Effects of Composition and Application




                                                              PREFACE
                                                              Problem
                                                              The food processing economy is growing steadily and you have
                                                              determined that the addition of a new facility will best help you meet
                                                              the increased demand. You have toured existing facilities and you are
                                                              concerned that the flooring systems in these buildings do not provide
                                                              protection from the typical forms of floor abuse within a food processing
                                                              facility.

                                                              You have acquired a site that provides the required acreage for current
                                                              and future demands, transportation access to major thoroughfares
                                                              and appropriate space for staff parking. With the construction of a new
                                                              facility, your goal is to incorporate a flooring system that will provide
                                                              the characteristics needed to achieve protection from the everyday
                                                              production challenges. What concrete substrate should be used?
                                                              Should the floor have an epoxy or polyurethane finish? How is the floor
                                                              finish applied?

                                                              Solution
                                                              In order to design and construct the floor system within a food processing
                                                              facility, you must understand a floor’s composition, characteristics,
                                                              reactions to finishes and applications before choosing the correct
                                                              system.




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Flooring systems The Effects of Composition and Application

 Concrete (substrate)                                                         FLY ASH
                                                                              The use of volcanic ash, known as pozzolanic, was introduced as a
 The intent of this investigation is to determine which industrial flooring   component of the ancient Roman aqueducts and building structures.
 system is best suited to meet the needs of a specific food processing        Fly ash, having similar properties to the ancient pozzolanic, greatly
 facility. It is important to understand that it is the concrete substrate    improves the strength and durability of concrete. Also known as flue-
 and its exposure to chemical, mechanical and thermal aggressions             ash, fly ash is a residue generated during the combustion of coal. The
 that will determine which flooring system should be used to provide          ash that does not rise is known as bottom ash and the ash that rises and
 the highest level of protection. Because the concrete substrate is the       is caught in an electrostatic precipitator or particle filtration equipment
 building component at risk, an understanding of its composition and          before reaching the chimney is named fly ash.
 behavior will be reviewed.
                                                                              There are two classes of fly ash: Class F fly ash and Class C fly ash.
 Concrete is the mixture of water, large and small aggregate, and             The primary difference between the two classes is the percentage of
 Portland cement. Portland cement mixed with water creates a paste            calcium, silica, alumina and iron. Class F fly ash can have a volatile
 that coats the surfaces of the aggregates, hardens and gains strength        effect on the entrained air content in concrete, reducing its resistance
 as it dries. The strength and durability of the rock-like mass is achieved   to the freeze/thaw damage. Class F fly ash also contains less than 20
 by the proportional mixing of ingredients. If the amount of paste is         percent lime and requires the use of an activator. For these reasons,
 not great enough to fill the voids between the aggregate, the finished       Class F is seldom used. Class C fly ash has more than 20 percent lime
 concrete will produce a honeycomb surface and be porous. However,            and does not require the addition of an activator.
 if there is more paste than required, the surface will be smooth but the
 concrete will be likely to shrink and require frequent patching, which       As a result, Class C fly ash is the primary additive to Portland cement.
 could be a costly error.                                                     While its spherical shape increases the workability of the cement and
                                                                              reduces the amount of water needed, it also has the ability to increase
 While the proportion of the basic ingredients is the key to providing the    the concrete’s strength, chemical resistance and durability. Fly ash can
 correct composition, there are a variety of other components within the      be substituted for up to 30 percent of the standard Portland cement
 concrete that will change and provide the characteristics needed for a       content of concrete.
 specific condition. The amount of time to set, the release of heat during
 the cure process, the introduction of microscopic air pockets to combat      There are five basic types of Portland cement.
 a freeze/thaw effect and the introduction of fly ash into the Portland
 cement mix all provide different qualities that address the needs of a       •	 Type I – General purpose
 specific facility or application.                                            The composition of Type I is suitable for all uses where special
                                                                              properties are not required. An example of a special property would
                                                                              be a need for temperature control during the hydration of the concrete.
 CONCRETE INGREDIENTS
                                                                              •	 Type II – Precaution against moderate sulfate action
 WATER                                                                        When concrete is located in a structure that comes in contact with
 The use of potable water in mixing the concrete batch is not necessary;
                                                                              groundwater drainage containing sulfate concentrations, the composition
 however, the use of water with excessive impurities might affect both
                                                                              of Type II is most appropriate. The moderate speed at which the heat is
 the setting time and strength. The water should be tested to verify
                                                                              released during the hydration stage is less than that of Type I. Type II is
 that levels of chloride, sulfates, alkalis and solids are within approved
                                                                              best suited for structures of considerable mass such as retaining walls.
 ranges to prevent concrete failures such as efflorescence, corrosion of
 reinforcement, staining, volume instability and reduced durability.
                                                                              •	 Type III – Achieves high strength quickly
                                                                              Type III is similar to Type I but contains a slightly higher amount of gypsum
 AGGREGATES                                                                   and a finer grind. When compared to type I and II, this modification
 Coarse aggregate (gravel or crushed stone) and fine aggregate (sand)
                                                                              obtains the seven day compressive strength in just three days and its
 comprise 60 to 75 percent of the concrete’s volume. Desired thickness
                                                                              twenty-eight day compressive strength in just seven. Because of this
 and end use will determine the type and size of the aggregate used.
                                                                              reduction in time, the long-term strength is reduced. Type III is typically
                                                                              used for the construction of precast concrete products because of its
 PORTLAND CEMENT                                                              quick turnover time.
 In 1824 Joseph Aspdin, an English mason, named his recently patented
 cement product ‘Portland’ cement. The term ‘Portland’ was chosen
                                                                              •	 Type IA, IIA, IIIA – Air Entraining
 because he felt that the color of the mixture resembled the natural
                                                                              This modified version of Types I, II and III introduces an air-entraining
 limestone located on the Isle of Portland in the English Channel.
                                                                              agent that produces microscopic air bubbles which create air pockets
                                                                              allowing space for the concrete to expand and contract during the
 This appearance is achieved by combining calcium, silicon, aluminum
                                                                              freeze/thaw process. These air pockets comprise 9 to 10 percent of
 and iron. Gypsum is then added in the final grinding process to regulate
                                                                              the concrete volume.
 the setting time of the concrete. The raw materials used to create the
 cement are limestone, shells, chalk (or marl) shale, clay, slate (or blast
 furnace slag), silica sand and iron ore.


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Flooring systems The Effects of Composition and Application

 •	 Type IV – Minimization of heat generated                                    CURING
 Type IV should be used in massive concrete structures such as a                Once the concrete has hardened enough to resist disfiguring marks and
 gravity dam where the temperature rise during the curing period is a           blemishes, known as marring, the process of curing will begin. Curing is
 critical factor. The speed of heat loss during the hydration period is low     the prevention of evaporation that can be achieved by applying moisture
 and the strength of the composition is developed at a slower rate than         retaining fabrics such as burlap or cotton mats, sprinkling of water
 Type I.                                                                        fog, or sealing the surface with a plastic or special curing compound
                                                                                to ensure that the hydration process continues. Much of the hydration
 •	 Type V – Precaution against severe sulfate action                           and strength gain occurs within the first month of the concrete life
 Type V is sulfate-resistant, and should be used when the concrete is           cycle and will be governed by the specific mixture proportions, climate
 exposed to high levels of sulfate typically located in the adjacent soils      temperature, moisture conditions and scheduling parameters.
 and groundwater.
                                                                                CHEMICAL ADMIXTURES
 CONCRETE PRODUCTION
                                                                                WATER-REDUCING
 PROPORTIONING                                                                  The traditional water-reducing agent reduces the amount of water
 Water, large aggregate, small aggregate and Portland cement comprise           needed by 5 to 10 percent, which increases the concrete’s strength
 the mix that, when designed properly, provides a workable concrete             without increasing the amount of cement, thereby reducing the water-
 that is both durable and strong. Typically, the mix is 15 to 20 percent        cement ratio. The development of a mid-range admixture reduces the
 water, 60 to 75 percent aggregate and 10 to 15 percent cement. If an           water content by 8 percent and provides a more consistent setting time
 air-entrained agent is included, it will make up 9 to 10 percent of the        within a wider range of temperatures.
 concrete volume. (Figure 1)
                                                                                RETARDING
                                                                                While having the additional ability to act as a water-reducing admixture,
                                      6% air                                    the primary function of a retarding agent is to counteract the acceleration
                                                                                rate of the concrete that occurs in hot weather conditions.

                                          11% Portland cement                   ACCELERATING
                                                                                Typically used in cold weather conditions, this agent increases the rate
                                                  41% course aggregate          of strength development and reduces the time needed for curing, which
                                                  (gravel or crushed stone)
                                                                                allows the finishing operations to begin earlier.

                                                                                SUPERPLASTICIZER
                                                                                The addition of this agent reduces the water content by 12 to 30
                                                                                percent and can be added on the job site to make a high-slump flowing
                                                  20% fine aggregate            concrete. The effect on the concrete is an increase in fluidity rendering it
                                                  (sand)
                                                                                workable and able to be placed with little to no vibration or compaction.
                                        16% water                               Also referred to as a plasticizer or high range water reducer (HRWR),
                                                                                the chemical reaction remains active for only 30 to 60 minutes, and the
 Figure 1: Concrete basics (approximate percentages)                            concrete becomes unworkable quickly.

 The workability of the concrete is determined by the quality of the paste.     AIR-ENTRAINING
 The strength of the paste depends on the ratio of water to cement. This        This surface-active agent stabilizes the microscopic air bubbles that are
 ratio is the weight of the water divided by the weight of the cement.          created by the shearing action of the mixture and aggregates during the
 Obtaining a high quality concrete is produced by lowering the water-           concrete’s plastic stage. When mixed properly, the presence of these
 cement ratio without sacrificing the workability of the concrete. Typically,   voids will increase the durability when exposed to moisture during the
 using less water produces a higher quality concrete but only if it is          cycles of freezing and thawing and improve the resistance to surface
 properly placed, consolidated and cured.                                       scalling caused by chemical deicers.

 HYDRATION                                                                      Variations in the air content is often a disadvantage when using this
 The setting and hardening of the concrete mixture begins with the              agent and several of the common causes to be aware of are the quality
 introduction of water to the Portland cement. This process, known as           and proportions of the materials; method and duration of the mixing;
 hydration, is the chemical reaction that begins when a node forms on           and the placing and finishing methods used.
 the surface of each cement particle. As the nodes expand and adhere to
 the adjacent aggregate, the process of progressive stiffening, hardening
 and strength development creates a workable mixture that will become
 a water-insoluble concrete.



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Flooring systems The Effects of Composition and Application

 CONCRETE BEHAVIOR                                                                                                                      Shrinkage and cracking

 While the ingredients of the mixture can be adjusted, chemical agents
 can be introduced and finish protectants can be applied, the natural                                                                              Concrete slab
 behavior of concrete will maintain its vulnerability to improper curing
 and unstable settings.

 SHRINKAGE                                                                                                                                         Subgrade
 Shrinkage occurs as concrete dries during the hydration process. The
 drying and shrinkage of concrete occurs over long periods of time with          Slab surface warmer and wetter than subgrade
 thick slabs shrinking slower than thin slabs. The top of a concrete slab
 generally shrinks more than the bottom causing the corner edges at
                                                                                                                                        Shrinkage and cracking
 joints or cracks to curl upward. This creates a visible rise in the concrete
 surface often seen at joint intersections.

 CRACKING                                                                                                                                          Concrete slab
 The effect of shrinkage and curling creates a tensile stress within the
 concrete. As the concrete rises, the tensile stress (the force required to
 pull something apart until the moment it breaks) exceeds the strength
 within concrete, creating a separation or crack. (Figure 2)                                                                                       Subgrade
                                                                                 Slab surface cooler and drier than subgrade
 Plastic Settlement Cracks
 These are cracks that occur during the plastic stage of concrete setting.      Figure 2: Concrete slab cracking
 During this stage, the solids within the mix settle while the water rises
 (bleed water) and if there is a restraint within the slab (reinforcing bars,
 etc.) the mixture above the restraint will not settle as far and create
 mirror like cracks along the restraints. (Figure 3)
                                                                                                                               Settlement cracks

 CONCRETE DEFECTS DURING INSTALLATION
 FREEZE/THAW EFFECT
 Concrete has strong compression strength but its tensile strength
 is weak. As water is absorbed into the porous surface, the internal
 moisture can freeze and cause spalling and cracking. In order to avoid                                                          Large aggregate particles
 these effects, the use of an air-entrained agent will provide micro-scopic                                 Reinforcing bars
 voids that allow the moisture to expand without damaging the concrete
                                                                                         Section A-A
 slab.

 CHEMICAL ATTACK
 Because cement is alkaline and chemically reactive, it can be damaged                                                           Settlement cracks
 by acids, alkalis, salt solutions and organics such as fermenting liquids,
 sugars, animal oils and sea water. The use of Portland cement types II
 and V will prohibit most chemical reactions.

 CRAZING
 Small cracks that weaken the surface are caused by water containing
 solid particles of sedimentation that have migrated to the surface of the
 concrete during hydration (bleed water). A small amount of this water is               A                                                                    A
 expected, but if spread throughout the slab with a trowel, the sediments
 will absorb back into the concrete, thus changing the water to cement
 ratio.

 SCALLING
 Improper curing, forms of nitrates, and agents that contain calcium
 or sodium chloride (typically working together) cause flaking of the
 concrete surface that then breaks loose, causing the surface to peel.
 These flakes typically increase over time in high traffic areas.                Figure 3: Plastic settlement cracking

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Flooring systems The Effects of Composition and Application

 SPALLING                                                                        Because the surface of this system is not monolithic, the use of cement
 This defect is similar to scalling except the surface breaks are larger         grouts located between the tile and brick are susceptible to absorption.
 than flakes, indicating severe problems within the concrete slab,               Even if sealed with a high level of epoxy sealer on a regular basis, the
 typically caused by freeze/thaw conditions.                                     mortar will easily stain and become inundated with debris. The severity
                                                                                 of these constraints when using the CRBT system is reflected by the use
 BLISTERS                                                                        of the monolithic system more frequently and, because of this tendency,
 As water and air work their way up during the curing process, it causes         the following investigation will focus on the monolithic resins only.
 a rise in the concrete forming blisters. These blisters, ranging from 1/4"
 to 4" in diameter, are not easily seen but can become chipped by direct         Monolithic System
 traffic.                                                                        A monolithic system is an aggregate-filled, resin based, coating system
                                                                                 that provides a seamless surface able to withstand chemical exposure,
 DUSTING                                                                         abrasion, impact and thermal shock. Epoxy, Acrylic, Polyurethane,
 A loose powder layer, similar to chalk in appearance, is produced by            Polyester and Vinyl esters are the primary forms of resin.
 a weak concrete surface. An unvented heat source, improper small
 aggregate (sand) to cement ratio or the use of bleed water are possible         Each resin is unique in its ability to protect the floor from the typical
 causes of this deterioration.                                                   abuse found within a food processing facility. The following investigation
                                                                                 reviews the characteristics of each resin along with several methods of
 FOREIGN OBJECTS                                                                 application.
 Debris from the surrounding job site can often work its way into the
 concrete while the concrete is being set and might not be noticed until         Epoxy Resin
 the forms are removed. If fully embedded, the object will not have an           Epoxy is the combination of two chemicals, referred to as (A) the resin
 effect on the coating process. However, if a foreign object such as             or compound and (B) the hardener or activator. Part (A) usually consists
 plastic stripping or rope is exposed, it must be removed, typically by          of Bisphenol A or Bisphenol F. Bisphenol A is a general purpose,
 chipping; then the concrete must be restored.                                   cost-effective resin that has an excellent alkali resistance, good acid
                                                                                 resistance and fair-to-good solvent resistance. Bisphenol F is a low
 EFFLORESCENCE                                                                   viscosity material that provides excellent alkali resistance, and a better
 As water migrates from a drying concrete, water-soluble salts within the        acid and solvent resistance than Bisphenol A.
 concrete work their way out to the surface in the form of white chalk.
                                                                                 Part (B), the hardener, is an industrial epoxy coating catalyst that falls
                                                                                 into one of five standard categories: Aliphatic and cycloaliphatic amines
 SPECIAL FLOOR SYSTEMS                                                           and polyamines; amides and polyamides; cycloaliphatic; amine adduct;
                                                                                 and novolac. The chemical makeup of each of these categories, play a
 When investigating the flooring system best suited for a food processing
                                                                                 major role in the properties of the final cured epoxy.
 facility, the driving factors that need to be addressed are the chemical
 exposure, abrasion, impact and thermal shock. While each facility will
 face similar challenges when looking at resistance to moisture vapor,
                                                                                 •	 Aliphatic and Cycloaliphatic Amines and Polyamines
                                                                                 This chemical solution is ammonia with one or more hydrogen atoms
 surface gloss, slip resistance, odor, repair-ability, project schedule, etc.,
                                                                                 replaced by organic groups. The amine-based curing agents are
 there will not be one ‘perfect’ system to be used in all facilities.
                                                                                 considered more durable and chemically resistant, but most likely to
                                                                                 produce a waxy surface layer on actively curing epoxy known as blush.
 High Performance Floor Surfacing Systems (HPFSS) are used to protect
 concrete substrates from chemical, mechanical and thermal aggression.
 The two systems most often used are the Chemical Resistant Brick and            •	 Amides and Polyamides
 Tile (CRBT) system, composed of grout, setting bed, ceramic tile, paver         This chemical solution is ammonia with a hydrogen atom replaced by
 tile and/or dairy brick and the monolithic system, formed by resin and/         a carbon/oxygen and organic group. Unlike the amines, the amide is
 or aggregate types.                                                             more tolerant to surface contact and less troubled by water.

 Chemical Resistant Brick and Tile Systems                                       •	 Cycloaliphatic
 In the past, bulky, conventional, thick bed methods were employed               This agent provides better water/moisture resistance, better
 for the installation of industrial ceramic tile, paver tile and dairy brick     weatherability, low blush and water spotting, and better chemical
 applications. With the improvement in adhesive technology, a more               resistance. The composition of this agent provides more of a “structural
 efficient and environmentally sensitive use of materials has been               stretch” and, in return, provides a better impact resistance.
 introduced, resulting in a reduced weight, lower cost of material and a
 more efficient use of natural resources. However, the use of the CRBT           Most top grade, high performance epoxies incorporate a blend of the
 in industrial installations places a large stress on the tile and paver         cycloaliphatics into the ‘part B’ curing agent and is often used to judge
 application and, in turn, an environment that is challenging not only for       the quality and performance of the final epoxy.
 the finish tile or paver but also for the installation system materials.




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Flooring systems The Effects of Composition and Application

 •	 Amine Adducts                                                                 •	 Cementitious
 Amine Adduct epoxies are two-part epoxies but the curing agent                   This form of urethane is thermal shock resistant, has good stain
 actually contains a small amount of epoxy resin. Because of this unique          resistance, has excellent organic acid resistance and demonstrates
 combination, the mixture starts to cure even before type (A) and (B) are         good moisture tolerance during the curing process.
 mixed. This mixture performs much like the other agents but with higher
 overall properties, such as a better color stability, curing at a cooler         •	 Aliphatic
 temperature and curing faster than the standard epoxy.                           This coating provides a high level of chemical resistance, good
                                                                                  weathering properties and excellent UV protection while providing a
 •	 Novolac Epoxy                                                                 durable adhesive quality.
 A fifth and more specialized epoxy is the Novolac Epoxy. This epoxy has
 excellent heavy duty chemical resistance, low odor and low shrinkage.            •	 Aromatic
 However, it is not thermal shock resistant, will not have full chemical          Aromatic coatings are useful where UV radiation is not an issue.
 resistance for up to 7 days and has a tendency to chalk and discolor             Polyurethane coatings made from aromatic polyisocyanates are very
 when exposed to UV light.                                                        sensitive to oxidation and, as a result, prone to degradation in direct
                                                                                  exposure to sunlight.

 ACRYLICS                                                                         •	 Aspartic
                                                                                  This coating is a two-component, low VOC, urethane resin designed for
 Also referred to as Methyl Methacrylate (MMA) this water-based floor             high performance protection with outstanding exterior gloss and color
 system will cure much faster than other applied coating systems. The             retention. This resin has a high resistance to corrosion, weathering, and
 coating can be applied in very cold temperatures (-20° F), resist a              chemicals; offers color and gloss retention; and is suitable for use in
 wide range of acids and alkalis, and provide high impact and abrasion            USDA-inspected facilities
 resistance. Minimum surface preparation is required and fresh
 applications melt and bond, creating a monolithic system that won’t
 peel. Reseal costs and down time are much shorter than other coatings.           POLYESTERS/VINYL ESTERS
 This system provides a much more durable finish.
                                                                                  Polyester prepolymers are produced by a condensation reaction of
 The negatives are the need for adequate ventilation during application           organic acids and polyols. The choice of reactants will establish the
 due to strong odors, low adhesive strength, and extreme susceptibility           resulting polymer mechanical properties, thermal stability and chemical
 to poor adhesion in substrates that contain some level of humidity.              resistance. This resin has a high solvent and chemical resistance, and
                                                                                  the ability to withstand highly corrosive exposures. It provides a good
                                                                                  adhesive quality, and flake fillers can be added to increase resistance
 POLYURETHANES                                                                    to permeation by water vapor.
 The polyurethane floor coating is a solvent based, two-component                 The negative of this resin is the creation of a trapped tensile strain (pre-
 system. This coating is abrasion resistant, antibacterial, UV resistant,         stress) by the heat and shrinkage produced during its drying process.
 antifungal, and easily cleaned. In addition, this coating provides a             This strain can lead to cracking or disbondment, especially in very low
 tough and flexible surface that has excellent adhesion to concrete, tiles,       operating temperatures, and can become brittle if not reinforced.
 metals and packing unit floors.
                                                                                  See (Table 1) for a synopsis of the characteristics of each resin.


                                    Cure                Bond Strength               Properties                 Resistance                   Safety
                Epoxies - Temperature sensitive - Excellent                   - High strength            - Good wear                - Allergy
                        - Mix ratios important                                - High-low uniformity      - Moderate chemical        - Odor

      Epoxy Novolacs - Cold, wet cure              - Excellent                - High strength            - Heat resistant           - Allergy
                                                                              - High uniformity          - Chemical resistant

       Polyesters/Vinyl - Moisture sensitive       - Will not bond to damp - High strength               - Heat resistant           - Flammable
                Esters - Catalyzed cure            surfaces                - High (low) uniformity       - Chemical resistant       - Odor
                        - Shrinkage
            Urethanes - Humidity sensitive         - Intercoat adhesion       - Gloss retention          - Excellent wear           - Allergy
                                                   difficult                  - Elastomeric              - Stain resistant          - Free isocyanate
                                                                                                         - Weather resistant        - VOC
  Methyl-Methacrylate - Cures quickly              - Moisture sensitive       - Clear                    - Abrasion resistant       - Flammable
              (MMA) - Cold cure                                               - Easy handling                                       - Odor
                      - Shrinkage                                             - High strength
 Table 1: Characteristics of polymer products


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Flooring systems The Effects of Composition and Application

 SPECIAL FLOOR SYSTEM APPLICATION                                                                                           Topcoat at 6-20 mils
                                                                                                                                     Optional intermediate
 COATING                                                                                                                             coat at 8-16 mils
 The positive qualities of the coating system are that it is the most                                                                   Primer at 6-8 mils
 economical at 40 mils or less, and provides moderate chemical
 resistance, easy cleanability, simple repair and maintenance, and UV
 protection. It also seals concrete from absorption of microorganism or
 contaminants, and protects concrete from sterilants.

 The negatives are that it can easily scratch and develop traffic patterns,
 is subject to damage from impact and thermal shock, and does not
 mask surface imperfections. In addition, this application cannot be used
 to modify the slope of a substrate and will need to follow the existing                                                          Concrete substrate
 contour of the substrate. (Figure 4)

 SELF LEVELING SYSTEMS
 •	 Slurry                                                                      Figure 4: Coatings
 Slurry is a thin mixture of a liquid (typically water) and a cement, plaster
 of Paris or clay particles. A primer is placed directly on the substrate
 (typically 60 mils) and is then covered with a thin topcoat.
                                                                                                                            Topcoat at 8-10 mils
 As an intermediate priced system, the positive qualities of the slurry                                                            Slurry at 60 mils
 system are the improvement of substrate properties for thermal shock
 and impact, and the masking of minor imperfections. The system also                                                                       Primer at 6-8 mils
 requires less skill to install, thereby increasing the installed square
 footage per day.

 The negatives are that it is not suitable for sloped surfaces,
 requires more skill to install than coatings alone, and is less
 resistant to thermal shock and impact than mortars. (Figure 5)

 •	 Broadcast systems
 Forming a seamless, monolithic floor, the broadcast system is composed                                                              Concrete substrate
 of low viscosity, 100 percent solid epoxy resin and aggregate filler in the
 form of finely graded silica within the slurry mix. The combination of
 slurry and broadcast aggregate will range from 60 mil to 1/4" depending
                                                                                Figure 5: Slurry-Smooth
 on the amount of mechanical abuse, impact and abrasion.

 The broadcast system provides a good slip and chemical resistance,
                                                                                                                            Topcoat at 10-20 mils
 and is most suitable for areas of light to moderate chemical, impact
 and traffic exposure. Similar to the slurry system, the addition of the                                                        Broadcast and grout coat
 broadcast system is not suitable for sloped surfaces and is less resistant                                                              Slurry at 60 mils
 to thermal shock and impact than mortars. (Figure 6)                                                                                    Primer at 6-8 mils

 •	 Thick-Mil Troweled
 This system is a 3/16 - 3/8" thick mortar material with aggregate fillers
 in a resin matrix placed on a primer covering and substrate surface. The
 troweled flooring system provides the highest physical properties and
 is resistant to impact, thermal shock and abrasion. This application is
 suitable for sloped surfaces, masks surface imperfections and is able to
 provide pitch toward the drain while having the lowest life cycle costs.
                                                                                                                                      Concrete substrate




                                                                                Figure 6: Slurry-broadcast slip resistant


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Flooring systems The Effects of Composition and Application

 The negatives of this system are that the thickness of the application
 might affect equipment and door clearances; it requires the highest                                                         Topcoat at 10-20 mils
 level of skill and additional time for installation; and it has the highest                                                      Grout coat
 initial cost. (Figure 7)                                                                                                               Trowelled base
                                                                                                                                       Primer at 6-8 mils
 SAFE QUALITY FOOD (SQF) CODE
 After reviewing the special floor systems and applications, the
 development of a sanitation and health program for all facility
 flooring systems must be addressed. The SQF is one of several food
 management programs that is recognized worldwide and benchmarked
 by the Global Food Safety Initiative (GFSI). This program develops
 specific management training to develop, document and record safety
 procedures while working directly with HACCP plans. This program has a
 three level certification that can be obtained through the implementation                                                           Concrete substrate
 of the safety process and procedures.
                                                                               Figure 7: Thick-mil trowelled
 While this safety code is composed of 16 modules that include a
 checklist for all sections of the food industry, the checklist for a food
 processing facility is located in module 11. Below is a clip from the SQF     SELECTING A FLOOR SYSTEM
 Code, 7th Edition, July 2012.
                                                                               Chemical exposure, abrasion, impact and thermal shock are the four
 SQF-CODE-ED-7-MODUAL – COVERS ALL FOOD                                        macro-categories of adversities that every food processing flooring
                                                                               system will encounter. Is there a perfect floor coating and application that
 PROCESSING TYPES
                                                                               will protect a food processing facility? Yes, however the final decision
                                                                               must be based on the challenges that are present in that specific facility.
 11: FOOD SAFETY FUNDAMENTALS – GOOD                                           What are the environmental conditions for this project? When must
 MANUFACTURING PRACTICES FOR PROCESSING OF                                     this facility be up and running? Is cost a factor? What form of cleaning,
 FOOD PRODUCTS (GFSI, EI, EII, EIII, EIV AND L)                                pressure and/or chemical mixtures will be required? Is there high traffic
                                                                               or low? The needs will be specific to each facility as will the solutions.
 11.2 Construction and Control of Product
 Handling and Storage Areas                                                    CONCLUSION
 11.2.1 Materials and Surfaces                                                 The mixture of water, large aggregate, small aggregate and Portland
 •	 11.2.1.1 Product contact surfaces and those surfaces not in direct         cement; the manipulation of strength, speed and workability; and the
      contact with food in food handling areas, raw material storage,          resistance to chemical contact, abrasions, high impact and thermal
      packaging material storage, and cold storage areas shall be              shock are the components, that when designed for a specific facility,
      constructed of materials that will not contribute a food safety risk.    provide the perfect flooring system.

 11.2.2 Floors, Drains and Waste Traps                                         Looking for the best flooring system for your facility will bring forth many
 •	 11.2.2.1 Floors shall be constructed of smooth, dense impact               solutions and each will address the challenges at hand. However, with
      resistant material that can be effectively graded, drained,              an understanding of the systems’ composition and how it might react to
      impervious to liquid and easily cleaned.                                 your specific conditions will increase the value of the investigation and
 •	   11.2.2.2 Floors shall be sloped to floor drains at gradients suitable    in turn clarify your solution.
      to allow the effective removal of all overflow or waste water under
      normal working conditions.
 •	   11.2.2.3 Drains shall be constructed and located so they can be          Kevin Franz, AIA, LEED AP BD+C
      easily cleaned and not present a hazard.                                 Project Architect
 •	   11.2.2.4 Waste trap system shall be located away from any food           A M King Construction, LLC
      handling area or entrance to the premises.

 (SQF Code, 7th Edition, July 2012)


                                                                               References:
                                                                               SQF Code A HACCP-Based Supplier Assurance, Code for the Food Industry,
                                                                               7th Edition, 2012 - Module 11: Food Safety Fundamentals – good manufacturing
                                                                               practices for processing of food products (GFSI, EI, EII, EIII, EIV and L)


                                                                                                                             www.amkingconstruction.com 8

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2 Flooring Systems; The Effects of Composition and Application

  • 1. Flooring systems The Effects of Composition and Application 1610 East Morehead Suite 200 Charlotte, NC 28203
  • 2. Flooring systems The Effects of Composition and Application PREFACE Problem The food processing economy is growing steadily and you have determined that the addition of a new facility will best help you meet the increased demand. You have toured existing facilities and you are concerned that the flooring systems in these buildings do not provide protection from the typical forms of floor abuse within a food processing facility. You have acquired a site that provides the required acreage for current and future demands, transportation access to major thoroughfares and appropriate space for staff parking. With the construction of a new facility, your goal is to incorporate a flooring system that will provide the characteristics needed to achieve protection from the everyday production challenges. What concrete substrate should be used? Should the floor have an epoxy or polyurethane finish? How is the floor finish applied? Solution In order to design and construct the floor system within a food processing facility, you must understand a floor’s composition, characteristics, reactions to finishes and applications before choosing the correct system. www.amkingconstruction.com 1
  • 3. Flooring systems The Effects of Composition and Application Concrete (substrate) FLY ASH The use of volcanic ash, known as pozzolanic, was introduced as a The intent of this investigation is to determine which industrial flooring component of the ancient Roman aqueducts and building structures. system is best suited to meet the needs of a specific food processing Fly ash, having similar properties to the ancient pozzolanic, greatly facility. It is important to understand that it is the concrete substrate improves the strength and durability of concrete. Also known as flue- and its exposure to chemical, mechanical and thermal aggressions ash, fly ash is a residue generated during the combustion of coal. The that will determine which flooring system should be used to provide ash that does not rise is known as bottom ash and the ash that rises and the highest level of protection. Because the concrete substrate is the is caught in an electrostatic precipitator or particle filtration equipment building component at risk, an understanding of its composition and before reaching the chimney is named fly ash. behavior will be reviewed. There are two classes of fly ash: Class F fly ash and Class C fly ash. Concrete is the mixture of water, large and small aggregate, and The primary difference between the two classes is the percentage of Portland cement. Portland cement mixed with water creates a paste calcium, silica, alumina and iron. Class F fly ash can have a volatile that coats the surfaces of the aggregates, hardens and gains strength effect on the entrained air content in concrete, reducing its resistance as it dries. The strength and durability of the rock-like mass is achieved to the freeze/thaw damage. Class F fly ash also contains less than 20 by the proportional mixing of ingredients. If the amount of paste is percent lime and requires the use of an activator. For these reasons, not great enough to fill the voids between the aggregate, the finished Class F is seldom used. Class C fly ash has more than 20 percent lime concrete will produce a honeycomb surface and be porous. However, and does not require the addition of an activator. if there is more paste than required, the surface will be smooth but the concrete will be likely to shrink and require frequent patching, which As a result, Class C fly ash is the primary additive to Portland cement. could be a costly error. While its spherical shape increases the workability of the cement and reduces the amount of water needed, it also has the ability to increase While the proportion of the basic ingredients is the key to providing the the concrete’s strength, chemical resistance and durability. Fly ash can correct composition, there are a variety of other components within the be substituted for up to 30 percent of the standard Portland cement concrete that will change and provide the characteristics needed for a content of concrete. specific condition. The amount of time to set, the release of heat during the cure process, the introduction of microscopic air pockets to combat There are five basic types of Portland cement. a freeze/thaw effect and the introduction of fly ash into the Portland cement mix all provide different qualities that address the needs of a • Type I – General purpose specific facility or application. The composition of Type I is suitable for all uses where special properties are not required. An example of a special property would be a need for temperature control during the hydration of the concrete. CONCRETE INGREDIENTS • Type II – Precaution against moderate sulfate action WATER When concrete is located in a structure that comes in contact with The use of potable water in mixing the concrete batch is not necessary; groundwater drainage containing sulfate concentrations, the composition however, the use of water with excessive impurities might affect both of Type II is most appropriate. The moderate speed at which the heat is the setting time and strength. The water should be tested to verify released during the hydration stage is less than that of Type I. Type II is that levels of chloride, sulfates, alkalis and solids are within approved best suited for structures of considerable mass such as retaining walls. ranges to prevent concrete failures such as efflorescence, corrosion of reinforcement, staining, volume instability and reduced durability. • Type III – Achieves high strength quickly Type III is similar to Type I but contains a slightly higher amount of gypsum AGGREGATES and a finer grind. When compared to type I and II, this modification Coarse aggregate (gravel or crushed stone) and fine aggregate (sand) obtains the seven day compressive strength in just three days and its comprise 60 to 75 percent of the concrete’s volume. Desired thickness twenty-eight day compressive strength in just seven. Because of this and end use will determine the type and size of the aggregate used. reduction in time, the long-term strength is reduced. Type III is typically used for the construction of precast concrete products because of its PORTLAND CEMENT quick turnover time. In 1824 Joseph Aspdin, an English mason, named his recently patented cement product ‘Portland’ cement. The term ‘Portland’ was chosen • Type IA, IIA, IIIA – Air Entraining because he felt that the color of the mixture resembled the natural This modified version of Types I, II and III introduces an air-entraining limestone located on the Isle of Portland in the English Channel. agent that produces microscopic air bubbles which create air pockets allowing space for the concrete to expand and contract during the This appearance is achieved by combining calcium, silicon, aluminum freeze/thaw process. These air pockets comprise 9 to 10 percent of and iron. Gypsum is then added in the final grinding process to regulate the concrete volume. the setting time of the concrete. The raw materials used to create the cement are limestone, shells, chalk (or marl) shale, clay, slate (or blast furnace slag), silica sand and iron ore. www.amkingconstruction.com 2
  • 4. Flooring systems The Effects of Composition and Application • Type IV – Minimization of heat generated CURING Type IV should be used in massive concrete structures such as a Once the concrete has hardened enough to resist disfiguring marks and gravity dam where the temperature rise during the curing period is a blemishes, known as marring, the process of curing will begin. Curing is critical factor. The speed of heat loss during the hydration period is low the prevention of evaporation that can be achieved by applying moisture and the strength of the composition is developed at a slower rate than retaining fabrics such as burlap or cotton mats, sprinkling of water Type I. fog, or sealing the surface with a plastic or special curing compound to ensure that the hydration process continues. Much of the hydration • Type V – Precaution against severe sulfate action and strength gain occurs within the first month of the concrete life Type V is sulfate-resistant, and should be used when the concrete is cycle and will be governed by the specific mixture proportions, climate exposed to high levels of sulfate typically located in the adjacent soils temperature, moisture conditions and scheduling parameters. and groundwater. CHEMICAL ADMIXTURES CONCRETE PRODUCTION WATER-REDUCING PROPORTIONING The traditional water-reducing agent reduces the amount of water Water, large aggregate, small aggregate and Portland cement comprise needed by 5 to 10 percent, which increases the concrete’s strength the mix that, when designed properly, provides a workable concrete without increasing the amount of cement, thereby reducing the water- that is both durable and strong. Typically, the mix is 15 to 20 percent cement ratio. The development of a mid-range admixture reduces the water, 60 to 75 percent aggregate and 10 to 15 percent cement. If an water content by 8 percent and provides a more consistent setting time air-entrained agent is included, it will make up 9 to 10 percent of the within a wider range of temperatures. concrete volume. (Figure 1) RETARDING While having the additional ability to act as a water-reducing admixture, 6% air the primary function of a retarding agent is to counteract the acceleration rate of the concrete that occurs in hot weather conditions. 11% Portland cement ACCELERATING Typically used in cold weather conditions, this agent increases the rate 41% course aggregate of strength development and reduces the time needed for curing, which (gravel or crushed stone) allows the finishing operations to begin earlier. SUPERPLASTICIZER The addition of this agent reduces the water content by 12 to 30 percent and can be added on the job site to make a high-slump flowing 20% fine aggregate concrete. The effect on the concrete is an increase in fluidity rendering it (sand) workable and able to be placed with little to no vibration or compaction. 16% water Also referred to as a plasticizer or high range water reducer (HRWR), the chemical reaction remains active for only 30 to 60 minutes, and the Figure 1: Concrete basics (approximate percentages) concrete becomes unworkable quickly. The workability of the concrete is determined by the quality of the paste. AIR-ENTRAINING The strength of the paste depends on the ratio of water to cement. This This surface-active agent stabilizes the microscopic air bubbles that are ratio is the weight of the water divided by the weight of the cement. created by the shearing action of the mixture and aggregates during the Obtaining a high quality concrete is produced by lowering the water- concrete’s plastic stage. When mixed properly, the presence of these cement ratio without sacrificing the workability of the concrete. Typically, voids will increase the durability when exposed to moisture during the using less water produces a higher quality concrete but only if it is cycles of freezing and thawing and improve the resistance to surface properly placed, consolidated and cured. scalling caused by chemical deicers. HYDRATION Variations in the air content is often a disadvantage when using this The setting and hardening of the concrete mixture begins with the agent and several of the common causes to be aware of are the quality introduction of water to the Portland cement. This process, known as and proportions of the materials; method and duration of the mixing; hydration, is the chemical reaction that begins when a node forms on and the placing and finishing methods used. the surface of each cement particle. As the nodes expand and adhere to the adjacent aggregate, the process of progressive stiffening, hardening and strength development creates a workable mixture that will become a water-insoluble concrete. www.amkingconstruction.com 3
  • 5. Flooring systems The Effects of Composition and Application CONCRETE BEHAVIOR Shrinkage and cracking While the ingredients of the mixture can be adjusted, chemical agents can be introduced and finish protectants can be applied, the natural Concrete slab behavior of concrete will maintain its vulnerability to improper curing and unstable settings. SHRINKAGE Subgrade Shrinkage occurs as concrete dries during the hydration process. The drying and shrinkage of concrete occurs over long periods of time with Slab surface warmer and wetter than subgrade thick slabs shrinking slower than thin slabs. The top of a concrete slab generally shrinks more than the bottom causing the corner edges at Shrinkage and cracking joints or cracks to curl upward. This creates a visible rise in the concrete surface often seen at joint intersections. CRACKING Concrete slab The effect of shrinkage and curling creates a tensile stress within the concrete. As the concrete rises, the tensile stress (the force required to pull something apart until the moment it breaks) exceeds the strength within concrete, creating a separation or crack. (Figure 2) Subgrade Slab surface cooler and drier than subgrade Plastic Settlement Cracks These are cracks that occur during the plastic stage of concrete setting. Figure 2: Concrete slab cracking During this stage, the solids within the mix settle while the water rises (bleed water) and if there is a restraint within the slab (reinforcing bars, etc.) the mixture above the restraint will not settle as far and create mirror like cracks along the restraints. (Figure 3) Settlement cracks CONCRETE DEFECTS DURING INSTALLATION FREEZE/THAW EFFECT Concrete has strong compression strength but its tensile strength is weak. As water is absorbed into the porous surface, the internal moisture can freeze and cause spalling and cracking. In order to avoid Large aggregate particles these effects, the use of an air-entrained agent will provide micro-scopic Reinforcing bars voids that allow the moisture to expand without damaging the concrete Section A-A slab. CHEMICAL ATTACK Because cement is alkaline and chemically reactive, it can be damaged Settlement cracks by acids, alkalis, salt solutions and organics such as fermenting liquids, sugars, animal oils and sea water. The use of Portland cement types II and V will prohibit most chemical reactions. CRAZING Small cracks that weaken the surface are caused by water containing solid particles of sedimentation that have migrated to the surface of the concrete during hydration (bleed water). A small amount of this water is A A expected, but if spread throughout the slab with a trowel, the sediments will absorb back into the concrete, thus changing the water to cement ratio. SCALLING Improper curing, forms of nitrates, and agents that contain calcium or sodium chloride (typically working together) cause flaking of the concrete surface that then breaks loose, causing the surface to peel. These flakes typically increase over time in high traffic areas. Figure 3: Plastic settlement cracking www.amkingconstruction.com 4
  • 6. Flooring systems The Effects of Composition and Application SPALLING Because the surface of this system is not monolithic, the use of cement This defect is similar to scalling except the surface breaks are larger grouts located between the tile and brick are susceptible to absorption. than flakes, indicating severe problems within the concrete slab, Even if sealed with a high level of epoxy sealer on a regular basis, the typically caused by freeze/thaw conditions. mortar will easily stain and become inundated with debris. The severity of these constraints when using the CRBT system is reflected by the use BLISTERS of the monolithic system more frequently and, because of this tendency, As water and air work their way up during the curing process, it causes the following investigation will focus on the monolithic resins only. a rise in the concrete forming blisters. These blisters, ranging from 1/4" to 4" in diameter, are not easily seen but can become chipped by direct Monolithic System traffic. A monolithic system is an aggregate-filled, resin based, coating system that provides a seamless surface able to withstand chemical exposure, DUSTING abrasion, impact and thermal shock. Epoxy, Acrylic, Polyurethane, A loose powder layer, similar to chalk in appearance, is produced by Polyester and Vinyl esters are the primary forms of resin. a weak concrete surface. An unvented heat source, improper small aggregate (sand) to cement ratio or the use of bleed water are possible Each resin is unique in its ability to protect the floor from the typical causes of this deterioration. abuse found within a food processing facility. The following investigation reviews the characteristics of each resin along with several methods of FOREIGN OBJECTS application. Debris from the surrounding job site can often work its way into the concrete while the concrete is being set and might not be noticed until Epoxy Resin the forms are removed. If fully embedded, the object will not have an Epoxy is the combination of two chemicals, referred to as (A) the resin effect on the coating process. However, if a foreign object such as or compound and (B) the hardener or activator. Part (A) usually consists plastic stripping or rope is exposed, it must be removed, typically by of Bisphenol A or Bisphenol F. Bisphenol A is a general purpose, chipping; then the concrete must be restored. cost-effective resin that has an excellent alkali resistance, good acid resistance and fair-to-good solvent resistance. Bisphenol F is a low EFFLORESCENCE viscosity material that provides excellent alkali resistance, and a better As water migrates from a drying concrete, water-soluble salts within the acid and solvent resistance than Bisphenol A. concrete work their way out to the surface in the form of white chalk. Part (B), the hardener, is an industrial epoxy coating catalyst that falls into one of five standard categories: Aliphatic and cycloaliphatic amines SPECIAL FLOOR SYSTEMS and polyamines; amides and polyamides; cycloaliphatic; amine adduct; and novolac. The chemical makeup of each of these categories, play a When investigating the flooring system best suited for a food processing major role in the properties of the final cured epoxy. facility, the driving factors that need to be addressed are the chemical exposure, abrasion, impact and thermal shock. While each facility will face similar challenges when looking at resistance to moisture vapor, • Aliphatic and Cycloaliphatic Amines and Polyamines This chemical solution is ammonia with one or more hydrogen atoms surface gloss, slip resistance, odor, repair-ability, project schedule, etc., replaced by organic groups. The amine-based curing agents are there will not be one ‘perfect’ system to be used in all facilities. considered more durable and chemically resistant, but most likely to produce a waxy surface layer on actively curing epoxy known as blush. High Performance Floor Surfacing Systems (HPFSS) are used to protect concrete substrates from chemical, mechanical and thermal aggression. The two systems most often used are the Chemical Resistant Brick and • Amides and Polyamides Tile (CRBT) system, composed of grout, setting bed, ceramic tile, paver This chemical solution is ammonia with a hydrogen atom replaced by tile and/or dairy brick and the monolithic system, formed by resin and/ a carbon/oxygen and organic group. Unlike the amines, the amide is or aggregate types. more tolerant to surface contact and less troubled by water. Chemical Resistant Brick and Tile Systems • Cycloaliphatic In the past, bulky, conventional, thick bed methods were employed This agent provides better water/moisture resistance, better for the installation of industrial ceramic tile, paver tile and dairy brick weatherability, low blush and water spotting, and better chemical applications. With the improvement in adhesive technology, a more resistance. The composition of this agent provides more of a “structural efficient and environmentally sensitive use of materials has been stretch” and, in return, provides a better impact resistance. introduced, resulting in a reduced weight, lower cost of material and a more efficient use of natural resources. However, the use of the CRBT Most top grade, high performance epoxies incorporate a blend of the in industrial installations places a large stress on the tile and paver cycloaliphatics into the ‘part B’ curing agent and is often used to judge application and, in turn, an environment that is challenging not only for the quality and performance of the final epoxy. the finish tile or paver but also for the installation system materials. www.amkingconstruction.com 5
  • 7. Flooring systems The Effects of Composition and Application • Amine Adducts • Cementitious Amine Adduct epoxies are two-part epoxies but the curing agent This form of urethane is thermal shock resistant, has good stain actually contains a small amount of epoxy resin. Because of this unique resistance, has excellent organic acid resistance and demonstrates combination, the mixture starts to cure even before type (A) and (B) are good moisture tolerance during the curing process. mixed. This mixture performs much like the other agents but with higher overall properties, such as a better color stability, curing at a cooler • Aliphatic temperature and curing faster than the standard epoxy. This coating provides a high level of chemical resistance, good weathering properties and excellent UV protection while providing a • Novolac Epoxy durable adhesive quality. A fifth and more specialized epoxy is the Novolac Epoxy. This epoxy has excellent heavy duty chemical resistance, low odor and low shrinkage. • Aromatic However, it is not thermal shock resistant, will not have full chemical Aromatic coatings are useful where UV radiation is not an issue. resistance for up to 7 days and has a tendency to chalk and discolor Polyurethane coatings made from aromatic polyisocyanates are very when exposed to UV light. sensitive to oxidation and, as a result, prone to degradation in direct exposure to sunlight. ACRYLICS • Aspartic This coating is a two-component, low VOC, urethane resin designed for Also referred to as Methyl Methacrylate (MMA) this water-based floor high performance protection with outstanding exterior gloss and color system will cure much faster than other applied coating systems. The retention. This resin has a high resistance to corrosion, weathering, and coating can be applied in very cold temperatures (-20° F), resist a chemicals; offers color and gloss retention; and is suitable for use in wide range of acids and alkalis, and provide high impact and abrasion USDA-inspected facilities resistance. Minimum surface preparation is required and fresh applications melt and bond, creating a monolithic system that won’t peel. Reseal costs and down time are much shorter than other coatings. POLYESTERS/VINYL ESTERS This system provides a much more durable finish. Polyester prepolymers are produced by a condensation reaction of The negatives are the need for adequate ventilation during application organic acids and polyols. The choice of reactants will establish the due to strong odors, low adhesive strength, and extreme susceptibility resulting polymer mechanical properties, thermal stability and chemical to poor adhesion in substrates that contain some level of humidity. resistance. This resin has a high solvent and chemical resistance, and the ability to withstand highly corrosive exposures. It provides a good adhesive quality, and flake fillers can be added to increase resistance POLYURETHANES to permeation by water vapor. The polyurethane floor coating is a solvent based, two-component The negative of this resin is the creation of a trapped tensile strain (pre- system. This coating is abrasion resistant, antibacterial, UV resistant, stress) by the heat and shrinkage produced during its drying process. antifungal, and easily cleaned. In addition, this coating provides a This strain can lead to cracking or disbondment, especially in very low tough and flexible surface that has excellent adhesion to concrete, tiles, operating temperatures, and can become brittle if not reinforced. metals and packing unit floors. See (Table 1) for a synopsis of the characteristics of each resin. Cure Bond Strength Properties Resistance Safety Epoxies - Temperature sensitive - Excellent - High strength - Good wear - Allergy - Mix ratios important - High-low uniformity - Moderate chemical - Odor Epoxy Novolacs - Cold, wet cure - Excellent - High strength - Heat resistant - Allergy - High uniformity - Chemical resistant Polyesters/Vinyl - Moisture sensitive - Will not bond to damp - High strength - Heat resistant - Flammable Esters - Catalyzed cure surfaces - High (low) uniformity - Chemical resistant - Odor - Shrinkage Urethanes - Humidity sensitive - Intercoat adhesion - Gloss retention - Excellent wear - Allergy difficult - Elastomeric - Stain resistant - Free isocyanate - Weather resistant - VOC Methyl-Methacrylate - Cures quickly - Moisture sensitive - Clear - Abrasion resistant - Flammable (MMA) - Cold cure - Easy handling - Odor - Shrinkage - High strength Table 1: Characteristics of polymer products www.amkingconstruction.com 6
  • 8. Flooring systems The Effects of Composition and Application SPECIAL FLOOR SYSTEM APPLICATION Topcoat at 6-20 mils Optional intermediate COATING coat at 8-16 mils The positive qualities of the coating system are that it is the most Primer at 6-8 mils economical at 40 mils or less, and provides moderate chemical resistance, easy cleanability, simple repair and maintenance, and UV protection. It also seals concrete from absorption of microorganism or contaminants, and protects concrete from sterilants. The negatives are that it can easily scratch and develop traffic patterns, is subject to damage from impact and thermal shock, and does not mask surface imperfections. In addition, this application cannot be used to modify the slope of a substrate and will need to follow the existing Concrete substrate contour of the substrate. (Figure 4) SELF LEVELING SYSTEMS • Slurry Figure 4: Coatings Slurry is a thin mixture of a liquid (typically water) and a cement, plaster of Paris or clay particles. A primer is placed directly on the substrate (typically 60 mils) and is then covered with a thin topcoat. Topcoat at 8-10 mils As an intermediate priced system, the positive qualities of the slurry Slurry at 60 mils system are the improvement of substrate properties for thermal shock and impact, and the masking of minor imperfections. The system also Primer at 6-8 mils requires less skill to install, thereby increasing the installed square footage per day. The negatives are that it is not suitable for sloped surfaces, requires more skill to install than coatings alone, and is less resistant to thermal shock and impact than mortars. (Figure 5) • Broadcast systems Forming a seamless, monolithic floor, the broadcast system is composed Concrete substrate of low viscosity, 100 percent solid epoxy resin and aggregate filler in the form of finely graded silica within the slurry mix. The combination of slurry and broadcast aggregate will range from 60 mil to 1/4" depending Figure 5: Slurry-Smooth on the amount of mechanical abuse, impact and abrasion. The broadcast system provides a good slip and chemical resistance, Topcoat at 10-20 mils and is most suitable for areas of light to moderate chemical, impact and traffic exposure. Similar to the slurry system, the addition of the Broadcast and grout coat broadcast system is not suitable for sloped surfaces and is less resistant Slurry at 60 mils to thermal shock and impact than mortars. (Figure 6) Primer at 6-8 mils • Thick-Mil Troweled This system is a 3/16 - 3/8" thick mortar material with aggregate fillers in a resin matrix placed on a primer covering and substrate surface. The troweled flooring system provides the highest physical properties and is resistant to impact, thermal shock and abrasion. This application is suitable for sloped surfaces, masks surface imperfections and is able to provide pitch toward the drain while having the lowest life cycle costs. Concrete substrate Figure 6: Slurry-broadcast slip resistant www.amkingconstruction.com 7
  • 9. Flooring systems The Effects of Composition and Application The negatives of this system are that the thickness of the application might affect equipment and door clearances; it requires the highest Topcoat at 10-20 mils level of skill and additional time for installation; and it has the highest Grout coat initial cost. (Figure 7) Trowelled base Primer at 6-8 mils SAFE QUALITY FOOD (SQF) CODE After reviewing the special floor systems and applications, the development of a sanitation and health program for all facility flooring systems must be addressed. The SQF is one of several food management programs that is recognized worldwide and benchmarked by the Global Food Safety Initiative (GFSI). This program develops specific management training to develop, document and record safety procedures while working directly with HACCP plans. This program has a three level certification that can be obtained through the implementation Concrete substrate of the safety process and procedures. Figure 7: Thick-mil trowelled While this safety code is composed of 16 modules that include a checklist for all sections of the food industry, the checklist for a food processing facility is located in module 11. Below is a clip from the SQF SELECTING A FLOOR SYSTEM Code, 7th Edition, July 2012. Chemical exposure, abrasion, impact and thermal shock are the four SQF-CODE-ED-7-MODUAL – COVERS ALL FOOD macro-categories of adversities that every food processing flooring system will encounter. Is there a perfect floor coating and application that PROCESSING TYPES will protect a food processing facility? Yes, however the final decision must be based on the challenges that are present in that specific facility. 11: FOOD SAFETY FUNDAMENTALS – GOOD What are the environmental conditions for this project? When must MANUFACTURING PRACTICES FOR PROCESSING OF this facility be up and running? Is cost a factor? What form of cleaning, FOOD PRODUCTS (GFSI, EI, EII, EIII, EIV AND L) pressure and/or chemical mixtures will be required? Is there high traffic or low? The needs will be specific to each facility as will the solutions. 11.2 Construction and Control of Product Handling and Storage Areas CONCLUSION 11.2.1 Materials and Surfaces The mixture of water, large aggregate, small aggregate and Portland • 11.2.1.1 Product contact surfaces and those surfaces not in direct cement; the manipulation of strength, speed and workability; and the contact with food in food handling areas, raw material storage, resistance to chemical contact, abrasions, high impact and thermal packaging material storage, and cold storage areas shall be shock are the components, that when designed for a specific facility, constructed of materials that will not contribute a food safety risk. provide the perfect flooring system. 11.2.2 Floors, Drains and Waste Traps Looking for the best flooring system for your facility will bring forth many • 11.2.2.1 Floors shall be constructed of smooth, dense impact solutions and each will address the challenges at hand. However, with resistant material that can be effectively graded, drained, an understanding of the systems’ composition and how it might react to impervious to liquid and easily cleaned. your specific conditions will increase the value of the investigation and • 11.2.2.2 Floors shall be sloped to floor drains at gradients suitable in turn clarify your solution. to allow the effective removal of all overflow or waste water under normal working conditions. • 11.2.2.3 Drains shall be constructed and located so they can be Kevin Franz, AIA, LEED AP BD+C easily cleaned and not present a hazard. Project Architect • 11.2.2.4 Waste trap system shall be located away from any food A M King Construction, LLC handling area or entrance to the premises. (SQF Code, 7th Edition, July 2012) References: SQF Code A HACCP-Based Supplier Assurance, Code for the Food Industry, 7th Edition, 2012 - Module 11: Food Safety Fundamentals – good manufacturing practices for processing of food products (GFSI, EI, EII, EIII, EIV and L) www.amkingconstruction.com 8