Brewery and “wet” side packaging operations tend to be wet, slippery environments best served by sealed floors and floor drains. Although it is still possible to visit very old operations in Europe that actually have wooden floors in the brewhouse and sometimes even the cellars (Figure 1), most modern breweries start with a solid concrete slab.
Figure 1. Wooden floor in a U.K. FV cellar
Floors begin with floor drains and drainage plumbing. Sewer lines should be resistant to both chemicals and heat. Drainage plumbing options include ABS black plastic (light duty and not recommended), schedule 80 PVC, fused poly propylene “fuse-seal” piping, and cast iron. Each has its advantages and disadvantages, and there may be local regulations and codes dictating which are required. In any event, the drainage lines must be dug out and the pipes laid and tested for leaks. Normally sewer clean outs are placed so that the lines can be jetted out routinely and easily. The floor design will take into account the type, style, and position of the floor drains.
Floor drains generally come in several types:
- Simple round drains are the cheapest and easiest to install but do not drain well for large volumes of liquids.
- Long rectangular trench drains handle large volumes efficiently but are more expensive. They come in materials ranging from plastic (poor) to polyurethane (better) to stainless steel (best).
- Stainless or mild steel catch basins are good in areas where solid debris is mixed into the drainage, such as near the filler, labeler, bottlewasher, or keg racking areas. The catch basin allows the solids to settle and the liquid to overflow out. Stainless steel screens can be installed for easier clean out.
- Floor sinks can be used for direct applications such as drains for a CIP system when piping is directed to the drain.
- For areas with poor drainage capacity, catch basins with a sump pump can be used.
Do not install floor drains directly under bottle or can fillers. The rotation of the filler creates a suction vortex and can draw bacteria from the drain into the filling zone.
When considering floor construction you may decide to either remove the existing structure or pour a thin “topping slab.” The topping slab has the benefit that if poured over sound and solid concrete you can form it to slope to your drains without the expense of removing and repouring it. The topping slab construction will commonly utilize steel pins and bonding glues and forms to the installed floor drains that have been cut into the existing slab. Drain lines will have to be cut through the existing slab and installed prior to installing the topping slab. The minimum thickness of the concrete topping will vary but will normally be at least 2 inches.
Complete removal and re-pouring of the floor may be necessary for areas where the existing concrete is unsound or cannot support the weight of the vessels or equipment to be installed. Generally, for either application a 3,000 psi concrete mix is used for pouring. In new floors a rebar pattern and footings should be engineered to accommodate the weight and flux of the equipment to be installed. In areas with seismic earthquake standards, stamped engineered specifications will be required. Seismic and weight requirements may necessitate footings to be formed to reinforce the floor in areas with tanks and heavy equipment (e.g., a bottle or can filler, a pasteurizer, etc.).
Floors should be poured with a 1/4–3/8 inch per foot slope to the drains to assure good and thorough drainage of the floor. If possible during the design phase, lay out the tanks and equipment to determine the best position of the floor drains and how the floor slope should be run.
When forming up for pouring, include perimeter curbing with a slightly sloped top at least 6 inches high to contain the moisture going onto the floor and provide a water shedding base for the walls. Expansion joints are typically used to accommodate expansion and contraction of the slab and avoid cracking. Once the floor is poured and the forms knocked away, allow the floor to cure for at least 30 days prior to sealing or loading.
Once the floor is installed and cured it should be sealed. Beer is mildly acidic and will eat away the cement material in the concrete leaving only a weak stony aggregate that will fail; this is especially problematic around floor drains. The choice in sealing method should be carefully considered as once the floor is sealed and equipment brought in it may be difficult and expensive to change course. Various sealing option are available, including:
- Urethanes: Paintable urethanes are cheap but very light duty and are really suited to nothing more than foot traffic. Expect to get less than five years of service life (not recommended).
- Epoxy, polyurethane, or MMA (methyl methacrylate) acrylic: These types of mortars offer good floor protection and are very cleanable (Figure 2). These materials are commonly a three-part application with a primer, epoxy mortar, and then sealer coat usually containing silica grit for traction. The mortar is troweled on to 1/4 inch thick or more covering the entire floor. After the mortar sets up it is then sealed with a protective epoxy or acrylic coating along with grit. The coatings come in various colors, but expect the coatings to stain with exposure to cleaning chemicals. Cracks and expansion joints in the concrete floor must be carefully ground out and sealed with a flexible compound prior to the mortar going down to avoid “telescope” cracking up from the slab. Cracking will allow moisture to penetrate down to the concrete, weakening the substrate and allowing the mortar to peel up. Expect to get about 10 to 15 years of service life for this type of covering depending on the severity of the application and quality of the installation. Older epoxy type flooring can be ground off and new material applied (a dusty and interfering operation). The main issue with these floors is heat flux differences between the concrete substrate and the epoxy during heating and cooling. If the epoxy expands more quickly than the concrete it can cause a rupture of the surface, allowing moisture to penetrate and degrade the concrete and cause peeling of the mortar.
Figure 2. Epoxy floor system in a craft brewery
- Tile: A tile floor offers the best floor protection and sealing value and is comparable in pricing to the mortar compounds. These are not typical bathroom tiles but are thick, hardened quarry tiles typically 3/8 inch in thickness and made of high-fired ceramic compounds capable of supporting tanks and equipment without cracking. Although expensive to install, tile offers the longest service life and best floor protection. A properly installed tile floor using epoxy grouting should essentially never wear out, although it may require periodic regrouting especially around floor drain areas. Tiles can come with a texture or slip resistant pattern cast into the ceramic. Using homeowner-grade bathroom tiles is not recommended as these are light duty, slippery when wet, and will not hold up to the severe loading, chemical, and heat duty required. Figure 3 shows a classic red quarry tile floor in an older brewery. Figure 4 shows a hexagonal ceramic tile floor in a modern bottleshop.
Figure 3. Classic red quarry tile in an older brewery
Figure 4. Hexagonal ceramic tile in a bottleshop
- Decorative floor treatments: Many breweries have gone to decorative floor treatments, especially in modern brewhouses, which are entirely contained and where moisture and cleaning are not as much of an issue. It is not uncommon for tour groups to see stone tiles or even wooden floors in a brewhouse tour (Figure 5).
Figure 5. Decorative stone tile in a modern brewhouse
Regardless of the type of sealer used, make sure that the installation is reinforced around floor drains, where liquids congregate and commonly make their way under the mortar or tile. Once moisture undermines the sealer it will degrade the underlying concrete and require expensive repairs.
When choosing a brewery floor sealer, do not rely on warranty representations alone; fixing a badly installed floor is going to be expensive and a huge interruption to your operation. It pays to interview the contractors and ask for referrals on installations more than five years old as well as recent installations. Talk to the references and determine just how robust the materials have proven to be, the quality of the installation, and any warranty resolutions they may have had.
The service life of the floor will be affected by several factors:
- The quality of the sealing material and its installation
- Areas where thermal shock might cause rapid expansion of the material (especially true for epoxy type sealers)—This can be somewhat mitigated by piping outlets for kettles, CIP machines, and keg washers directly to the drain openings rather than allowing hot liquids to run across open floors.
- Strong chemicals, especially acids—These will attack the composition of most sealing materials, even tile. Protect floors by using chemical containment where chemicals are stored.
- Wear and tear, including abrasions caused by hoses ends, kegs, pallets, etc.—This will cause physical damage to floors of any type. This kind of damage will chip and weaken epoxy and tile and may allow moisture to penetrate directly to the concrete.
Properly designed and installed brewery floors are almost as critical to the process function as any other piece of equipment. Take time to design, engineer, install, and protect the floor in order to receive maximum performance and reduced maintenance costs. Investigate sealing materials and talk to your colleagues about their experiences and recommendations.