Keeping the FDA, FSMA, and USDA at Bay

Food and Beverage Plant Construction 101

Process Areas

Unlike many manufacturing facilities, food plants must be constructed with cleanliness to a microbiological level, with production, sanitation, and maintenance at the forefront of decisions on methods and materials of construction.

In processing areas, plants must be designed so that there are no cavities or voids where things like moisture, product, and dirt can accumulate, leading to microbes, insect and/or rodent infestation, and possible product contamination.

In plant design and construction, the following are critical items to consider:

• Wall surfaces must be designed to be impervious and easy to clean.
• Adequate clearance must be allowed around equipment for cleaning and maintenance.
• Any suspended ceilings used in process areas should be structural in nature, with personnel access to the “interstitial” areas between the suspended ceiling and the underside of the roof. This area can provide an excellent space to run utility piping and other needed services.
• Traffic aisles in process rooms need to be adequate in size and free of obstructions.
• Cross-contamination of raw/cooked products should be eliminated by using physical barriers or proper procedures considering process, people flow, and employee amenity areas.

Foundations

Normally, soil characteristics will dictate which type of foundation is most economical. A geotechnical investigation to determine what soil type and support capacity is necessary involves boring into the soil, retrieving and lab-testing samples, and preparing a soil report, which should provide sufficient information to allow for the use of the optimum foundation based on structure and equipment loads.

Floors

Floors in a process area – and food plants in general – must be of high quality. A poorly constructed or improper floor material will be more costly to maintain and can create major problems. Poorly constructed and planned floors can interfere with drainage and clean-up, creating contamination issues. Generally, floors in wet process rooms should be sloped at 1/4 inch per foot to maintain proper drainage. This applies to floors with both floor point drains and trench drains.

The floor’s usage will usually determine the type of floor chosen, especially regarding the various floor finishes that are available for today’s processing areas. These finishes can range from acid brick (commonly used in high-traffic/high-corrosive areas, such as cook kitchens), quarry tile, and plain concrete with added hardeners or urethane coatings. In processing areas that are exposed to thermal shock from process equipment and/or sanitation, a urethane floor topping is recommended, given its similar expansion properties to the concrete on which it is applied. Epoxy floors are acceptable in some areas but may delaminate over time in areas that are exposed to thermal shock. Wet process areas should always have floors that have non-slip and non-skid surfaces.

Walls

While walls can be constructed of varying materials, they must be impervious (non-porous) and able to be easily cleaned. Walls may be constructed of:

• Insulated metal panels with Kynar, stainless steel, or other special finishes.
• Precast concrete panels. (Care must be taken to eliminate pockets in the  concrete surface.)
• Cast-in-place tilt-up concrete panels. (Care must be taken to eliminate pockets in the  concrete surface.)
• Concrete walls, whether tilt-up or precast panels, must be coated with a sealer to allow for surface cleaning. All joints need to be tightly sealed. Due to its porosity, lightweight concrete blocks should be avoided as wall material.
• Masonry with tile or epoxy finishes.
• Glazed block or tile.

In all cases, painted walls in process areas should be avoided due to heat, steam, washdown, and cleaning issues, all of which can contribute to deterioration and de-lamination of painted surfaces.

Insulated panels can be used in process areas if the finish is compatible with the environment and clean-up procedures.

Ceilings

Ceilings in process areas are critical to plant maintenance and cleanliness. In process areas, ceilings should not have exposed steel joists, beams, or metal decks where dust, condensation, and other materials can accumulate. Ledges, cracks, and cavities, which are difficult to clean, can allow contaminants to fall onto the product and equipment below.

Although a lay-in ceiling may present similar problems, appropriate materials can make it workable. These ceilings can be utilized if the grid is plastic or stainless steel and the tiles are non-porous and sealed so water doesn’t penetrate the interstitial space during sanitation.

In refrigerated areas, ceiling systems can consist of insulated panels with a similar non-porous finish. This solution can allow for the interstitial space to be accessed by personnel and also house all utility horizontal runs, allowing for a vertical drop to equipment connection points.

Designers may sometimes specify pre-cast concrete panels and double-T concrete sections in process areas. As always, all cracks and voids must be filled and a concrete sealer applied to provide for an easy-to-clean surface. All utility piping and conduits should be run on pipe racks around the perimeter of the process areas or within the interstitial space to ensure that they are not installed over open process or packaging equipment.

Structural Frames

Members which support the walls, roofs, and elevated floors or mezzanines within a food plant comprise the building’s structural system.

Structural materials in these instances usually consist of either tubular steel or concrete.

Steel

Buildings supported by structural steel are typically lightweight, flexible, and noncombustible, allowing long spans between columns. Roof members usually consist of a metal roof deck supported by open-web joists, which are supported by either joist girders or wide flange beam sections. Columns support the roof using either wide flange sections or tube sections.

Concrete

Concrete structures are heavier than steel and require larger foundations but have greater fire resistance than wood and steel. The concrete wall surface presents an excellent finish for food processing applications. In food-processing facilities, concrete structures provide a high degree of cleanliness and are easier to maintain than other systems. Pre-cast concrete structures, where the members are usually cast off-site at a pre-cast manufacturing plant and then assembled on-site to form the building, are typically used for industrial-type exterior concrete walls, which may be load-bearing or non-load bearing. 

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