J. Peter Clark

Converting an existing building to use as a food processing facility is fairly common and often tempting because it would seem to be less expensive than building a new facility from scratch. Sadly, it is not always less expensive, and it usually involves some compromises in design and construction. However, done properly, with experienced leadership, creative reuse of an existing building can be a satisfactory solution to a need for additional capacity. Exterior of a typical building.

Why Convert?
First, why might we need additional capacity? The best motivation is healthy growth in a new or existing business. If new, it is important to minimize risk, because of the inherent uncertainty of projecting demand and the unfortunate fact that many new products fail. Often, new products are manufactured by third parties, co-manufacturers or co-packers, until their success is assured. Some firms are reluctant to expose new ideas to outsiders, while others routinely use such arrangements. One approach is to outsource established products and perform initial production of new products in a semi-works or small, flexible facility. In any event, the time comes when something larger is needed.

Growth in an existing business is more likely to be reliable than projections for a new business. The need may be to service a new region of the market or simply to satisfy overall increase in demand. Before rushing to invest, however, it is important to be sure that existing facilities are fully utilized. Food plants have often operated five days per week, two shifts per day, with a third shift for sanitation, and weekends for maintenance and occasional “emergency” production. Many companies have demonstrated that they can operate their lines almost 24 hr/day and 7 days/week. A common strategy is to run 13 days in a row and perform maintenance on the 14th. This may require careful design for sanitation and skilled operation, but it significantly increases the capacity of an existing line.

Another potential source of unrealized capacity is seasonality. Many agricultural raw materials are only available at certain times in a given area. Plants that use such materials may be largely idle for long periods of time. However, with global sourcing and bulk storage of raw or partially processed raw material, seasonality of manufacturing can be reduced and capacity increased. Bulk aseptic storage of tomatoes, peaches, orange juice, and other fruits and vegetables (for which IFT Past President Phil Nelson recently received the World Food Prize) has increased capacity of canneries and other processors of seasonal crops.

Potatoes, apples, carrots, and some other crops are routinely stored for long periods, extending the time for processing. Southern hemisphere sources of raw or partially processed materials can extend the season for Northern hemisphere plants. Frozen tomato paste is a good example of such a material. Using it has greatly improved the utilization of existing processing plants.

What Are Our Choices?
Having satisfied ourselves that we need the additional capacity, and having chosen a location (a topic for another time), what are our choices for additional capacity? If time and cost are not constraints, a new building designed and built specifically for the need is often the ideal solution. But time and cost usually are constraints. If a need for capacity is demonstrated, then the sooner it is available, the more valuable it is as a contributor to cash flow.

The initial costs of a purpose-built facility and of a converted building may be similar, but a purpose-built facility may have a reduced salvage or resale value, because it may have unique characteristics that are not needed nor valued for other potential uses. Industrial real estate tends to deal in generic buildings that are most often used for storage and distribution activities. These buildings are simple boxes with flat floors and high-enough roofs to permit stacking of pallet loads 3 or 4 high.

Modern industrial buildings often have 30 ft of clear height, while older buildings may have about 25 ft. These are taller than most food processes require, so a purpose-designed food plant might have a lower clear height in some areas, in an effort to economize building cost. This is a false economy when considering future resale value. A knowledgeable architect will not allow a food client to be so shortsighted in designing a new plant.

It is rare that a plant previously used for food processing becomes available, but it does happen. Such a building may have floor drains, though not usually exactly where they ought to be. There might be some refrigerated or frozen storage, which most food plants need. Walls and ceilings might be of sanitary design, or might once have been. Walls and doors are unlikely to be where they are wanted, and an older plant, especially if it has been unoccupied for a while, may be in poor shape. Real estate agents, not understanding the uniqueness of food processes, will present an existing food plant as the answer for any food client, which is not often true.

Much more common on most real estate markets are new or used generic warehouses or distribution centers. These can be quite large—500,000-sq-ft and even larger buildings are frequently found. If a food plant needs that much space, the company might be well advised to design and build (or have built for it) a “greenfield” (i.e., new) plant. More likely, the food company needs a portion of such a building. This means either finding a smaller candidate building, sharing the large building with one or more other occupants, or taking the entire space and finding another use for the excess area. Controlling the entire building gives the food company more influence over the nature of other tenants, though most leases will allow some right of review so that competitors or potentially noxious neighbors are not introduced.

Finding a “right-sized” new or used building is ideal, but there still are challenges. Most food plants want to have the potential to expand, but most industrial buildings are designed to occupy as much of a given piece of land as is permitted. The typical generic building also usually has about one truck dock for every 5,000– 6,000 sq ft. Parking for cars is also usually limited because buildings designed as warehouses are assumed to have relatively few employees and few visitors. Food manufacturing can be relatively labor intensive, with several hundred employees not unusual.

In shopping for a new or used building to use as a food plant, it is important to know how many truck docks are needed, how much car and truck parking is needed, and how much expansion is anticipated. Most likely, a larger building than is initially required will be chosen, to accommodate future expansion. The extra space can be used as storage or left undeveloped until needed.

Other Considerations
Most buildings designed as warehouses or for light manufacturing have relatively light roof structures, to save costs. These are typically made from metal trusses or, in California, laminated wooden beams. Such roofs are not designed with any extra load-carrying allowance, whereas food plants often have piping and refrigeration units that are routinely hung from the roof or mounted outside on the roof. One of the more-or-less-inevitable costs of converting an existing building into a food plant is strengthening the roof structure or providing separate structural steel for piping and equipment.

Another predictable cost is cutting the floor and installing process drains. Existing buildings rarely have floor drains, and if they do in some areas they will not be where they are needed for the new use. A frequent issue is whether to also slope the floors in areas of heavy water use. Good Manufacturing Practices require no standing water in food-contact areas, so this often means sloping floors toward hub or trench drains.

Replacing a large amount of existing floor can be expensive and hard to justify, but may be the correct long-term decision. If it is not done, then measures should be taken to reduce water use and to provide squeegees to workers to prevent falls and reduce the potential biological hazard of standing water.

Sometimes a newly constructed building is left with no finished floor, so that the first occupant can define and have provided what they want.

Finally, lighting, fire protection, and utilities, such as electricity, water, sewers, and fuel supply, must be evaluated and often need to be upgraded. It is common that walls need new paint or panel covering, and the floor, whether new or old, will need a food-grade coating.

Taken all together, the upgrades and improvements required in converting an existing building to food use are not very different from those encountered in building a new plant. One big difference is that most of the work occurs inside the structure, is not dependent on the weather, and can start anytime, while site work and steel erection for a new building must wait for construction season, where that applies.

by J. Peter Clark,
Contributing Editor, Consultant to the Process Industries, Oak Park, Ill. 
[email protected]