Plant Building Design – Internal

Plant Building Design – Internal

Outdated and classic ways is still used by many food manufacturers to control food safety, however, the it is well known that hygienic design of food process, equipment and factories can contribute significantly to enhance food safety.

The sanitary objectives for interior building design and construction are to minimize potential harborages of pests and microorganisms, maximize cleanability and maximize the protection of the food products from contamination. Ideally, a facility should be designed to provide a flow pattern for food products (as well as personnel and equipment) to prevent potential contact of the finished product with raw materials. Flow should be in one direction and follow a logical sequence from raw material handling to finished product storage.

1. Interior Walls: A cleanable, sanitary wall is one that is hard, flat, and smooth which is free of any type of pits, cracks, checks, and crevices. Walls should be covered with a light colored paint and caulked, sealed or grouted appropriately at joints and junctions. Junctures between walls and ceilings, and between walls and floors should be rounded (or coved) with a radius of one inch or greater. Coving minimizes a right angle crevice, which is difficult to clean and maintain.

2. Ceilings: Improperly installed ceilings, ceilings that promote condensation, or poorly maintained ceilings (e.g., flaking paint) can increase the potential for overhead contamination of food products. The most recommended installation is the concrete slab with exposed double tee beam construction, which avoids ledges associated with I-Beam construction. Concrete ceilings should be ground smooth, appropriately finished, and caulked at the joints. Dropped ceilings are acceptable only if properly installed. False ceilings, which create a crawl space above the ceiling for utilities and services, should be avoided.

3. Floors: Floors should be smooth, impervious, non-absorbent, corrosion resistant, cleanable and in good repair. For safety considerations, floors should not be so smooth that they cause employees to slip and fall. Floor should be installed to provide adequate slope for drainage to prevent pooled water. The most recommended are sealed concrete, epoxy sealed concrete, quarry tile, and glazed tile. Unsealed concrete floors should be avoided as they are highly porous and break down with continued exposure to chemicals.

4. Drains: Floor drains should be of adequate number and size with appropriately located in reference to requirement. Designing and installation should focus on cleanability and scheduled maintained should be followed for good repair. Circular, catch basket drains are most often recommended provided that they are appropriately sealed and grouted to the floor, and are maintained in good repair. A trench drain should be constructed and installed to provide adequate slope or grade ensuring there is no standing water in the trench.

5. Interior Lighting: Light fixtures should be of the type approved for food facilities, and should be equipped with break resistant lenses or shatterproof shielding. The fixtures should be designed to be moisture resistant and cleanable. Electrical boxes and related equipment should be water proof and of acceptable sanitary design

6. HVAC Systems: Heating, ventilation, and air conditioning (HVAC) systems function to maintain the temperature and humidity of a facility. Systems should be constructed, designed, installed, cleaned, and maintained so that they are not a source of contamination. For example, the air supply should be located to not draw air from nearby sources of contamination (e.g., chemicals, bird droppings); adequate filters should be installed and duct work should be located outside of the processing areas. 

7. Employee Facilities, Locker Rooms & restrooms: Employee facilities should not open directly into processing or other critical areas. Most food regulations require a two-door separation between locker rooms or restrooms and food processing areas or food handling areas. Lockers should be sealed to the wall and should have sloped, rather than flat, tops to prevent accumulation of dust and debris.
8. Physical Separation: As much as is practicable, there should be a physical separation between raw and finished products and minimal entry into critical areas. Such physical separation should be accomplished by installation of walls and doorways with anti-back tracking features, and by adjusting air handling systems to provide positive pressure in finished product rooms. As the best physical separation can be undermined by human error or improper personnel flow, there should be an operational and philosophic separation between raw and finished product. This can be accomplished by barring employees working with raw materials from entering finished product rooms, this includes maintenance and janitorial staff.

A sanitary food processing and handling facility must also have designed-in (integrated) features to protect the food products from contamination. Facilities should be periodically inspected and evaluated for potential contamination of product due to the facilities themselves. Utility and water supply lines, and other accoutrements hung or attached to the wall or ceiling must be appropriately caulked and sealed to the wall or mounted in such a way to allow cleaning behind and around. Having a facility designed and built to sanitary specifications does not guarantee a safe food product if the facility is not adequately cleaned and maintained on an appropriate schedule.