3.  GENERAL PRINCIPLES OF DESIGN AND CONSTRUCTION

The following general principles of design and construction shall apply to all equipment covered in these standards, except where exemption from compliance is specifically stated in the Special Principles of Design and Construction relating to individual types of equipment. Particular attention is called to accessories, such as pumps, valves, pipe couplings and thermometers which may be an integral part of the equipment.

3.1 Product Zone

3.1.1 All surfaces shall be smooth.

3.1.2 All surfaces should be readily accessible or readily removable, and shall be accessible or removable.

3.1.3 All surfaces shall be non-toxic.

3.1.4 All surfaces shall be non-absorbent.

3.1.5 All surfaces shall be of corrosion-resistant material.

3.1.6 Dissimilar materials shall not be used where electrolytic corrosion may take place during use or during exposure to cleaning or sanitizing materials.

3.1.7 Cadmium or antimony shall not be used.

3.1.8 Wood shall not be used.

3.1.9 Lead and tin alloy solder shall not be used.

3.1.10 Copper, brass, monel and other copper alloys shall not be used where edible oils, liquid shortening, chocolate liquor and other fatty food products come in contact with the metal.

3.1.11 Permanently joined metal surfaces shall be butted and welded, brazed or silver soldered, and finished flush and equal to surrounding area. Types of chemical adhesives which are non-toxic and the use of which results in a joint of sufficient mechanical strength for the purpose intended are permissible.

Figure 3.1.11

3.1.12 Permanently joined surfaces with a total included internal angle less than 135° shall have a radius of not less than 6 mm (1/4 inch) tangential to both adjacent surfaces.

Figure 3.1.12

3.1.13 Bearings should be outside the product zone and should be sealed or self-lubricating. Bearings or other surfaces requiring lubrication in the product zone shall conform to the requirements of 3.1.1, 3.1.2, and 3.1.3, and lubricants shall be of food grade material. Bearings requiring other than edible lubrication shall be outside the product zone, and the design and construction of these shall be such that lubricant cannot leak, drip or be forced into the product zone.

3.1.14 Seals shall be non-t oxic, non-absorbent, non-exuding, self-lubricating and smooth, and shall not affect or be affected by the product, ingredients or cleaning and sanitizing compounds. Seals shall be removable.

3.1.15 Belting, other than metal, shall be coated, impregnated or made of odorless, non-toxic and non-absorbent material.

3.1.16 Gaskets shall be non-toxic, non-absorbent, non-exuding and self-lubricating, and shall not affect or be affected by the product, ingredients, or cleaning and sanitizing compounds, and shall be installed in a manner which results in a true fit to prevent protrusion in the product zone or creation of recesses or ledges between the gasketed joints.

Figure 3.1.16

3.1.17 Hinges and latches shall be of the simple, take-apart type, and shall be so constructed that, when taken apart, no cracks or crevices exist.

Figure 3.1.17

3.1.18 Inspection windows and light ports shall be of shatter-resistant material. They shall be sealed or readily removable.

3.1.19 Air or other gases mechanically introduced into the product or product zone shall be filtered or washed to remove particles 5 microns or larger, and shall not contain oil, water or other liquids unless such materials are specifically required as an operational procedure. Air within the bakery delivered by small centrifugal blowers at pressures less than 250 mm (10 inches) water column shall be filtered or washed to remove particles 50 microns or larger. All air for comfort ventilation shall be conditioned only to the extent required by regulatory agencies.

3.1.20 Covers shall be of the overlapping type and, if they are in two or more parts, shall be designed with drip protectors. Hinged covers shall pivot outward.

Figure 3.1.20

3.1.21 Dead ends shall not be permitted.

Figure 3.1.21

3.1.22 Thermometers and sensor measuring devices shall be designed to prevent contamination by any portion of the measuring elements. Where protecting wells are provided, weep holes shall be provided and shall drain to the outside of the product zone. Mercury or other toxic materials shall not be used in the product zone unless enclosed within a corrosion-resistant well or case which drains to the outside of the product zone.

3.1.23 Tracks and guides for doors, covers and access panels shall be designed and constructed so as to minimize retention of food particles, condensation, spillage and soil.

Figure 3.1.23

3.1.24 Bottom guides for sliding doors shall have sufficient opening to facilitate cleaning and drainage. Bottom guide grooves shall have open ends.

3.1.25 Surfaces shall be made of odorless materials.

3.2 Non-Product Zone

3.2.1 All surfaces, unless sealed, shall be accessible or removable for cleaning.

3.2.2 All materials shall be suitable for the purpose intended and shall conform to the requirements of cleanability.

3.2.3 All surfaces, including joints and surfaces of insulation unless sealed, shall be cleanable and impervious to moisture.

3.2.4 Screws, bolt heads, nuts, rivets and similar projections shall not form pockets or areas difficult to clean.

Figure 3.2.4

3.2.5 All joints and edges where two members are permanently joined shall be joined in such a manner as to minimize horizontal ledges, cracks, crevices and protrusions.

Figure 3.2.5

3.2.6 Equipment other than that on solid bases sealed to the floor shall provide a floor clearance of at least 150 mm (6 inches) or shall be accessible for cleaning. Structural members shall be arranged so as not to form traps, recesses or pockets. If made of hollow stock, frame members shall have the ends closed.

Figure 3.2.6

3.2.7 Guards shall either be hinged or readily removable or removable, or shall be fitted with covers that are either hinged, readily removable or removable. If hinges or latches are used, they shall be of simple take-apart type. All guards shall be constructed so that transient fluids, splash and spillage will not be retained.

3.2.8 Permanently joined surfaces having interior angles shall be accessible and should be curved, rounded or cove-shaped with not less than 1.5 mm (1/16 inch) minimum radius or curvature.

Figure 3.2.8

3.2.9 Where lubrication is required, the design and construction shall be such that the lubricant cannot leak, drip or be forced into the product zone.

3.2.10 Name plates, if present, shall be sealed to the surface.

3.2.11 Motors and accessory equipment shall be mounted with at least 2 inches (50mm) minimum space on all sides, top and bottom of the motor or motor and accessory to allow cleaning around the motor or motor and accessory.

Figure 3.2.11

3.2.12 Face-flange or base-mounted motors or accessory equipment with machined surfaces are permitted if sealed.

Figure 3.2.12

3.2.13 The electrical wiring system shall be constructed so that dust shall not enter. When located in a wet or washdown area, the electrical system shall be constructed so that liquids shall not enter.

3.2.14 All electrical enclosures shall be sealed to the mounting surface and any adjacent surface, or shall be spaced away at least ¾ inch (20mm) or at a distance equal to one-fifth of the shortest dimension of the electrical enclosure parallel to the surface, whichever is greater, but not necessarily more than 18 inches (460mm) to allow for adequate access for cleaning. Hinges on electrical panels are exempt from Section 3.1.17.

3.2.15 Conduits shall be installed so that hard-to-clean areas or crevices are not formed, or shall be spaced away from adjacent surfaces at least 20 mm (3/4 inch) to allow for cleaning. Flexible conduit and fittings shall be liquid-tight.

3.2.16 Hollow spaces within the frame which do not contain functional parts shall be sealed. Hollow spaces within the frame which contain functional parts shall be sealed or closed, and readily accessible.

3.2.17 All light bulbs, lamps and tubes shall be protected against falling, and shall be shatter- resistant, housed in shatter-resistant fixtures, or otherwise protected against breakage.

3.2.18 Inspection windows and light ports shall be of shatter-resistant material. They shall be sealed.

3.2.19 Tracks and guides for doors, covers and access panels shall be designed and constructed so as to minimize retention of food particles, condensation, spillage and soil.

3.2.20 Bottom guides for sliding doors shall have sufficient opening to facilitate cleaning and drainage. Bottom guide grooves shall have open ends.

3.2.21 The frame and/or base of the equipment shall be so designed that areas difficult to clean are not created when the equipment is installed.

3.2.22 Surfaces shall be corrosion-resistant and non-absorbent, or shall have a protective coating.

3.2.23 Surfaces shall be made of odorless materials.