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Since 1925 the Public Health Service, the States and the shellfish industry have cooperated in a program designed to maintain a high level of sanitation in the growing, harvesting, and processing of oysters, clams and mussels to be marketed as a fresh or frozen product. The basic sanitary standards used in this program are fully described in PHS Publication No. 33, Manual of Recommended Practice for Sanitary Control of the Shellfish Industry, Parts I and II. General construction standards for equipment used by the shellfish industry are an integral part of these basic standards.
The need for more specific construction guides for equipment used by the shellfish industry was reviewed at the 1958 Shellfish Sanitation Workshop1 and the Public Health Service (PHS) was requested to initiate development of such guides. As result of this request, the PHS developed drafts of equipment construction guides. Agencies and organizations which received these initial drafts and thus contributed to the development of the completed construction guides included: Oyster Institute of North America, Bureau of Commercial Fisheries, Food and Drug Administration, Canadian Department of National Health and Welfare, and two equipment manufacturing companies. The completed construction guides were reviewed and adopted by the 1961 National Shellfish Sanitation Workshop. Subsequently, the 1993 annual meeting of the Interstate Shellfish Sanitation Conference asked FDA to review and update the definitions to be consistent with other documents such as Model Code, Pasteurized Milk Ordinance, National Sanitation Foundation, and Code of Federal Regulations. FDA agreed to provide an update to the committee.
It is the purpose of this guide to describe construction and fabrication procedures which will ensure that blower tanks, skimmers, returnable shipping containers, shellfish shucking buckets and pans and will meet the equipment construction standard of the Cooperative program and the functional needs of the industry. However, the development of new methods of equipment construction or fabrication with acceptable materials, construction and fabrication is also encouraged. Therefore, shellfish equipment specifications developed which differ in design, material, fabrication, or otherwise do not to conform with the following standards, but which in the fabricator's opinion are equivalent to or better may be submitted for consideration.
ScopeThis guide covers the sanitary construction aspects of (1) shellfish blower tanks, including the sanitary piping for air, water, and drain lines; (2) the stand-supported skimmer, including the supporting stand; (3) returnable shipping containers; (4) shellfish shucking buckets; (5) shellfish shucking pans; (6) tables; (7) conveyors; (8) mechanical shucking devices.
This guideline will aid FDA, state regulatory officials and other interested individuals in making evaluations of the materials, construction and fabrication of equipment used to collect, convey, store, transport, process and package molluscan shellfish products.
This guideline will also provide manufacturers with knowledge of what documentation reviewers might expect them to provide in order to verify the acceptability of materials, construction and fabrication.
Definitions(1) Air break - A piping arrangement in which a drain from a fixture, appliance, or device discharge indirectly into another fixture, receptacle, or interceptor at a point below the flood level rim. (2) Air Gap - The unobstructed vertical distance (twice the diameter of largest inlet pipe) through the free atmosphere between the water inlet supplying a tank, plumbing fixture or other device and the effective overflow level of the receptacle. (3) Air Under Pressure - The pressure of which has been increased by mechanical means to exceed atmospheric pressure, and which is used for agitation of shucked shellfish. (4) Alternate Materials - Is whenever specific materials are mentioned, it is understood that the use of materials proven to be equally satisfactory from the standpoint of sanitation and protection of food is acceptable. (5) Blower - A tank-like device for immersion washing of shucked shellfish. Air may be introduced at the bottom of the tank to produce agitation. (6) Coatings - The results of a process where a different material is deposited to create a new surface. There is appreciable build-up of new material, typically more than 1µm. (7) Corrosion Resistant Materials - Those materials that maintain their original surface characteristics under normal exposure to the foods being contacted, normal use of cleaning compounds and bactericidal, and other conditions of use. (8) Cleaned-in-place - Refers specifically to the cleaning and sanitizing of food processing equipment and piping in its assembled condition by recirculation of the necessary rinse, detergent and sanitizing solutions under appropriate conditions of time, temperature, detergency and physical action. (9) Dead End - Area or space wherein a product, ingredient, cleaning, or sanitizing agent, or other extraneous matter may be trapped, retained or not completely displaced during operational or cleaning procedures. (10) Drain gate and chute - The opening located either in the blower or skimmer through which the washed shellfish are eliminated. (11) Drain valve - The valve through which the wash water is released to the floor or waste line. (12) Easily Cleanable - A surface which is readily accessible and is made of such materials, has a finish and is so fabricated that residue may be effectively removed by normal cleaning methods. (13) Equipment - Blower, skimmer, tables, shucking benches, can seamer, sinks, refrigerators, and similar items other than utensils, used in the operation of a shellfish processing facility. (14) Filter Media - Filters for the air intake of a blower shall consist of fiberglass with down stream backing dense enough to prevent fiberglass break off from passing through, cotton flannel, wool flannel, non-woven fabric or other suitable materials which under conditions of use, are non-toxic and nonshedding and which do not release toxic volatile or other contaminants to the air, or volatile which may impart any flavor or odor to the product. Dispos (15) Flood Level Rim - The edge of the receptacle from which water overflows. (16) Food contact surface - Surface of equipment or a utensil which food normally comes into contact; or a surface of equipment or a utensil from which food or liquid may drain, drips, or splash into a food; or onto a surface normally in contact with food. Food contact surfaces include, but are not limited to, equipment and utensils such as; shucking knives and handles, shucking hammers and handles, shucking blocks, ice scoops and shovels, ice bins, skimmer (17) Metals - Metals which are nontoxic, nonabsorbent and corrosion resistant under conditions of intended use. (18) Nonfood Contact Surfaces - All exposed surfaces other than food or splash contact surfaces. (19) Nontoxic Materials - Materials which are free of substances which may render shellfish injurious to health or which may adversely affect the flavor, odor, composition or bacteriological quality of the product and which meet the requirements of the Federal Food Drug and Cosmetic Act as amended. (20) Plastic - A material that contains as an essential ingredient an organic substance of high molecular weight, is solid in its finished state, and at some stage in its manufacture or in its processing into finished articles, can be shaped by flow. (21) Rim - An unobstructed open edge of a fixture. (22) Readily accessible - Exposed or capable of being exposed for cleaning and inspection without the use of tools. (23) Readily Demountable or Removable - Capable of being taken away from a unit with the bare hands or the use of simple tools such as screwdriver, pliers or an open end wrench. (24) Returnable Shipping Container - Multiple use container for holding or shipping of shucked shellfish. (25) Safe Materials - Articles manufactured from or composed of materials that may not reasonably be expected to result, directly or indirectly, in their becoming a component or otherwise affecting the characteristics of any food. (26) Sealed - Free of cracks or other openings that permit the entry or passage of moisture. (27) Molluscan Shellfish - All edible species of oysters, clams, mussels and whole scallops or roe-on scallops (scallops are excluded when the final product is the shucked adductor muscle only). Shellfish products which may contain any material other than the meats and /or shell liquor of oysters, clams, mussels or scallops will be regarded as a "processed food" and will not be included in the Cooperative Program. (28) Shellfish Shucking Bucket - Containers for temporarily holding shucked shellfish during the shucking process. (29) Shellfish Shucking Pan - Containers for temporarily holding shucked shellfish during the shucking process. (30) Shucked Shellfish - Shellfish, or parts thereof, which have been removed from their shells. (31) Single Service Articles - Any metal or plastic containers, lids and closures, wrapping materials such as burlap or hessian bags and similar materials intended for one-time use, one person use and then discarded. (32) Skimmers - A perforated tray in which shucked shellfish are sprayed washed and/or drained. (33) Skimmers Paddle - The utensils used as the gate on the skimmer exit chute and/or one used to scrape the product through the exit chute. (34) Smooth - A surface free of pits and inclusions having a clean ability or better than the following: (a) food contact a No. 4 (150 grit) or better finish as obtained with silicon carbide, properly applied on stainless steel surface; (b) Non-food contact surfaces free of visible scale. (35) Splash Contact Surfaces - Any surfaces other than food contact surfaces which are subject to routine splash (wet or dry), spillage and contamination during normal use. (36) Toxic - Having an adverse physiological effect on man. (37) Utensils - Any implement used in the preparation, transportation, and storage of molluscan bivalves such as shucking knives, skimmer paddles, strainers, shucking buckets, shucking pans, etc. (38) Weld - Permanent seams or joints. When welded seams are used, the weld area and the deposited material shall be as corrosion-resistant as the parent material. |
Stainless steel is a family of iron based alloys that must contain at least 10.5% Chromium (Cr). The presence of chromium creates an invisible surface film that resists oxidation and makes the material “passive” or corrosion resistant (i.e. “stainless”). This family can be simply and logically grouped into five (5) branches. Each of these branches has specific properties and a basic grade or “type.” In addition, further alloy modifications can be made to "tailor" the chemical composition to meet the needs of different corrosion conditions, temperature ranges, strength requirements, or to improve welding, machine, work hardening and form.
Stainless is designated by three different systems: Metallurgical structure - Austenitic; Grade - 304 (most used see photos 1 and 2 for Polish No. 3 and No 4) and Unified Numbering System UNS.
Stainless steel product contact surfaces of the American Iron and Steel Institute
(AISI) 303, 304, 316 Series3 or corresponding Alloy Cast Institute
(ACI) types.4 Cast grades of stainless steel corresponding to types
303, 304, and 316 are designated CF-16F, CF-8, and CF-8M, respectively. The
chemical compositions of these cast grades are covered by ASTM specifications
A351/A351M, A743/A743M and A744/A744M.5 Metal which under conditions
of intended use is at least as corrosion resistant as stainless steel of the
foregoing types, and is nontoxic and nonabsorbent, can also be used, except that:
Equipment may also be made of stainless steel of the AISI 400 Series that is
made as corrosion resistant as AISI 300 Series by surface treatment or coating(s)
or made of nontoxic, nonabsorbent metal that is as corrosion resistant, under
the conditions of intended use, as stainless steel of the AISI 300 Series.
Metal alloy of the following types may be used but only in applications requiring disassembly and manual cleaning. (See Table 1; values are in percentages)
Equipment made of optional metal alloy may have product contact surfaces modified by surface treating or coating.
Photo 1 – Stainless Steel Type 304, No.3
Polish satisfactory for many industrial and commercial products
requiring a good polished surface. Typical applications include
vent hoods.
Photo 2 - Stainless Steel Type 304, No.4
Polish is exceptionally uniform normally used without further
finishing. This is the established standard for dairy and
food processing equipment because it is easy to keep clean
and sanitary.
An electroless nickel alloy coating having the following composition is acceptable:
Equipment to be manually or mechanically cleaned may be covered by an engineering coating of electroless nickel alloy conforming to the applicable provisions of military specification MIL-C-26074 E, as amended. 6
Equipment may also be made of other nontoxic structurally suitable metal(s) that have their product contact surfaces modified by surface coating(s).
Solder, when used, should be silver bearing solder and should be corrosion resistant, free of cadmium, lead and antimony, nonabsorbent, and should not impart any toxic substance to the product when exposed to the conditions encountered in the environment of intended use and in cleaning and bactericidal treatment (or sterilization).
UNS NO8367 ASTM A743 Grade CN-3MN |
UNS S21800 ASTM A743 Grade CF-10 SMnN |
UNS S20161 |
UNS N26055 ASTM A494 Grade CY5SnBiM |
UNS N26455 ASTM A494 Grade CW-2M |
UNS S17400 ASTM A747 Grade CB7Cu-1 |
UNS S15500 ASTM A747 Grade CB7Cu-2 |
UNS S32900 |
UNS R20500 ASTM A560 Grade 50Cr-50Ni |
UNS R50400 ASTM B67 Grade C-2 |
|
---|---|---|---|---|---|---|---|---|---|---|
C | 0.03 |
0.1 |
0.015
|
0.05
|
0.02
|
0.07
|
0.07
|
0.2
|
0.1
|
0.1
|
Mn | 2.00
|
7.00 -9.00
|
4.00 -6.00
|
1.5
|
1.00
|
0.70
|
0.70
|
1.00
|
0.30
|
|
Si | 1.00
|
3.50 -4.50
|
3.00 - 4.00
|
0.5
|
0.80
|
1.00
|
1.00
|
0.75
|
1.00
|
|
P | 0.040
|
0.040
|
0.040
|
0.03
|
0.03
|
0.035
|
0.035
|
0.040
|
0.02
|
|
S | 0.010
|
0.030
|
0.040
|
0.03
|
0.03
|
0.03
|
0.03
|
0.030
|
0.02
|
|
Cr | 20.0-22.0
|
16.00 - 18.00
|
15.0 - 18.0
|
11.0 - 14.0
|
15.0 - 17.5
|
5.50-17.7
|
14.0-15.5
|
23.0-28.0
|
48.0 - 52.0
|
|
Ni | 23.5-25.5
|
8.00-9.00
|
4.00-6.00
|
Balance
|
Balance
|
3.60-4.60
|
4.50-5.50
|
2.5-5.0
|
Balance
|
|
Mo | 6.0-7.0
|
|
|
2.0-3.5
|
15.0-17.5 |
|
|
1.0-2.0 |
|
|
Cb |
|
|
|
|
|
0.15-0.35 |
0.15-0.35 |
|
|
|
Cu |
0.75 |
|
|
|
|
2.5-3.2 |
2.5-3.2 |
|
|
|
N | 0.18- 0.26 |
0.08- 0.18 |
0.08-0.020 |
|
|
0.05 |
0.05 |
|
0.30 |
|
Fe | Balance |
Balance |
Balance |
2.00 |
2.00 |
Balance |
Balance |
Balance |
1.00 |
0.30 |
Sn | |
|
|
3.0-5.0 |
|
|
|
|
|
|
Bi | |
|
|
3.0-5.0 |
|
|
|
|
|
|
W | |
|
|
|
1.0 |
|
|
|
|
|
Tl | |
|
|
|
|
|
|
|
0.50 |
Balance |
Al | |
|
|
|
|
|
|
|
0.25 |
|
Other | |
|
|
|
|
|
|
|
|
H=0.015 N=0.03 O=0.25 |
NOTE: Metal alloys or metals other than the above may be as corrosion resistant as 300 Series Stainless steel. This may be shown when metal alloys or metals are tested in accordance with ASTM G31 Laboratory Immersion Corrosion Testing of Metals and have a corrosion rate of less than 20 mil per year. The test parameters such as the type of chemical(s), their concentration(s) and temperature(s) should be representative of cleaning and sanitizing conditions used in dairy equipment. Alloys containing lead, leachable copper or other toxic metals should not be used.
Aluminum is satisfactory for certain dry products applications. Aluminum may be used for liquid or high moisture content product contact surfaces only when a specific functional requirement exists and the parts are not subjected to strong caustic cleaning solutions or to the corrosive action of dissimilar metals.
The aluminum type chosen for the application shall be demonstrated to be appropriate and acceptable for the intended use. (Provisions have been made in existing 3-A (dry product) Standards for Aluminum Association designations 5052, 6061, 6063, A-360, A-380, A-319, A-315G, and C-413, Danish Standards DS#3002 and #4261, and ASTM standards B179, and S12c for certain specified uses.)
Non-metallic materials may be used for food contact and non-food contact equipment and service items. When utilized these materials shall be in compliance with appropriate sections of the 21 Code of Federal Regulations, Parts 170-199 (21 CFR 170-199).
These materials shall be relatively inert, resistant to scratching, scoring, and distortion by the temperature, chemicals, and methods to which they are normally subjected in operation, or by cleaning and bactericidal treatment. They shall be non-toxic, fat resistant, relatively non-absorbent, relatively insoluble and shall not release component chemicals or impart a flavor to the product.
Materials for non-product contact surfaces should be of corrosion-resistant material or material that is rendered corrosion resistant. If coated, the coating used should adhere. All non-product contact surfaces should be relatively nonabsorbent, durable, and cleanable. Parts removable for cleaning having both product contact and non-product contact surfaces should not be painted.
All product contact surfaces should have a finish at least as smooth as No. 4 ground finish on stainless steel sheets and be free of imperfections such as pits, folds and crevices in the final fabricated form. Surface finish equivalent to 150 grit or better as obtained with silicon carbide, properly applied on stainless steel sheets, constitutes a No.4 ground finish. A maximum Ra of 32 micro-inch (0.80), when measured according to the recommendations in ANSI/ASME B46.18 - Surface Texture, is considered to be equivalent to a No. 4 finish.
Where welding is involved, the carbon content of the stainless steel should not exceed 0.08%.
All permanent joints in metallic product contact surfaces should be continuously welded. Welded areas on product contact surfaces should be at least as smooth as No. 4 ground finish on stainless steel sheets, and be free of imperfections such as pits, folds, and crevices when in the final fabricated form except that:
In such cases where welding is impractical, soldering, may be employed where necessary for essential functional reasons. Silver bearing solder may be used for producing fillets for minimum radii or other appropriate functional purposes.
Press-fits or shrink-fits may be used to produce crevice free permanent joints in metallic product contact surfaces when neither welding nor soldering is practical. Joints of these types may only be used to assemble parts having circular cross sections, free of shoulders or relieved areas. For example: they may be used to assemble round pins or round bushings into round holes. In both of these fits the outside diameter of the part being inserted is greater than the inside diameter of the hole.
In the case of the press-fit the parts are forced together by applying pressure. The pressure required is dependent upon the diameter of the parts, the amount of interference and the distance the inner member is forced in.
In shrink-fits, the diameter of the inner member is reduced by chilling it to a low temperature. Dry ice is commonly used to shrink the inner member. Heat may also be applied to the outer member of the press-fit. Less assembly force is required for this type of fit.
The design of these fits depends on a variety of factors. The designer should follow recommended practices to assure that a crevice-free joint is produced. A recognized authoritative reference is Machinery’s handbook published by Industrial Press Inc., 200 Madison Avenue, New York, NY 10157.
Press-fitting, shrink-fitting or soldering should produce contact surfaces which are at least as smooth as No. 4 ground finish on stainless steel sheets and which are free of imperfections such as pits, folds and crevices.
Bonded rubber and rubber-like materials and bonded plastic materials having product contact surfaces should be bonded in a manner that the bond is continuous and mechanically sound so that when exposed to the conditions encountered in the environment of intended use and in cleaning and bactericidal treatment (or sterilization if applicable) the rubber and rubber-like material or the plastic material does not separate from the base material to which it is bonded.
Coatings, if used, should be free from surface delamination, pitting, flaking, spalling (chipping), blistering and distortion when exposed to the conditions encountered in the environment of intended use and in cleaning and bactericidal treatment (or sterilization).
Equipment that is to be mechanically cleaned should be designed so that the product contact surfaces and all non-removable appurtenances thereto can be mechanically cleaned and are easily accessible and readily removable for inspection. Removable parts shall be readily demountable employing simple hand tools, which are available to operating or cleaning personnel; except that equipment that is to be CIP cleaned should have representative product contact surfaces easily accessible for inspection.
Product contact surfaces, not designed to be mechanically cleaned, should be accessible for cleaning and inspection when in an assembled position or when removed.
Appurtenances having product contact surfaces should be readily removable using simple hand tools or they should be cleanable when assembled or installed and should be easily accessible for inspection.
All product contact surfaces, when properly installed, should be self-draining except for normal clingage. However, if the product contact surfaces are not self-draining, they should have sufficient pitch to suitable drain points so they can be drained.
Sanitary fittings and connections which conform with the appropriate 3-A Sanitary Standards are acceptable. All other fittings must be reviewed using the criteria in this document.
The thermometer connections and/or openings, if provided or required, should be located so that the thermometer is not influenced by a heating or cooling jacket.
If the fittings for temperature sensing devices do not pierce the tank lining, either the temperature sensing element receptacles should be securely attached to the exterior of the lining or means to attach the temperature sensing element(s) securely to the exterior of the lining should be provided.
All metal tubing should conform with the applicable provisions for welded sanitary product pipelines found in the 3-A Accepted Practices for Permanently Installed Product and Solution Pipelines and Cleaning Systems Used in Milk and Milk Product Processing Plants, Number 605- or equivalent and with the 3-A Sanitary Standards for Polished Metal Tubing for Dairy Products, Number 33- or equivalent.
Gaskets having a product contact surface should be removable or bonded.
Grooves in gaskets should be no deeper than their width unless the gasket is readily removable and reversible for cleaning, (i.e., storage tank door gaskets).
Gasket retaining grooves in product contact surfaces for removable gaskets should not exceed 1/4" (6.35 mm) in depth or be less than 1/4" (6.35 mm) wide except those for standard O-rings smaller than 1/4" (6.35 mm) and those allowed in the 3-A Standard for Sanitary Fittings, Number 63.
All internal angles 135° or less on product contact surfaces should have a minimum radii of 1/4" (6.35 mm) except that:
There should be no threads on product contact surfaces accept where necessary for non-permanent joints in piping and for making various attachments to equipment.
In such case(s) the threads should conform with the “Acceptable Sanitary Thread”. The thread angle should be not less than 60° and with not more than eight threads to the inch (25.4 mm), nor less than 5/8" (15.88 mm) major basic diameter. The length of the nut should not exceed three-quarters of the basic thread diameter. The nut should be of the open type. Equipment with exposed threads as described above should be manually cleaned. Equipment with enclosed threads, (such as “acorn” nuts used to attach impeller blades to pump shafts), should be designed for mechanical cleaning.
Perforations in product contact surfaces may be round, square, or rectangular. If round the holes should be a minimum of 1/32" (0.794 mm) in diameter. If square, or rectangular, the least dimension should be no less than 0.020" (0.51 mm) with corner radii of no less than 0.0050" (0.13 mm). All perforations should be free of burrs.
Shafts entering equipment should have a seal of the packless type and sanitary
design, and should be readily accessible for cleaning and inspection.
Where a shaft passes through a product contact surface, in a milk room or processing
area, the portion of the opening surrounding the shaft should be protected to
prevent the entrance of contaminants.
Bearings having a product contact surface should be of a non-lubricated type.
Lubricated bearings, including the permanent sealed type, should be located outside
the product contact surface with at least 1" (25.4 mm) clearance open for
inspection between the bearing and any product contact surface unless specifically
provided for in a 3-A standards.
(a.) | Plastic materials may be used for the blower tank drain gate and drain valve. These materials shall be relatively inert, resistant to scratching, scoring, and distortion by the temperature, chemicals, and methods to which they are normally subjected in operation, or by cleaning and bactericidal treatment. They shall be non-toxic, fat resistant, relatively nonabsorbent, relatively insoluble, and shall not release component chemicals or impart a flavor to the product3. |
(b.) | Rubber and rubber-like materials may be used for blower tanks paddles or gate, drain gate, and drain valve. These materials shall be relatively inert, resistant to scratching, scoring, and distortion by the temperature, chemicals, and methods to which they are normally subjected in operation, or by cleaning and bactericidal treatment. They shall be non-toxic, fat resistant, relatively non-absorbent, relatively insoluble and shall not release component chemicals, nor impart a flavor to the product.3 |
(Figure 1) – Product contact surface seams
Figure 2 – Internal angles of 135° or less on product
contact areas
Figure 3 – Sanitary Pipe Fitting
Figure 4 – Blower Tank
Figure 5 – Close up for a smooth and rounded leg
Figure 6 – Blower false bottom plate
Figure 7 – Air pump
Figure 8 – Air manifold installed inside the blower tank
Figure 9 – Air manifold located inside tank
(a.) | Suitable plastic materials or rubber and rubber-like materials may be used for the skimmer paddle or gate. These materials shall be relatively inert, resistant to scratching, scoring, and distortion by temperature, chemicals, and methods to which they are normally subjected in operation, or by cleaning and bactericidal treatment. They shall be non-toxic, fat resistant, relatively nonabsorbent, relatively insoluble, and shall not release component chemicals nor impart a flavor to the product.3 |
Figure 10 – Photo front view of a skimmer
Figure 11 – Front view of skimmer frame; broken lines
are the removable part of the skimmer food contact area
Figure 12 – Skimmer perforations or slots in the strainer
shall be at least 1/4 ” in diameter
Figure 13 – Skimmer cross sectional side view
(a.) | Structural parts not in contact with the product, and parts constructed with a smooth finish so as to be readily cleanable. |
(b.) | Self-draining exterior surfaces. |
(c.) | A minimum of 6" (15.24 cm) of space between the lowest part of the frame and the floor to provide ready access for cleaning legs and feet and those parts not readily removable. |
Figure 14 – Skimmer frame table
(a.) | Horizontal angle reinforcing and gussets shall not be placed where food or debris may accumulate thereon. |
(b.) | Where angles are used horizontally, they shall have one leg turned down wherever the nature of the equipment permits or shall be formed integral with the sides. |
(c.) | All vertical sections shall be either completely closed or open to the floor. |
Figure 15 – Returnable container with lid
Figure 16 – Mya arenaria shucking pan, four pint capacity
Figure 17 – Oyster shucking bucket, nine pint capacity
Figure 18 – Shucking bucket handle 180° apart side by side
(a.) | Nosings shall be open 3/4" (19.05 mm) or completely closed against the body of the unit on all sides to prevent the harborage of insects. |
(b.) | The space between the top and the flange shall be not less than 3/4" (19.05 mm). |
(c.) | The space between the sheared edge and the frame angle shall not be less than 3/4" (19.05 mm) to provide access for cleaning. |
Figure 19 – Exposed edges and nosings on horizontal surfaces
(a.) | When the outside dimension of the leg is greater that the outside dimension of the foot by 1/2 " (12.7 mm) or more in the same plane, the foot shall, at minimum adjustment extended 1” (2.54 cm) below the leg. |
(b.) | All opening to hollow sections between feet and legs shall be drip proof construction with no opening greater than 1/32" (0.794 mm) All other opening to hollow sections shall be sealed. |
(c.) | Gussets, when used, shall be assembled to the equipment in such a manner as to insure easy cleanability and to eliminate insect harborage. The assembly shall have no recessed areas or spaces. (Figure 21) |
Figure 20 – Legs and gussets
(a.) | All framing and reinforcing members shall be so placed as to eliminate harborage for vermin. |
(b.) | The ends of all hollow sections of reinforcing and framing members shall be sealed. |
(c.) | Horizontal angle reinforcing and gussets shall not be placed where food or garbage may accumulate thereon. |
(d.) | Where angles are used horizontally, they shall have one leg turned down wherever the nature of the equipment permits, or shall be integral with the sides. |
(e.) | All vertical sections shall be either completely closed or open to the floor. |
Figure 21 – Reinforcing and framing
Figure 22 – Low profile fasteners for nonfood contact surfaces
Figure 23 – Mechanical stainless steel oyster grinder