TABLE TABLE 1.-DIMENSIONS OF ROOMS OF TYPICAL LOCKER PLANTS OF DIFFERENT CAPACITIES ARE AS FOLLOWS 1 Approximate outside dimensions of plant 30 by 25 feet. 2 Approximate outside dimensions of plant 38 by 32 feet. 3 Approximate outside dimensions of plant 48 by 36 feet. 4 In this plant the ice machine was located in 1 corner of the cutting room. 22' x 10' x 10'. Some small anteroom leading to the sharp-freeze and locker rooms. plants provide a receiving or pre-chill room where carcasses are washed and held for a short period before being moved into the chill room. Others provide a small curing room, a smoke oven, and equipment for preparing fruits and vegetables. Figure 6 shows the floor plan of a modern locker plant. 12'4" EQUIPMENT TOILET 12'4" LOBBY PROCESSING CHILL ROOM ROOM MEAT RECEIVING OVERHEAD COILS 22' 0" SINK (KETTLE) DRIVEWAY FIGURE 6.-FLOOR PLAN OF A TYPICAL REFRIGERATED-LOCKER PLANT. Proper arrangement of rooms saves time and labor in handling products. 35'6" In designing the size of rooms it is very important that a chill room of ample size be provided in order to be able to handle a peak load and to be in a position to properly age meat before having it cut. Some operators advise a chill room from one-third to onehalf the size of the locker room. Others divide the chill room by either a heavy canvas curtain or a partition, using one side for chilling warm meat and the other for aging meat. INSULATION Constant temperatures must be maintained in cold-storage locker plants to avoid chemical changes, moulds, and other bacterial action which would result in undue shrinkage and spoilage of foods stored. For that reason, and also to reduce power costs, it is highly important that the plant be well insulated. Skimping on the insulation is false economy. Materials which may be used are of many types and kinds, ranging from cork to sawdust and shavings. Some are much better than others, though they may cost more. Many materials are good for a few years but deteriorate rapidly or lose their insulating properties. Properties to look for in an insulating medium are: (1) Thermal efficiency (nonconduction of heat); (2) moisture resistance-moisture is one of the worst enemies of insulation; (3) long life-medium should resist decay and disintegration; (4) stability or maintenance of density when installed; (5) space occupied; (6) rodent-proof characteristics. Some of the most popular kinds of insulating material in common use in locker plants include: 1. "Cork board," or bark of cork oak imported from Spain and North Africa. While among the highest-price mediums, cork oak is among the best and has been used in packing plants, refrigerator cars, and cold-storage plants for many years. It is among the easiest to install and retains its insulating properties for long periods. If used, it should be 6 inches thick around the locker room, 8 inches around the sharp-freeze room, and 4 inches thick around the chill room. 2. "Rock (or mineral) wool" is made from limestone blown into cotton-like form. It is vermin and fire proof. When used in loose form, it should be properly packed at 5 pounds to the cubic foot. This material calls for inside walls and ceilings between which the wool is packed. It is also installed in batt form. 3. "Rock cork" is a low-temperature insulating material, manufactured from a loose rock wool combined in production with a waterproof binder, molded into sheet form, and baked. It is verminproof and has very good insulating properties. It is manufactured in sheets of varying thickness and can be installed in a manner similar to cork board. 4. Certain kinds of fiberboard, which have approximately the same insulating qualities as cork or rock cork are also used. 5. The shredded bark of California redwood is specially treated to make it fireproof and verminproof. For good insulation this material should be packed 5 pounds to the cubic foot. If used it should be 8 to 10 inches thick around the locker room, 10 to 12 inches thick around the sharp-freeze room, and 6 to 8 inches thick around the chill room. This type of installation calls for inside walls and ceilings between which shredded bark is packed. While less expensive than cork, it takes more space and more material and labor to install. Insulation costs were reported to vary from $4 to $8 per locker, depending upon size of plant and type of insulation used; the usual cost runs from $5 to $6 per locker. REFRIGERATION EQUIPMENT One of the largest items of cost in equipping a locker plant is that of a good refrigerating machine, together with the coils and piping. Artificial refrigeration is obtained by compressing volatile gases, condensing the gas under pressure into a fluid and then regulating by valves the amount of fluids flowing into the refrigerated coils, where the expansion and evaporation causes absorption of heat and thus lowers the temperatures of the space to be cooled. When the refrigerating medium has been evaporated, it is returned to the compressor in the form of gas and the process is repeated. The oldest and most commonly used refrigerant is ammonia. Practically all large packing plants, cold-storage plants, creameries, and milk plants use this refrigerant. However, in recent years with the development of electric refrigeration in the home, other gases such as "freon" and methyl chloride have been used quite extensively. There are numerous reliable refrigerating machines on the market. The necessary size and capacity of the machine varies with the number of lockers, area to be refrigerated, and the quantity of meat or other food to be cooled and frozen. Some of the smaller plants with 100 to 200 lockers use a 3 by 3 compressor with a 3-horsepower motor, while larger units of 300 to 450 lockers use a 4 by 4 compressor with a 5- to 7%1⁄2-horsepower motor, and large plants up to 1,000 lockers use a 5 by 5 compressor with a 10- to 15-horsepower motor. It is desirable to equip the plant with a refrigerating machine capable of handling peak loads without being taxed to capacity. Most manufacturers do not recommend that machines be required to operate for more than 16 to 18 hours per day. Because of the wide variance in temperatures to be maintained in the different rooms, some refrigeration engineers recommend the installation of two machines of smaller size instead of one large 148610°-39-3 machine one to operate the low-temperature sharp-freeze room and one to operate the chill and locker room. Besides some economy in operation, two machines offer additional advantages in case one of them should break down. The temperature in each room is kept constant by means of automatic temperature controls. Refrigeration equipment costs vary from $1,500 to $3,500 per plant, or from $4 to $8 per locker in plants of from 300 to 500 lockers. LOCKERS The early locker plants were equipped with "home-made" woodenslat or chicken-wire containers. Modern plants use all-metal lockers, which are attractive, well ventilated, sanitary, and of substantial construction. Some are of galvanized sheet iron with heavy wire mesh sides while others are of sheet-steel baked-enamel finish, with sides and ends perforated to insure ventilation. Most are equipped with built-in locks, some with padlocks. Most popular sizes of lockers come 20 inches wide by 17 inches high by 30 inches deep, in tiers 5 units high; and 20 inches wide by 15 inches high by 30 inches deep, in tiers 6 units high. While manufacturers claim these lockers hold around 300 pounds of meat, in actual practice 200 to 250 pounds is about the maximum for convenience. Costs of lockers range from $4 to $5.50 each. BUTCHER EQUIPMENT In addition to refrigeration, insulation, and lockers, a modern locker plant is supplied with a more or less complete line of butchering equipment which includes cutting block, tables, overhead meat tracks, scales, meat grinders, saws either hand or electric, lard press, rendering kettle, cleavers, knives, twine, wrapping paper, rubber stamps, etc. While some plants are more complete than others, it is essential that adequate butcher equipment be provided. Costs of such equipment vary widely depending upon completeness of service rendered. Some plants have from $200 to $300 invested while others with power saws, grinders, and other additional equipment have from $1,000 to $1,500. THE COST OF PLANT HE TOTAL investment in land, buildings, refrigeration machines, insulation, lockers, and other equipment installed in the 300 to 500-locker plant varies from about $25 to $50 per locker. These costs are so variable for individual plants that such averages are only rough estimates. Illustrations of actual investments of 17 plants are given in table 2 to afford some idea of construction costs. TABLE 2.-COST OF 17 REFRIGERATED LOCKER PLANTS IN FOUR STATES Estimated from information furnished to the author. In some of these plants, estimated savings of $4 to $6 per locker were effected by 1 county association through the building of several plants at one time. IN OPERATING COSTS NFORMATION concerning operating costs is very limited because most of the plants are new enterprises. Data obtained from a few plants and engineering firms would seem to indicate that average yearly operating expenses for plants having from 300 to 500 lockers range from $9 to $12 per locker. Expenses of two plants are shown in table 3. The principal expenses are for labor, power, water, depreciation, and supplies. The cost of power varies with the wide differences in rates, construction, and size of power plants. The average yearly cost per locker for power, light, heat, and water ranges from $1.50 to $2; for salaries and wages, $4 to $6; and for depreciation from $1.50 to $2. Taxes and insurance costs amount to about $1 a year, as do miscellaneous supplies and repairs. Operating costs can be materially reduced when a locker plant is run as a side line to another business, such as a creamery, a milk plant, or an ice plant. |