The modern packing house

Warehouse Design.

—Under this heading we will discuss the standard pork building for curing meats and for chilling hogs.

Floor Area.

—The warehouse building as usually laid out should provide 10,000 square feet on each floor, and as many stories in height as needed and as many units as needed. It is common and usually best to set posts sixteen feet centers in each direction, making sections sixteen feet square. This area seems to lend itself best to practical usage in packing house work.

Fire-Proof Buildings.

—The permanence of the premises, the value of the product in storage, and many other points make the advocacy of fire-proof warehouses commendable. The warehouse, where floors are likely to be used for storing moist or wet goods, or for curing meats, should preferably be solid concrete floors, rather than tile, with concrete joists and concrete topping.

Floor Construction.

—The ideal packing house floor is as yet to be discovered. What appears to be the best in a warehouse is a monolithic floor, treated under the zones where meats are to be piled, and all trucking thoroughfares paved with brick or tiles, or perhaps an asphaltum preparation, as the latter can be replaced.

Coolers.

—In most instances it is best to arrange the coolers on one or more of the upper floors. Cooler design varies, but late practice has been drifting back to the old system of open spray brine which is described elsewhere. The customary practice in the United States is for some type of natural circulation, as by the use of ducts with air chilling facilities above the chill rooms. Practice has proven for fresh meats that the use of this system is far superior to that of forced draft, sometimes called “indirect” refrigeration.

Fan and Ventilation.

—In northern climates it is a good practice to place a window at each end of the pipe or brine loft to admit a circulation of air during cold weather, locating an exhaust fan centrally over the coolers with a duct connecting with the fan from each room, drawing air from either end toward the center via the open windows in the end of the loft. This induces a circulation through the hot and cold air ducts which produces quite sufficient circulation and a uniformity of temperature in the contents in the room below.

In warm climates the use of roof plugs, and airing or venting the cooler at each filling, is, in our judgment, an expensive method, and not justified by the results obtained.

Spray System.

—The “spray system” has been rejuvenated and is very popular. This system is particularly effective for warm beef and sheep coolers and for hog coolers. It can well be installed at slaughter and shipping points, but its use in hanging rooms where beef is aged and held for sale is questionable, by reason of the probability of shrinkage owing to the rapid air circulation maintained.

Width of Rooms.

—There are various opinions as to the width and height required in a bunker room for installation of the spray system. A room from thirty-two feet to forty-eight feet wide can be successfully operated. Increased width beyond that means increased height and this, in turn, means more construction cost.

Rooms twenty-five feet wide with twenty feet pans have been built and successfully operated, but at less widths the brine is likely to carry over. The value of the spray system, and the rapidity with which a room and its contents can be cooled by its use, seems to be due to two causes, the direct contact of the air with the finely divided brine spray and the induced air currents created by a mechanical circulation.

Types of Construction.

—The accompanying diagrams show two types of construction. One wherein the brine pan is made of cast concrete and the rails suspended from wood rail beams hung on rods attached to the ceiling. The other one shows the brine pan made of wood built up from supported rail beams. In the first instance the brine spray is collected on what might be termed a composition roof (without the gravel covering) made from asphalt saturated paper, and asphalt laid over a cork sub-base spread upon and cemented to the concrete pan. In the second instance the pan is made from wood, exhibiting a wood paneled surface on the underside, covered with cork, more wood and then lined with a galvanized iron pan.

Arrangement of Piping.

—In both instances the brine spray header was located near the top of the hot air flue partition and the sprays directed to a line below the horizontal, to insure the brine falling well within the pan, to prevent splash through the cold air flue.

The brine is collected and returned through a main pipe to the brine tank in which are placed the submerged coils.

Salt Brine—Calcium Brine.

—One system is operated on salt brine in which the accumulation is sterilized by boiling, then filtered and used for curing purposes. The other is operated on calcium brine which is concentrated by passing over a concentrator. It is then returned to the brine tank.

Spray Devices.

—There are various spray devices purchasable on the market, some approaching atomizers. The owner usually selects something to his taste. A common spigot can be used with a piece of bent tin to distribute the brine at the outlet, but more efficient devices are obtainable.

The location of the nozzles at a distance of about four feet apart seems to be ample for most purposes. The outlet opening should be about one-half inch, valve controlled to suit. It is well to arrange long length of pipe so that each cock is supplied with an equal quantity of brine by use of forked connections on a complete supply circuit.

Galvanized Sheet Iron Pipes.

—For room cooling, formerly used to a considerable extent was sheet iron pipes. The three-inch galvanized iron spiral riveted pipe is recommended, or where this is not readily obtainable three-inch galvanized iron crimp-joint and soldered seam pipe may be substituted. While not quite so substantial as the spiral riveted pipe, it will, with ordinary care and attention last a long time.

The use of spiral riveted pipe has been found unnecessary, provided No. 24 gauge metal is used in lock seamed pipe. Open-hearth steel, galvanized, is preferable to Bessemer. The writer experienced one failure with the latter.

Ten different pieces of this pipe ten feet long were capped on either end and submitted to a hydrostatic pressure test; the bursting pressure average of the ten pieces was found to be 146 pounds to the square inch, while some of the samples stood a pressure of over 180 pounds to the square inch. In actual practice the pipe used for this purpose is never subjected to a pressure exceeding forty pounds to the square inch.

Coil Rooms.

—Fig. 24 shows the end view of the cooler with the detail of the hangers on which the pipe rests. Fig. 25 shows the end view of one bay with the pipe located and connected.

Quantity of Pipe.

—In brine pipe refrigeration for cattle the author would recommend to each sixteen-foot bay, eight series of three-inch galvanized spiral riveted pipes with six pipes in each series. These make a total of forty-eight pipes for the fore-cooler, where the largest proportion of pipe is needed, and forty pipes per section in storage beef cooler. For hog coolers forty-eight pipes per section throughout is recommended.

Method of Erecting.

—Adoption of this system where brine circulation is used can be made for meat storage rooms. (See Fig. 26 for detail of the end pipes with fittings for the hose connections.) Pipes are usually furnished in ten-foot lengths, riveted and soldered, and are slipped together like ordinary stovepipe joint, all of these slip joints being carefully soldered to be brine tight, a sufficient number joined together to make runs of the required length to suit the pipe chamber. At the end of the runs one of the three hose connection fittings shown in Fig. 26 (feed connection, intermediate connection and return connection) is put on for the purpose of connecting the runs together by means of the rubber hose. Chatterton’s compound is put on the nipple of the fitting connection quite warm, the hose being slipped over at once and a wire clamp then put around the hose very tightly, when the connection is complete.

Life of Pipe.

—This pipe is recommended for the following reasons: First, for its economy; second, for its lasting qualities. As proven by experience, galvanized pipe will last fully twice as long as the ordinary black iron pipe. This would hardly seem possible when first considered by anyone not having had the experience, and would naturally seem contrary to his judgment. There was installed in 1890 over 100,000 lineal feet of this light galvanized pipe in a Chicago plant, some of which is still in use.

Samples of the galvanized pipe that had been in use for upward of ten years were found to have a very slight coating or deposit of rust on the inside of the pipe, less than one-thirty-second of an inch thick, and adhering very tightly to the surface. By removing this rust with a sharp instrument it was found that the galvanizing was as clear and bright as when originally put on.

Cellar Ceiling Suspension.

—In Fig. 27 is shown a very simple, inexpensive and effective method of supporting brine pipes in cold storage rooms, or in rooms used as curing cellars, etc. This arranges a combination whereby a drip pan can be suspended for catching the drip, the construction being illustrated. It is preferable to line the pans with galvanized iron so as to preclude possibilities of leakage. The wooden construction of the ordinary class is usual.

Ratio of Piping.

—Regarding the quantity of pipe required, this in a measure depends upon the insulation of the cellars and the temperature of brine circulated. With brine at a temperature of 10° F., one lineal foot of pipe will supply radiation sufficient for twenty cubic feet of cellar.

Length of Coil.

—The inlet and outlet pipe should have a 1¹⁄₄-inch connection, this being ample for a coil about four hundred feet in length.

Defrosting.

—To dispose of the accumulation of frost that collects on the coils within the coil bunkers over the beef and hog coolers, it is usual to have a warm brine arrangement consisting of an independent feed header, cross connections to the coils, a tank containing a heating coil and a small pump.

When the frost collects so as to be detrimental, a supply of brine in the small storage tank is heated to about 60° F., and it is continuously pumped through the small auxiliary header, thence into the coil it is desired to remove the frost from, until the frost is loosened, when it is lightly tapped and falls to the floor of the bunker pan. Unless the cellar temperatures are carried low it is unnecessary to use this system in the curing cellars, as the coils will drip from natural melting.

The use of this system of brine installation with a proper defrosting arrangement has much to recommend it as to economy and efficiency, particularly in use with a balanced brine system.

Later Practice.

—A better system superseding that just described is to arrange the coil loft or cooler coils with a brine drip over them to remove the frost, the drip being collected in the pan, conducted to a reservoir and re-circulated. Similar to the manner used with direct expansion piping.

Gardner Curtain System.

—One of the early types of open brine chilling was the Gardner curtain system.

For this system a refrigerator or curtain room is provided, directly above the meat coolers, and of same length and width, in which is fixed an open pan or brine distributing trough, located over the sheets and distributing the brine thereon. Fig. 28 shows a photograph of the curtains in a refrigerator or bunker room.

A plan of installation showing position of curtains is given in Fig. 29, and Fig. 30 shows a cross section of a bunker room with the arrangement and insulation in a wood constructed building.

Direct Expansion Piping.

—There is a decided opinion among many operators that direct expansion ammonia system piping, is preferable over any brine circulation system, owing to the non-requirement of pumps for circulating purposes. Caution is necessary in erecting all direct expansion piping. It must be amply and securely erected, avoiding the use of coach-screws or lag-bolts, owing to the danger of rotting and giving away, thus causing perhaps fatal injuries. Room piping will appear best situated when grouped over alleys and arranged with drip pans so located as to avoid drip onto meats or packages. The ratio of piping given for brine pipe will hold as to lineal feet, substituting foot for foot of two-inch instead of three-inch pipe.

Chill-Room Bunkers.

—In chill-room bunkers there should be a brine system arranged to drip the brine over the pipes for use during the early hours of filling, since a double advantage can be gained by so doing. This is quite effective when intelligently operated.

Freezer and Storage Buildings.

—The use of freezer buildings have become of such consequence in larger packing plants for the storage of meats that it would seem opportune to introduce a description of a freezer storage building and to discuss the requirements necessary for it.

Growth.

—The growth to include as it now does, in most instances, a produce merchandising business with its seasons of production and storage together with the necessity of providing low temperature storage space for storing delicately cured hams and bacon over seasons, make it almost a necessity to provide low temperature storage or seek it away from the premises, with the incident expense involved in transfer and return, storage charges, and the damage resultant from exposure.

Location.

—A first consideration is the location of the building for operating advantages, which is a local matter, but involves shipping facilities by team and by car, convenience to the source of production, and power plant. Naturally the value of the commodity in storage, which at present prices, reaches a considerable amount, and the safety of the product becomes a matter of no small thought.

Permanence.

—The permanence of a building for this purpose once constructed, and the likelihood of changes due to variation in business being small, together with the safety of its contents and a consequent low insurance rate, makes fire-proof cold storage buildings highly desirable. In these days of increasing insurance rates, buildings that are rated from twenty to thirty cents per thousand dollars—non-sprinkled—appeal to us. These rates are not uncommon. Such can be obtained on properly constructed buildings with adequate exposure protection.

Concrete or Steel Frames.

—Fire-proof cold storage buildings can be of various styles of construction. The two types mostly used being, first, of steel frame with either cast iron or steel columns, girders and beams with tile or concrete in combination for floors, or secondly, reinforced concrete frame with concrete and tile in combination, or monolithic concrete floors.

For moderate heights the walls can be self-sustaining, that is, built up solidly; but beyond a certain height it becomes economical to use curtain walls similar to the well known “skyscraper.” In buildings up to eight stories, reinforced concrete frame with monolithic floors prove more economical than steel frame with tile or concrete floors. Reinforced concrete buildings are more lasting, since it is impossible to closely fit tile around steel columns and girders and exclude air, moisture, heat and condensation, existing in this class of building, conditions most contributing to rust. The life of steel framing under these conditions is an untried experiment. On the other hand, in the reinforced concrete building the strength is much derived from the concrete and when well designed and the work well executed the steel is imbedded and thoroughly concealed in the concrete, remote from the conditions above stated and contributing to an indefinitely long life. However, steel columns and girders encased in concrete make them practically the same.

Limit for Economic Concrete Columns.

—Eight-story warehouses with basement appear to be ample in height for ordinary conditions. Meeting the insistent demands of building ordinances in some cities like Chicago, these can be constructed of reinforced concrete with a maximum column diameter of twenty-eight inches, with all floors designed for 200 pounds per square foot. This height of building with such loadings approximates the practical limit of sustaining on footings on the usual underlying earth, with building panels sixteen feet square, the column spacing best adapted to storage purposes.

Types of Construction.

—In concrete buildings just referred to, our preference in style of construction is either of the mushroom type, that is, flat ceilings without girders; or secondly, with girders extending in one direction only. An inexperienced engineer in his efforts to minimize the quantity of steel and concrete requirement will invariably wish to carry girders from column to column and cross beams between girders, making the ceiling look like a checkerboard, losing perhaps twenty inches or more head room on every story and making a much more expensive building to construct and operate. The same fault is noticeable in steel frame buildings, since nearly always there are cross beams between girders. This drops the chilling pipes, curtailing head room and makes an unsatisfactory arrangement. Whereas with a mushroom or flat ceiling with girders in one direction, the difficulty is overcome.

Space Losses; Beams Two Directions.

—In an eight-story building the additional height above referred to amounts to from ten to fifteen feet of unnecessary building and adds greatly to the construction cost.

Exterior Walls.

—As for the exterior surface of the building, this should be brick, the lighter the color the better, making absorption of heat less probable. When building reinforced concrete frame with curtain walls, the design should be such that the brick work entirely covers the concrete frame, since it is very difficult to obtain tight joints abutting beams and columns when attempting to build panels of brick in concrete framing. It is desirable to prevent air and moisture leakage.

Qualities in Brick.

—In the selection of brick sufficient attention is rarely paid to the obtaining of brick burned approximately to vitrification. The presence of salt, as is frequently noticed on exterior walls of packing houses adjacent to floor lines, indicates that brine has been percolating the walls, due to their porosity. In the same manner water will pass through the opposite direction, and very far disqualify the insulation materials unless they be non-absorbing, and even these are lessened in value owing to the accumulating moisture.

Wall Construction.

—All kinds of tile and plaster or concrete exteriors should be avoided, since it is impossible to prevent shrinkage cracks which permit percolation of water, eventually shelling off plastered surfaces and deteriorating insulation.

Ventilation.

—In northern climates it is desirable to take advantage of the winter air when it equals or is lower in temperature than the rooms where product is stored, or when empty to air and cleanse an apartment. For convenience in this it is advisable to locate refrigerator windows in the same line to permit ready flow through the room; these being put on hinges similar to a door.

Insulation.

—When undertaking to construct buildings fire proof, problems in insulation are encountered. The more dense or heavier the material used in building, the more cold radiated from all surfaces unless effectually cut off. In ordinary type of construction the various floors rest on exterior walls and in no way is it possible to prevent a very great loss of cold being carried through the floors, thence to the walls and dissipated thereby. Such matters are not trivial in their importance. At one wholesale distributing market deterioration in insulation during six or seven years has necessitated the doubling of refrigerating machine service and the volume of business is practically the same. To obviate this the remedy seems to be to surround the building on all sides and cover the roof with an encasing of insulation, putting an exterior covering of brick or impervious material over this to protect the insulation, and to prevent moisture coming in contact with the insulation. It is just like dropping a small box within a larger one, the space between the sides being the insulation.

Double Posts or Walls.

—This is accomplished when building self sustaining walls by constructing a set of columns adjacent to the walls with girders from column to column and supporting floor slabs upon the girders, not permitting either columns, girders or slab to be in contact with the exterior wall. In a skeleton construction design there are twin columns, girders and beams, the inner set carrying the floor loading and the outer the building walls, the insulation lining being unbroken between them.

Varying Temperatures.

—Commercial demands require a variety of temperatures, some at zero, some at fifteen degrees and some at thirty-two or over, in the one building. The maintaining of these varying temperatures in one building requires most careful designing, since the concrete everlastingly conveys cold and attempts to cut off a floor from that above can only be done by comprehensive and extravagant insulating.

There have been storage houses where with a freezer situated over or under an egg room a stove was maintained in the egg room to offset the cold temperature from above or below. A dangerous, costly expedient as well as the risk of freezing eggs. To encase and isolate a room to maintain zero to fifteen degrees in it and, say, thirty-two above, it is necessary to perform the following insulating: Line the ceiling and beams; cover the floor; cover the columns, so as to really envelop the cold. When insulation is placed on the floor, naturally the question of a wearing surface over the insulation is apparent and to maintain it fire-proof this must be cement or perhaps mastic. This causes an expenditure for wearing surface over the floor insulation, increased column quantity and strength, increased deadload of floors, insulation of floor and ceiling, of columns, and this, conservatively speaking, amounts to a total of eighty-five to ninety cents per square foot of area. This over one foot is but a small amount, but on a building one hundred feet square it becomes eighty-five hundred dollars per story.

How to Sub-divide.

—To meet the variety of temperatures required, subdividing the premises into sections, but doing it vertically rather than attempt to divide it horizontally, with a portion set aside for each division of temperature. If the business is of such volume as to permit this, make no attempt to insulate one floor from that above, as there is no practical way to do it and obviate an investment in insulation from which there is no return. A thorough external wall and roof insulation is strongly recommended, and the cold radiating into a room above that may be only partially filled or empty may be considered as no great loss, provided the outer contacts are eliminated or minimized.

In fire-proof construction the loss of cold through the ground is an unsolvable problem. To effectually do so it would be required to insulate every floor slab, top and bottom, all wall beam and column surfaces. From the foregoing deduction the cost would be prohibitive.

Basement Freezers.

—It is obvious from this argument that freezers should not be located in basements. It is far better to locate them on the upper floors of the buildings and make the cellar a moderately cold room, permitting the cold that will to radiate from the columns to chill it, but supplying such additional piping as may be required to maintain a regular temperature. If a freezer is placed on a first floor, it requires insulating the basement ceiling, which can be readily done. The basement columns are not insulated.

Piping Systems.

—With reference to piping for freezing boxed goods or beef cuts, the shelving system made from coils of pipe upon which to store the product while freezing is preferable. They are equally efficacious, whether used in brine circulation or direct expansion of ammonia. The coils in the freezing rooms are located on ceilings, making one layer over ceiling for fifteen-degree rooms where conditions permit, for handiness in removing frost. If the rooms be carried at thirty-two degrees or over, group the coils in alleys to enable easy location of pans for collecting drip, when coils are out of service. Whether one uses direct refrigerating by expansion of ammonia or brine circulation through pipes hung in rooms or indirect refrigerating by circulation of chilled air is a matter governed by local conditions and requirements.

Area and Division.

—The plant shown in Figs. 31, 32 and 33 has a large ground area and is a non-sprinkled risk. This building has a frontage of 230 feet by 130 feet depth. To avoid an insurance area charge for too large floor areas, and because of a desire to carry several temperatures, the building was subdivided into three sections, A, B and C, by putting in fire walls. It was designed to have Section “C” subdivided into two halves, permitting the maintenance of two classes of low temperature. Section “B” was set aside primarily for carrying eggs and apples and thoroughly isolated. Section “A” was treated in like manner to Section “C,” except that provision was made for the division wall, which was not put in at time of construction. Illustrating the design is a general floor plan of the premises together with a longitudinal section drawing and a cross section drawing of Section “C.”

Receiving and Discharging.

—Referring to the plan, attention is drawn to the three sections. Ingress and egress have been provided by railroad track at one end of Section “A” and double track with platforms on each side connected at end. Twin elevators with stairs are located within a continuous vestibule and the center section can be served from either elevator and stairs in either vestibule. The corner stairs in Sections “A” and “B” were demanded by the City Building Department, but not necessary to the operation of the plant.

Insulation Lines.

—Referring to the longitudinal section observe the twin columns, twin girders on each floor level, the inner carrying the floor construction and the outer the curtain walls. Notice the inlay of insulation. The outer walls entirely enclose the concrete skeleton, making the brick work continuous and sightly.

The transverse drawing of Section “C” shows a partition continuous from basement to ceiling of sixth floor. This partition is not built from floor to floor, but continuous through the floors, making either end virtually an isolated building.

Warm Storage—One Floor.

—It was desirable in this instance to use the upper floors of the building for warm storage, consequently the top encasing insulation is placed on the ceiling of the sixth story, continuing to and meeting the wall insulation, which with the wall insulation encases the cold storage, as spoken of for the ideal. The floor construction is of flat ceiling type, there being no girders to contend with in piling product or installing piping.

Part Freezers.

—Frequently the space required for freezing purposes will not be sufficient to justify the construction of an independent building. Sometimes consideration is given to building freezers in a horizontal belt, horizontally across the building. This is not a proper construction, since it costs much more to insulate than if the same volume were arranged vertically with one section above the other. In other words, if one desires to cover a floor surface of 20,000 square feet it would be far better to make it four areas of 5,000 feet in a four-story building than on one or two floors.