WAREHOUSES.
WAREHOUSE DESIGN -- FLOOR AREA -- FIRE PROOF BUILDINGS -- FLOOR
CONSTRUCTION -- COOLERS -- FAN AND VENTILATION -- SPRAY SYSTEM --
GALVANIZED SHEET IRON PIPES -- COIL ROOMS -- QUANTITY OF PIPE --
METHOD OF ERECTING -- LIFE OF PIPE -- CELLAR CEILING SUSPENSION --
RATIO OF PIPING -- DEFROSTING -- GARDNER CURTAIN SYSTEM -- DIRECT
EXPANSION PIPING -- CHILL-ROOM BUNKERS -- LOW TEMPERATURE BRINE
SYSTEM -- FREEZER AND STORAGE BUILDINGS.
=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.
[Illustration: FIG. 22.--SECTION OF COLD STORAGE HOUSE EQUIPPED WITH
SPRAY SYSTEM.]
_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.
[Illustration: FIG. 23.--SECTION SHOWING BRINE SALT AND SPRAY SYSTEMS.]
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.
[Illustration: FIG. 24.--END VIEW OF COOLER; DETAIL OF PIPE HANGERS.]
=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.
[Illustration: FIG. 25.--END VIEW OF BAY SHOWING REFRIGERATING PIPE
HUNG TO CEILING.]
=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.
[Illustration: FIG. 26.--DETAIL OF END PIPES, SHOWING DIFFERENT
FITTINGS.]
=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.
[Illustration: FIG. 27.--SIMPLE METHOD OF SUPPORTING BRINE PIPES.]
=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.
[Illustration: FIG. 28.--GARDNER’S “CURTAIN” SYSTEM FOR BRINE
CIRCULATION AS INSTALLED IN A CHICAGO PACKING HOUSE.]
=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.
[Illustration: FIG. 29.--PLAN OF GARDNER “CURTAIN” SYSTEM OF
REFRIGERATION.]
=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.
[Illustration: FIG. 30.--CROSS SECTION COOLER, BUNKER “CURTAIN” SYSTEM.]
_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.
[Illustration: FIG. 31.--GROUND PLAN OF A FREEZER AND STORAGE
BUILDING.]
_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.
[Illustration: FIG. 32.--LONGITUDINAL SECTION OF A FREEZER AND STORAGE
ROOM.]
_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.”
[Illustration: FIG. 33.--TRANSVERSE SECTION THROUGH FREEZER 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.