12 BULLETIN 849, U. S. DEPARTMENT OF AGRICULTURE. 
Floors in the milk-handling or washing rooms should have a slope 
of about one-fourth inch per foot toward the floor drains. Drains 
should be located when the floor is laid to insure a correct slope of 
floor and should be trapped and connected with the sewer. They 
should be from 6 to 8 inches wide and have perforated, removable 
covers. Great care should be taken. in laying the floor to avoid 
making hollows in which water may collect. Before installing the 
plumbing it is advisable to be sure that it conforms to local plumbing 
regulations. 
THE COLD-STORAGE ROOM. 
The milk-storage or refrigerator room must be well insulated to 
keep the milk always at low temperature. The most common insulat- 
ing materials are cork board, mineral wool, vegetable fiber, sawdust, 
and shavings, which are used as fillers in walls of wood, cement, or 
masonry. Cement should be put over the insulating material for the 
* inside walls and ceilings to protect that material from moisture. The 
floors of the refrigerator should be of concrete laid solidly on the 
insulating material. The most satisfactory construction is about 4 
inches of cork-board insulation with cement on the inside and out- 
side.1 Good drainage to a drain pipe, carefully trapped to prevent 
warm air from entering the room, is very important. 
ARRANGEMENT OF PLANT. 
HANDLING THE MILK AT ENTRANCE. 
In the arrangement of rooms and machinery, economy of operation 
as well as sanitation must be considered. In the layout of the plant, 
provision should be made for the convenient and rapid loading and 
unloading of wagons. This applies to the delivery wagons and also 
to the trucks which bring the milk to the plant. 
Some plants are so arranged that it is necessary for the trucks to 
be unloaded inside the building. Such a system is not conducive to 
rapid unloading. When the trucks drive inside the building there is 
a smaller space to turn in, and greater danger of contamination from 
dirt and dust of the street coming in through the open door of the 
receiving room. The use of a platform on the outside of the plant 
at the receiving room allows the milk to be handled much more 
readily. The platform need be only a few feet wide, but there should 
be ample space for two or more trucks to drive up to the platform 
at one time. | 
Upon the arrival of the trucks the milk is unloaded at once and 
sent to the receiving room, where it is dumped immediately. There 
is no needless driving and backing, as is the case when the trucks 
unload in the interior of the plant. If the unloading platform is 
1For detailed information as to construction of storage rooms, see U. S. Department 
of Agriculture Bulletin 98. 
