Motion Picture Herald (Jan-Mar 1956)

be no contamination with surface water. To be pure, Uie well water must be so located with reference to sewerage lines, and so deep in relation to drainage ditches, pools formed by run-off water, and so on, that it will never have contact with poisons or disease germs. It is equally important to see that surface water does not drain into the well and get into the already filtered ground water. In most localities a Sanitary Code will apply to the water supply and related installations. In drilling an artesian well, it is necessary to bore through porous rock, such as sandstone, and down through harder layers of rock or clay. The water may be dangerous for human consumption if the well is in limestone soil, as this is not a satisfactory filter. Sand, sandstone, clay and gravel are good filters. A dug, or surface, well is not safe for drinking if the water table is less than 10 feet below the surface. Even a dug well should be at least 25 feet below the surface. In addition, a dug well should not be less than 100 feet away from a cesspool, or septic tanks, or an underground disposal field. Never should any well be located so the sewage drains towards the well. SEWERAGE SYSTEM REQUIREMENTS The disposal field must be installed to drain off not only the water that actually flows through the plumbing fixtures, but also an additional volume created by rain water that will seep through from the surface of the ground. The most efficient way to dispose of sewerage where one does not have access to municipal sewers is to install a septic tank and drainage fields. Local health authorities will have to be consulted for requirements in tank materials and construction, also with respect to field capacity. In any case, it is better to go beyond the minimum; an inadequate sewerage disposal system is not easy or cheap to rectify. To carry sewerage from the plumbing in the main building to the septic tank, cast-iron pipe of 6-inch diameter is best. Some health authorities, however, permit the use of asbestos conduit for this purpose. Asbestos conduit is lower in cost than cast-iron, but it is relatively brittle, which introduces the possibility of a crack in the line should an extremely heavy vehicle pass over it, or a sharp instrument be driven into the ground above it. The septic tank and drainage field installation should be made by a contractor who is experienced in such work and is thoroughly reliable, and the drive-in owner should be sure that the workmen are constantly supervised. Supervision is especially indicated for the fields, for here common labor is used, and while the job requires no special skill, it does need certain simple know-how and application of it consistently. If the fields are not laid correctly, stoppage results, and probing and digging for it may reveal that much of the installation, if not all of it, has got to be done over. Glazed pipe is used for the fields, and they should be set below the frost line. It is sometimes believed thal selling the tiles that deep is not necessary because the j)oIluted water and piping supplies some protection from freezing. However valid that idea may be, it is safer to discount it and go down a few inches farther so that the water will always run below the frost line, which is in the neighborhood of 2 feet below the surface. The line of tiles must have a downward slope with neither too little nor too much incline. The flow must be gentle. Space between the tiles should be consistently between a half and three-quarters of an inch. The tiles should set in a bed of washed gravel, to a depth of at least 6 or 7 inches beneath the tiles, and around that along the sides. Some septic system contractors place tar paper, or its equivalent, only over spaces between the tiles; others take the extra precaution of covering the entire line of tiles. Electric Power Service A drive-in requires 220-volt or 208-volt service, whichever is available. Either is satisfactory, but it is important to know which it is in ordering equipment. In-car heaters extend the operating season in tlie more northern regions, and may make it feasible to operate the year around in northerly areas of milder temperatures and little snowfall. Whether in-car heaters would be of value should be determined at the outset so that ramps can be wired for them when they are wired for in-car speakers, and while electric service lines are being installed. Heaters for a third to half the capacityare normally sufficient, with wiring for them concentrated in ramps nearest the refreshment-restroom building. Such a number adds around 40% to power requirements. Drive and Ramp System JUST ABOUT every piece of land suited to a drive-in has characteristics — in dimensions, shape, relation to the highway, etc — which will advise, usually compel, location of entrance and disposition of traffic lanes and storage space more or less peculiar to itself. It should not be difficult to lay out an entrance scheme if one knows what the objective is. Basic is the necessity to take cars off the highway fast enough at any time to prevent interference with highway traffic. Highway authorities require this; moreover, patronage is discouraged by conditions which make it dangerous or even awkward for a driver to turn into the theatre tract so as to get promptly and completely off the highway. Whether by laying out a winding type, or one that is 38 Better Theatres 1956 Market Gitide