used to permit the meter being set on the ground when the valve is in a manhole.

(c) Isolate the section and test all control valves for tightness.

(d) Feed the section through the metered by-pass, reading the meter at the end of each minute. Successively close the valves on all branch lines in the section, noting in each case the time of closing. Allow several minutes between successive closings so that the effect of each will be independently shown by the meter readings. If, after closing all secondary valves, a flow through the metered by-pass is still noted, reduce the size of the section step by step, by closing valves in order, beginning with the farthest from the meter. These observations can best be made during the night hours, say from 11 p. m. to 7 a. m., or other suitable night hours, because interference with the water supply to buildings, ships, and quarters will thus be avoided, and also because during most of this period the system will be comparatively free from fluctuating drafts of water.

(e) Locate leaks and make repairs. By using time and rate of flow as coordinates, a curve can be plotted showing the variations in flow throughout the test of any section. By noting the time of closing each valve on the curve it can be readily seen which valves have affected the rate of flow and leaks can then be definitely identified with particular sections of pipe. When a leak is to be located in a long section of water main, the use of the "aquaphone" in test pits frequently gives good results without excessive excavation. Other methods failing, such leaks may be located with reasonable accuracy by installing test cocks at suitable points and then introducing into the main a quantity of harmless colored liquid having a density different from that of water. The rate of leakage being known in advance, the time required for the solution to reach certain points in a tight section of pipe of the size in question can be easily computed. The position of a leak will be indicated by a comparison of the actual with the theoretical time required for the colored liquid successively to reach the selected outlets or test cocks along the line.

20-78. Survey arrangements to be made permanent. The arrangements for making water-waste surveys should be made permanent, so that surveys may be repeated with slight cost. It is also very necessary to instruct the testing crew thoroughly as to the various steps and the reasons therefor, so that in succeeding surveys the same procedure may be followed without special study and instruction.

20-79. The quarterly night test, mentioned in par. 20-71, is simply the comparison of main meter readings with those of the night consumers from midnight to 8 a. m., or other appropriate night hours, in order to determine the losses due to leakage.

20-80. Constant vigilance required to prevent wastage. Even after a successful survey, wastage can not be prevented except through constant vigilance in controlling issues to ships and other consumers not permanently metered, and in keeping the number of unmetered connections to the absolute minimun.

BUILDINGS, CHIMNEYS, WALLS, AND FENCES.

20-81. Maintenance work consists of the execution of any measures necessary to insure continued stability of the structure in whole or in part, such measures to include the prevention of overloading or otherwise hazarding the structure or any of its parts; the prevention of avoidable deterioration through the prompt detection and repair of defects and damages; the reduction of deterioration from the elements by such preservative measures as may be practicable; and decorative treatment to secure appearance appropriate to the intended purpose of the structure.

20-82. Scope of instructions. Since types of structures, in the case of buildings, vary from single-story wooden structures to multistoried structures of steel and masonry, with wide variation also obtaining in types of chimneys, walls, and fences, it is impracticable to prescribe maintenance rules in complete detail. The succeeding instructions in this section will therefore be limited to those considerations common to all such structures, and furthermore without regard to particular climatic conditions.

20-83. Foundations. Any material or general settlement of footings must be promptly and thoroughly investigated, and necessary corrective measures adopted. If the structure is of any considerable value or importance, full report shall be made to the bureau. Temporary foundations should be given such attention as the importance of the structure justifies.

20-84. Roofs should be so maintained that the necessity for their complete renewal may be postponed as long as economically practicable. Roofs should be renewed when the annual maintenance cost exceeds the interest on the capital investment required for renewal; shortage of funds under the appropriation applicable, may, however,

often delay such work beyond the point of justifiable renewal. The system of routine inspections should be such as to disclose leaks and other defects, particularly during rainy weather, without relying upon the occupant to report them. Buildings with skylights require extra attention on account of the inherent likelihood of leaks developing in this type of construction. Gutters and leaders should habitually be kept tight and free from obstruction.

20–85. Painting of exposed masonry forbidden. The painting of exposed exterior brick, stone, or concrete in building walls, boundary walls, or retaining walls is forbidden, the practice being not only wasteful but useless. In the case of masonry structures already painted, the bureau's advice as to proper future treatment should be obtained before repainting such structures.

20-86. Painting for decorative purposes only shall not be performed except in buildings or parts thereof used for administrative or living purposes. Instructions as to the bureau's standards and practice regarding the use of paints have been placed under a separate heading in this chapter.

20-87. Linoleum not to be shellacked. Linoleum is frequently used for covering floor areas used for offices and hallways. Subject to certain limitations, the bureau approves such practice. Linoleum purchased under standard Navy specifications is usually carried in store by the supply officer, and is entirely suitable for offices and hallways, although the medium three-sixteenths-inch weight is preferable. New linoleum shall not be covered with shellac, because it induces rot, and when once applied prevents any treatment other than repeated applications of more shellac. Immediately after laying, linoleum should be well rubbed with linseed oil and allowed to dry. At necessary and convenient intervals and after cleaning with water, the application of linseed oil with a small quantity of Japan drier can be repeated to renew the life of the linoleum. When badly discolored, linoleum may be treated with a stain containing the following ingredients per gallon:

Venetian red in oil, 2 pounds.
Raw linseed oil, gallon.

Turpentine, 2 pints.
Japan drier, pint.

This stain should be well rubbed in and allowed to stand 24 hours before traffic is permitted. Another approved treatment for linoleum is the following: Dissolve any satisfactory brand of commercial

floor-wax in turpentine substitute, brush it over the clean linoleum and allow to dry, then polish.

20-88. Periodic inspection of elevators, both freight and passenger, shall be made by a competent employee under the direction of the officer responsible for their safety, and the notice of such inspections, showing date and the signature of the inspector, shall be conspicuously posted in the elevator car. Hoistway-door and car-gate interlocks, contacts, control apparatus, controller, automatic stop, limit stops, car and counterweight cables, "safeties," guide rails, and elevator machines shall in passenger-elevator installations be inspected quarterly and in freight-elevator installations shall be inspected semiannually. Plunger shoes, by-passes, and piston rods of hydraulic elevators shall be inspected at least once in three years.

20-89. Maintenance of elevators. The following rules of the A. S. M. E. safety code for the maintenance and care of elevators are to be observed in all cases:

(a) Cables, guides, and all parts of machinery shall be kept well lubricated. The oil in bearings and gear casings shall be renewed every six months. The use of a lubricant containing graphite or other opaque substance shall not be permitted on elevator cables.

(b) Pressure and discharge tanks of hydraulic elevators shall be thoroughly cleaned at least once every three years.

(c) Pressure tanks of hydraulic elevators shall be tested with hydrostatic pressure 50 per cent in excess of the maximum working pressure at least once every three years. (d) Elevator hoistways and pits shall be kept clean. No rubbish shall be allowed to accumulate therein nor shall any part be used for storage.

(e) A hatch cover of the vertical lifting type for a platform elevator shall not be used for storage or a similar purpose.

(f) No explosives or highly inflammable substances shall be stored under or near any elevator hoistway.

(g) No material not a permanent part of the elevator equipment shall be permitted on the top or cover of an elevator car.

(h) No wire or current-carrying device shall be substituted for the proper fuse or circuit breakers in an elevator circuit.

(i) Freight elevators shall have legible signs posted on the car and at each landing prohibiting unauthorized persons from riding on the elevator car.

(j) The water level in the pressure tank of a hydraulic elevator should be maintained at about two-thirds of the capacity of the tank.

The operating rules of the elevator safety code, published by the American Society of Mechanical Engineers, 29 West Thirty-ninth Street, New York, N. Y., are recommended for general observance in so far as they may be applicable to Navy installations. A card

containing printed instructions to operators should be posted in every elevator car.

20-90. Safe loads for elevators and floors to be indicated. In each elevator there shall be placed a card or plate indicating its safe carrying capacity; for passenger elevators, the safe capacity shall be expressed in maximum number of passengers to be carried; for freight elevators, in number of pounds. On all floors of buildings, except ground floors whose safe load is not limited by reason of the design of the building, there shall be placed one or more permanent signs of placards indicating conspicuously the safe load which the floor is capable of sustaining; the safe load should be expressed in pounds per square foot.

20-91. Fire prevention. Instructions covering the prevention of loss by fire have been included in Chapter 23. Special reference is directed to those paragraphs pertaining to the inspection and maintenance of sprinkler systems and other fire-fighting apparatus in buildings, requirements for electric wiring and fixtures, and directions as to proper storage of materials to reduce fire hazards. Extension of power or lighting distribution systems and the installation of additional fixtures or machines shall not be made unless duly authorized under conditions prescribed by the commanding officer.

20-92. Quarters. For instructions regarding allowances of furniture and repairs to quarters, attention is directed to Chapter 25.

BRIDGES, TOWERS, AND MASTS.

20-93. Scope of maintenance. In the majority of cases structures under this heading are constructed of steel, and in most other cases of heavy timber. Normally their maintenance involves protection against damage from overloading or improper use, and the adoption of suitable preservative measures to prevent deterioration of the superstructure and the foundations, anchors, or other supports.

20-94. Painting. Special reference should be made to the section of this chapter devoted to this subject, where instructions will be found concerning the painting of exposed structural steel and of heavy timber.

20-95. Transfer bridges require unusual attention to insure stability through proper functioning of the pontoon support, pumps, and locking bars. Corrosive action of sea water, especially where parts of the steelwork are periodically submerged by the tides, must be guarded against.

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