International projectionist (Jan-Dec 1936)

December 1936 INTERNATIONAL PROJECTIONIST 31 FIRE PREVENTION IN THE M. P. INDUSTRY (Continued from page 16) or connected by piping to fixed outlets. It depends for its effectiveness upon displacing or diluting the air that would otherwise support combustion, thus smothering the fire. It is suitable for use upon ordinary combustible materials and inflammable liquids and for marine use. Fixed installations are made for use in confined spaces. Small rooms or compartments may be filled with the carbon dioxide gas, thus cutting off the oxygen supply. Some consideration must be given to the possible ill effects of the gas, inasmuch as carbon dioxide will not support life. To detect leakage the extinguishers should be tested by weighing at least annually. Precautions Against Carb. Tet. Carbon Tetrachloride. — These are the familiar hand-pump type, and are particularly adapted for electrical fires, as the liquid is non-conducting. They are suitable in certain special cases for use upon burning oils, but are not recommended for general use. In confined or unventilated spaces, precautions should be taken to avoid breathing the gases and vapors liberated when they are used en fires. The gases are also corrosive, which is of importance in connection with delicate electrical apparatus. The extinguishers should be tested at least annually by partly discharging and refilling. Dry Chemical. — These employ an inert gas to discharge a dry chemical in powdered form through a hose. They are effective in oil fires, and may be used about electrical apparatus. Pails of Sand Useless There are on the market a great number of other miscellaneous fire fighting devices, such as glass bombs, bottles filled with various liquids, and tin cans filled with sand or powder, comparatively few of which have any real value except in special cases. Sand pails are often prescribed for projection rooms by local fire departments. There would appear to be no possible conditions under which they might be effective in room fires. One important guide in the selection of the extinguisher is the label of the Underwriters' Laboratories, which is assurance that the device is reliable; but the mere labeling does not mean that the extinguisher may be used indiscriminately for every kind of fire. Each extinguisher must be selected for the purpose for which it is intended. Recently some success has been had in controlling and extinguishing oil fires by means of a special spray nozzle, developed in England, using water at high § BRENKERT COPPER-OXIDE RECTIFIER 1 BRENKERT R-6 is thoroughly reliable . . . economical . . . quiet in operation . . . and superior in performance. FOR SUPPLYING DIRECT CURRENT TO LOW-VOLTAGE PROJECTION LAMPS The BRENKERT R-6 rectifier is the result of combining the long experience of Westinghouse Electric and Mfg. Co. in producing copper-oxide rectifying elements with the Brenkert Co.'s broad experience in the requirements of current supply for arc lamps. Its correct engineering and rugged construction have been proven in installations across the continent. See your nearest BRENKERT distributor, or write for complete information: to RECTIFIER DIVISION B RENKERT LIGHT PROJECTION ENGINEERS & MANUFACTURERS Detroit, Michigan, U. S. A. c° How Many? Was this copy dog-eared when it came to you? How many men read it ahead of you? You would receive a clean, fresh copy if you had a personal subscription — and you wouldn't have to wait — you would be first to read it. Use coupon below. INTERNATIONAL PROJECTIONIST. 580 Fifth Ave., New York. N. Y. □ 1 year — 12 issues — $2.00 □ 2 years — 24 issues — $3.00 Foreign: Add 50c per year. Enter my subscription for Name Address City ... State