piping in sections, say one floor at a time, because then it is much easier to locate leaks. After each section is tested they may be connected, and then subjected to a final test.

The pipes should not be covered until the tests are completed. The owner, architect, or inspector should witness the tests.

ACETYLENE GAS-FITTING.

The Piping. The chief differences between ordinary gasfitting and acetylene gas-fitting are: (a) special burners or tips, (b) a gas machine or generator, and (c) smaller distributing pipes. Otherwise, there is no substantial difference between them. Buildings piped for coal gas can ordinarily be lighted by acetylene by disconnecting the service pipe from the street and attaching it to a gas machine, and by substituting acetylene tips for the common gas tips.

If a building is piped for acetylene gas only, the sizes of the piping may be about as follows:

Underwriters' Requirements.-The requirements of the New York Board of Fire Underwriters for the installation of acetylene-gas generators are as follows:

1. Plans and specifications in detail of acetylene-gas generators must be submitted to this Board for approval, and a copy of the same placed on file in this office. If the plans are approved, a special examination of the generating apparatus

will be made (at the expense of the applicant), and if it is found to be in compliance with the following requirements, a certificate of approval will be granted:

2. The generating apparatus must be located in an outside, fireproof, and well-ventilated building, where it will not be an exposure to any adjoining property. The buildings in which generators having a capacity of more than 25 lb. and not exceeding 100 lb. of calcium carbide are placed, shall not be located within 10 ft. of any other building; and the buildings in which generators having a larger capacity than 100 lb. and not exceeding 500 lb. of calcium carbide are placed, shall be restricted to a distance of not less than 25 ft. from any other building, and these shall have the constant supervision of a competent person.

3. The dimensions of the generator building must be con. fined to the requirements of the apparatus, and the limited supply (hereinafter mentioned) of surplus calcium carbide, which must be packed in water-tight metal cans, and said buildings shall be located as follows:

For generators with capacity of more than 25 lb. and not exceeding 100 lb. of calcium carbide, and, in addition, 100 lb. of surplus carbide-not less than 10 ft. from other buildings.

For generators with a capacity of over 100 lb., and not exceeding 500 lb. of calcium carbide, and, in addition, not over 500 lb. of surplus carbide-not less than 25 ft. from other buildings.

The storage of calcium carbide on premises, other than in generator building, is absolutely prohibited.

4. In constructing the building, dryness and ventilation must be secured. To meet these requirements, the floor must be raised above the grade on which the building is located, and suitable drainage provided. Ventilation is to be obtained by air passing from the outside of building through holes at the floor and through a pipe at least 6 in. in diameter, at the roof. The said pipe must extend at least 4 ft. above the roof, and must be topped with a guard cap, and if there be any building within 10 ft. of said pipe, then the ventilating pipe must be carried 4 ft. above the roof of the higher building.

5. The maximum pressure of gas stored in a gas holder shall be limited to 8 in. of water, and both the generator and gas holder shall have water safety seals (not to exceed the same limit) in connection with escape pipes of not less than 1 in. in diameter. The escape pipes must be connected above the roof with the ventilating pipe of the building in which the generator is located.

6. A generator in which the gas is both generated and stored (the maximum pressure of which shall not exceed 5 lb. per sq. in.) and having no water seal, shall be tested to withstand a hydraulic pressure of 20 lb. per sq. in. The generator shall have a pressure gauge, also a safety valve (not less than 1 in. in diameter) adjusted to release the pressure of the gas should it rise above the prescribed maximum limit. An escape pipe must be affixed to the safety valve, and connected above the roof to the ventilating pipe of the building in which the generator is located. A certificate attesting the hydraulic test is to be placed on file in this office.

7. The pressure of the gas shall be regulated at the generator or gas holder, so that it will not exceed 4 in. of water on the pipes inside of the building to be lighted. A mercurial seal, set to that pressure, must be attached to the supply pipe at the generating building. A stop-valve shall be placed on the supply pipe at the place where it enters the inside of the building to be lighted

8. All generators and gas holders shall be connected by at least 1" escape pipes and stop-valves with the ventilating pipe at the roof of the building, through which the gas can be conveyed and discharged with safety on the outside of the building.

9. Generators must be constructed so that they can be charged with calcium carbide at all times without allowing the gas to escape into the building.

10 Generators shall be filled with calcium carbide by daylight only and all generating apparatus must be in charge of persons who are familiar with their operation and are fully competent to manage them under all circumstances.

11. No artificial light, except a wire-guarded incandescent

electric light, may be used inside of the building in which the gas is generated, and no heat except low-pressure steam.

12. All acetylene-gas generators, and all receptacles containing acetylene gas, shall be made of iron or steel throughout.

13. The residuum of the calcium carbide when removed from the generator must be deposited in a safe location outside of the building apart from any combustible material.

LIQUID ACETYLENE.

14. The storage of liquid acetylene in any building, or the use of liquid acetylene gas, is absolutely prohibited.

Requirements of a Good Generator.-The following are the points on which judgment was passed in awarding medals to the acetylene generators at the Pan-American Exposition at Buffalo, N. Y., in 1901:

1. The contact of the carbide should be with the water (in other words, the machine should be of the drop type).

2. The carbide should be fed into the water in proportion to the consumption of gas.

3. The gas pressure at the point of delivery should remain practically constant, irrespective of the number of jets burning, or of the amount of carbide, or of gas, in the generator.

4. The pressure should be equal in all parts of the machine and should not exceed that exerted by a 6" column of water. 5. When the lights are turned out the generation of gas should cease.

6. The gas should be delivered to the burners clean, cool, and dry.

7. The heat of generation must not exceed 200° F.

8. When the generator is recharged, there should be no escape of gas.

9. If the generator is left idle for a long period, there should be no deterioration of the carbide.

10. The gas holder attached to the generator should be of ample capacity and made tight with a water seal.

11. The pressure in the service pipe should never exceed that of a 3" column of water, and a provision must be made to blow off into the air at a pressure of 6 in.

12. The water capacity of the generator must be at least 1 gal. of water to 1 lb. of carbide.

13. There must be a convenient method of getting rid of the slacked carbide without escape of gas.

14. The generator must be entirely automatic in its action. That is to say, after it has been charged it will need no further attention until the carbide is entirely exhausted.

15. There should be a simple method of determining the amount of unconsumed carbide in the generator at any time.

16. The generators should be so simple in operation that they can be tended by unskilled labor without danger of accident.

17. The various operations of discharging the refuse, filling with fresh water, putting in carbide, and starting the generator should be so arranged that it is impossible to do them in the wrong order.

18. The generators must be so arranged that there can be no possibility of mixing air with acetylene gas.

19. Generators must be built of substantial materials well adapted to their purpose.

20. Generators must be so constructed that an addition to the charge of carbide can be made at any time, without affecting the light.

Any generator that is built according to the preceding points may be considered excellent.

LOCATING FIXTURES.

The chief considerations that govern the location of gas fixtures are: first, that they shall light the rooms to good advantage, and second, that they shall cause no danger from fire.

A gas fixture should never be placed in a closet or other very small room, if there is any chance that the door may be closed and the light left burning. If that should happen, the temperature will rise rapidly, and there will be great danger of setting fire to any combustible material that might be in the room.