As the result of a special investigation, the accompanying table and recommendations are submitted as the basis for proper specifications for the gas-piping of buildings to meet the demands of modern requirements for lighting, heating, cooking, and manufacturing:

General Requirements

1. All lines of piping throughout the building, except drops, must be laid with grade so as to drip or drain back into the risers, with no depressions to hold condensation. Drips with drip pipes where needed must be provided at meters and at such other points as the plan of piping may render necessary.

2. No riser must be less than three-fourths inch in diameter in any case, and all risers must be covered up on inside partitions so as to be thoroughly protected from freezing. Wherever risers or other pipes cannot be guarded in this manner, they shall be protected from frost by special and effective coverings.

Table of Maximum Lengths of Pipe and Number of Lights with Corresponding Diameters.

The results in this table are based upon a specific gravity of o.6 and a pressure of gas of 0.5 inch of water.

* One burner delivering 6 cubic feet per hour.

Gas Logs and Ranges*

* The numbers for gas logs and ranges in the third column of the table refer to sizes for which the consumption in any log or range does not exceed 35 cubic feet per hour.

The sizes of piping for gas logs and ranges are for single lines run from or near the meter, or source of supply, for the specific purpose indicated.

When gas logs and ranges are supplied by branch pipes, or when any branch pipes are run from the main system of the building, the combined sectional areas of all the pipe sections must exceed the sectional area of the main supply pipe sufficiently to maintain the proper flow.

3. Wherever practicable all piping shall be exposed, but piping that must be concealed shall first be thoroughly inspected by the gas company, and the gasfitter shall give due notice when the piping is ready for inspection. Unexposed piping must be so concealed as to be readily accessible in case of examination or repairs. Wherever practicable, as in floors, the concealment shall be made by boards over the pipes, secured by brass or other non-corrodible screws.

4. In cases where extensions are made care must be taken to extend with such sizes that the rules already prescribed shall be maintained.

5. All drop pipes must be left perfectly plumb and well secured in that position.

6. Long runs of piping must be firmly supported at frequent intervals so that no sagging nor depressions can occur in which condensation can collect.

7. If pipes run across wooden beams or joists the requisite cutting, notching, or boring shall never be more than 2 inches in depth nor more than 3 feet from bearings, and as near the latter as possible.

8 Lines of piping shall not be placed under tiled or parquet floors, marble or other stone or metal platforms, or under hearthstones, unless the local conditions render such procedures imperatively necessary. , ii. All pipes shall be firmly and safely secured in position with hooks, wrought-iron straps, or holdfasts, secured with screws at close intervals, so that continued use in proper line and grade may be effectively secured.

9.All pipes shall be of the best quality of wrought-iron welded gas pipe, and all fittings, including couplings, elbows, bends, tees, crosses, reducers etc. under 2 inches diameter, shall be extra heavy malleable fittings; those of larger diameter may be of cast iron. These pipes and fittings may be plain, galvanized, or made non-corrodible by any effective method.

10 Pipes and fittings are to be put together with screw joints and red lead, or red and white lead mixed with joints made perfectly gas-tight.

12. Meters shall be placed where they will be most conveniently accessible for reading the index and for examination and repairs, and when placed on the walls the minimum height above floors shall be 2 feet for the bottom of the smallest meters and the maximum height shall be 8 feet for the top of the largest meters. The sizes of connections shall be as follows:

13. The completed piping shall be tested by some competent authority, who shall give a written certificate of the results before any of it is covered at any point All outlets shall be tightly capped and the whole system shall be tested preferably with a mercury gauge, or by a low-pressure spring gauge which has been recently and authoritatively tested by a mercury column. When air is pumped into a completed system of pipes until the pressure reaches 12 inches of mercury and stands or remains stationary for five minutes, or if the column of mercury does not fall more than 1 inch per hour, the system may be considered satisfactorily tight. Otherwise leaks must be sought and stopped and the testing repeated until the preceding requirements are satisfied. When extensions to completed systems are made the same tests shall be applied to the extensions before they are put in use. In the case of large buildings the entire system may be tested in suitable sections.