DEPRECIATION OF WATERWORKS PLANTS.

DEPRECIATION OF WATERWORKS PLANTS.

In a paper recently read before the Wisconsin League of Municipalities by Charles B. Burdick, an hydraulic and sanitary engineer of Chicago, the author explained why sometimes, just at the most critical moment during a had fire, the waterworks system suddenly breaks down, as if its life had given out through depreciation of some vital part through wear and tear, carelessness the action of the elements or the soil. "So durable is cast iron pipe (he said) that its use for a period of more than one hundred years has not been sufficiently lengthy to demonstrate its ultimate life. Cncoated cast iron pipe has been in service for that length of time, ami medern pipe coatings appear to furnish almost perfect protection, although there are certain soils and waters, rarelv met with, however, whose chemical qualities cause rile pipe to he rapidly destroyed. Electrolysis is a source of danger; hut it is known that this danger is confined to a small part of the system, and, furthermore, may be largely avoided by proper bonding in the electrical construction. Certain waters produce tubercles or incrustations upon the interior surfaces of pipes, thus reducing their capacity, usefulness and consequent value; hut, with the increasing use of cleaning appliances, there need in the future be l ttle depreciation from this cause. Reservoirs of masonry or earth, when properly constructed and maintained, arc almost indestructible, and their depreciation is usually confined to coverings or minor features. Steel reservoirs, standpipes or riveted tanks have a much shorter life. Many standpipes are now twenty to thirty years old, and, although some of them are in fairly good condition, a number have been taken down as dangerous, have been destroyed by accident or have been displaced through life or capacity. Buildings usually depreciate by being outgrown rather than by actual deterioration. Pumping machinery has a durable life, and is more often replaced from lack of capacity than for any other reason. Good machines are now operating after fifty years of service, and it is probable that such, if well maintained, can give good service for a very long period; even when no longer economical, they may have a considerable value as a reserve. In assigning the depreciation to any particular case, local conditions must he considered; hut. while it is, therefore, impracticable to make any close general estimate on the lire of waterworks structures, the periods ordinarily assigned by appraisal boards have closely approximated the following: Well-coated cast iron pipe and specials, seventy-five to 100 years; wrought iron pine, well coated, twenty-five to fifty years; hydrants and valves, fifty to seventy-five years; buildings, twenty-five to fifty years; reservoirs, fifty to 100 years; standpipes, twenty-five to fifty years; pumping machinery, fifteen to fifty years; boilers, ten to twenty years; electric machinery, twentylive to fifty years.”

In a paper recently read before the Wisconsin League of Municipalities by Charles B. Burdick, an hydraulic and sanitary engineer of Chicago, the author explained why sometimes, just at the most critical moment during a had fire, the waterworks system suddenly breaks down, as if its life had given out through depreciation of some vital part through wear and tear, carelessness the action of the elements or the soil. "So durable is cast iron pipe (he said) that its use for a period of more than one hundred years has not been sufficiently lengthy to demonstrate its ultimate life. Cncoated cast iron pipe has been in service for that length of time, ami medern pipe coatings appear to furnish almost perfect protection, although there are certain soils and waters, rarelv met with, however, whose chemical qualities cause rile pipe to he rapidly destroyed. Electrolysis is a source of danger; hut it is known that this danger is confined to a small part of the system, and, furthermore, may be largely avoided by proper bonding in the electrical construction. Certain waters produce tubercles or incrustations upon the interior surfaces of pipes, thus reducing their capacity, usefulness and consequent value; hut, with the increasing use of cleaning appliances, there need in the future be l ttle depreciation from this cause. Reservoirs of masonry or earth, when properly constructed and maintained, arc almost indestructible, and their depreciation is usually confined to coverings or minor features. Steel reservoirs, standpipes or riveted tanks have a much shorter life. Many standpipes are now twenty to thirty years old, and, although some of them are in fairly good condition, a number have been taken down as dangerous, have been destroyed by accident or have been displaced through life or capacity. Buildings usually depreciate by being outgrown rather than by actual deterioration. Pumping machinery has a durable life, and is more often replaced from lack of capacity than for any other reason. Good machines are now operating after fifty years of service, and it is probable that such, if well maintained, can give good service for a very long period; even when no longer economical, they may have a considerable value as a reserve. In assigning the depreciation to any particular case, local conditions must he considered; hut. while it is, therefore, impracticable to make any close general estimate on the lire of waterworks structures, the periods ordinarily assigned by appraisal boards have closely approximated the following: Well-coated cast iron pipe and specials, seventy-five to 100 years; wrought iron pine, well coated, twenty-five to fifty years; hydrants and valves, fifty to seventy-five years; buildings, twenty-five to fifty years; reservoirs, fifty to 100 years; standpipes, twenty-five to fifty years; pumping machinery, fifteen to fifty years; boilers, ten to twenty years; electric machinery, twentylive to fifty years.”