d. Distribution in both above tests to be approximately uniform over the 10 feet square area.

e. Water should not be cut up into fine spray.

f. Rotary deflectors are allowable, but the distribution must be satisfactory with deflector fixed.

g. The distribution in any direction shall not be obstructed by yoke, levers or other parts of sprinkler.

8. Materials.-Automatic sprinklers must contain no iron, stcel or fibrous material subject to the effect of corrosion.

NOTES.-Sprinkler heads are ordinarily set to fuse at 165 degrees, 286 degrees and 360 degrees.

Corroded heads are apt to be found in chemical works, galvanizing works, sulphur bleaching looms, paper mills, sulphite and other chemical pulp mills, starch works, certain classes of dye works, and where arsenic is used for preserving skins.

"It is much more difficult to protect sprinkler heads in such factories where from the nature of the process of manufacturing the head soon becomes coated with a fine dust. This class of factories comprise flouring mills, grain elevators, saw mills, furniture factories where sand-paper drums are operated, grinding rooms in sugar refineries, candy factories, cement mills, plaster mills, drug and spice mills, etc. In all of these classes, the mere covering of the head with loose dust will only slightly retard its action; should, however, aqueous vapor be present, the fine dust soon becomes set and hardened, rendering the sprinkler head entirely inoperative. * This is less likely to occur in flouring mills, but is a very serious matter in cement mills, where the fine cement dust on the head, if aqueous vapors are present, will soon become as hard as stone."

* *

"The coating of the sprinkler head with a deposit of varnish or hardened oil occurs principally in dry rooms of oilcloth factories, patent leather works, rubber works, and in fact all factories where varnish products are dried by artificial heat. The drier, in evaporating, carries with it portions of the varnish or oil, as the case may be, and this coating deposited on the cold sprinkler head, in time covers it with a coating, which, by reason of the heat of the dry room, is soon baked into a hard covering not easily removed by a fire which would ordinarily melt the fusible solder."-(Extracts from report of committee, presented by

C. A. Hexamer at the fourth an al meeting of the National Fire Protection Association.)

The approximate amount of water to fill a sprinkler system is one gallon per head for all pipe in the system, especially in systems of from 75 to 115 heads on each floor, when fed from center; if fed from one end, about 14 gallons; where a 6-inch riser is used with about 250 heads on a flcor, about 14 gallons when feed is from center, and 11⁄2 gallons when feed is from end.

The following treatment for rendering sprinkler heads not liable to corrosion is recommended by the Western Factory Insurance Association. Begin with the ordinary automatic sprinkler without any special anti-corrosion treatment. Wash the heads in lye water, rinse in clean water and ict dry. Have ready a mixture of equal parts resin and paraffin. Heat the mixture to a temperature of 400 degrees, stir thoroughly, let cool to a temperature of 150 degrees by thermometer. Dip the sprinklers in this liquid, allow them to remain until the sprinkler heads are as warm as the mixture. On drawing the sprinklers out of the dip a very thin coating of the mixture will adhere. A thin coating is better than a thick coating. The coating should not be lumpy. Place the sprinklers on the pipes, being careful not to rub the mixture from off the small parts. The scraping off of the coating where the screwing-in wrench touches the shank of sprinkler, will do no harm. This treatment should last for a year or two years. After that the sprinklers and piping can be touched up with the mixture on a brush, if corrosion appears.

The following in reference to the treatment of automatic sprinkler heads to prevent corrosion is from "Hand-Book of Fire Protection for Improved Risks": Various methods have been tried for preventing or retarding corrosion, and most of these have been unqualified failures."

"Perhaps the most common coating for sprinklers found in practice is the so-called 'Nigger' head. This is a sprinkler given a thin coat of asphaltum or similar paint, and is also some times in addition to this dipped in paraffin. This method of coating a sprinkler head has not been found to be satisfactory, as it does not prevent corrosion, except, possibly, to a very slight degree, and where the corrosive influences are at all severe, the coating is entirely ineffective. It should be classed as of little value. Lead

coatings have been used by various sprinkler manufacturers, but here again the protection afforded is slight, and then only under certain favorable conditions or else the sensitiveness of the head is destroyed. Paraffin coating is too soft and melts at too low a temperature for general use. Glass caps covering all but the base of sprinkler have been used in a few cases and apparently they protect the sprinkler from corrosive vapors at least temporarily" *

66

* *

'Corroproof' is a wax-like coating which has been used to some extent in New England, and this coating has shown up to much better advantage in practice than any of the above."

CHAPTER VIII.

STEAM FIRE PUMPS.

It is unfortunately a fact that in such an essential and important matter as the purchase and installation of a fire pump, a thing on which very often the entire protection of a plant depends, false economy is used, and an inferior and weak pump is bought and set in a poor location; it is not always the purchaser who is at fault, for some pump manufacturers, in order to secure trade by underselling competitors, place upon the market pumps of inferior construction while of apparently the same size and capacity as pumps of much higher price. It is quite an ordinary thing to find pumps in places so exposed as to be practically unreachable in case of fire; to find upon testing them that they stick, will not operate promptly, or are entirely cut of order, and while the pump is known to be, as a rule, the mainstay of the fire protection, yet it usually receives less care and attention than any other piece of machinery at a plant.

UNDERWRITER STEAM FIRE PUMP.-These pumps are made under specifications as prepared by Mr. John R. Freeman, May, 1895, and are, as yet, the highest type of fire pump; the ideas in their construction is that the pump may have proper strength of parts to withstand sudden and excessive pressures, to give positive and continual maximum delivery, to withstand the action of rusting to the greatest extent, to have large steamvalve-ports, large suction-valve-areas, large water-pipe connections and in all ways to be of greater strength and better workmanship than the regular trade fire pump.

The main points of difference between the regular trade fire pump and the Underwriter Fire Pump are-brass plungers instead of cast-iron plungers, wrought-iron side levers instead of cast-iron, bronze piston-rods and valve-rods instead of iron, or steel, brass lined stuffing boxes instead of cast-iron, brass bushed rock shafts, areas of water-valves is 25 to 50 per cent greater, steam and exhaust passages 20 to 50 per cent greater, suction pipe connections two to four inches greater in diameter, cushion valves better arranged, air chamber much larger, shells and boltings are warranted especially strong.

This pump is a duplex steam pump, has size plate on inboard side of air chamber, and being brass fitted throughout and having valves and piston-rods of gun-metal composition it is rust proof. It is made strong enough to withstand 80 pounds steam pressure when all valves on water outlet pipes are closed and steam valve is wide open, and to have such arrangement of thickness of metal that it shall be safe to instantly turn a full head of steam on to a cold pump without cracking or breaking the same by unequal expansion, due to this cause. Area of steam and water valves are large. It is provided with stroke gauge, and pressure gauges for steam and water, has suitable priming pipes, a relief valve of sufficient capacity to discharge excess of water, and suction pipe has a vacuum chamber for the purpose of insuring a constant flow and regular delivery of water. Has hose connections attached to neck of air chamber.

TABLE OF UNDERWRITER FIRE PUMPS AS PER SPECIFICATIONS OF J. R. FREEMAN, MAY, 1895.

Capacity at
Full Speed.

Ratio of
Piston
Areas.

SIZE OF PUMP.

12 x 6 x 12

One Stream Pump

too small for a fire-pump, but may sometimes be all that the steam boiler of a very small factory can drive.

Sometimes it is desirable at a larger factory to use this size of pump for boiler feeding, and thereby obtain one additional fire stream,Size recommended:

Diam. steam cylinder 12 ins.

Diam. water plunger 6 ins.

Length of stroke either 12 ins. or 10 ins.. To drive this at fire speed requires boiler of about 50 horse-power.

Exact capacity Underwriter rating:

For 12-inch stroke, 359 gal. per minute. For 10-inch stroke, 321 gal. per minute, For continuous use on tanks or boilers, pump should run at only about half the above speed. This size pump is adapted to feed boilers aggregaung about 1200 horse-power.

If a pump of smaller size must be adopted, use the 10 x 5 x 10 size.

Exact capacity (Underwriter's rating) 220 gals. per minute, but for continuous service the speed should be only half this.

To drive this pump at fire speed requires boiler of about 35 horse-power. This size is adapted to feed boilers aggregating about 900 horse-power.