N. Y. DEPUTY CHIEF EXAMINATION
Questions, with Answers and Supplementary Comments by Battalion Chief John J. T. Waldron, Who Received Highest Mental Rating
(Continued from last issue)
LAW AND ORDINANCES (Continued) Weight 1—To Be Finished by 1:00 P. M.
Question No. 5—You have been ordered to prepare written instructions for the members of the companies engaged in the inspection of buildings in their districts. Prepare an outline of a set of such instructions to cover the inspection of dry and wet sprinkler systems in factory buildings, that will guide firemen in determining whether such systems conform in all respects with the requirements of the law.
Answer to Question No. 5
The following instructions are herewith forwarded for the instruction and guidance of members making inspections of buildings:
1st. I will quote the salient features of the rules for sprinkler installation. There are three kinds of sprinkler systems: automatic wet systems in which pipes and heads are constantly filled with water. Second, automatic dry-pipe systems where pipes and heads are filled with air under pressure but there is a dry pipe valve set against the water supply and when a head fuses, releasing the air pressure the lines will be supplied with water as the dry pipe valve is released. Third, non-automatic system with fire department Siamese connection supply only.
As to sources of water-supply; there are the automatic supplies of gravity tank, pressure tank, direct connection to street mains, and the auxiliary sources of fire pump and fire department Siamese connection.
The gravity tank should be located above roo-f, be of at least 5,000 gallons capacity, and at least able to supply 25 per cent, of the heads in the largest fire area for at least 20 minutes; an air pressure of 75 pounds to be maintained on the pressure tank which will be 2/3 full of water and pressure from air pump to be so supplied and maintained that when tank is empty there will still be 15 pounds pressure on head. Proper tell-tale for height of water and pressure gauge to be on this tank. Pressure tank to be at least 5,000 gallons capacity, and shall be capable of supplying 12 1/2 per cent, of head in largest area for 20 minutes.
Direct connection to street main to be not less than 4-inch pipe connected to main which will give 60 minutes supply and 15 pounds on highest line of sprinkler heads.
Fire pump to be 750 gallons per minute capacity and if steam operated there must be 50 pounds of steam available at all times; if electric driven, public service company accepted.
Fire department Siamese connection to be two-way 3-in. Siamese, independent clapper valve for each inlet, Siamese to be placed in accessible place, not over 18 or more than 24 inches above street. Be marked with raised letters on top to indicate its purpose and portion of building it supplies.
The number of sprinkler heads to be provided depends upon the character of ceiling construction and the following is the general provision. Where there are smooth ceilings or mill constructed ceiling with bays each head will cover 100 square feet. If there are bays one pipe line should be placed in centre of way (from 5 to 12 foot bays) and head should be spaced 8 feet on 12 foot bay 9 feet in 11 foot bay, 10 feet in 10 foot bay, 11 in 9 foot and 12 in 8 foot.
Where there are joisted ceilings, open construction pipe lines and spacings of head should be so each head covers not over 64 square feet; general plan of pipe lines 8 ft. apart; heads 8 ft. apart. Heads on adjoining lines to be staggered.
The foregoing applies to both automatic wet and automatic dry sprinkler systems where regular 1/2-inch heads are used. Where Conran heads (special type) are used general plan is to have 1-inch head cover about 400 square feet and the l 1/4-mch head cover 625 square feet. Shafts with inflammable sides, in addition to sprinklers at top should have heads at sides, at alternate floors, if practical, covering 200 square feet of surface per head.
The location of risers should be noted. Central or “side central feed” is approved and desired arrangement. End feed riser will be noted as undesirable.
The number of heads to be supplied by a given size pipe is in accordance with following table:
See that excessive heads are not installed.
There should be a control valve at base of system and a floor control on each floor. Also see that there is a drain valve to permit draining branch lines on floors and a drain valve at base to drain entire system if necessary.
The floor control valves should be outside screw and yoke type, sealed open with leather strap and lead seal.
Sprinkler heads should be placed not less than 3 inches nor more than 10 inches below ceiling, and it is desirable that curtain boards be installed around openings such as stairs and shafts, when same are not enclosed, curtain boards to bank up heat and prevent too many remote heads from fusing in case of fire.
Inspectors will see that all provisions of the rules are carried out and in addition will pay particular attention to the following: Note that all valves which should be open are in such positiSh and sealed so.
See that sprinkler heads are not obstructed with stock to prevent proper distribution of water from same.
In boiler rooms or other positions where excessive temperatures obtain there should be high degree heads installed instead of the regular 165 degrees heads, but note that such high degree heads are not in places where they should not be.
Where control of sprinklers is in odd location, as for example where tanks are located on one building to supply system in an adjacent premises, inspector will find control valve, make special note of same, and see that commanding officer of his company is informed. Chief officer will welcome such information as well.
Of course requirements provide that there shall be check valves inside on lower run from Siamese and check valve under tanks, these to keep up supply from flooding into tank and down supply from running out to street.
Siamese on outshore end of piers and wharf buildings where fire boats might connect should be two-way 3 1/2-inch connections.
The dry pipe valves are of two types. Type A being used where same is released when air pressure is vented by fusing of head, and type B is one where release is affected by an electric control actuated by a thermostatic device.
Where dry valves are installed, chamber should be heated in cold weather to prevent freezing.
There should be a test pipe at top of system, to permit test for water flow, or operation of supervisory alarm system if same is present.
The mention of quantity of water supply in gravity and pressure tanks for 25 per cent, and 12 1/2 per cent, of heads in largest area is based on 20 gallons per minute for %-inch head.
Proper ladders and means of reaching floor control valves should be placed at same.
Where direct street main connections are used for supplying system, there should be a post indicator valve in a pit outside building, top of valve level with sidewalk, and key at top of type to fit fire department wrenches. This to permit shutting off supply from outside if necessary.
Answer to Question No. 5 received a rating of 96 per cent.
(To be continued)
Amarillo Will Vote on $1,750,000 Bonds for Adequate System—An election will be held early in March at Amarillo, Texas, at which the issue of $1,750,000 bonds will be voted to finance the establishment of an adequate water supply system for that city and to settle a problem that has been facing the city for years. The issue will provide for the construction of an entirely new water works system. $700,000 of the total going toward the distribution system lines. A storage reservoir of 3,000.000 gallons capacity will he constructed near the city.
Oregon Water Supply Project’s Figures to Be Submitted —The commissioners of the Home Water District who are planning the construction of a water works project to supply Multonomah, Ryan Place and Capitol Hill, Oregon, have announced that Barr & Conningham, engineers, who are making the plans, would soon submit their report on the cost of the proposed system and other figures and specifications. As soon as all the figures are in the possession of the commissioners they will be printed and placed in the hands of the property owners for study before the bond election some time in the near future.