High-pressure fire-fighting water supply system-one type of high-pressure fire hydrant provides more water than three fire trucks-the fire-fighting water tank is used as a backup water tank in case there is no fire hydrant available
San Francisco has an auxiliary water supply system that is used only for fire protection. It consists of a distribution system that is filled with high-pressure fresh water, fed by gravity from a water tank and a large water storage tank, and connected to two pumping stations along the coast of the bay, capable of pumping salt water directly into the system. The distribution system consists of a pipe network that burns the densely built-up areas of the city and provides fire protection for an area of approximately 9 1/2 square miles. In order to protect the piers and infill areas and ports in coastal areas, two firefighting ships have been built. These ships can be connected to the distribution system through two manifolds placed in convenient locations, allowing the ships to pump seawater from the bay into the distribution system. A total of 141 concrete fire-fighting water tanks were built in various places throughout the city, even on the streets outside the areas covered by the high-pressure pipeline system.
These water tanks should be kept full of fresh water and used without fire hydrants. The water supply system for domestic purposes, completely independent of the system described in this article, is connected to low-pressure fire hydrants throughout the city, thus providing additional protection in crowded areas. A lira alarm system was established together with the auxiliary water supply system, and a fire alarm station was set up in the center.
The work on the auxiliary water supply system began in 1909 and was completed by the end of 1913 under the leadership of the current city engineer MM O’Shaughnessy. The total cost of the system is $5,756,000, and it can save insurance money every year. The amount exceeds $1,400,000.
The distribution system consists of 74.5 miles of cast iron pipes. The tube basically complies with the specifications of the New England Water Association and has been tested in the factory. When testing the pipeline, for each straight seam measured on the inner circumference of the pipeline, one gallon of water leaked every 24 hours. The size of the pipe ranges from 20 inches in diameter to 8 inches in diameter, with an average diameter of 14 inches. The 8-inch pipe is only used for the wires from the main street to the fire hydrant. Except in some areas (the number is four), all pipes are bell-shaped and casing pipes. Some of the pipes are laid on the filled ground to play a greater role in the joints in the event of an earthquake or earthquake disaster. The role of. A ground double-plug pipe was laid in these areas, which was cut off from the pipe on the firm ground by a closed valve. One of the valves was open near the fire station, allowing access to the area.
Since San Francisco is mainly built on a series of hills, in order to account for the difference in elevation, people found it necessary to divide the system into two areas, called the “upper area” and the “lower area”. The upper area is the part above 150 feet in height, and the lower area is the part below 150 feet in height. The closed valve in the upper area is cut off from the lower area. Each area is supplied through a separate storage tank. A large reservoir, called Shuangfeng Reservoir, has been placed high and connected to the storage tanks in the upper area, lower area and upper area through the upper pipeline that leads directly to the reservoir. These pipelines usually pass through closed valves. shut down. If there is a big fire, or the pressure required by the fire is greater than the pressure provided by the height of the fuel tank, you can open it. Where pipelines cross each other at street intersections, four valves are placed, one on each property pipeline, so that any block can be cut off from the rest of the system in the event of an interruption.
There are 907 fire hydrants in the system, and each fire hydrant has 3 outlets with a diameter of 3 1/2 inches, of which two outlets are reduced to 3 inches in diameter. The average pressure at the fire hydrant in the upper area is 130 pounds. Per square inch, 143 pounds in the lower area. Per square inch.
The valve is a parallel face disc non-rising stem, bronze lining, and a diameter that is 2 inches smaller than any manifold with a size greater than 10 inches. The 16-inch and 18-inch valves have 3-inch and 4-inch bypass valves, respectively, and can be placed vertically or horizontally. The helmet and bypass valve required for the horizontal position are different from those for the vertical position. Place valves with a diameter of more than 10 inches in reinforced concrete manholes, install 8-inch and 10-inch valves underground, where 8-inch valves have 6-inch risers, and 10-inch valves are concrete cones Riser.
There is a storage reservoir with a capacity of 10,000,000 gallons on Twin Peaks. The water is 758 feet high. It has an oval shape with an axis of 375 feet and 280 feet. The side slope is two in the horizontal direction and one in the vertical direction, and the water depth is 25 feet. The sides and bottom are lined with reinforced concrete slabs, and there are expansion joints between each slab. It is divided into two equal compartments by a reinforced concrete partition wall, with strong supports on each side. Each bay has an independent front bay and gate compartment. The two front bays are connected by a 20-inch pipe with a gate at each end. The two lock chambers are connected by a 20-inch pipe, with a gate valve at each end. Each compartment has a 20-inch pipe leading from the pipe to the upper area storage tank and area. However, they are disconnected from the distribution system by shut-off valves in these 20-inch pipes and opened only in emergency situations. The storage tank is filled from the upper storage tank by two electric centrifugal pumps located in the upper storage tank, and each centrifugal pump has a capacity of 700 gallons per minute.
This is commonly called the Asbury Heights Tank and is located on Asbury Street between 17th and 18th Streets. It is a steel plate structure on a reinforced concrete foundation with a diameter of 55 feet, a height of 29 inches 1/2 inch, and a capacity of 500,000 gallons. The water elevation is 493.5 feet. Three 18-inch pipes lead from this pipe to the upper zone system and are filled under gravity through a 6-inch pipe connected to the Spring Valley Water Company’s Clarendon Heights storage tank. A reinforced concrete gatehouse is located in front of the water tank.
This is also known as the Jones Street Tank and is located between Jones Street, Sacramento and Clay Street. It is a reinforced concrete structure with a capacity of 750,000 gallons. The inner diameter is 60 feet and the height is 35 feet 10 inches. The water level is 369 feet.
The lower area is supplied from the water tank by two 18-inch pipes. If necessary, the water tank can be bypassed and the lower area can be provided from the upper area. The storage tank was filled by gravity through a 6-inch pipe leading from the Clay Street storage tank of the Spring Valley Water Company. A reinforced concrete concierge was connected to the water tank, and a fireman was present.
The station is located on Second Street and Townsend Street near the southern end of the distribution system and is designed to pump salt water from the bay into the system. The building is a reinforced concrete structure. Built on solid rock and designed to withstand earthquakes, it is said to be the strongest building in San Francisco.
It is equipped with four sets of multi-stage turbo pumps, which are directly connected to a 750-horsepower Curtis type horizontal non-condensing steam turbine. Each turbine has a guaranteed capacity of 2700 gallons and an actual capacity of 3,000 gallons of brine per minute. The head weighs 300 pounds. Per square inch. The pump is supplied through a reinforced concrete tunnel with a diameter of 6 feet, which starts from the bay. The suction port of the pump has a diameter of 12 inches and a head of 15 feet. They are discharged directly into the lower area system through two 20-inch pipes. There are a total of eight 350 HP Babcock & Wilcox boilers. These boilers are placed in four batteries, each of which consists of two boilers and is enclosed in an airtight enclosure of brick and steel. Each battery is connected to a separate reinforced concrete chimney, which is 68 inches in diameter and 90 feet above the cabin floor. These boilers are used to burn fuel oil, and there is an oil storage tank with a capacity of 2,000 barrels under the street outside the building.
The basement has been dug to an appropriate depth to provide six rectangular reinforced concrete water tanks that form the support of the boiler room floor and provide 1,000,000 gallons of fresh water for the boiler. The fresh water and grease storage provided is sufficient to run the entire workstation for 96 hours.
The station is located at Black Point in Fort Mason, at the northern end of the distribution system. The equipment is almost the same as that of the first station, except that a Stirling boiler is used instead of the Babcock & Wilcox boiler. Lead out two 20-inch pipes from the station, one leading to the upper area and one leading to the lower area.
The entire system is always kept full of fresh water under high pressure. In the event of a fire, engines, hose carts, hooks, ladders and water towers, all motor-driven equipment should answer the phone. The reason why the engine answers the call is due to the fact that the fire hydrants of the Spring Valley Water Company cover the area more completely than the fire hydrants of the high-pressure fire fighting system. Therefore, it is often found that using these low pressure hydrants is more convenient to use the fire hydrant and use the engine. Instead of clearing one block or more of the street and using high-pressure fire hydrants. The hose trolley in use is equipped with a monitor battery, so there is no need to use a battery trolley.
When using a high-pressure fire hydrant, first connect the pressure relief valve to an outlet of the fire hydrant. The valve is usually set to 120 pounds. Pressure, this will produce about 90 pounds of nozzle pressure. A hose with a length of 200 feet. A high-pressure fire hydrant will have more water under pressure than the three largest fire trucks in the city. This is achieved through the use of a pressure reducing valve, which has two outlets from each of the three fire hydrant outlets, and two hoses leading from it are provided with a conjoined connection, so that one fire hydrant 8 hoses were produced, 1 1/4 inches in diameter. The weight of the nozzle is 100 pounds. The nozzle pressure can get 2290 gallons per minute from the fire hydrant, compared to 2250 gallons per minute for three fire trucks.
In Pumping Station No. 1, one set of boilers is always kept under steam pressure, and the remaining boilers can be put into operation within 30 minutes. However, only in the event of a large fire or severe earthquake, followed by a large fire, should the brine in the pumping station or firefighting ship be used.
If a large fire occurs in the lower area, one or more gate valves can be opened to generate 214 pounds of pressure in the lower area, and the lower area system can be directly connected to the pipes in the upper area. Per square inch, or can be connected to the double peak reservoir in the same way, the peak pressure is 328 pounds. Per square inch in the lower area. The fire alarm box is located on the street, so that the personnel in command of the fire control can directly telegraph to the guards of the tanks and reservoirs.
When a small amount of water is drawn through fire connection A (for example, less water than a sprinkler needs), the water will flow through metered bypass B because the resistance of this path is less than the resistance of disc C of the alarm valve. E, the quantity will be recorded on the water meter D. However, as the flow through the system increases, the resistance in the bypass will become so great that it forces the water through the alarm valve. In this case, the valve flap in the alarm valve will rise, thereby opening the port G in the small tube H. An air chamber J is placed on the tube to take care of the water hammer and act as a reduction chamber to prevent false alarms. Then, the pipe H is connected to the recording pressure gauge K. When the valve clack on the alarm valve returns to the valve seat, the cock M keeps the partially closed exhaust pipe L releasing the pressure of the pipe H. Therefore, the recorder records the time when the water flows through the alarm valve. The small pipe N is led out from the pipe H, and is connected with a circuit breaker or a water motor. When the water in the pipe N rises, the circuit breaker or water motor will work, thereby issuing a fire alarm.
As mentioned earlier, the system has four parts built on the filled ground, and each part has an open valve. In the event of a severe earthquake, it is recommended to close these open valves. If there is a fire in the area, the fire truck will try to check through the fire water tank. This assumes that the domestic water supply system is out of service. Once the fire elsewhere in the city is extinguished, the firefighters who have been disbanded from the fire will turn their attention to the open space and will lead the long rows of hoses out of the fire hydrants and fire extinguishers on the adjacent solid ground. In order to extinguish the fires in these areas, fire boats are set up on the waterfront.
In order to provide fire protection services, a water supply system must be installed at Camp Sherman in Circleville, Ohio. Improvements will include laying additional power sources on each building and erecting vertical pipes with a water pressure of 90 pounds.
Post time: Apr-19-2021
