.png)
Technical Specifications of a Fire Hydrant
The following information provides technical specifications of a fire hydrant. You may find these specifications useful if you plan to purchase a fire hydrant for use at home.
Fire hydrants are a type of water supply system used to provide firefighters and emergency personnel with a reliable source of water. These devices were designed to prevent the spread of fires from homes and buildings to public places, and protect property from damage caused by fires.
Hydrants are installed under ground near a street, and allow the flow of water through them. They are connected to a network of pipes called mains. Once the necessary components are provided, installing a fire hydrant requires only minor set-up work. A fire hydrant should be inspected regularly to ensure proper operation.
A typical fire hydrant consists of four main parts: the body, nozzle, regulator, and pressure gauge.
• The Body of a hydrant typically contains four to six inches of steel pipe attached to a smaller diameter (approximately 1/8 inch) metal rod. This rod attaches directly to a larger diameter (approximately 2 inches) iron tube. The iron tube connects to the main line. This connection is referred to as the trap. When a hydrant is turned on, the water flows through the trap, into the interior of the body where it passes through the internal passages of the body before exiting out the nozzle.
• The Nozzle serves to direct the flow of water. Usually, nozzles have three openings: two outlets and one inlet. Inlets are used to fill the tank, while outlets are used to release the water.
• The Regulator regulates the pressure of the water flowing through the outlet. Typically, regulators control both the volume of water passing through them, and the rate at which this volume is released. There are many different types of regulators. One common type is a lever-operated ball valve. Other types of valves regulate water pressure based on the level of pressure inside the pipe.
• The Pressure Gauge measures the pressure of the water leaving the hydrant.
The pressure gauge should read approximately 15 PSI. If the reading exceeds 20 PSI, then the hydrant is likely leaking. If the reading falls below 10 PSI, then the water is not flowing properly.
The pressure of the water is measured in Pounds per Square Inch (PSI). To convert PSI to pounds, multiply PSI by 0.0046 psi. For example, 30 PSI equals 14.8 lbs/in^2.
To determine how much water a hydrant will produce, first calculate the flow using the formula Q VT/P, where Q is the flow in gallons per minute, V is the volume of the hydrant, T is the time period over which the flow occurs, and P is the pressure of the water in PSI (pounds per square inches). Then add the total quantity of water produced by all outlets of the hydrant.
For instance, a 6-inch x 4-foot hydrant produces about 120 gallons of water per hour, and each outlet discharges 5 gallons per hour. Therefore, the total output of the hydrant is 960 gallons per hour (120 + 75), or 100 gallons per minute. Multiply the total production by 0.05 (which represents the amount of water discharged per minute from each outlet), and divide the result by 60 (minutes per hour), resulting in 95 gallons per minute (100 x.050 / 60).
In addition to its function as a water supply device, a fire hydrant can serve another purpose. Many fire departments require certain fire hydrants to double as emergency warning systems. Such devices are known as “hydrant alarms.” Using a hydrant alarm is simple; simply turn on the hydrant whenever there is a need to notify others of potential danger. As long as the hydrant remains open, the alarm will activate until the hydrant is shut off.
To determine whether a particular hydrant is equipped with an alarm, look for a small tab on the side of the body. If present, then the hydrant does indeed have an alarm associated with it.
1. Pressure Rating
Hydrants are rated by their pressure rating. The higher the number, the stronger and safer the hydrant. A good rule of thumb is to choose a fire hydrant with a rating between 0-2400 psi (that's about 13-100 atmospheres). Most cities require at least a 600 psi (40 atmospheres) hydrant.
2. Size
The size of the hydrant should be based on the area where the hydrant will be installed. The larger the area, the bigger the pipe. Bigger pipes mean less water flow, so make sure the hydrant you buy fits the amount of water you need. You may have to purchase two smaller hydrants if you want enough water.
3. Pipe Shape
Pipe shape refers to how round the pipe is. Rounder pipes will allow the water to travel further before hitting any obstacles. Square and rectangular pipes will cause the water to hit harder against the side of the pipe, causing the water to bounce back and forth and possibly even shoot out of the pipe.
4. Flow Rate
Flow rate refers to the speed of the water. High flow rate means more water per second, while low flow rate means less water per second. Low flow rates work well for small gardens where you don't need as much water, while high flow rates are ideal for larger projects.
5. Pressure Relief Valve
A pressure relief valve allows the hydrant to release excess pressure build up. If it fails, it could potentially damage the structure surrounding the hydrant. The pressure relief valve should be placed above ground level (at least 6 inches), preferably near the top of the hydrant, and accessible to you.
6. Ease of Installation
Ease of installation refers to whether the hydrant comes preassembled or requires some type of assembly. Preassembled hydrants are easier to install since they do not require any extra tools. On the downside, they are generally more expensive than those requiring assembly.
The specifications listed below are only a basic summary of what would normally appear on a fire hydrant. Please refer to your local municipal authority for specific information about any fire hydrants that may be installed near your home.
1. Size
Fire hydrants range in size from 50 mm (2 inches) to 200 mm (8 inches). Most hydrants have a diameter between 100 mm (4 inches) and 150 mm (6 inches), but larger sizes are sometimes used. Fire hydrants must be designed to withstand the pressure of water at a minimum distance of 30 m (100 ft).
2. Construction
The construction of fire hydrants should be resistant to corrosion and extreme temperatures, and the materials used should not produce any hazardous fumes or gases. The fittings used in installation should be tight-fitting and easily accessible.
3. Drip Height
Drip heights vary depending on the type of pipe being used. A standard drop height for copper piping is 12 cm (4 inches), while plastic piping requires 13 cm (5 inches). PVC pipes require 15 cm (6 inches) of drop height.
4. Flow Rate
The maximum flow rate allowed for a hose connection is 45 liters per minute (10 gallons per minute). No hose connections should exceed this limit. However, some municipalities may allow higher flow rates.
5. Pressure Rating
Most fire hydrants have a pressure rating of 1.5 bar (20 psi). Higher pressures are possible if necessary. These ratings are based on the design of the nozzle and its dimensions.
6. Weight
Nozzle weights can range from 8 kg (17 pounds) to 20 kg (44 pounds). Heavy nozzles are recommended for use in high-rise buildings to prevent them from becoming dislodged in the event of severe weather conditions.
A fire hydrants is a piece of equipment used to supply water to firefighting apparatus. Water pressure may vary greatly depending on where the hydrants are placed. A fire-rescue squad may use several hydrants at different locations while a single fire truck may have only one or two hydrants. In some cases, a fire department may need to supplement its fire trucks' supply of water by using hydrants.
The following information explains the technical specifications of a standard fire hydrant.
• The height of the nozzle opening ranges from 4.8 to 6 inches (12 to 15 cm).
• The length of the nozzle varies but is generally about 12 feet (about 3 meters) long.
• The diameter of the top of the pipe is about 2.75 inches (70 mm).
• There are normally two valves located near the bottom of the pipe for shutting off flow to the nozzle. These valves are called check valves and they allow the trapped air inside the pipe to escape before flowing out.
• The diameter at the bottom of the pipe is usually between 1 inch and 1.25 inches (22 to 31 mm), which makes it easier to pour concrete around the base of the pipe.
• Depending on the location of the hydrant, the pipe may be buried underground or above ground. If it's above the ground, the pipe may be completely enclosed in concrete.
• The pressure of the pipe is normally equalized by running electrical wires along the length of the pipe.
Hydrants tend to use much less water than sprinklers and therefore are preferred in places where water conservation is a concern. However, if the cost of installing hydrants is too high compared to the cost of sprinkler systems, then sprinklers are sometimes installed instead of hydrants.
Access all the previous parts of this full fire fighting series by clicking the links provided below:
.png)
.png&description=Full Fire Fighting & Fire Protection Course - (Part 14)){kind=link}
0 Comments
If you have any doubts, please let me know