Dry Hydrant Fire Fighting Concept
A dry hydrant is a non-pressurized pipe permanently installed in existing lakes, ponds, or streams that provides a supply of water, by means of suction, to a tanker truck. The dry hydrant system concept includes not only the strategic location of the hydrant itself, but also the equipment and trained personnel to use it efficiently. All three of these components are essential for an effective dry hydrant system. The concept is not new. Many fire departments have successfully used dry hydrants for a number of years, but their use has not been widespread until recently.
In many rural areas, a lack of water and domestic fire hydrants can sometimes impair a fire department's ability to do its job quickly and efficiently. Tanker trucks must be used to carry large amounts of water to the fire scene. The success of the operation hinges on the distance the trucks must travel to water "fill-up" points around the country. Unfortunately, the fill-up points are often a long distance from the fire, and fire fighters are unable to retain an uninterrupted water supply at the scene in many cases.
Some counties have begun to take advantage of "natural water sources" for fire fighting. Most areas have a number of privately owned ponds, lakes, and streams that could be used, with permission, as fill-up points.
The installation of a non-pressurized pipe system into these water sources provides a ready means of a suction-supply of water to tank trucks. The dry hydrant system gives the pumping units access to ponds and streams from the main road. As in figure 1, one end of the dry hydrant sticks out of the ground to give tankers a hose connection, and the other end is a strainer submerged in the pond or stream to draw water directly through the system.
The dry hydrant can be made of any hard, permanent metal (steel, iron); however, polyvinyl chloride (PVC) is becoming commonly used due to price, accessibility, and low-friction performance. The other elements of the system include an intake strainer section, hydrant head with suction screen and cap. All component parts should be expertly engineered and built for trouble-free service.
NOTE: All references to tank truck in this publication means the same as tender or mobile water supply.
Benefits of Dry Hydrant System
A properly installed dry hydrant allows natural, unprocessed water to be used for road maintenance and fire protection. This allows small towns to better use its limited water supply for drinking water. A well planned and designed dry hydrant water delivery system can improve fire fighting capability of rural fire departments, save fuel and reduce the cost of operations.
An additional benefit to citizens where dry hydrants have been properly used is in the reduction of the fire classification for fire insurance. For example, when one county volunteer fire department, with proper training and equipment, used the dry hydrant water delivery system, county homeowners saw their insurance rates drop by 49 percent. For an $85,000 home, this means $200 savings per year on homeowner's insurance.
Improve Fire Protection
recommended distance between dry hydrants is one every 3 square miles.
This would ensure that fire tankers would travel no more than 1.5 miles
to a fill-up point. And since the fill-up through the system
usually takes about two minutes to complete, there could be an
uninterrupted water supply and better fire control.
Lower Insurance Rates
Fire insurance premiums for each area are based on classification by the Insurance Service Organization (ISO). The classification depends on each area's ability to fight fires.
Areas with no fire departments are given a Class 10 rating. As the fire-fighting capability increases, the rating decreases. This can be accomplished through higher training levels, better equipment, etc. If a fire department can demonstrate the ability to keep 250 gallons of water per minute, for two hours at a fire scene, the area's fire rating could potentially decrease to a six or a seven. The ISO, however, makes the final determination regarding the rate.
With a dry hydrant system, the goal can be easily achieved. A fire rating decrease from a nine to a seven can often reduce insurance rates by 45 to 50 percent.
Conserve Treated Water Supply
Dry hydrants are installed in untreated water supplies, which means that fire departments do not have to use the treated water from the towns in the county. As water becomes more scarce, the treated water would be available to the citizens for drinking.
Since tanker trucks have less travel time between fill-up points, the would save fuel. The overall operating costs of the fire department would be lessened by the use of dry hydrants.
Promote Economic Development
With lower insurance rates and higher fire fighting capability, the area would be more attractive to developer's and homeowners.
Improve Road Maintenance
A large amount of water is usually needed for the installation of the base on gravel roads. The water allows for better compacting of the road, which will often improve gas mileage for cars that travel on it.
A number of pre-planning activities should take place by local government or community fire departments as a prerequisite to the consideration of dry hydrants.
A master fire plan should be developed stating goals and objectives for rural fire protection. The plan should serve as the guide for organization, equipment, training, and water supply needs to reach the level of fire protection desired. Assistance in developing such a plan is available from the State Forestry Commission RFD coordinator.
Plans should include, but are not limited to:
Local county or city governments are encouraged to set up an organizational structure to allow community volunteer fire departments to work together to promote dry hydrants for maximum benefit. Ideally, the county/city government should have a full-time fire coordinator to work with volunteer fire districts implementing the goals and objectives of the master fire plan, including the implementation of the dry hydrant water delivery system.
Choosing Hydrant Locations
A rural fire department operating without a water system has two means of getting the necessary water. The department may obtain water supplies on the fire scene, which may be natural or constructed, or from water supplies transported to the scene. Dry hydrants should be strategically located in natural water sources at intervals necessary to supply adequate and reliable water supply all year. Natural bodies of water are defined as bodies of water contained by earth, and include ponds, lakes, rivers, streams, bays, creeks, springs, and irrigation canals. Constructed water sources include swimming pools, elevated gravity tanks, cisterns, wells, etc. The total water supply for suburban and rural fire-fighting from all sources should meet the minimum requirements as set forth in Chapter V of the National Fire Protection Association (NFPA) Standard 1231.
The fact that a water source is in sight of the main road does not assure that the water may be used for fire fighting purposes. Some circumstances necessitate developing alternative approaches and accessibility for fire vehicles. It is advisable to consult highway officials, particularly if on State roads, to determine requirements for parking on roadways or bridges for fire operations. In some states, a fire department is not allowed to use a bridge or a roadway to park a fire unit while it is being filled.
It is also advisable to become familiar with road conditions and ratings of existing bridges in the area. The county or State road department will have this information.
Using a county road map, mark the good sites (Rating of "1" and "2" on the map). A study of the Master Fire Plan for the county and the aforementioned map showing possible dry hydrant sites will assist county planners in selecting strategic hydrant sites for water supply.
Past experience has shown that dry hydrants should be placed at an interval of one in every 3 square miles. This spacing would require tankers to travel approximately 3 miles round trip to any location. The following formula can be used to plan water availability at any point in the area. To be recognized as ISO Class 8 or better, you must be able to deliver at least 250 gallons per minute (gal/min) for a 2-hour period.
After the locations have been mapped, it is time to check them out in the field. During the field inspection, the following items should be evaluated.
Water Usage Easements
Should the proposed site retain a rating of "1" or "2" after a field inspection, the fire department water supply officer, fire chief, or other county official should contact the legal property owner and secure permission to use the water source. Such permission should be given in writing in close cooperation with the municipal town or county attorney. It is recommended that the easement be reviewed by a representative of the highway or county road department or others who will be required to build, service, and maintain access roads and areas adjacent to hydrants.
The property owner should have a copy of the agreement. It is highly recommended that a copy be on file in the official records of the county or city.
Dry Hydrant Design and Survey
The survey notes and design of each hydrant site should be maintained and kept in an official record. An example of one such record is shown in Figure 5. Such a record provides valuable information needed for future certification.
Assistance may be available from the local Soil Conservation Service office and/or local State forestry agencies to make the survey and design. The SCS office will prepare the design as outlined in its Dry Hydrant Technical Guide and Engineer Manual. In most cases, SCS will have a certified engineer sign the design. This will facilitate the certification of the hydrant by ISO.
Testing and Maintenance of Dry Hydrants
Dry hydrants require periodic checking, testing, and maintenance. This should be done semi-annually. Checking and testing by actual drafting should be a part of the fire department training and drills. Thorough surveys should reveal any deterioration in the water supply in ponds, streams, and cisterns.
Particular attention should be given to streams and ponds. Frequent cleaning may be needed to remove debris, dredging or excavation of silt, and protection from erosion. The hydrants should be tested at least once a year with a pumper. Back flushing, followed by a pumper test at a maximum designed flow rate, with records kept of each test, is desired. Tests of this kind will not only verify proper condition, but also keep the line and strainer clean of silt, and the water supply available for any fire emergency.
The pond should be free of aquatic growth. It may be necessary to drain the pond to control this growth. Consult the Cooperative Extension Service or USDA (Natural Resources Conservation Service) office for assistance in weed control.
Inspections should include safety procedures such as posting warning signs and seeing that life preservers, ropes, etc. are available. Give particular attention to local authority regulation governing such water points.
It is important to consider appearance of this water point. Keep grass trimmed and neat. The cap should be painted a reflective color to improve visibility during emergencies.
The facilities require periodic checking, testing, and maintenance semi-annually. Checking and testing by actual drafting should be a part of the fire department training and drills. Thorough surveys should reveal any deterioration in the water supply in ponds, streams, or cisterns.
A record of inspection should be maintained for each hydrant by the Responding Fire Department.
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