BY JOHN MITTENDORF
When considering the subject of con-trolling utilities, particularly at an incident when time is of the essence, electrical and gas utilities are typically at the top of everyone’s priority list. However, the control of water can suddenly become extremely popular when there is a noteworthy water leak inside or outside of a structure.
Similar to air, water is one of the most abundant substances on earth and is also one of the most important elements necessary to sustain life. Water is comprised of two atoms of hydrogen and one atom of oxygen, hence the chemical name and symbol of dihydrogen monoxide and H2O. Although water covers about two-thirds of the earth’s surface, it is still necessary to deliver water to residential, commercial, and industrial customers to sustain the common necessities of life. Unfortunately, the presence of calamities such as earthquakes, tornadoes, fires, building collapses, and common problems such as broken water pipes and activated sprinklers often result in the need to quickly control the flow of water to minimize unnecessary damage to life and property. The action of fire service personnel is often needed to abate the hazard of uncontrolled flow in a timely and professional manner (photo 1).
|(1) The uncontrolled flow of water can be problematic. (Photos by author.)|
Water is a liquid that descends from the clouds as rain and forms streams, lakes, and seas. As water is the lifeblood of every community, it is necessary to supply water for domestic usage and fire protection considerations. This is accomplished through a combination of supply systems and distribution systems.
Gravity. Gravity systems use a source of water (such as lakes and reservoirs) that is higher than a municipality. The pressure of the water delivered into a distribution system within a municipality is determined by the elevation of the water source above a municipality. As an example, a height of 100 feet will create a pressure of 43 pounds per square inch (psi) (.433 psi per foot of elevation × 100 feet = 43 psi).
Pump. When a source of water is below or at the same elevation as a municipality or cannot naturally provide sufficient pressure through adequate elevation, pumps are used to supply water at the proper pressure into a distribution system within a municipality.
Combination. Water is initially supplied into a distribution system by a combination of pumps and/or gravity. Reservoirs or elevated tanks are at strategic locations within a system to provide a source of reserve water if necessary. As water demands vary with the time of day and changing weather conditions, a sufficient flow of water at adequate pressure under varying conditions necessitates the storage of water. Municipalities can use large open reservoirs or steel or concrete storage tanks (photo 2) of 10,000 to 10 million gallons.
|(2) Municipalities can use large, elevated storage tanks to supply water.|
Water is delivered throughout municipalities by a distribution system of pipes, valves, check valves, and water meters that are normally cross-connected at specific intervals to supply water to areas that can be affected by repairs, breakage, and other similar problems. Pipes within a distribution system can be classified as follows:
Trunk lines. These lines carry water from a primary source (reservoirs, pumps, for example) to mains within a distribution system. Trunk lines can vary from 36 inches to 10 feet and are constructed from iron or concrete.
Mains. Mains, which normally run beneath a street and parallel to a curb, can vary from two to 72 inches in size and are constructed from iron pipe or plastic. Mains can be cross-connected to form loops that allow shutting down a specific main within a distribution system for repairs and other reasons.
Service and customer lines (Figure 1). Water is delivered to individual structures by a combination of service and customer lines. A service line runs between a main and a water meter; can vary from ½ inch to 12 inches; and is constructed from iron, copper, or galvanized pipe. A customer line runs between a water meter and a structure; can also vary from ½ inch to 12 inches; and is constructed from iron, copper, and galvanized or plastic pipe. Water utility companies are normally responsible for the maintenance and repair of a water distribution system and service lines, including the water-metering device and the shutoff valve on the supply side of a water-metering device.
|Figure 1. Water Delivery System|
|Water is delivered to customers through a combination of service and customer lines, valves, and a meter.|
Building owners are normally responsible for the maintenance and repair of plumbing from the shutoff valve (on the output side of a water-metering device) and into a structure and all plumbing inside a structure.
The type and size of water service to a structure are determined by a combination of applicable plumbing code requirements and water consumption needs that result in the following types of water service configurations:
- Domestic water only.
- Domestic water and water for fire protection through a single service.
- Domestic water and water for fire protection through separate services.
Water service systems are comprised of the following components:
Meter box. A meter box, vault, or manhole cover provides access to water meters and shutoff valves. A meter box, vault, or manhole often has a centerpiece or lid with a hole that can be used to remove the cover (photo 3). The centerpiece or lid normally identifies the type of utility with the word(s) “WATER” or “CITY WATER METER” and is often marked with blue paint.
|(3) A meter box provides access to water meters and shutoff valves.|
Shutoff valves. These valves (service valves, curb valves) provide a means for controlling the flow of water through service and customer lines, which may include shutting off the flow of water to repair a service or customer line or a water meter or to abate an unwanted water-flow problem. Two types of shutoff valves are commonly used: nonindicating and indicating.
Nonindicating valves. These valves do not indicate an open or closed position and are characterized by the following:
- —A ball or cone valve (photo 4). This valve has a rectangular valve-nut attachment on the top of the valve. When the valve is fully open and the valve nut is turned perpendicular to the valve, a ball or cone rotates 90° to the closed position.
(4) Ball and cone valves have a rectangular valve nut on top. The valve nut is turned 90° to stop the flow.
- —A gate valve. This is a nonrising stem valve that has a square valve-nut attachment at the top of the valve stem (photo 5). When the valve is fully open and normally turned clockwise (some valves are turned counterclockwise), a gate lowers to the closed position.
(5) Gate valves are nonrising stem valves. Turn the stem clockwise to stop the flow..
- —A ball or cone valve (photo 4). This valve has a rectangular valve-nut attachment on the top of the valve. When the valve is fully open and the valve nut is turned perpendicular to the valve, a ball or cone rotates 90° to the closed position.
- Indicating valves. These valves indicate the position of a valve (open or closed) and are characterized by outside stem and yoke (OS&Y) valves (rising stem-type valves) and post indicator valves (photo 6). Post indicator valves are connected to an underground gate valve.
|(6) Post indicator valves are connected to an underground gate valve and are indicating-type valves.|
WATER METERS AND DETECTOR CHECK VALVES
Water meters are used to calculate water usage, and check valves are used to allow the flow of water in one direction only. The type of meter or check valve depends on the type of water services as follows:
Water meter (photo 7). Used to calculate water usage for a domestic water service. Water meters are normally directly adjacent to shutoff valves and vary in size from ½ inch to 10 inches (inlet-outlet size).
(7) Water meters of various sizes are used to measure domestic water use.
Compound meter. Used to calculate water usage for domestic water services that can use low- and high-water flows (photo 8). During low-water flows, a compound meter operates as a standard water meter. However, if high flows are necessary, a check valve opens and allows large flows, which are metered separately, to pass. Compound meters are four inches or larger (inlet-outlet size) and are normally directly adjacent to shutoff valves.
(8) Compound meters are used for domestic water services that can use low- and high-water flows.
- Detector check valve with bypass meter. Used to supply water for a closed fire protection system (photo 9). When necessary, a check valve opens and allows water to flow straight through, unmetered.
|(9) Detector check valves flow water in one direction only and are commonly used in fire protection systems to prevent water from flowing back into the distribution system. Most are also equipped with a small bypass meter to detect unauthorized use and the presence of leaks.|
In the closed position, a check valve prevents water from flowing back into a water distribution system (i.e., from fire department apparatus pumping into standpipe inlets and potentially contaminating the system). Most detector check valves will use a small water meter in parallel with the check valve(s) (visible in the bottom of photo 9) to detect leaks and the unauthorized use of water. Detector check valves can vary from two to 10 inches in inlet-outlet size.
- Factory Mutual (FM) meter. A high-flow meter that provides water for fire protection purposes, it can vary in size from four to 10 inches. A domestic water service may be in the same vault as an FM meter.
- Combination water service. A domestic water meter and detector check valve are used for providing separate water services (photo 10). A water meter and detector check valve may be in the same area or vault or separated in an adjacent area or vaults.
|(10) A combination service provides water through a meter for domestic use and water through a detector check valve for fire protection.|
Pressure-reducing valves (photo 11) are normally used in domestic services to reduce high water pressures to an acceptable working pressure inside a structure (i.e., dwellings commonly use 40 to 80 psi). These valves are not normally used in fire protection services.
|(11) Pressure-reducing valves reduce high water pressure in domestic systems to acceptable working levels.|
Although a typical domestic water service normally consists of piping, a water meter, shutoff valve(s), and a pressure-reducing valve, and a typical fire protection service normally consists of piping, detector check valves, and shutoff valves, the order in which the water system components are positioned in a main and structure can vary depending on the municipality. Additionally, the location of water system components also depends on climate as follows:
- In cold climates, water meters, pressure-reducing valves, detector check valves, and shutoff valves may be below the frost line or in the basement of a structure.
- In warm climates, water meters can be placed just below grade level, and pressure-reducing valves, shutoff valves, and detector check valves can be above or below grade level.
STRUCTURAL WATER SERVICE SYSTEMS
An overview of common structural water service systems follows.
Domestic water services will normally consist of a ½- to two-inch single water meter with a shutoff valve on one or both sides of a meter. A customer line runs underground from the meter to a riser that enters a structure on the exterior or in a basement. A pressure-reducing valve can be near the meter or structure. Water service for a domestic sprinkler system is dependent on the size of the sprinkler system. Small systems are serviced by the domestic system, and larger systems may consist of up to a two-inch detector check valve in a separate vault.
Domestic water service will normally consist of one-inch to three-inch customer lines and a single one-inch to three-inch water meter with a shutoff valve on one or both sides of a meter. Similar to single-family dwellings, and depending on water requirements, a customer line runs underground from a water meter to a riser that enters a structure on the exterior or interior. A pressure-reducing valve can be near the water meter or structure. Water service for fire protection will vary between two to four inches. The water services for domestic water and fire protection are in separate belowground or aboveground vaults. A common alternative to a single one- to three-inch water meter is a three-inch equivalent water service (photo 12). This system consists of two two-inch water meters in adjacent vaults connected to a single three-inch customer line that enters a structure on the exterior or basement. In this configuration, the pressure-reducing valve is near the structure.
|(12) An equivalent service uses two water meters connected to a single three-inch customer line.|
A combination water service provides water for domestic and fire protection services. Domestic water uses a four- to six-inch water meter, and water for fire protection uses a four- to eight-inch detector check valve. Shutoff valves are normally adjacent to the water meter and detector check valves; a post indicator valve is normally present between the detector check valves and the structure. The water meter and detector check valves can be in the same vault, in separate vaults, or above ground.
Water services to these types of structures are not primarily based on the size of a structure but will depend on the water requirements of a structure. As an example, a large warehouse with a small office area and large storage area can have a large (four- to 10-inch) water service for fire protection and a small (one- to two-inch) water service for a domestic water system. Conversely, a moderate size commercial occupancy can have a two- to four-inch service for fire protection and a large (four- to eight-inch) domestic water service for specific requirements. Common applications are as follows:
- One- to two-inch water meter for domestic water service and two- to four-inch detector check valves for fire protection in separate vaults. Shutoff valves are normally adjacent to a water meter and detector check valves, and a post indicator valve should be present between the detector check valves and the structure.
- Combination water service with a four- to eight-inch water meter for domestic water service and four- to 10-inch detector check valves for fire protection in the same vault. This configuration is used for large water volumes. Shutoff valves are normally adjacent to a water meter and detector check valves, and a post indicator valve should be present between the detector check valves and the structure.
- A commercial occupancy with multiple occupancies (such as a mini-mall) can be serviced with water for a domestic water service by multiple, single one- to two-inch water meters in separate vaults, which can supply each individual occupancy (referred to as a battery, photo 13), or a single water meter for an entire building. Shutoff valves are normally adjacent to water meters in separate vaults or a single meter that serves an entire building. Water for fire protection can be provided by detector check valves in a separate vault or a separate or common vault with a water meter that serves an entire building. Shutoff valves are normally adjacent to detector check valves, and a post indicator valve may be present between the detector check valves and the structure.
|(13) Structures that use multiple water meters normally have a battery of vaults in front of the structure.|
Domestic water and fire protection service are provided by a combination water service that consists of a four- to 10-inch water meter for domestic water and four- to 12-inch detector check valves for fire protection in the same vault. Aboveground risers may be present for domestic and fire protection services. Shutoff valves are normally adjacent to water meters and detector check valves in this type of configuration, and a post indicator valve is normally present between the detector check valves and the structure.
STRUCTURAL FIRE PROTECTION SYSTEMS
An overview of common structural fire protection systems follows.
- Automatic wet pipe system. The pipes in this system are filled with water at all times. When a head is activated, water immediately flows from activated heads. Water is supplied to this system by a gravity tank, pressure tank, automatic fire pump, or water service system.
- Automatic dry pipe system. The pipes are filled with compressed air. When a head is activated, air is immediately released from activated heads. This causes a drop in air pressure, which allows water to enter the system and flow from activated heads. Water is supplied to this system by a gravity tank, a pressure tank, an automatic fire pump, or a water service system.
- Nonautomatic system. Pipes are maintained dry. To charge this system with water, it is necessary for fire department apparatus to pump into fire department siamese connections to supply water to activated heads.
Deluge system. Sprinkler heads are typically open and are supplied with water by a heat-actuated valve. Water is supplied to this system by a gravity tank, a pressure tank, an automatic fire pump, or a water service system. Depending on the type of sprinkler system and source of water, shutoff valves are normally located as follows:
- —Post indicator valves are between a main and sprinkler system within a structure.
- —OS&Y valves are near a sprinkler alarm system. This includes wall-indicating valves (photo 14). Shutoff valves are near the outlet for a gravity tank, pressure tank, fire pump, or detector check valves.
|(14) Wall-indicating valves are mounted on an exterior wall and indicate the closed or open position of the valve.|
- Dry standpipe. Dry standpipes are not directly connected to a water supply and consist of a siamese connection, piping, and 2½-inch outlets on each floor (stairway and fire escape balcony) and roof. Fire apparatus must supply water to this system. Be aware that the inlets to these systems can be blocked with debris that has been inserted by pranksters.
- Wet standpipe (Class II). Wet standpipes are directly connected to a water supply, are primarily designed for occupant use, and commonly consist of 100 feet of 1½-inch unlined single jacket hose, a ½-inch straight tip, and a shutoff. Water is supplied by a water service system, gravity, a pressure tank, or a combination standpipe system.
- Combination standpipe (Class III). Combination standpipes are directly connected to a water supply and are equipped with 1½-inch outlets with hose and nozzle (primarily intended for occupant use) and 2½-inch outlets for use by fire department personnel. Water is supplied by a water service system, gravity, a pressure tank, or a combination of these systems.
Combined sprinkler-standpipe system. A sprinkler system is connected to a combination standpipe system. Depending on the type of standpipe system and source of water, shutoff valves are normally located as follows:
- —Post indicator valves are between a main and a sprinkler system within a structure.
- —OS&Y valves are near a sprinkler alarm system. Shutoff valves are near the outlet for a gravity tank, a pressure tank, a fire pump, or detector check valves.
TURNING OFF WATER
You can stop the uncontrolled flow of water in a timely manner only by consistently achieving a combination of prefire planning and training that can provide the knowledge to quickly locate and identify a water source that needs to be eliminated. To increase the effectiveness of this operation in concert with the type of leak encountered, consider the following:
- For leaks outside a structure, use multiple personnel to locate the appropriate shutoff location (one person may not find the correct location in the least amount of time).
- When encountering a leak outside a structure, determine if the leak is from the domestic or fire protection service. Domestic water services have a water meter for calculating water usage and a pressure-reducing valve for reducing the water pressure; fire protection services do not.
- For leaks inside a structure, use multiple personnel to simultaneously investigate the interior and exterior of a structure to locate the most appropriate shutoff location. This approach will enhance the ability of personnel to locate the appropriate shutoff location in a timely manner.
- When encountering a leak inside a structure, determine if the leak is from the domestic or fire protection service. Next, if a leak is from a domestic service, determine if it consists of hot or cold water. Hot water leaks can normally be quickly turned off at a water heater (or boiler); cold water leaks may need to be turned off at the source or outside a structure. Finally, determine if a leak can cause or contribute to structural instability (potential collapse) because of the weight of water-soaked materials (building materials and contents).
- Occasionally, you may encounter a shutoff valve with a sign (photo 15) as follows: “LIFE SUPPORT MACHINE IN AREA” or “SHUT GATE SYSTEM DIVIDE.” Do not turn these valves off unless you obtain appropriate approval.
- When closing ball, cone, or gate valves that are three inches or larger, you may have to exercise a valve to completely eliminate the flow of water, as valves can become encrusted with rust and scale. Therefore, it is often necessary to open and close a valve several times to loosen any encrustation and allow a valve to fully seat.
- Occasionally, encrustation may make it difficult to close a ball or cone valve. Forcing a stubborn ball valve can break the rectangular valve-nut attachment on the top of a valve, making it impossible to close. If you encounter a stubborn cone valve, slightly loosen the nut on the bottom of the valve (if accessible) and strike the threaded shaft with a hammer. This will drive the shaft into the valve and free the valve. The valve may now be shut. Ball and cone valves can be identified by the lack or presence of a nut on the bottom of a valve. Ball valves do not have a nut on the bottom of a valve; cone valves do.
(15) If a shutoff valve has a sign that reads, “Life support machine in area” or “Shut gate system divide,” do not turn it off.
- Slowly close and open all shutoff valves to avoid water hammer and potential damage.
- Ball, cone, and gate valves two inches or larger necessitate specific tools (photo 16) to provide the necessary leverage to close these valves.
|(16) Valves larger than two inches require specific tools to provide the proper leverage necessary to close them.|
WATER SERVICES OUTSIDE OF STRUCTURES
Utility company personnel normally shut off water leaks outside of structures in mains and service lines. Fire service personnel can usually handle leaks in customer lines (between a water meter-detector check valve and the structure) as follows:
Domestic Water Services
• ¾- to one-inch service
A shutoff valve (ball or cone valve) is normally adjacent to a water meter and may be above ground or underground. If the valve is underground and not in a meter box, it may be necessary to dig down outside a meter box to access the valve. Turning these valves 90° will eliminate the flow of water. If a valve has an arrow on the valve nut, the valve nut must be turned 180° so the arrow is pointing in the opposite direction. In cold climates, a round metal lid is normally located between the street and the structure (normally by a parkway, sidewalk, or so on). Removing this lid will allow access to the shutoff valve below the frost line.
• One- to three-inch equivalent service
A shutoff valve (ball or cone valve) is normally on both sides of a water meter on equivalent services. Remove both vault covers to access the meters-valves. Shut off a valve in both vaults to completely eliminate the flow of water past this service configuration.
• Four-inch and larger services
Gate and OS&Y valves are located on both sides of a water meter. When closing these valves, remember that it may be necessary to exercise a valve to completely eliminate the flow of water. Large aboveground or underground installations may consist of back flow valves that are in line with the water meter and multiple OS&Y or gate valves. Because of the size of these water services and the possibility of damage to building heating, cooling, and other similar systems, personnel should not close these valves unless absolutely necessary. Normally, the appropriate water utility company should be requested to handle these systems.
Fire Protection Services
• Two-inch services
A shutoff valve (ball or cone valve) is normally adjacent to a detector check valve. Turning this valve 90° will eliminate the flow of water past this service.
• Four-inch and larger services
Indicating valves (post indicator valve) can be used to eliminate the flow of water past these valves. Post indicator valves are outside of structures, are connected to an underground gate valve, and have a handle or wrench to operate the valve.
To operate a post indicator valve, do the following:
- —Remove any padlocks or chains securing the control valve.
- —Turn the valve in a clockwise direction to close the valve. The valve will visually indicate the position of the valve by an arrow or display that states “OPEN” or “CLOSED.”
- —Shutoff valves (gate and OS&Y valves) normally directly adjacent to detector check valves on four-inch and larger fire services (photo 17) are not normally used to eliminate the flow of water past these valves. However, if necessary, turn a gate valve clockwise to stop the flow of water past this service. Remember to turn OS&Y valves (photo 18) counterclockwise (so the stem is visible) to allow the flow of water.
|(17) If necessary, turn these gate valves clockwise to stop the flow of water to a fire protection system.|
|(18) Turn OS&Y valves counterclockwise so the stem is visible to allow the flow of water.|
• Fire hydrants
You can normally shut off water to a sheared fire hydrant by locating the gate valve cover between the hydrant and the center of the street. Removing the gate cover will provide access to the gate valve that controls the water from the main to a hydrant. Use an appropriate tool to close the gate valve. Remember that these valves may have right- or left-hand threads and it is easy to shear valve stems.
WATER SERVICES INSIDE OF STRUCTURES
Determine if an interior leak can be most effectively eliminated inside or outside a structure. Shut off water leaks inside of structures as follows:
Domestic Water Service
• Exterior operations
Depending on the type of leak, closing accessible shutoff valves near a water meter (or the globe valve that can normally be found on the vertical riser that enters a structure in warm climates, as in photo 19) will quickly eliminate the water service to the interior of a structure until an interior leak is located and repaired.
|(19) Globe valves on vertical risers can be easily accessible and can be used to stop the flow of water into a structure.|
• Interior operations
Common sources for cold water leaks are the following:
- —Broken pipes in walls normally require shutting off the flow of water to a structure using exterior shutoff valves near a water meter, and so on.
- —Toilets are found in two configurations: residential and commercial. Easily eliminate leaks from residential toilets by shutting off the angle valve at the wall near the toilet. In these applications, plastic tubing has replaced metal tubing and is more susceptible to splitting because of hardening. Eliminate leaks from commercial toilets by removing a cap over the relief valve (photo 20) and using a slot-head screwdriver to turn the relief valve screw inward or outward. This should let the valve seat and stop the flow of water to the toilet.
(20) To stop the flow of water from a commercial toilet, remove the relief valve cap and turn the screw in or out to free the valve.
- —Eliminate leaks from commercial urinals by removing a cap over the relief valve and using a slot-head screwdriver to turn the relief valve screw inward or outward.
—Eliminate leaks from sinks and other types of residential appliances normally by shutting off the angle valve(s) at the wall near the sink or appliance.
- —Leaks from a manufacturing process that uses water will often have readily available shutoff valves near the process. If these types of valves are not readily found, using exterior shutoff valves may be necessary to eliminate the flow of water.
- —Elminate hot water leaks normally by shutting off the appropriate valve at a water heater or boiler. However, remember to shut off the gas or electricity to the heater to prevent a possible rupture because of expanding water in the heater.
Fire Protection Service
Exterior Operations. Depending on the type of fire protection system and the location of the leak, closing the following valves will eliminate the flow of water past a valve (and normally stop a leak between a valve and the structure) and to a fire protection system inside a structure:
- —Post indicator valve. Use the attached handle to turn the valve until the word “CLOSED” appears in the window on the post.
- —Gate valves. Remember, it may be necessary to exercise these valves to completely eliminate the flow of water.
- —OS&Y valves (photo 21). Similar to gate valves, it may be necessary to exercise these valves. Closing an OS&Y valve that is near a sprinkler-alarm mechanism will eliminate the flow of water to a sprinkler system. However, once a valve has been closed, open the drain valve to drain residual water in the system, as this amount of water can be noteworthy.
(21) Common on sprinkler systems, OS&Y valves are turned clockwise to close.
• Interior Operations
- —Broken pipes. Use exterior shutoff valves (post indicator valves, OS&Y, and so on).
- —Sprinklers. Use appropriate sprinkler shutoff tools and/or replace fused sprinkler heads.
NATIONAL COLOR CODE
(22) A national color code can be used to enhance the quick identification of utilities.
A national color code (photo 22) has been adopted that significantly enhances the identification of utilities as follows:
• Green—Sewers and drains.
Battery: Multiple water meters used for multiple units within a single structure can be in separate vaults (normally in front of the structure).
Combination system: Water is delivered to a municipality through a combination of pumps and/or gravity.
Combination water service: A domestic water meter and detector check valve providing separate services to a structure.
Compound meter: Used to calculate water usage for a domestic service that can have both high and low demand.
Customer line: Connects a water meter and a structure.
Detector check valve: Used in a closed fire protection system. Detector check valves allow water to flow in one direction only and do not meter the usage.
Equivalent service: Twin two-inch water meters connected to a single three-inch customer line.
Exercise a valve: When closing a valve of three inches or larger, it may be necessary to open and close it several times to loosen any encrustation and allow the valve to seat fully.
Factory Mutual (FM) meter: A high-flow meter that provides water for fire protection purposes.
Fire protection system: Common systems are comprised of a sprinkler system, standpipe system, or combination of both.
Gravity system: Entails a water source that is higher than a given municipality, developing water pressure through elevation.
Indicating valve: They indicate open and closed positions. Examples are OS&Y valves, post indicator valves, and wall-indicator valves.
Location: The location of water system components generally depends on climate. In cold climates, the components will be placed below the frost line. In warm climates, the components can be placed below or above ground.
Mains: Lines that normally run beneath a street and are anywhere from two inches to 72 inches in diameter.
Nonindicating valve: These valves do not indicate an open or a closed position. Examples are gate valves and ball-and-cone valves.
Pressure-reducing valve: Normally used in domestic services to reduce high water pressure to an acceptable working pressure (40 to 80 psi).
Service: May be domestic service, common domestic and fire protection service, or a separate domestic and fire protection service.
Service lines: Service lines run between a main and a water meter.
Trunk lines: They carry water from a primary source to mains within a distribution system; they are 36 inches to 10 feet in diameter.
Water: A compound comprised of two atoms of hydrogen and one atom of oxygen.
Water meter: A device used to calculate water usage for a domestic water service.
Wall-indicating valve: An OS&Y indicating valve mounted on an exterior wall.
JOHN MITTENDORF was a 30-year veteran of the Los Angeles City (CA) Fire Department when he retired as a battalion chief. He has an associate degree in fire science and has nationally and internationally instructed in fireground operations for the past 25 years. He was the recipient of the Fire Engineering 2008 Lifetime Achievement Award and is a member of the editorial advisory board of Fire Engineering. He is the author of Truck Company Operations, Second Edition (Fire Engineering, 2010) and presenter of the DVD Ten Commandments of Truck Company Operations—An All-Day Seminar.
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