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CDC - Mobile Water Supply Exam 2024
A column of water 1"x1"x12" high exerts how much psi? - ANSWER-0.434 psi A column of water 1"x1"x24" high exerts how much psi? - ANSWER-0.868 psi A hose has a flow rate of 500 gpm with a friction loss of 4 psi. If the flow rate increases to 1,000gpm, then the friction loss will increase to: - ANSWER-FL= 2^2 x 4 FL= 4 x 4 FL= 16 psi According to what NFPA, how much water must an apparatus carry to be considered a MWS or Tender? - ANSWER-NFPA 1901 Standard for Automotive Fire Apparatus, At least 1,000 gallons. An important feature of most screw-on intake pressure relief valves is that they: - ANSWER-They have bleeder valves to vent air when a connected line is being charged. An MWS apparatus is resupplying 1,000 gpm to a pumper using 50' of 5inch. The pumper is in a gully 4 feet below the location of the MWS. Show Work for determining the PDP. - ANSWER-12 psi As you move around the apparatus, what general problems are you looking for? - ANSWER-Fluid leaks, dents, low tire pressure, cleanliness, and broken, or missing equipment. Bleeder valves allow the driver/operator to do what? - ANSWER-To vent air to the atmosphere when a dry supply line is being charged. Discharges are usually equipped with a locking ___ valve. - ANSWER-Ball Discharges can also be used to cool the pump when no lines are flowing. TorF? - ANSWER-True During a resupply operation which formula is used to determine the PDP? - ANSWER- PDP= Required Intake Pressure + TPL During Water shuttle operations where is the pumper that is not at the fill site positioned? What is this location commonly referred to as? - ANSWER-The second pumper is located at or near the emergency scene and is used to draft water from the portable water tanks. The dump site.
Each department must choose the size of the tank for its apparatus based on what? - ANSWER-Local water requirements Water system limitations Road conditions Bridge weight restrictions Engine compartment: air Filter Restriction Gauge - ANSWER-Check the air filter restriction gauge to determine if the air filter needs to be changed. Engine compartment: Air system - ANSWER-Check the air system for leaks in the system. Engine compartment: Automatic transmission fluid - ANSWER-Check the transmission fluid level. perform both a cold and a hot check. Cold ensures there is transmission fluid, hot ensures the fluid is at the correct level for operation. Engine compartment: Batteries - ANSWER-Check the terminals for corrosion and clean in accordance with the manufacturers specifications. Inspect battery cables for any loose connections Engine compartment: Coolant Overflow Reservoir - ANSWER-Coolant in the overflow reservoir should be clean and halfway between max and min level for your apparatus. Engine compartment: Cooling Fan, Hoses, and Radiator - ANSWER-Check the cooling fan, hoses, and the radiator for cracks. Engine compartment: Drive Belts - ANSWER-Check all drive belts for wear and proper tension. 1/2" to 3/4" deflection at midpoint. Engine compartment: Engine oil - ANSWER-Check whether engine oil is clean and at full mark. Engine compartment: Exhaust System - ANSWER-Check the exhaust system for leaks and damage. Engine compartment: Fuel filter - ANSWER-Check fuel filter for fuel/water separation and leak/damage. Check site glass to ensure that the water has been separated from the fuel. Engine compartment: Hydraulic fluid - ANSWER-Check all hydraulic fluid levels and look for any leaks on engine. Engine compartment: Leaks - ANSWER-Checks for leaks of any fluids within the engine compartment, including the fuel lines and their components.
For the daily inspection of the aux. cooling system, what should be done? - ANSWER- Bring the engine to normal operating temperature, and then activate the cooling system valve. You should see a noticeable drop in the engine water temp. For the daily inspection of the aux. fire suppression system, what should be done? - ANSWER-Ensure that any on board auxiliary fire suppression system is ready for operation. Check for damage and leaks and make sure that all valves are in the working order. Also confirm that the foam levels are full. For the daily inspection of the Pump Drive Control, what should be done? - ANSWER- Make sure that it can be engaged. For the daily inspection of the Pump Pressure control device, what should be done? - ANSWER-Ensure that it is operating properly. For the daily inspection of the pump primer what should you be checking? - ANSWER- Check the primer oil reservoir level. close all pump valves and make sure that the pump primer operates properly. Hard suction hoses are founf in what size lengths? - ANSWER-6 to 14 foot lenghts Hard suction hoses are non collapsible hoses generally found in what sizes? - ANSWER-4 to 6 inches Has a self-adjusting part that lowers maintenance. - ANSWER-Rotary Vane Pump How are Ball valves usually controlled? - ANSWER-Either though mechanical push-pull and quarter-turn handles or pneumatic, hydraulic or electric switches. How do Gravity dumps work? - ANSWER-they rely on natures gravitational pull to empty water from the tank. How do Jet -assisted dumps work? - ANSWER-Sometimes called jetdumps, they employ the use of a small diameter in-line discharge that is inserted into the piping of the large tank discharge. The discharge is supplied by the fire pump on the apparatus. The in-line discharge creates a Venturi effect that increases the water flow. How do you calculate head pressure? - ANSWER-Divide the head height by 2. Discharge pressure is a little less than half the head height. How does a midship transfer drive work? - ANSWER-The midship transfer case diverts power from the rear axle and transmits it to the fire pump. This is accomplished by either a series of gears or a chain.
How does PTO work? - ANSWER-The pump is driven by a drive shaft that is connected to the PTO on the transmission. This type of system may be used for pumps mounted on the front or midship of the MWS. How does the Rotary Gear work? - ANSWER-Two Meshed gears form watertight areas between teeth that turn, thereby pulling water into the pump. The water is moved through the pump and pushed out of the discharge. How many inches of mercury should the priming device and pump achieve? - ANSWER-22 inches How often do should the Pump Gearbox and Packing Glands be inspected? - ANSWER-Weekly If the MWS apparatus is equipped with a FIRE PUMP, it may be referred to as a... and must have a tank-to-pump line that is: - ANSWER-Tanker-pumper or a tender- pumper.
- Capable of supplying the pump with a 500 gpm until at least 80% of the water in the tank is emptied.
- At least two inches diameter. If water is flowing through 100 feet of a 4" hose at 500 gpm, then the friction loss is approximately: - ANSWER-5 psi IFSTA recommends how many pumpers for an effective water shuttle operation: - ANSWER-At least two pumpers It is important to monitor the water level in the onboard tank because: - ANSWER-You need to know if the incident requires additional water before the tank is empty. Large diameter hose is used then... - ANSWER-one connection to the tank is adequate. Large diameter hoses are generally defined as hoses between what sizes? - ANSWER- 4 to 6 inches in diameter with 4 to 5 inch being the most common. Large diameter hoses can be hard to handle. TorF - ANSWER-True Medium diameter hose supply lines are used for filling then... - ANSWER-the MWS should have at least two external or direct tank fill intakes piped directly to the tank. Medium diameter hoses are generally defines as what sizes? - ANSWER-2 1/2 to 3 inch Medium Diameter hoses are typically found in what size lengths? - ANSWER-50 foot lengths
The tank discharge should be capable of discharging how much of the tank volume at what rate? - ANSWER-90% of the tank volume at an average of 1,000 gpm. There are three sources of water that can be used for fire fighting: - ANSWER-Internal or onboard tanks Pressurized sources static sources Three conditions that could cause you to lose control of an MWS apparatus. - ANSWER-Liquid Surge withing the water tank Traveling at 50 mph around a turn Wet, icy roadways Using the condensed Q method, the friction loss for 100 feet of 5" hose flowing at 500 gpm is approx.: - ANSWER-1.7 PSI Using the hand method to calculate fireground pressure losses, the estimated friction loss for 100 feet of 2 1/2" hose at 300 gpm is approx.: - ANSWER-18 psi Water pressure is typically referred to in what? - ANSWER-Pounds per square inch (psi) What allows all the water to be drained? - ANSWER-The pump drains are useful in cold climates. What are some examples of man made static sources - ANSWER-Cisterns, Irrigation Systems, Swimming Pools, Reservoirs, and Private Water Tanks What are some examples of natural sources? - ANSWER-Lakes, Streams, Ponds, Rivers, and Oceans What are some requirements, if a pumper is going to be used a fill site pumper? - ANSWER-They should be equipped with hard suction hose so they can be used to draft, fill site pumpers should also have a minimum pump capacity of 1,000 gpm What are some uses of medium diameter hose? - ANSWER-Can be used as pre- connects or supply line Can be used in single or multiple supply line operations to fill the MWS apparatus. They allow flexibility for positioning an MWS at a hydrant. Generally Two or three medium diameter lines are used in fill site supply operations what are the four pre-service tests that are normally done for an MWS apparatus? - ANSWER-1. Manufacturer's Road Test
- Hydrostatic Tests
- Independent Pump Certification Tests
- Purchase Acceptance Tests
What are the four types of fire pumps? - ANSWER-Piston Rotary Gear Rotary Vane Centrifugal Pump What are the three inspections that should be performed on an MWS apparatus on a weekly basis? - ANSWER-1. Pump and intake strainers
- Pump gearbox and packing glands
- Rapid dump system What are the three main factors to consider when selecting a drafting site? - ANSWER- Amount of water available for drafting operations Type of water Accessibility of water What are the two braking systems that MWS have? - ANSWER-Air Breaks and Hydraulic breaks. What are the two primary types of apparatuses required to operate an effective water shuttle operation? - ANSWER-Pumper or fire apparatus, and MWS apparatus What are the two primary types of rapid dump systems or large tank discharges used on MWS apparatus? - ANSWER-1. Gravity Dumps
- Jet-assisted Dumps What are the two types of performance test should be done on all fire service apparatuses? - ANSWER-1. Pre-service tests
- Fire pump service tests What are water shuttle operations used for? - ANSWER-Used to supply water to emergency scenes that require additional water supply. what are you checking for when inspecting the Pump Gearbox and Packing Glands? - ANSWER-Check the oil level in the pump gearbox and for traces of water. Ensure that the pump packing glands do not leak excessively. What can provide cavitation protection? - ANSWER-Electronic pressure governor What device is driven by an electric motor? - ANSWER-Priming device What device uses a spring-loaded pilot valve? - ANSWER-Discharge pressure relief valve What do drain valves on the line side allow? - ANSWER-Allow the driver/operator to relieve hose pressure once the discharge valve has been closed.
what is water pressure? - ANSWER-The force of water per unit area What kind of valve might you find on large diameter lines? How are they controlled? - ANSWER-Gate Valves controlled by handwheels or butterfly valves operated by quarter-turn handles. what makes the hard suction hose non collapsible? - ANSWER-the hoses have an internal reinforcement What needs to be airtight and can control both intake and discharge lines? - ANSWER- Valves What NFPA requires three dump valves to be installed on all MWS apparatus? - ANSWER-NFPA 1901 What prevents the primary intake from vortexing with water? - ANSWER-The connection near the intake is circular and square near the pump itself. What seven pump certification test must be performed according to NFPA 1901? - ANSWER-1. Engine speed check
- Vacuum test
- Priming test
- Pumping test
- Pressure control test
- Gauge test
- Tank-to-pump flow rate test What should be inspected daily on the MWS apparatus? - ANSWER-Pump primer, pump pressure control device, pump drive control, hose lines, cooling system, auxiliary fuel tank, and fire suppression system if applicable. Operating all valves, including relief valves, checking all other pump panel instruments for proper operation. What should be provided from the discharge side of the pump? What does it allow? - ANSWER-A tank fill line should be provided, allowing the tank to be filled without making any additional connections when the pump is being supplied form an external water source. what size lengths are large diameter hoses generally found in? - ANSWER-50 to 1oo foot lengths What size water tanks are the most efficient during stationary water supply operations?
- ANSWER-MWS with tanks for the 2,500 gallons.
What size water tanks are the most efficient during water shuttle operations? - ANSWER-MWS with tanks less than 2,500 gallons. what sze piping do gravity dumps employ? - ANSWER-Usually employ 8" or larger round or square piping with a valve that extends to the exterior of the apparatus. What test requires that each pump be hydrostatically tested a at a minimum of 500 psi gauge pressure for 10 minutes? - ANSWER-The hydrostatic test What three external fill connections can be equipped on the MWS apparatus? - ANSWER-1. Allows the tank to be filled at a min rate of 1,000 gals/min.
- Equipped with a valve, strainer, and a 30 degree elbow.
- Has Valves of slow-closing design (if three inches or larger). What uses a linkage to reduce engine rpm> - ANSWER-Mechanical pressure governor What would happen without a bleeder valve? - ANSWER-Air would be forced into the pump. When approaching an underpass or low clearance: - ANSWER-Check to see if the underpass height is marked When looking at the body panel, what should you be looking for? - ANSWER-Looking for rust, dents, or exposed areas needing touch-up paint. When looking at the circuit breakers and/or fuses what should you be looking for? - ANSWER-Looking at the main panel to see if any circuits are tripped or if any fuses are blown. When looking at the windows and exterior lights, what should you be looking for? - ANSWER-Looking for cracks and discoloration. When performing drafting operations, for a pump to operate at its rated capacity, how many inches of water must be above a traditional strainer? - ANSWER- When referring to static sources of fire fighting operations, how is a static source defined? - ANSWER-As water supplies that are not under pressure, this includes both natural sources and manmade sources. When two pumper are used, where is each one placed? This location is formally known as what? - ANSWER-One pumper is positioned at the water supply source and is used to fill MWS apparatuses. The fill site. When using a static body pf water as your water source during fire apparatus service testing, the water surface must not be more than how many feet above the centerline of
