Chpt 7 Flashcards by Joshua Boswell

Fire service _______ is the study of the characteristics and movement of water as they pertain to calculations for fire streams and fire ground operations

Hydraulics

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The scientific or more exact calculations are commonly referred to as

Theoretical hydraulics

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Is the term for the less exact but certainly more user friendly and forgiving calculation methods used on the fire ground

Fireground hydraulics

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To be as accurate as possible when performing hydraulic calculations, you should use the manufactures recommended ________specific to the actual used on your hose or appliance, with your fire apparatus under the guidelines of your fire department

Nozzle pressure

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Flow tests with your equipment will confirm the most precise _____ to use

Pressures

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Fighting fire with water is a matter of ______ versus heat generation, British thermal units, joules, or kilocalories

Flow rate

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To extinguish a fire, sufficient flow must be applied to over come the heat generated by the fire a rate referred to as the _______

Critical rate of flow

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The real goal of the driver operator is to deliver the correct ______ to the nozzle

Flow

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The ______ is the total pressure needed to overcome all friction, appliance, and elevation loss while maintaining adequate nozzle pressure to deliver effective fire streams

PDP

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PDP equation

PDP = NP + FL

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Is the pressure required at the nozzle to deliver the fire stream and flow rate for which the nozzle was designed

Nozzle pressure

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Smooth bore nozzles on a handline are normally flowed at a NP of _____.

50 psi

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Some master stream smooth bore nozzles are rated less than

80 psi

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Fog nozzles are generally rated at

100 psi

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Three standard nozzle pressures, all of which are dictated by the type and the use of the nozzle, are generally sufficient for most fire ground operations

70 psi for all fog nozzles

50 psi for smooth bore handline nozzles

80 psi for smooth bore master stream nozzles

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When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction to that of the first body.

Newton third law of motion

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Is the opposing reaction that occurs as water is expelled from the nozzle or the force that pushes back on the firefighter when he or she flows water

Nozzle reaction

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Calculating nozzle reaction should not be attempted at the fire scene but rather determined during

Training sessions

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To calculate nozzle reaction in a smooth bore use the formula

NR = 1.5 x d2x np

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To calculate nozzle reaction in a fog nozzle use the formula

NR= 0.0504 x gpm x NP

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Is the volume of water moving through the nozzle during a specific time period; it is measured in units or gpms

Flow rate

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Is the pressure lost from turbulence as water passes through pipes, hoses, fittings, adapters, and appliances

Friction loss

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Friction loss formula

FL = C Q2 L

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When flowing two identical lines that have the same nozzle pressure and flow and that are of equal size, length, and elevation, both lines require the same

Pressure

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Under normal conditions you always fully open a valve to prevent excess turbulence and FL through the valve; however, partially closing a valve sometimes necessary to prevent excessive pressure from being delivered. For those discharged requiring a lesser pressure, you must open the valve just enough to deliver the desired pressure, a practiced referred to as

Gating the valve

Calculations must be adjusted for the distance the nozzle is above or below the pump, which is referred to as

Elevation pressure

The pressure lost when the nozzle is above the pump is known as

Elevation loss

The pressure gained when the nozzle is below the pump is known as

Elevation gain

EP could be _____ if the nozzle and the pump are at the same elevation

Zero

Water exerts a pressure of _____ psi per 1 foot of water column

0.434 psi

A common application for this rule would be ____ per gain or loss for each floor of elevation change in a residential structure where floor spacing is commonly 10 ft

5 psi

Are devices that are used to connect and adapt hoses, and to direct and control water flow in various hose layouts

Appliances

Generally, the appliance FL is considered insignificant and maybe recorded as zero when water flows are less than

350 gpms

Allow ____ FL in appliances when the flow rate is 350 gpm or greater

10 psi

Allow ____ FL for all master stream appliances

25 psi

Fire streams of less than 350 gpm are generally considered

Handlines

Whereas fire streams of 350 gpm or greater are considered

Master streams

In your calculations, you should assume _____ of appliance loss for master streams and _____ of AL for handlines with a flow of 350 gpm or greater

25 psi 10 psi

Total pressure loss equation

TPL = (cxq2xL) + AL + EP

A _____ is a device that allows multiple hoselines to converge into one hoseline

Siamese connection

A _____ is used by fire departments that do not have large diameter hose and need to supply large amounts of water at a reasonable amount of pump pressure

Siamese connection

Portable master stream devices such as a removable deck gun and the inlet of aerial water ways on squirts, quints, and ladder trucks may be supplied by a single LDH supply or a _____

Siamese connection

The fire department connection on buildings with standpipe sprinkler systems will have a Siamese connection consisting of two _____ connections or one LDH

2 1/2 inch connections

The three methods used to calculate the FL in the lines to the Siamese connections when the lines are of equal size and length are the ______

Split flow method Coefficient method Percentage method

The term ______ refers to an aerial fire apparatus with a fixed water way attached to the underside of the ladder such that a water inlet at the base supplies a master stream device at the end

Prepiped elevated master stream

The master stream device may have a ______ that places the nozzle on the bed section for rescue or on the fly section for water tower operations

Locking mechanism

Unless the loss in the intake, piping, and nozzle has been established for the specific apparatus, you should assume a minimum of ______ FL for all master streams

25 psi FL

It is extremely beneficial to predetermine pump discharge pressure for high rise structures to limit the amount of calculations needed on the fireground during excitement of an actual incident.as a general rule, you should not exceed a PDP of _____ unless you know the system is designed to handle the greater pressure required

200 psi

The one pressure that you control from the pump panel is the ______ needed at any one discharge (regardless of the floor it’s on)

Highest pressure

Any lower pressures needed at subsequent discharges will have to be controlled by a firefighter staged at the discharge valve of the _____ used

Standpipe riser

A _____ is the vertical portion of the system piping within a building that delivers the water supply for fire hose connections, and sprinklers on combined systems, vertically from floor to floor.

Standpipe riser

The use of the _______ will compensate for any discrepancies if calculations are off or circumstances have changed

In line gauge

Use of an ____ is highly advantageous for standpipe operations

In line gauge

If no preincident plan exists and the size of the riser is unknown, then it’s too late to try and measure this riser. Instead simply add ____ to account for stand pipe riser

25 psi

Are installed on standpipe risers where static pressures exceed 175 psi per NFPA 13 standard for the installation of sprinkler systems.

Pressure regulating valves

The height of a column of water above the discharge is known as

Head

The pressure in that column of water is referred to as

Head pressure

To determine head pressure, divide the height of the column in feet by ______

2.304

Static sources such as lakes and streams require establishing a

Draft

Dynamic sources such as hydrants or another fire apparatus are

Positive pressure sources

Is the amount of pressure created by the pump after it receives water under pressure from a hydrant or another pump

Net pump discharge pressure NPDP

Are more exact, generally require more mathematical skills, and take more time to compute.

Theoretical hydraulic calculations

May be used on the fireground or for preincident planning purposes, such as determining the appropriate pump pressures for high risk or high hazard targets as well as buildings requiring complex hose layouts and standpipe systems

Theoretical hydraulic calculations

Employ methods intended to estimate calculations more quickly due to the urgency of the incident

Fire ground hydraulics

Firefighters often create a ___ of typical handline and master stream calculations for the hoses, nozzles, and devices specific to the fire apparatus within their department

Chart

The _____ may consist of a sliding card or a slide rule

Manual hydraulic calculator

Mounted calculators are seldom encountered today, where as the ______ type is quite common

Hand held type

The hand held pocket size ________ allows you to calculate engine pressure, FL, application rate, and reaction force also know as normal reaction.

Electronic calculator

The purpose of the _____ is to quickly determine the amount of FL per 100 ft

Hand method

The ______ method determines FL in 21/2 in hose only and for flows of 160 gpms or greater

Subtract 10 method

The ______ is a quick method calculating FL per 100 ft in 3 in. to 5in hoseline only. It is especially useful when the apparatus is part of the relay operation and is supplying another pumper.

Condensed Q method

Because most fire departments use a supply line with a diameter in the range of 3 in to 5 in, the ______ is a quick and easy way to determine the PDP

Condensed Q method

When developing a suppression strategy, there is no more useful tool than knowledge of the target structure and a well developed

Preincident plan

To calculate the available water from a hydrant, use the

First digit method

Fire service hydraulic calculations are used to determine the required _______ for fireground operations

Pump discharge pressure PDP

The major variables are the many numerical values influencing

Calculations

As the driver/operator, you must combine your knowledge of the specific equipment on your fire apparatus with the methodology underlying _____

Hydraulic theory

Combination nozzles (fog nozzles) traditionally have a NP of _____ but come with different features that have varied NP levels.

100 psi

Low pressure fog nozzles have a NP that varies from

50 to 75 psi

Unless manufacturers instructions vary, limit nozzle pressure for smooth bore nozzles on elevated master streams to a maximum of

80 psi

This calculation works for fog nozzles that are operating in a straight stream pattern only

NR= 0.0504 X GPM X NP

Fog nozzles are designed with predetermined flow rates based on a set

Nozzle reactions for smooth bore nozzle and fog nozzles can be calculated, with each reaction expressed in terms of the _____ that the firefighter must overcome to control the nozzle

Pounds per force

If you exceed 50 psi of FL per 100 ft of hose, then the flow may begin to decrease either from the increasing turbulence in the hose or from a reduction in the pump capacity owing to excessive

PDP

In any pumping scenario, if appliances are used or elevation gain or loss is present, you must insert ________ into the FL formula

AL and EP appliance loss or elevation pressure

A _____ is used to split a single line into two lines

Wye

On the discharge side of the pump, this device may be used to bring two or three lines into one attack line, thereby reducing the FL in a long reach.

Siamese

In the _______ , you divide the flow among the equally and calculate the pressure to supply one line because that pressure will support all lines.

Split flow method

The ______ utilizes the fl equation with the appropriate coefficient for the lines entering the Siamese connection

Coefficient method

In the _______, you calculate the total flow through one line.

Percentage method

The FL in two hoselines will be 25 percent of the total flow through one hoseline, and the fl in three hoselines will be approximately 10 percent of the total flow through one hoseline.

Percentage method

No single FL amount can be identified that will adequately encompass all prepiped elevated master streams devices; therefore it is imperative that each aerial device be tested for its unique amount of

FL friction loss

In multistory buildings, the attack lines should be supplied from the floor below with an _______ on the standpipe outlet

In line gauge

You may boost the pressure to the maximum design pressure; however, if calculations require a pressure lower than the system minimum, default to the design pressure so that the ______ can operate properly

PRV pressure reducing valve

On the fireground, ________ are performed mentally

Theoretical calculations

200 ft of 2 1/2 in hose with a 1 1/4 inch solid tip may require a pressure of _____ to achieve desired flow

90 psi

Hydraulic calculators may be either

Manual or electronic

______ offer a fire stream calculator on one side and a FL calculator on the other side

Slide rule hydraulic calculators

Electronic calculators may be either

Mounted or hand held

The hand method for 2 1/2 in hose works so nicely because the coefficient for 2 1/2 in hose is ____ when using imperial units

The simplicity of this method is its strength; using this technique, you can determine FL in 2 1/2 in hose very quickly.

Subtract 10 method