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Pumping Apparatus Driver/Operator — Lesson 6

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Pumping Apparatus Driver/Operator — Lesson 6. Pumping Apparatus Driver/Operator Handbook, 2 nd Edition Chapter 6 — What Is Water and Where Does It Come From?. Learning Objectives. 1.Select facts about the characteristics of water. - PowerPoint PPT Presentation

Text of Pumping Apparatus Driver/Operator — Lesson 6

  • Pumping Apparatus Driver/Operator Lesson 6Pumping Apparatus Driver/Operator Handbook, 2nd Edition

    Chapter 6 What Is Water and Where Does It Come From?

    Instructor

  • Learning Objectives1.Select facts about the characteristics of water.

    2.List the ways in which water has the ability to extinguish fire.

    3.Answer questions about specific heat.

    4.Select facts about latent heat of vaporization.(Continued)

    Instructor

  • Learning Objectives5.Calculate latent heat of vaporization.

    6.Answer questions about the surface area of water.

    7.Explain the ways in which water smothers fire.

    8.Select facts about specific gravity.(Continued)

    Instructor

  • Learning Objectives9.List advantages of water as an extinguishing agent.

    10.List disadvantages of water as an extinguishing agent.

    11.Distinguish between pressure and force.

    12.Explain how force is determined.(Continued)

    Instructor

  • Learning Objectives13.State the principles of fluid pressure.

    14.Match to their definitions terms associated with pressure.

    15.Explain how to measure atmospheric pressure.

    16.Calculate head pressure.(Continued)

    Instructor

  • Learning Objectives17.List causes of friction loss in fire hose.18.List causes of friction loss in piping systems.

    19.List the principles of friction loss.

    20.Answer questions about other factors affecting friction loss.

    (Continued)

    Instructor

  • Learning Objectives21.List ways to reduce friction loss.

    22.Select facts about water hammer.

    23.Name the four primary components of a municipal water system.

    24.Answer questions about the primary components of a municipal water system.(Continued)

    Instructor

  • Learning Objectives25.Select facts about water main valves.

    26.Answer questions about water pipes.

    27.Match to their definitions water system consumption rates.

    28.Select facts about private water supply systems.(Continued)

    Instructor

  • Learning Objectives29.List the purposes of a private water supply system.

    30.List the advantages to have separate piping arrangements in a private water supply system.

    Instructor

  • Characteristics of Water

    Water is a compound of hydrogen and oxygen formed when two hydrogen atoms (H2) combine with one oxygen atom (O).

    Between 32F and 212F (0C and 100C), water exists in a liquid state.(Continued)

    Instructor

  • Characteristics of Water

    Below 32 F (0C) (the freezing point of water), water converts to a solid state called ice.

    Above 212F (100C) (the boiling point of water), water converts into a gas called water vapor or steam; it cannot be seen.(Continued)

    Instructor

  • Characteristics of Water(Continued)

    Instructor

  • Characteristics of Water

    Water is considered to be incompressible, and its weight varies at different temperatures.

    Note: Water is measured in pounds per cubic foot (kg/L)

    (Continued)

    Instructor

  • Characteristics of WaterWater is heaviest close to its freezing point, weighing approximately 62.4 lb/ft3 (1 kg/L)

    Water is lightest close to its boiling point, weighing approximately 60 lb/ft3 (0.96 kg/L)

    For fire protection purposes, ordinary fresh water is generally considered to weigh 62.5 lb/ft3 or 8.33 lb/gal (1 kg/L)

    Instructor

  • Ways in WhichWater Extinguishes FireCoolingBy absorbing heat from the fire

    SmotheringWater can be used to smother fires in combustible liquids whose specific gravity is higher than 1.Smothering also occurs to some extent when water converts to steam in a confined space.

    Instructor

  • Specific HeatThe heat-absorbing capacity of a substanceAmounts of heat transfer are measured in British thermal units (Btu) or joules (J)A Btu is the amount of heat required to raise the temperature of 1 pound of water 1F.The joule has taken the place of the calorie (1 calorie = 4.19 joules).(Continued)

    Instructor

  • Specific HeatIs the ratio between the amount of heat needed to raise the temperature of a specified quantity of a material and the amount of heat needed to raise the temperature of an identical quantity of water by the same number of degrees.Of different substances varies. Refer to Table 6.1 on p. 136 of the manual.

    Instructor

  • Latent Heat of VaporizationIs the quantity of heat absorbed by a substance when changing from liquid to vapor.

    The temperature at which a liquid absorbs enough heat to change to vapor is known as its boiling point. At sea level, water begins to boil or vaporize at 212F (100C).(Continued)

    Instructor

  • Latent Heat of VaporizationVaporization does not completely occur the instant water reaches the boiling point. Each pound of water requires approximately 970 Btu (1 023 kJ) of additional heat to convert completely to steam.(Continued)

    Instructor

  • Latent Heat of Vaporization

    The latent heat of vaporization is significant in fire fighting because the temperature of the water is not increased beyond 212F during the absorption of the 970 Btu for every pound of water.

    Instructor

  • Surface Area of Water

    The speed with which water absorbs heat increases in proportion to the water surface exposed to the heat.(Continued)

    Instructor

  • Surface Area of WaterWater expands when converted to steam. At 212F (100C), water expands approximately 1,700 times its original volume.(Continued)

    Instructor

  • Surface Area of WaterSteam expansion is rapid inside a burning building. The use of a fog stream in a fire attack requires that adequate ventilation be provided ahead of the hoseline.

    Instructor

  • Ways in Which Water Smothers FireBy floating on liquidsWater floats on liquids that are heavier than water.If the material is water soluble, the smothering action is not likely to be effective.

    By forming an emulsionWater smothers fire by forming an emulsion over the surface of certain combustible liquids.(Continued)

    Instructor

  • Ways in WhichWater Smothers FireBy forming an emulsionWhen a spray of water agitates the surface, the agitation causes the water to be suspended in emulsion bubbles on the surface; the emulsion bubbles smother the fire.Emulsion bubbles can only form when the combustible liquid has sufficient viscosity the tendency of a liquid to possess internal resistance to flow.

    Instructor

  • Specific GravityThe density of liquids in relation to waterWater is given a value of 1. Liquids with a specific gravity less than 1 are lighter than water and float on water. Those with a specific gravity greater than 1 are heavier than water and sink to the bottom.Most flammable liquids have a specific gravity of less than 1.

    Instructor

  • Advantages of Water asan Extinguishing Agent

    Water has a greater heat-absorbing capacity than other common extinguishing agents.

    A relatively large amount of heat is required to change water to steam. This means that more heat is absorbed from the fire.(Continued)

    Instructor

  • Advantages of Water asan Extinguishing Agent

    The greater the surface area of water exposed, the more rapidly heat is absorbed. The exposed surface are of water can be expanded by using fog streams or deflecting solid streams off objects.(Continued)

    Instructor

  • Advantages of Water asan Extinguishing Agent

    Water converted into steam occupies 1,700 times its original volume.

    Water is plentiful, relatively inexpensive, and readily available in most jurisdictions.

    Instructor

  • Disadvantages of Water asan Extinguishing AgentWater has a high surface tension and does not readily soak into dense materials. However, when wetting agents are mixed with water, the waters surface tension is reduced and its penetrating ability is increased.

    Water may be reactive with certain fuels such as combustible metals.(Continued)

    Instructor

  • Disadvantages of Water asan Extinguishing Agent

    Water has low levels of opacity and reflectivity that allow radiant heat to easily pass through it.

    Water readily conducts electricity, which can be hazardous to firefighters working around energized electrical equipment.(Continued)

    Instructor

  • Disadvantages of Water asan Extinguishing Agent

    Water freezes at 32F (0C), which is a problem in jurisdictions that frequently experience freezing conditions. Water freezing poses a hazard to firefighters by coating equipment, roofs, ladders, and other surfaces. In addition, ice forming in and on equipment may cause it to malfunction.

    Instructor

  • Pressure vs. ForcePressureForce per unit areaMay be expressed in pounds per square foot (psf), pounds per square inch (psi), or kilopascals (kPa)ForceA simple measure of weightIs usually expressed in pounds or kilograms

    Instructor

  • Determining Force(Customary System)The weight of 1 cubic foot of water is approximately 62.5 pounds.

    Because 1 square foot contains 144 square inches, the weight of water in a 1-square-inch column of water 1 foot high equals 62.5 pounds divided by 144 square inches62.5 / 144 = 0.434 pounds(Continued)

    Instructor

  • Determining Force(Customary System)(Continued)

    Instructor

  • Determining Force (Customary System)A 1-square-inch column of water 1 foot high exerts a pressure at its base of 0.434 psi.

    The height required for a 1-square-inch column of water to produce 1 psi at its base equals 1 foot divided by 0.434 psi/ft.

    Therefore, 2.304 feet of water column

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