Water Distribution 1 Questions and Answers 100% Pass

Water Distribution 1 Questions and Answers 100% Pass Head is measured in ✔✔feet A plat is ✔✔A map Which type of valve will prevent the collapse of a pipe ✔✔Air-and-vaccume relief valve The highest degree of protecti ...

Water Distribution 1 Questions and Answers 100% Pass Head is measured in ✔✔feet A plat is ✔✔A map Which type of valve will prevent the collapse of a pipe ✔✔Air-and-vaccume relief valve The highest degree of protection of a coated steel pipe is ✔✔cathodic protection At which time of day is the age of the water stored in the distribution system the highest? ✔✔In the morning One of chlorines advantages is that it ✔✔has a persistent residual Chlorine gas is _____ times heavier than air. ✔✔2.5 After a water storage tank has been chlorinated, which bacteriological test must prove negative before the tank is put back into service. ✔✔Coliform test Which is the best and most reliable way of finding a very small chlorine leak? ✔✔Use a chlorine gas detector and place it near any area suspected of leaking. The minimum required free chlorine residual anywhere in the distribution system is ✔✔a detectable level First draw samples for the analysis of lead and copper water must be collected from taps where the water has stood motionless in the plumbing for at least ✔✔6 hours Samples collected for cloakrooms are collected in plastic bottles that must contain ✔✔Sodium thiosulfate The volume of a sample for coliform compliance is ✔✔100 ml If a water sample is not analyzed immediately for chlorine residual, it is acceptable to be analyzed within ✔✔15 minutes The heart of a pump is called the ✔✔impeller Which device serves the same function as the packing ✔✔Mechanical seal Which is used to stop air leakage into the casing around the pump shaft ✔✔seals Which is at the top of a stuffing box? ✔✔Packing gland Which assembly holds the lantern ring and packing? ✔✔Stuffing box Why is it important to monitor the speed of a variable speed pump? ✔✔To prevent cavitation from occurring Which basic electrical unit is used to measure a materials opposition of flow of electricity? ✔✔Ohm The first oil change on a pump should be done ✔✔After a month of operation How often should the temperature of centrifugal pump motor bearings be checked with a thermometer? ✔✔Once a month All sensors that respond to liquid pressure will preform poorly if _______ enters the air sensor ✔✔Air Which agency sets limits on the concentration levels of harmful contaminants in potable water distributed to costumers? ✔✔United States Environmental Protection Agency Which violations are most serious? ✔✔Tier 1 A positive fecal coliform test must be reported to the primacy agency within 24 hours ✔✔24 hours The number of monthly distribution system bacteriological samples is required is ✔✔based on the population served Which is the approximate angle of response for average soils when using the sloping method for the prevention of cave ins? ✔✔1.0 : 1.0 At what time of day is the age of the water stored in a distribution system the lowest? ✔✔Late Evening Which type of maps should not overlap each other? ✔✔Sectional maps Which of the following is a joint for ductile iron piping? ✔✔Flexible ball joint The amount of feet in energy required to overcome resistance to flow in a pipe is called ✔✔friction head The fire insurance underwriters recommend that no main should have a diameter less than ✔✔6 inches Water velocities in a pipe should be limited to 5 ft/sec in order to ✔✔minimize friction loss Which of the following is a type of joint in polyvinyl chloride piping? ✔✔Bell and spigot type Which of the following is a type of joint in polyethylene piping? ✔✔Thermal butt-fusion Which of the following is a type of joint for ductile iron piping? ✔✔Flanged joint The height of the water in three differently shaped tanks is 22.4 feet. In which tank is the psi at the bottom the highest? ✔✔It will be the same in all three tanks A water tank has a glass tube on its side showing the water level of the tank. What is its surface called? ✔✔Piezometric surface Minor head losses are caused by ✔✔Sudden changes in direction or velocity of flow Water mains should primarily be sized based on ✔✔Adequate fire flow at a appropriate pressure The most desirable residential pressure ranges from ✔✔50-75 psi Which is pipe strength expressed in? ✔✔Tensile and flexural strength The resistance of a material to longitudinal pulling forces before it breaks is called ✔✔Tensile Strength Most water systems use fire hydrants with two nozzles with diameters of ______ and one nozzle with a diameter of ____ ✔✔2.5 in and 4.5 in Which type of pipe is durable and strong, has high flexural strength and good corrosion resistance, and is easily tapped? ✔✔Ductile iron which of the following is a joint for concrete piping? ✔✔Bell and spigot type Precipitative softening water treatment plants try to end up with distribution system water that is ✔✔Slightly scale forming Which is a closed fire line? ✔✔Unmetered connection for fire protection system Comprehensive maps of medium to large systems generally have scales ranging from ✔✔500 to 1000 feet to 1 inch Sectional maps generally have scales ranging from ✔✔50 to 100 ft to 1 inch Which type of centrifugal pumps are the most common? ✔✔Radial flow impellers Name two types of joints for steel piping ✔✔Expansion joint and rubber gasket joint The pressure during fire flow conditions should not drop below ✔✔20 psi Which type of distribution system configuration has smaller mains that generally terminate as dead ends? ✔✔Tree system Which is applied to electrodes placed in the water of a water storage tank? ✔✔DC current The frequent starting of distribution system pumps probably indicates ✔✔inadequate distribution storage Which needs to be determined first when designing a pump station? ✔✔Head requirements Which is plotted on the x axis of a pump curve? ✔✔Capacity (flow rate) Hydraulics is the study of ✔✔fluids in motion and at rest Which type of pipe joint consists of two machined surfaces? ✔✔flanged joint Which type of pipe joint requires a movable follower ring? ✔✔Mechanical joint What is the height limit to which siphoned water can be lifted at sea level? ✔✔33.9 ft How many feet of water will equal the atmospheric pressure at sea level? ✔✔34 ft Which type of impeller is best to use for pumping water with low volumes of solids? ✔✔Closed Which type of pump has the ability to rotate its discharge 360 degrees ✔✔End suction pump How many times higher than the normal operating pressure should the pressure rating of distribution piping be? ✔✔2.5 to 4.5 times Which type of piping has been banned from the water industry? ✔✔Asbestos cement Which type of piping comes in diameters as large as 168 inches (14 feet)? ✔✔Reinforced concrete Which type of pipe has the highest normal maximum working pressure? ✔✔Ductile iron Which type of pipe has the lowest normal maximum working pressure ✔✔Polyvinyl chloride Ductile iron piping using flex ball joints is most appropriate for ✔✔river crossings and rugged terrain Ductile iron piping using push on or mechanical joints is most appropriate for ✔✔where flexibility is required Polyvinyl chloride piping using solvent weld joints is most appropriate ✔✔only for small lines Concrete piping using bell and spigot type joints is most appropriate ✔✔for all locations Which type of piping is available is both bolted and boltless flexible pipe joint designs? ✔✔Ball and socket joint Which type of pipe joint permits flexible pipe alignment, is inexpensive to manufacture, and is easy to assemble? ✔✔Push on joint Which type of pipe joint has machined ends? ✔✔Shouldered joint New polyvinyl chloride pipe has a C value of about ✔✔150+ Do you think an emergency storage tank is likely to contain potable water? ✔✔No Which type of valve is used on hydraulic lines connected to valve actuators? ✔✔Needle valve Which type of valve would be particularly useful for throttling the flow of corrosive liquids? ✔✔Pinch valve Water meter pits are usually used in ✔✔cold climates A horizontal load, parallel to a pump shaft is called a ✔✔thrust load Manufacturers typical design pumps such that the first critical speed is at least ____ higher or lower than rated speed ✔✔20% Regarding fire flow, mains smaller than 6 inches should only be used ✔✔to complete a grid Which type of pipe requires special external protection in high chloride soils? ✔✔Reinforced concrete Which type of pipe is most likely to collapse or become distorted under partial vacuum? ✔✔Steel piping Casing pipe used to house a large water main under a railroad crossing should have a diameter that is ___________ larger than the outside diameter of the water main bells. ✔✔2 to 8 inches Data manipulations using the basic elements of an automatic mapping system would include ✔✔modeling and analysis Which data category for water utility data sets includes the following map layers: Control information, planimetric features, and hydrology features? ✔✔Base data Which is the chlorine species called HTH ✔✔Calcium Hypochlorite Which is the proper detention time for disinfecting a water storage tank that is filled with already chlorinated water such that the free chlorine residual is 10 mg/L after the proper detention time is completed? ✔✔6 hours Which is the proper detention time for disinfecting a water storage tank with water that is mixed with hypochlorite already in the tank such that the free chorine is 10 mg/L after proper detention time is complete? ✔✔24 hours The disinfectant residual in treated water entering the distribution system must not be less than ✔✔o.2 mg/L for more than 4 hours during periods where the system is serving water to the public The chemical formula for hypochlorous acid is ✔✔HOCL Usually the best disinfectant to use in large diameter pipes or very long pipelines is ✔✔chorine gas Which method for controlling nitrification problems in a distribution system would result in a temporary increase in trihalomethanes ✔✔super chlorinating reservoirs and storage tanks Which is the available chlorine concentration used for disinfecting a water storage tank using a method that involves spraying or painting all of the interior tank surfaces? ✔✔20 mg/L When following a two step process for disinfecting a water storage tank, the initial dosage of 50 mg/L available chlorine should be held in a partially filled tank for ✔✔at least six hours Why are altitude valves used on water storage tanks? ✔✔To stop the flow of water into the tank when it is full If iron bacteria are causing corrosion problems in the distribution system, which is the most probable solution? ✔✔Use a corrosion chemical as treatment Which type of chlorine gas feeder is most commonly used? ✔✔Vacuum When concentration cell corrosion occurs in iron pipes the electrons will move through the ✔✔iron pipe from the anode to the cathode Which type of corrosion occurs when two types of dissimilar metals are electrically connected and immersed in a common flow of water, where one metal becomes the anode and the other the cathode? ✔✔Galvanic corrosion