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Question 1. Which pipe material provides the highest resistance to acidic wastewater? A) PVC B) HDPE C) Ductile Iron D) VCP Answer: B Explanation: HDPE’s polymer structure resists most acids better than PVC or metal. Question 2. The most common joint type used for PVC pipe connections in gravity sewers is: A) Bell & spigot with rubber gasket B) Flanged bolted joint C) Mechanical coupler D) Lead joint Answer: A Explanation: Bell‑and‑spigot with a rubber gasket is standard for PVC. Question 3. For a 12‑in. HDPE gravity pipe, the recommended minimum slope to maintain self‑cleansing velocity is: A) 0.1% B) 0.2% C) 0.4% D) 0.6% Answer: C Explanation: Minimum 0.4% slope is typical for 12‑in. HDPE to achieve ≥ 2 ft/s. Question 4. The “scouring” velocity commonly required to prevent solids buildup in sanitary sewers is: A) 0.5 ft/s B) 1.0 ft/s C) 2.0 ft/s D) 3.0 ft/s Answer: C Explanation: 2 ft/s is the accepted self‑cleansing velocity. Question 5. A drop manhole is primarily used to: A) Increase flow velocity B) Reduce pipe diameter C) Accommodate a change in pipe elevation D) Install a pump Answer: C Explanation: Drop manholes allow the pipe to step down to a lower elevation. Question 6. In a manhole bench design, the purpose of the bench’s slope is to: A) Direct flow to the inlet B) Prevent sediment accumulation C) Increase hydraulic head D) Support pipe joints Answer: B Explanation: Sloped benches guide solids toward the outlet, reducing buildup. Question 7. Service laterals must be installed with a minimum cover of: A) 12 in. B) 18 in. C) 24 in. D) 36 in. Answer: B Explanation: 18 in. cover protects laterals from surface loads and root intrusion. Question 8. The maximum allowable hydraulic grade line (HGL) drop across an inverted siphon is limited to: A) 5 ft B) 10 ft C) 15 ft D) 20 ft Answer: B Explanation: Excess HGL drop can cause air entrainment; 10 ft is a common limit.
Question 9. An inverted siphon functions on the principle of: A) Positive pressure B) Negative pressure (vacuum) C) Gravity only D) Pumped flow Answer: B Explanation: The siphon creates a vacuum that draws flow under the obstruction. Question 10. The preferred material for a large‑diameter (≥ 24 ‑in.) gravity main in a high‑traffic area is: A) PVC B) HDPE C) Ductile Iron D) VCP Answer: C Explanation: Ductile iron offers strength and durability for large, heavy‑load sections. Question 11. Hydraulic cleaning (“balling”) uses what type of device to scour pipe interiors? A) High‑pressure water jet B) Rotating brush C) Expanding rubber ball D) Mechanical scraper Answer: C Explanation: Expanding rubber balls create turbulence that removes deposits. Question 12. The most effective method to remove stubborn grease from a sewer line is: A) Mechanical rodding B) Chemical degreaser C) High‑velocity water jet D) Air scouring Answer: B Explanation: Grease‑liquefying chemicals break down fats better than mechanical methods. Question 13. During CCTV inspection, a “bellies” defect refers to: A) A collapsed pipe B) An out‑of‑round pipe segment C) A pipe joint offset D) A root intrusion Answer: B Explanation: “Bellies” are sections where the pipe wall has bulged outward, reducing flow area. Question 14. Smoke testing is primarily used to detect: A) Structural cracks B) Illegal connections C) FOG accumulation D) Pump failure Answer: B Explanation: Smoke will travel through unauthorized connections, revealing them at the surface. Question 15. In infiltration‑inflow (I&I) studies, infiltration originates from: A) Rainwater on streets B) Leaking water mains C) Groundwater entering the sewer D) Overflow from storm drains Answer: C Explanation: Infiltration is groundwater entering through cracks or faulty joints.
Question 23. The role of the Attendant during confined‑space entry is to: A) Perform the work inside B) Monitor atmospheric conditions C) Operate the pump D) Control traffic Answer: B Explanation: The attendant stays outside, continuously monitoring gas readings. Question 24. According to MUTCD, the standard color for a “No Entry” traffic control sign is: A) Red B) Yellow C) Orange D) Green Answer: A Explanation: Red indicates prohibition and is used for “No Entry” signs. Question 25. For a trench excavated in Type C soil (cohesive), the minimum shoring depth required to prevent collapse is: A) 3 ft B) 5 ft C) 7 ft D) 9 ft Answer: B Explanation: Cohesive soils need deeper shoring; 5 ft is the typical minimum. Question 26. Lockout/Tagout (LOTO) procedures require that energy sources be: A) Reduced to safe levels B) Documented C) Isolated and de‑energized D) Monitored continuously Answer: C Explanation: LOTO mandates isolation and de‑energization before work. Question 27. When handling raw sewage, the minimum PPE includes: A) Safety glasses only B) Gloves and boots C) Full‑body chemical suit D) Respirator and face shield Answer: B Explanation: Gloves and boots protect against biological contamination; additional PPE may be required for chemicals. Question 28. An NPDES permit for a wastewater collection system primarily regulates: A) Odor emissions B) Discharge limits of pollutants C) Noise levels D) Traffic impacts Answer: B Explanation: NPDES governs the quantity and quality of effluent discharged to waters of the U.S. Question 29. The first step after a sanitary sewer overflow (SSO) is to: A) Notify the EPA B) Begin cleanup C) Contain the spill D) File a report Answer: C Explanation: Immediate containment prevents further environmental damage. Question 30. In public relations, the most effective response to an odor complaint is to: A) Deny responsibility B) Offer a discount C) Conduct a field odor assessment D) Ignore the complaint Answer: C Explanation: Assessing the source shows responsiveness and guides remediation.
Question 31. GIS mapping of sewer networks is valuable because it provides: A) Real‑time flow data B) Visual location of assets C) Chemical analysis D) Pump performance curves Answer: B Explanation: GIS displays the spatial relationship of pipes, manholes, and lift stations. Question 32. The formula Q = A × V is used to calculate: A) Pressure B) Flow rate C) Pipe diameter D) Head loss Answer: B Explanation: Q (flow) equals cross‑sectional area (A) times velocity (V). Question 33. To determine the slope of a pipe, the “rise over run” calculation uses: A) Head loss ÷ length B) Elevation change ÷ horizontal distance C) Flow ÷ area D) Velocity ÷ diameter Answer: B Explanation: Slope = vertical rise divided by horizontal run. Question 34. The volume of a cylindrical wet well (in gallons) can be found using: A) V = π r² L ÷ 7. B) V = π r² L × 7.48 C) V = 2 π r L ÷ 7.48 D) V = π r L ÷ 7.48 Answer: A Explanation: Convert cubic feet (π r² L) to gallons by dividing by 7.48 ft³/gal. Question 35. Converting 30 psi to feet of head (using 0.433 psi = 1 ft head) yields: A) 30 ft B) 69 ft C) 100 ft D) 130 ft Answer: B Explanation: 30 psi ÷ 0.433 psi/ft ≈ 69 ft of head. Question 36. Which pipe material is most susceptible to root intrusion? A) PVC B) HDPE C) Ductile Iron D) VCP Answer: D Explanation: Vitrified Clay Pipe’s porous surface allows roots to penetrate more easily. Question 37. The recommended minimum internal diameter for a sanitary sewer main serving a population of 10,000 PE is: A) 8 in. B) 12 in. C) 16 in. D) 24 in. Answer: C Explanation: Design manuals often specify 16 in. for a 10,000 PE load. Question 38. A “sag” in a gravity pipe typically results in: A) Increased velocity B) Reduced capacity C) Higher head loss D) Improved self‑cleaning Answer: C Explanation: A sag reduces slope locally, increasing head loss and slowing flow.
Question 46. A submersible pump’s “shut‑off head” is: A) The head at which the pump stops due to low flow B) The maximum head the pump can achieve C) The head required to start the pump D) The head at which the pump reaches maximum efficiency Answer: A Explanation: Shut‑off head is the head produced when flow is zero. Question 47. The most reliable method to verify a sanitary sewer connection is: A) Visual inspection B) Smoke testing C) Dye tracing D) Flow meter reading Answer: C Explanation: Dye tracing shows the path of water from the connection to the main. Question 48. In a lift station, the “prime mover” refers to: A) The pump impeller B) The motor driving the pump C) The control panel D) The wet‑well vent Answer: B Explanation: The prime mover is the motor that provides mechanical energy to the pump. Question 49. A “positive displacement” pump is rarely used in sanitary sewers because: A) It cannot handle solids B) It requires high pressure C) It is too noisy D) It is expensive Answer: A Explanation: Positive‑displacement pumps are not suited for solids and variable flow typical of sewers. Question 50. The standard design velocity for a 6‑in. PVC gravity pipe is: A) 0.5 ft/s B) 1.0 ft/s C) 2.0 ft/s D) 3.0 ft/s Answer: C Explanation: 2 ft/s is the target self‑cleansing velocity for small‑diameter pipes. Question 51. When performing smoke testing, the smoke is introduced at: A) The downstream end of the system B) The upstream inlet C) The nearest manhole D) Any accessible cleanout Answer: D Explanation: Smoke is released at a cleanout to travel both upstream and downstream. Question 52. The primary cause of infiltration in older clay pipe systems is: A) Pipe sagging B) Joint misalignment C) Cracking due to freeze‑thaw D) Root intrusion Answer: C Explanation: Freeze‑thaw cycles cause cracks that allow groundwater infiltration.
Question 53. The term “head loss” in pipe flow is most directly caused by: A) Elevation change B) Friction and turbulence C) Pump operation D) Air entrainment Answer: B Explanation: Frictional resistance creates head loss along the pipe length. Question 54. A “check valve” installed downstream of a pump prevents: A) Over‑pressurization B) Back‑siphonage C) Air binding D) Cavitation Answer: B Explanation: It stops reverse flow when the pump stops. Question 55. In a force main, the recommended maximum operating pressure is: A) 10 psi B) 20 psi C) 30 psi D) 50 psi Answer: C Explanation: 30 psi is a common design limit for municipal force mains. Question 56. The most effective way to control root intrusion in a VCP pipe is to: A) Apply copper sulfate B) Install root barrier sleeves C) Increase flow velocity D) Use chemical cleaners Answer: B Explanation: Root barrier sleeves physically block roots from entering pipe joints. Question 57. During a CCTV inspection, a “bellies” defect is identified. The corrective action is most often: A) Pipe replacement B) High‑velocity jetting C) Pipe relining D) No action if flow is adequate Answer: C Explanation: Relining restores the pipe’s shape without full replacement. Question 58. The term “I&I” stands for: A) Inflow and Infiltration B) Intake and Intercept C) Internal and External D) Immediate and Indirect Answer: A Explanation: I&I denotes water entering the sanitary system from infiltration (groundwater) and inflow (storm water). Question 59. The most common chemical used for grease liquefaction in sewers is: A) Sodium hypochlorite B) Sodium hydroxide C) Enzyme‑based degreasers D) Hydrochloric acid Answer: C Explanation: Enzyme products break down fats biologically and are safe for pipe materials. Question 60. A “wet well” is primarily designed to: A) Store chemical reagents B) Provide a buffer for pump cycling C) Collect stormwater D) House the control panel Answer: B Explanation: Wet wells buffer flow variations and allow pumps to start/stop efficiently.
Question 69. During a lift‑station inspection, a “wet‑well alarm” that sounds at 80 % capacity indicates: A) Pump failure B) High FOG levels C) Impending overflow D) Low suction head Answer: C Explanation: Alarm at 80 % warns of possible overflow if pumps do not start. Question 70. The best practice for de‑watering a construction trench near a sewer line is to: A) Use a sump pump directly in the trench B) Install a temporary bypass force main C) Pump water into the nearest manhole D) Divert water to a storm drain Answer: B Explanation: A temporary bypass prevents surcharge on the existing sewer. Question 71. The term “hydraulic grade line” (HGL) is plotted on a profile diagram to show: A) Pipe diameter changes B) Pressure distribution C) Flow velocity D) Pipe material D) Answer: B Explanation: HGL represents the sum of pressure head and elevation head along the system. Question 72. In a CCTV video, a “joint offset” defect appears as: A) A sudden change in pipe diameter B) A misaligned pipe segment C) A smooth, round pipe interior D) A buildup of grease Answer: B Explanation: Joint offset is a lateral shift that can impede flow. Question 73. The most common cause of a “seal” failure in a manhole is: A) Corrosion of the frame B) Improper bench slope C) Heavy traffic loading D) Inadequate cover sealant Answer: D Explanation: Poor sealing allows infiltration and odor escape. Question 74. The typical design flow for a 4‑in. service lateral serving a single‑family residence is: A) 0.2 cfs B) 0.5 cfs C) 1.0 cfs D) 2.0 cfs Answer: A Explanation: Residential laterals are sized for low peak flow, about 0.2 cfs. Question 75. The primary advantage of “inverted siphons” over “culverts” for river crossings is: A) Lower cost B) No need for a bridge C) Ability to handle depressurization D) Reduced hydraulic losses Answer: B Explanation: Inverted siphons pass beneath the river without a bridge structure.
Question 76. The most appropriate chemical for controlling invasive roots in a sewer pipe is: A) Sodium hypochlorite B) Copper sulfate C) Sodium bisulfate D) Calcium nitrate Answer: B Explanation: Copper sulfate is toxic to roots and widely used for pipe root control. Question 77. In a gravity sewer, “velocity head” is calculated as: A) V²/2g B) V/g C) 2g/V D) V²g Answer: A Explanation: Velocity head = V²/(2 g), representing kinetic energy per unit weight. Question 78. The term “foaming” in a wet well usually indicates: A) High dissolved oxygen B) Presence of detergents C) Air entrainment D) Low temperature Answer: C Explanation: Air entrainment creates foam, often from surfactants or high turbulence. Question 79. The most common method to detect illegal connections in a sanitary sewer system is: A) CCTV inspection B) Dye tracing C) Smoke testing D) Flow monitoring Answer: C Explanation: Smoke will escape at illegal connections, making them visible at the surface. Question 80. The standard safety distance for a confined‑space entry zone around a manhole is: A) 5 ft B) 10 ft C) 15 ft D) 20 ft Answer: B Explanation: OSHA requires a minimum 10‑ft rescue zone. Question 81. The primary function of an “air release valve” in a force main is to: A) Prevent vacuum formation B) Release trapped air C) Regulate flow D) Measure pressure Answer: B Explanation: Air release valves vent air pockets that could impede flow. Question 82. In a lift‑station wet well, the recommended maximum “FOG” layer thickness before cleaning is: A) 0.5 in. B) 1 in. C) 2 in. D) 4 in. Answer: C Explanation: A 2‑inch FOG layer can significantly reduce pump efficiency. Question 83. The most common cause of a “pump trip” in a submersible pump is: A) Over‑speed B) Low suction head C) High temperature D) Power surge Answer: B Explanation: Insufficient NPSH causes the pump to overload and trip.
Question 92. A “dye test” for inflow detection typically uses which color dye? A) Fluorescein (green) B) Rhodamine (red) C) Methylene blue D) Tartrazine (yellow) Answer: A Explanation: Fluorescein is bright and easily detectable in water. Question 93. The most common material for manhole frames in the United States is: A) Concrete B) Steel C) Reinforced polymer D) Cast iron Answer: A Explanation: Concrete frames are durable, cost‑effective, and widely used. Question 94. In a gravity sewer, the “critical depth” is the depth at which: A) Flow becomes subcritical B) Flow becomes supercritical C) Pipe is half full D) Velocity equals design velocity Answer: B Explanation: Critical depth separates subcritical (slow) from supercritical (fast) flow. Question 95. The standard practice for “lockout/tagout” of a lift‑station pump is to: A) Remove the motor starter B) Disconnect the power source and apply tags C) Turn off the main breaker only D) Place a warning sign only Answer: B Explanation: LOTO requires physical isolation and tag placement. Question 96. The most appropriate PPE when performing a CCTV inspection in a confined sewer is: A) Hard hat and steel‑toe boots B) Full‑face respirator and waterproof gloves C) Safety glasses and hearing protection D) Disposable coveralls and chemical‑resistant boots Answer: D Explanation: Disposable coveralls protect against biological exposure; chemical‑resistant boots guard against splashes. Question 97. The primary function of a “sump pit” in a lift‑station wet well is to: A) Store chemicals B) Capture debris and FOG C) Provide a place for pump motors D) Act as a backup power source Answer: B Explanation: Sumps collect solids and grease that settle out of the flow. Question 98. When calculating flow in an oval (egg‑shaped) sewer pipe, the area is approximated by: A) π a b B) 2 a b C) π (a+b)/2 D) a b Answer: A Explanation: Area of an ellipse = π a b, where a and b are semi‑axes.
Question 99. The most common cause of “pipe root intrusion” in a VCP system is: A) Low flow velocity B) Joint misalignment C) Cracked joints D) Excessive pressure Answer: C Explanation: Cracks in VCP joints provide pathways for roots. Question 100. The standard design flow for a 600‑mm (24‑in.) gravity main serving a 20,000 PE population is approximately: A) 30 cfs B) 45 cfs C) 60 cfs D) 75 cfs Answer: B Explanation: Design tables give about 45 cfs for that size and population. Question 101. The term “hydraulic radius” (R) in open‑channel flow is defined as: A) Area ÷ Wetted perimeter B) Wetted perimeter ÷ Area C) Velocity ÷ Slope D) Flow ÷ Area Answer: A Explanation: R = A/P, where A is flow area and P is wetted perimeter. Question 102. The most effective method to prevent “sag” formation during pipe installation is: A) Use larger pipe diameter B) Increase bedding thickness C) Install pipe on a uniform slope D) Apply epoxy coating Answer: C Explanation: Maintaining a uniform slope prevents local low points. Question 103. In a lift‑station, “pump priming” is required when: A) The pump runs dry B) The wet well is empty C) Air is trapped in the suction line D) The motor overheats Answer: C Explanation: Priming removes air to allow the pump to create suction. Question 104. The typical design velocity for a 24‑in. HDPE force main under pressure is: A) 3 ft/s B) 5 ft/s C) 8 ft/s D) 10 ft/s Answer: B Explanation: Pressurized mains are often designed for 5 ft/s to limit friction losses. Question 105. The most common cause of “pipe collapse” in a low‑temperature region is: A) Soil erosion B) Frost heave C) Heavy traffic loads D) Chemical corrosion Answer: B Explanation: Frost heave exerts upward forces that can buckle shallow‑buried pipes. Question 106. The recommended minimum slope for a 4‑in. gravity pipe in a residential area is: A) 0.1% B) 0.2% C) 0.4% D) 0.6% Answer: C Explanation: 0.4% slope provides sufficient velocity for self‑cleaning.
Question 114. In a lift‑station, the “wet‑well level sensor” is typically a: A) Float switch B) Ultrasonic transducer C) Pressure transducer D) Conductivity probe Answer: C Explanation: Pressure transducers accurately measure water depth. Question 115. The most common cause of “pipe cracking” in vitrified clay pipe is: A) Chemical corrosion B) Freeze‑thaw cycles C) Root intrusion D) High velocity flow Answer: B Explanation: Repeated freeze‑thaw stresses cause cracks in brittle clay. Question 116. The standard design head for a 48‑in. force main in a municipal system is: A) 20 ft B) 40 ft C) 60 ft D) 80 ft Answer: C Explanation: Large force mains often design for 60 ft of head. Question 117. The primary purpose of a “sump” in a wet well is to: A) Store chemicals B) Capture grease and solids C) Provide a backup pump D) Reduce hydraulic shock Answer: B Explanation: Solids settle in the sump, protecting pumps. Question 118. The most appropriate method to clean a 12‑in. PVC pipe with heavy grease buildup is: A) High‑pressure water jet B) Mechanical rodding C) Chemical degreaser D) Air scouring Answer: C Explanation: Chemical degreasers dissolve fats that water jets cannot remove. Question 119. The typical design velocity for a 6‑in. HDPE force main under pressure is: A) 2 ft/s B) 4 ft/s C) 6 ft/s D) 8 ft/s Answer: B Explanation: Pressurized mains are often designed for 4 ft/s to limit friction. Question 120. The most common cause of “pump cavitation” in a lift‑station is: A) Excessive suction lift B) High discharge pressure C) Low temperature D) Air entrainment at inlet Answer: A Explanation: High suction lift reduces NPSH, leading to cavitation. Question 121. The term “I&I” is most often quantified by: A) Flow monitoring during dry weather B) Chemical analysis of influent C) Visual inspection of manholes D) Survey of pipe material Answer: A Explanation: Infiltration/inflow is measured by comparing dry‑weather flow to design flow.
Question 122. The recommended minimum cover for a 24‑in. HDPE gravity main in a road right‑of‑way is: A) 24 in. B) 30 in. C) 36 in. D) 48 in. Answer: C Explanation: 36 in. cover protects against loads and frost. Question 123. The most effective way to prevent “root intrusion” in a ductile‑iron pipe is: A) Install a root barrier sleeve B) Increase flow velocity C) Apply copper sulfate D) Use thicker pipe walls Answer: A Explanation: Sleeve barriers block roots from entering joints. Question 124. The primary function of a “check valve” installed downstream of a pump is to: A) Regulate flow B) Prevent backflow C) Release air D) Measure pressure Answer: B Explanation: It stops reverse flow when the pump stops. Question 125. In a gravity sewer, “self‑cleansing” velocity is generally achieved at a pipe slope of: A) 0.1% B) 0.2% C) 0.4% D) 0.6% Answer: C Explanation: 0.4% slope typically yields ≥ 2 ft/s velocity. Question 126. The most common method to locate a “broken joint” in a sewer line is: A) CCTV inspection B) Smoke testing C) Dye tracing D) Flow meter reading Answer: A Explanation: CCTV provides visual confirmation of joint condition. Question 127. The term “wet‑well” refers to: A) A dry storage tank B) The underground chamber housing pumps C) A surface treatment basin D) A pressure vessel Answer: B Explanation: Wet wells collect wastewater before pumping. Question 128. The primary cause of “air binding” in a submersible pump is: A) Low suction head B) High discharge pressure C) Excessive solids D) Overheating Answer: A Explanation: Insufficient NPSH allows air to accumulate.
Question 137. The typical design flow for a 300‑mm (12‑in.) gravity main serving a 15,000 PE area is: A) 30 cfs B) 45 cfs C) 60 cfs D) 75 cfs Answer: B Explanation: Design tables give about 45 cfs for that size and population. Question 138. The most common cause of “pipe blockage” in a gravity sewer is: A) Low flow velocity B) High pressure C) Excessive slope D) Large pipe diameter Answer: A Explanation: Low velocity allows solids to settle and accumulate. Question 139. The recommended minimum slope for a 24‑in. gravity pipe is: A) 0.1% B) 0.2% C) 0.4% D) 0.6% Answer: C Explanation: 0.4% slope provides sufficient self‑cleansing velocity. Question 140. The primary function of a “manhole bench” is to: A) Support the cover B) Separate inlet and outlet flows C) Provide a work platform D) Reduce odor Answer: B Explanation: Benches direct flow and prevent mixing. Question 141. The most common method to detect “illegal connections” in a sanitary sewer is: A) CCTV inspection B) Dye tracing C) Smoke testing D) Flow monitoring Answer: C Explanation: Smoke will escape at unauthorized connections. Question 142. The term “FOG” stands for: A) Fuel Oil Gas B) Fat, Oil, and Grease C) Flow‑Obstruction Gradient D) Fixed‑Object Gauge Answer: B Explanation: FOG refers to fats, oils, and greases that accumulate. Question 143. In a lift‑station wet well, the “level sensor” is most often a: A) Float switch B) Ultrasonic transducer C) Conductivity probe D) Pressure transducer Answer: D Explanation: Pressure transducers give precise level readings.
Question 144. The most appropriate chemical for controlling invasive roots in a sewer pipe is: A) Sodium hypochlorite B) Copper sulfate C) Sodium bisulfate D) Calcium nitrate Answer: B Explanation: Copper sulfate is toxic to roots. Question 145. The primary cause of “pipe collapse” in a low‑strength soil is: A) Heavy traffic B) Inadequate bedding C) High flow velocity D) Chemical corrosion Answer: B Explanation: Insufficient support leads to pipe deformation. Question 146. The recommended maximum “FOG” layer thickness before cleaning a wet well is: A) 0.5 in. B) 1 in. C) 2 in. D) 4 in. Answer: C Explanation: A 2‑inch layer significantly reduces pump efficiency. Question 147. The most common cause of “air binding” in a pump suction line is: A) High flow velocity B) Low inlet pressure C) Excessive solids D) Overheating Answer: B Explanation: Low pressure allows air to collect. Question 148. The term “hydraulic radius” (R) is calculated as: A) Area ÷ Wetted perimeter B) Wetted perimeter ÷ Area C) Velocity ÷ Slope D) Flow ÷ Area Answer: A Explanation: R = A/P. Question 149. The primary purpose of a “surge tank” in a force‑main system is to: A) Store excess flow B) Absorb pressure transients C) Filter solids D) Provide backup power Answer: B Explanation: It dampens pressure spikes. Question 150. The most common material for a “force‑main” pipe is: A) PVC B) HDPE C) Ductile Iron D) Stainless Steel Answer: B Explanation: HDPE is flexible, corrosion‑resistant, and suitable for pressurized flow. Question 151. The recommended minimum cover for a 12‑in. HDPE pipe in a roadway is: A) 24 in. B) 30 in. C) 36 in. D) 48 in. Answer: C Explanation: 36 in. provides protection from loads and frost.
