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Quiz & test questions Grade 6 Careers & CTE

Testing Hydrants in Orrinbeck: A Valve Technician Quiz

A grade 6 careers quiz on hydrant flow testing, asking students to find pressure drops, a hydrants-per-hour unit rate, and a percent from a crew's day log.

Objectives

  1. Students will calculate the pressure drop at a hydrant from static and residual readings.
  2. Students will express a crew's flushing work as a hydrants-per-hour unit rate and apply it.
  3. Students will explain what a hydrant and valve technician does with a low flow result.

Vocabulary

Distribution system
A distribution system is the network of pipes, pumps, valves, and storage tanks that carries treated water from a treatment plant to homes, schools, and businesses. Most of it is buried underground beneath streets.

Also: hydrant, static pressure, residual pressure, flow test

Teacher overview

This 35-minute quiz is worth 30 points and checks whether students can read a hydrant flow test log the way a hydrant and valve technician reads one, and whether they understand how a person enters that line of work. It mixes two multiple-choice items, two short-answer items, and five computation items, all taken from one day of testing in the fictional town of Orrinbeck. The misconception to correct first is the belief that pressure and flow are the same measurement. A hydrant can sit on a street with high pressure and still deliver very little water, because the main feeding it may be narrow, partly blocked by rust, or served through a valve someone closed years ago and never reopened.

Testing Hydrants in Orrinbeck: A Valve Technician Quiz — Grade 6 Careers & CTE
Name: ____________________________ Date: ______________

Assessment

A day with the Orrinbeck hydrant crew. In the fictional town of Orrinbeck, a two-person hydrant and valve crew tests and flushes every hydrant in the distribution system. Pressure is measured in pounds per square inch, which is written psi. The crew first reads the static pressure, which is the pressure with no hydrant flowing. Then a second hydrant is opened and the crew reads the residual pressure, which is the pressure while water is flowing. The difference between the two readings tells the crew how much water the main can give up before pressure falls too far. Every reading goes on a map that the fire department also uses. Show your work on every item that asks for a number.

Hydrant Static pressure (pounds per square inch) Residual pressure (pounds per square inch) Flow measured (gallons per minute)
H-12 68 54 900
H-13 64 44 750
H-14 70 58 1,050
H-15 62 38 600
  1. (2 points) Why does the crew run a flow test on a hydrant?
    • A) To find out how much water a house uses in a month.
    • B) To find out how much water the hydrant can deliver and how far pressure falls when it does.
    • C) To add chlorine to the water in the main.
    • D) To measure how deep the pipe is buried.
  2. (4 points) Find the pressure drop at hydrant H-13. Use the static and residual readings in the table.
  3. (4 points) Find the pressure drop at hydrant H-15.
  4. (2 points) Which of the four hydrants in the table had the largest pressure drop?
  5. (4 points) Later that week the crew flushed 18 hydrants in 6 hours of work. How many hydrants is that per hour?
  6. (4 points) The town has 360 hydrants in all. The crew flushes for 6 hours a day at the rate you found in item 5. How many days of flushing would the whole town take?
  7. (4 points) Of the town's 360 hydrants, 90 sit on the north side of the river. What percent of the hydrants is that?
  8. (3 points) Which statement best describes how most hydrant and valve technicians qualify for the work?
    • A) They must hold a four-year engineering degree before they may touch a hydrant.
    • B) They finish high school, train on the job, and earn a state distribution operator license by exam, and some add a two-year water technology degree.
    • C) They need no training of any kind, because hydrants are simple.
    • D) They must first work for ten years as a firefighter.
  9. (3 points) Hydrant H-15 gave the lowest flow and the largest pressure drop on the street. Explain in one or two sentences what the technician should do about that result and why the homes and businesses on that street care.

From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.

Answer Key
  1. Answer: B.
    A flow test measures both the water a hydrant can deliver and the pressure that remains while it delivers it. Choice A describes a meter reading, and choice C describes a treatment step.
  2. Answer: 20 pounds per square inch.
    The static reading at H-13 is 64 and the residual reading is 44. 64 minus 44 equals 20.
  3. Answer: 24 pounds per square inch.
    The static reading at H-15 is 62 and the residual reading is 38. 62 minus 38 equals 24.
  4. Answer: Hydrant H-15.
    Its drop of 24 is larger than the drops at H-12 (14), H-13 (20), and H-14 (12).
  5. Answer: 3 hydrants per hour.
    18 hydrants divided by 6 hours equals 3 hydrants per hour.
  6. Answer: 20 days.
    At 3 hydrants per hour for 6 hours, the crew flushes 18 hydrants a day. 360 divided by 18 equals 20 days.
  7. Answer: 25 percent.
    90 divided by 360 equals 0.25, and 0.25 written as a percent is 25 percent.
  8. Answer: B.
    The usual route starts with a high school diploma and on-the-job training, followed by a state distribution license earned by exam. A two-year degree helps but is not required, and the engineers who model the whole system hold four-year degrees.
  9. Answer: Accept any answer that has the technician report the low flow and ask for the main to be checked for a closed valve, rust, or an undersized pipe, and that explains that the fire department counts on that hydrant to protect the buildings nearby.

Differentiation

Support

Give these students the fictional Orrinbeck table with a fifth column headed "Static minus residual" so the subtraction in items 2 and 3 has a place to live. Print item 6 as two steps, one for hydrants per day and one for total days, and allow a calculator on every item.

Extension

Ask students to rank all four hydrants from strongest to weakest using both columns of the fictional Orrinbeck table, then write a short paragraph arguing which hydrant the crew should investigate first and naming the numbers behind the choice.

ELL supports

Pre-teach "static," "residual," and "flush" using a drawing of one hydrant with two gauges, one closed and one open. Provide the sentence frame "The pressure drop at hydrant ____ is ____ because ____ minus ____ equals ____." Allow item 9 to be answered in two short sentences or as a labeled sketch with captions.

Extensions

Have students walk the block around the school with adult supervision, mark every hydrant on a simple map, and measure the distance between them in paces, then compare their spacing with the fictional Orrinbeck crew's route of 18 hydrants in a day. Students can also write three questions for a local water department crew about which valves are hardest to find.