Plumbing and Pipe-Fitting Challenges

Students often wonder when they will use the math they learn in school. These activities are designed to answer that question as it relates to measuring, working with fractions and decimals, basic geometry, and the Pythagorean Theorem. Plumbers and pipe-fitters need to have a good working knowledge of these and other math concepts to solve problems that arise frequently on the job. To enter any of the building trades, an apprentice must score well on basic math tests. A solid understanding of basic math opens the door to many financially and personally rewarding careers.

Day 1 -- 60 to 90 minutes

Introductions -- 5 minutes

Introduce the plumbers to students (if they are present) and ask them to talk about their careers.

Fraction Counting Warm-ups -- 5 minutes

If the students need to review reading a ruler, ask them to complete the fraction counting warm-ups.

Adding and Subtracting Fractions on the Ruler -- 10 minutes

Even if the students know how to add and subtract mixed numbers on paper, it is useful to ask them to learn to use their rulers to complete the addition and subtraction problems in this section. The purpose of this part of the activity is to improve computational flexibility and number sense relating to fractions.

Determining Take-Offs -- 10 minutes

Ask students to look at the various fittings. Explain that plumbers name angles in terms of the deviation from a straight line of flow rather than in terms of the interior angle. Thus, a ``45 degree fitting'' has an interior angle of 135 degrees.

Discuss the concept of a take-off as a group and ask students to discover take-off values for various fittings. Come back as a group to compare the values obtained. The following are the expected take-offs for 3/4'' PVC pipe: 90 degree fittings have a take-off of 1/2'', 45 degree fittings have a take-off of 3/8'', and T degree fittings have a take-off of 5/8''. However, actual values may differ by a small amount because we are not filing or lubricating the edges of the pipe ends as a plumber would. Students should use the values they find rather than the official take-offs.

Blueprint Challenges -- 25 to 45 minutes

• Discuss safe use of tools. -- 5 minutes
• Ask students to figure take-offs for first blueprint and create a supply list. -- 5 minutes
• Obtain supplies. Measure and cut pipes to proper lengths and assemble model. -- 10 minutes
• To prevent leaks, a plumber must create a model that is accurate to the nearest 1/8 of an inch. Once model is complete, students should check the model against the appropriate poster board template outline. (Trace a model with correct measurements onto the posterboard to create the template.)
• If time allows, repeat these steps for two other blueprints. -- 10 minutes

Create Their Own Models and Blueprints -- 10 to 30 minutes

If there is extra time, allow students to create their own models and blueprints.

Cleanup -- 5 minutes

Day 2: Offset and Travel -- 50 to 90 minutes

Finishing Work From Day 1

Teams that still need to finish blueprint challenges from Day 1 can continue to work on those.

Fraction to Decimal Conversion Chart -- 10 minutes

The purpose of this part of the activity is to make it easier for students to approximate irrational numbers obtained from the Pythagorean Theorem to the nearest 1/8 of an inch. Making the chart also reviews concepts of fraction equivalence.

Offset, Advance, and Travel -- 20 minutes

To complete this challenge, students should use the Pythagorean Theorem together with the fact that a 45-45-90 triangle is an isosceles triangle. This means that the Offset and the Advance are always equal. Students will need to remember to subtract the take-offs for the two 45 degree fittings.

Computing Travel -- 15 minutes

In this part of the activity, two pipe clamps holding pipes with an offset are taped with masking tape to the work surface. Students use their tools to determine the offset. They can either slide the pipes or use straight fittings to adjust the Advance to the correct value.

Pipe-Running Challenge -- 40 minutes

If there is enough time, create a pipe-running course for each team. A pipe clamp marks the starting line for the run of pipe. The students must make the pipe go around the wooden frame, but the pipe should pass close enough to be clamped to the outside of the frame. The pipe should continue to another point where it T's, sending one pipe to a styrofoam or cardboard box representing a furnace needing coolant, and sending the other pipe farther along the table and then down to hit a taped X on the floor which represents the drain.

Ideally, students should plan their design before acquiring the pipes. They should cut the pipe away from the work site and bring them back to their course only after cutting. This will encourage students to measure and think ahead. They tend to hold the pipe up and cut it in place without this requirement. Remind students that real pipes are often too large to be held in place while being cut, so plumbers usually need to measure and plan carefully.

Clean-up -- 5 minutes

This work placed into the public domain by the Riverbend Community Math Center.