Pipefitter Pipefitting Trade Math 2 — Questions and Answers
Question 1: A pipe run requires a 45° offset with a travel distance of 14.14 inches. What is the approximate offset rise?
- 8 inches
- 10 inches (Correct answer)
- 12 inches
- 14 inches
Correct answer: 10 inches
For a 45° offset, the rise equals the travel multiplied by 0.707; 14.14 × 0.707 ≈ 10 inches.
Question 2: A circular pipe has an outside diameter of 6.625 inches. What is its circumference? (Use π = 3.1416)
- 18.42 in
- 20.81 in (Correct answer)
- 22.34 in
- 24.50 in
Correct answer: 20.81 in
Circumference = π × D = 3.1416 × 6.625 ≈ 20.81 inches.
Question 3: A pipe is to be cut to leave a 3/8-inch gap for a weld. If the overall run is 120 inches and there are 4 welds, what is the total cut allowance?
- 1 inch
- 1-1/2 inches (Correct answer)
- 1-3/4 inches
- 2 inches
Correct answer: 1-1/2 inches
Total cut allowance = 4 welds × 3/8 inch = 1-1/2 inches.
Question 4: What is the volume of a cylindrical pipe section with an inside diameter of 4 inches and a length of 24 inches? (Use π = 3.1416)
- 201.06 in³
- 301.59 in³ (Correct answer)
- 401.92 in³
- 501.33 in³
Correct answer: 301.59 in³
Volume = π × r² × L = 3.1416 × 4 × 24 = 301.59 in³.
Question 5: If a 6-inch pipe carries flow at 500 GPM, and you reduce to a 3-inch pipe, what is the approximate velocity ratio change?
- Flow doubles
- Flow quadruples (Correct answer)
- Flow stays the same
- Flow halves
Correct answer: Flow quadruples
Halving the diameter reduces the area by a factor of 4, so velocity must quadruple to maintain the same flow rate.
Question 6: A welder needs to wrap a pipe with 2-inch-wide insulation tape at a 45° helix angle. If the pipe OD is 10 inches, how many linear inches of tape are needed per foot of pipe?
- 18.85 in
- 25.13 in
- 53.41 in (Correct answer)
- 75.40 in
Correct answer: 53.41 in
At 45° helix the pitch equals the tape width; inches of tape per foot ≈ (12/2) × π × 10 = 6 × 3.1416 × 10 ≈ 188.5 / wrap, requiring ≈ 53.41 in total per lineal foot given the helix geometry.
Question 7: A system uses 300 feet of 2-inch Schedule 40 pipe weighing 3.65 lb/ft. What is the total weight of the piping?
- 912.5 lb
- 1,095 lb (Correct answer)
- 1,278 lb
- 1,460 lb
Correct answer: 1,095 lb
Total weight = 300 ft × 3.65 lb/ft = 1,095 lb.
Pipefitter Pipefitting Trade Math 2
A pipe run requires a 45° offset with a travel distance of 14.14 inches.
What is the approximate offset rise?