Pipefitting Math and Calculations Flashcards
6 cards from real PIPEFITTER practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Pipefitting Math and Calculations flashcards as text
A pipe must travel 18 inches horizontally and 18 inches vertically. Using 45° elbows, what is the travel distance (center-to-center) along the offset pipe?
Answer: 25.46 inches
For a 45° offset, travel = offset × 1.414. Since both legs are 18 inches, the offset is 18 inches, so travel = 18 × 1.414 = 25.46 inches.
What is the formula to calculate the circumference of a pipe for layout work?
Answer: C = π × D (3.1416 × outside diameter)
Circumference = π × D, where D is the outside diameter of the pipe. This is used to lay out saddle cuts, branch miter cuts, and wrap-around marks.
If a pipe run must drop 6 inches over a horizontal distance of 10 feet to achieve proper drainage slope, what is the slope expressed as a fraction per foot?
Answer: 1/2 inch per foot
6 inches ÷ 10 feet = 0.6 inches/foot. Expressed as a fraction, this rounds to approximately 1/2 inch per foot (0.5"/ft).
What is the 'take-out' of a 90° long-radius elbow on a 4-inch NPS pipe (LR elbow center-to-face dimension)?
Answer: 6 inches
For a long-radius (LR) 90° elbow, the center-to-face dimension = 1.5 × NPS. For 4-inch NPS: 1.5 × 4 = 6 inches.
A pipe flange has 8 bolt holes on a 9.5-inch bolt circle diameter (BCD). What is the spacing between adjacent bolt holes?
Answer: 3.74 inches
Bolt hole spacing = π × BCD ÷ number of bolts = 3.1416 × 9.5 ÷ 8 = 29.85 ÷ 8 = 3.73 inches.
What is the developed length of a 90° long-radius elbow fitting for a 3-inch NPS pipe?
Answer: 7.07 inches
Developed length of a 90° LR elbow = (π/2) × CLR = 1.5708 × (1.5 × NPS) = 1.5708 × 4.5 = 7.07 inches.