FREE Certified Pipefitter Pipefitting Math and Calculations Questions and Answers

Question 1

A pipefitter needs to install a simple offset using two 45-degree fittings. The required offset distance (Set) is 20 inches. What is the center-to-center travel distance of the pipe connecting the two fittings?

Accepted Answer

28.28 inches

Answer

For a 45-degree offset, the travel distance is calculated by multiplying the set (offset distance) by the constant 1.414. Therefore, Travel = Set x 1.414. In this case, Travel = 20 inches x 1.414 = 28.28 inches.

Question 2

A pipe run of 80 feet needs to be installed with a uniform grade of 1/4 inch per foot for proper drainage. What is the total fall of the pipe over the entire run?

Accepted Answer

1 foot, 8 inches

Answer

To find the total fall, multiply the length of the pipe by the required grade. Total Fall = Pipe Length x Grade. Total Fall = 80 feet x (1/4 inch/foot) = 20 inches. To convert inches to feet and inches, divide by 12. 20 inches / 12 inches/foot = 1 with a remainder of 8. So, the total fall is 1 foot, 8 inches.

Question 3

A pipefitter is fabricating a rolling offset. The horizontal offset (or 'spread') is 12 inches and the vertical offset (or 'rise') is 16 inches. What is the true offset length?

Accepted Answer

20 inches

Answer

The true offset is the hypotenuse of the right triangle formed by the horizontal and vertical offsets. It is calculated using the Pythagorean theorem: True Offset = √(Rise² + Offset²). True Offset = √(16² + 12²) = √(256 + 144) = √400 = 20 inches.

Question 4

When calculating the required cut length of a pipe to be installed between two 6-inch, 90-degree, long-radius butt-weld elbows, what critical dimension must be subtracted from the center-to-center measurement?

Accepted Answer

The take-off dimension for each fitting.

Answer

The 'take-off' is the dimension from the centerline of the fitting to the face where the pipe butts against it. To get the actual 'end-to-end' cut length of the pipe, you must subtract the take-off for each of the two fittings from the overall center-to-center measurement.

Question 5

A piping system requires an equal spread offset using two 45-degree fittings. The spread (center-to-center distance between the parallel pipes) is 10 inches. Which of the following calculations determines the 'extension' piece length required to maintain the equal spread?

Accepted Answer

Spread x 0.414

Answer

For an equal spread offset with 45-degree fittings, the length of the extension piece needed to connect the fittings and maintain the spread is calculated by multiplying the spread distance by the constant 0.414. Extension = 10 inches x 0.414 = 4.14 inches.

Certified Pipefitter Practice Test

Certified Pipefitter Practice Test

FREE Certified Pipefitter Pipefitting Math and Calculations Questions and Answers