Certified Pipefitter Rigging, Hangers, and Supports Questions and Answers

Question 1

A vertical steam pipe (riser) must be supported at each floor level it passes through. Which type of support is specifically designed to clamp onto the pipe and transfer the pipe's dead weight to the building's structure at that elevation?

Accepted Answer

Riser Clamp

Answer

A Riser Clamp is specifically designed for supporting vertical runs of pipe. It clamps tightly around the pipe, and the clamp itself rests on the floor or structural steel, thereby transferring the weight of the pipe section to the structure.

Question 2

A high-temperature piping system is expected to have significant vertical movement due to thermal expansion. To avoid transferring stress to sensitive equipment, the support must provide a consistent lifting force throughout the entire range of movement. Which hanger is best suited for this application?

Accepted Answer

Constant Support Hanger

Answer

A Constant Support Hanger uses a mechanism of springs and levers to provide a consistent supporting force throughout its full range of travel. This is critical for applications with large thermal movements, as it prevents transferring variable loads to nozzles or other hangers. A variable spring hanger's supporting force changes as the pipe moves.

Question 3

When using a two-leg sling bridle to lift a 2,000-pound pipe, what happens to the tension in each sling leg as the horizontal angle between the sling and the pipe decreases (i.e., the slings become flatter)?

Accepted Answer

The tension increases significantly

Answer

As the sling angle relative to the horizontal load decreases, the tension on each sling leg increases dramatically. At a 90-degree angle (vertical lift), each sling supports half the load. At 30 degrees, the tension on each sling is equal to the full weight of the load. This is due to the vector forces involved in the lift.

Question 4

A pipefitter is installing a trapeze hanger using 1/2-inch threaded rods to support a group of pipes. According to common standards like MSS SP-58, what is the correct practice for securing the nuts on the threaded rods?

Accepted Answer

The rod must extend fully through the nut with some threads visible.

Answer

For a threaded rod connection to achieve its full rated strength, the rod must be fully engaged with the nut. Best practice and standards require the rod to pass completely through the nut, with at least a few threads visible beyond the nut, ensuring full engagement and a secure connection.

Question 5

Which of the following is the primary purpose of a variable spring hanger?

Accepted Answer

To support a pipe's weight while allowing for vertical thermal movement.

Answer

A variable spring hanger is designed to support the dead weight of a pipe system while accommodating vertical displacement caused by thermal expansion or contraction. Unlike a rigid support, it allows movement, and unlike a constant support, its supporting force varies as the spring compresses or extends.

Certified Pipefitter Practice Test

Certified Pipefitter Practice Test

Certified Pipefitter Rigging, Hangers, and Supports Questions and Answers