SPED Pipe Support Design 2

Question 1

Which load category per ASME B31.3 is used to evaluate sustained (primary) stresses in a piping system?

Accepted Answer

Pressure, weight, and other sustained mechanical loads combined

Answer

Occasional loads — wind and seismic only

Answer

Thermal expansion loads only

Answer

Hydrostatic test pressure only

Question 2

What is 'cold spring' in pipe support and piping design?

Accepted Answer

An intentional cut-short or offset during installation to pre-compensate for thermal growth

Answer

A cryogenic-rated spring hanger assembly

Answer

A support used exclusively in cold-service (sub-zero) piping

Answer

A spring constant measured at ambient temperature

Question 3

When calculating allowable pipe support span, which single geometric factor most increases the permissible span length?

Accepted Answer

Larger pipe diameter and schedule (greater section modulus)

Answer

Higher operating temperature

Answer

Thicker insulation layer

Answer

Higher fluid specific gravity

Question 4

A constant-effort (constant load) hanger is preferred over a variable spring hanger when:

Accepted Answer

Thermal movement is so large that a variable spring would have unacceptable load variation (>25%)

Answer

The pipe operates below 200°F with negligible thermal movement

Answer

The pipe is subject to frequent external vibration

Answer

The line is a small-bore drain with minimal load

Question 5

What maximum mid-span deflection is most commonly specified in piping project standards to avoid flow and stress problems?

Accepted Answer

1/2 inch (12.7 mm) or as defined by the applicable code and project specification

Answer

1 inch regardless of pipe size

Answer

10% of the pipe nominal diameter

Answer

No explicit limit — stress alone governs

Question 6

How are 'occasional loads' such as wind and seismic treated differently from sustained loads in ASME B31.3?

Accepted Answer

They are combined with sustained loads but checked against higher allowable stress limits

Answer

They are ignored if the pipe is insulated

Answer

They are evaluated with the same stress limits as sustained loads

Answer

They only apply to outdoor piping above 50 ft elevation

Question 7

What is the function of a 'limit stop' (travel stop) in a pipe support system?

Accepted Answer

It restricts pipe displacement to a defined range, allowing normal thermal movement but preventing excessive travel

Answer

It sets the maximum allowable support span on engineering drawings

Answer

It is a regulatory shutdown device on pressurized lines

Answer

It permanently anchors the pipe in all directions