What does the red, white, and blue markings mean on a constant spring support?

November 23, 2021

Red, White and Blue Marks:

All constants are shipped with at least 3 color-coded rivets (red, white and blue).
Red: operating (HOT) position
White: installation (COLD) position
Blue: over travel (MAX AVAILABLE) position

Below are sketches of one direction vertical travel:

Installation maintenance rivets one direction



Below is a sketch of dual direction vertical travel:


Rivets two directions

What are individual Stress-Intensification Factors (SIF) applied for?

September 29, 2015

Welds, fittings, branch connections , and other piping components where the possibility of fatigue failure could occur.

What is the Stress-Intensification Factor?

September 28, 2015

The Stress-Intensification Factor is the ratio of the maximum stress intensity compared to the nominal stress.

What does the Maximum Shear Stress Theory state?

September 18, 2015

The maximum shear stress theory states that failure of a piping component occurs when the maximum shear stress exceeds the shear stress at the yield point in a tensile test.

Out of the Six Theories of Failure, which are the 2 that are the most widely used?

September 17, 2015

The Maximum Principle Stress Theory and Maximum Shear Stress Theory

What does the Maximum Principle Stress Theory state?

This theory states that yielding in a piping component occurs when the magnitude of any of the three mutually perpendicular principal stresses exceeds the yield strength of the material.

What are the 5 modes of failure of piping design?

September 16, 2015

Failure by general yielding, yielding at sub-elevated temperature, brittle fractures, and fatigue.

What is the purpose of Stress Analysis?

Stress analysis ensures the safety of piping and piping components, safety of connected equipment and supporting structure, and that piping deflections are within limits.

What is Stress Analysis?

September 11, 2015

A term applied to calculations, which address the static and dynamic loading, resulting from the effects of gravity, temperature changes, internal pressures, fluid flow, seismic activity, and any external loads.

What is the Stress-Strain curve?

It is a visual representation of the effects of various loading conditions on a piping system between stress and strain.

What are the 5 majority causes of failures (after flexibility analysis) of a system?

Vibration, thermal bowing, creep, thermal fatigue, and steam/water.

What are the effects of excessive flexibility?

September 9, 2015

Excessive flexibility causes an increase in material costs, pressure drops, and loss of pump efficiency.

What are the methods of incorporating flexibility in a piping arrangement?

Using flexible piping with bends and turns, use of expansion loops between fixed locations, or use of expansion joints between two anchor points of a pipe run.

What is the purpose of flexibility analysis?

September 4, 2015

Flexibility analysis assures that there is not any overstress or fatigue, leakage at joints or distortions are piping connections or terminals.

What is the objective of having flexibility within a piping system?

To produce neither excessive stress within the configuration and limit excessive end reaction at the piping terminal.

What are some applications for a piping system?

September 3, 2015

Conventional and nuclear power plant, petroleum refinery, chemical industry, natural gas transmission, food processing and pharma industry, water and sewage plants, air conditioning and refrigeration system.

What are some adverse operating conditions of a piping system?

Fluctuating temperatures, changes in pressure, and modification in flow rate.

Why is fluid velocity controlled?

July 29, 2015

Fluid velocity is controlled to prevent operational problems such as water hammer, steam hammer, relief valve discharge loading, and vibrational loads.

What is a two phase flow?

A two phase flow is when phases do not consist of same chemical substance.

Why do piping systems use pumps?

Piping systems use pumps to develop the pressure or head required to maintain the system design flow rates.