I have some questions generally about vibration.
- B31-1 is really superfiacialy saying that the designer should consider vibration .The exact wording is B31.1(101.5.4) :
" Piping shall be arranged and supported with consideration of vibration [see paras.120.1c and 121.7.5]". But simply there is no clue what to do at the design stage.

so the first question is
1- What actions must the designer take acc. to ASME B31-1 to avoid severe vibration at the design stage?

2- 120.1(c) states " Where resonance imposed vibrationand/or shock occurs during operation, suitable dampeners, restraints, anchors, etc. shall be added to remove these effects."

Now let us consider during operation(or commisioning) vibration is noticed. Then what the design engineer's responsibilities. I am working for a company which was responsible for only design work, not the assembly or commisioning etc. I am not sure if they had done the installation acc. to my designwork. But they are asking me to check the system at the field. What action should I take? Am I supposed to go there and stop operation wait till it gets cold start to check isometric drawings and the installation? Or simply am I supposed to analyse the vibration if it is necessary to take action or not?

3- I am simply not well knowlegded about vibration analysiss, can any one help me especially give the outlines (such as responsibilities, procedure,old histories etc. )?

Should all piping designers be vibration analysts ?

Really appreciate any expert help.
Thank you all in advance.

Answering your points:

1. You try to identify potential sources of vibration such as connected equipment, fluid flow, wind, seismic or other imposed excitation.

2. Clearly at the design stage, predicted vibration and resulting resonance can be prevented with proper use of restraints, snubbers etc.

Are you a piping designer (draftsman)or a stress engineer ? I would expect a stress engineer to be able to deal with site vibration problems.

Many problems with vibration are only evident in the field. You may need to employ an expert for your field work. Don't try to wing it. Catastrophic failures can and do occur due to vibration, and they can happen without warning.

Dear Friend,

As far as general troubleshooting is concerned, once relationships between symptom and cause are determined, the remedy for the problem is usually easy to determine. In piping vibration problems, however, symptom, cause, and fix are frequently difficult to separate.

During design phase, it's not easy to find out the source of vibration. Normally potential excitation sources are:
- Mechanical energy from machinery unbalanced forces and moments
- Pulsations generated by reciprocating compressors and pumps
- Pulsations emanating from centrifugal compressors and pumps; i.e., vane passing frequencies
- Pulsations originating from flow across or through an object
- Pulsations generated by restrictions and pressure drop
- Pulsations initiated by cavitations and flashing
- Pulsations caused by water hammer and surge
- etc.

But when investigating piping vibrations during operation or commisioning, the first step is to make an initial survey or walkdown of the piping system to identify piping spans or sections with high vibration levels. It is necessary to look for common symptoms of piping vibrations problems.
The second step is to make vibration and frequency measurements in order to evaluate specific piping spans that are suspected of having excessive vibration amplitudes. The third stage is to model the problem in CAESAR II and try to make a fix.

I believe that it is stress analyst's responsibility to take care of piping vibration. You may need some special training courses or have an expert to help you at the beginning.