Posted by: bag_piper
Literature on minimum natural frequency requirement - 12/17/12 04:02 AM
Is anyone having any literature / basis / company guideline regarding:-
1. Minimum natural frequency required for two phase flow carrying piping . ( 2 Hz or 4 Hz?)
2. Minimum natural frequency required for transfer lines in refineries with two phase flows . ( 4 Hz or more ?)
3. Slug / plug flow lines ( 5 Hz or more?)
Regards,
bag_piper
Posted by: MoverZ
Re: Literature on minimum natural frequency requirement - 12/17/12 07:17 AM
Norsok gives GUIDANCE about minimum natural frequencies. They are relevant to smaller bore systems, i.e. not big bore FCC unit pipework etc.
There are no mandatory limits.
You need to use some good engineering judgement.
Posted by: danorc
Re: Literature on minimum natural frequency requirement - 01/09/13 10:28 PM
DNV‐RP‐D101 Clause 2.2.7.1 specifies 4-5 Hz.
Posted by: MoverZ
Re: Literature on minimum natural frequency requirement - 01/10/13 02:09 AM
Danorc,
Your reference to DNV‐RP‐D101 is correct, but it is ONLY recommended practice. It is not a requirement, nor is it pipe size specific.
Reading the Foreward to DNV‐RP‐D101 it is clear that the document is aimed at offshore appllications. See my comments above.
Posted by: Richard Ay
Re: Literature on minimum natural frequency requirement - 01/10/13 10:11 AM
Everything I've seen on this topic is "Recommended Practice", or a "Guideline". These may be pulled into a project as "requirements", but I've never seen a published requirement for a minumum natural frequency.