Re: Re: Fire Case

From: <Rajesh.Balapure@ril.com>
Date: Mon Sep 08 2003 - 05:44:00 EDT

Dear Tushar,
1)there often requirement of minimum frequency to be maintained in flare lines.??
---->Can you please clarify the above requirement .What is the minimum
frequency to be maintained?
What is the basis apart from the 7 Hz as specified in some tender bid packages,where no basis is mentioned.
2)
Analysing lines with very wide temp. diff. is not only difficult but also results in improper supporting. In such cases Analysis Temperature should be established and line should be analysed at analysis temperature and operating temperature.
---->Can you please clarify the basis for arriving at the Analysis
Temperature??
3)Pipe line should be deigned to withstand these conditions mechanically (material selection, thickness etc) but should not be stress analysed for such conditions. Do you expect plant to operate in fire case ?

------>Do you expect that the only material selection is sufficient for safe functioning of the Flare Header??
  We had observed an Incident that entire Flare Header was at the upset temperature,due to upset condition and we are saved from the problems because of the analysis done at upset temp.

Also my previous query is still unanswered,Request the member to throw some light.

Query:-

The cut off for percentage variability of spring is limited to 25 % ( or 50 mm deflection ) industry-wide, except for locations close to strain sensitive equipments.

Other than that for, non critical locations, why the deflection is typically
limited to 50MM? If 50 mm does not cause a variability change of more than 25 % in what way can it harm the spring /the system?

Also for critical lines some adopt to restrict variation of the spring to 10 to 15 %
How does it affect the system?
when it is recommended to restrict variation of spring to 10 -15%. Your comments are appreciated.

Regards,
Rajesh Balapure

Regards,

Rajesh V Balapure

                       "Tushar
                       Rajyaguru"               To:       "piping design"
<PipingDesign@yahoogroups.com>
                       <trajyagu@ltcis.l        cc:       (bcc: Rajesh V
Balapure/JAMNAGAR/RIL)
                       tindia.com>              Subject:  [PipingDesign] Re: Fire
Case
                                          Importance: Normal  Sender's OU:
Reliance |------------------|
                       09/08/2003 11:42
| [ ] Confidential |
                       AM
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                       Please respond to
                       PipingDesign

No, This is over-designing. Generally it is seen that there is always very wide difference in design temperature (which is often derived considering worst situations like fire case etc.) and operating temperature in case of flare lines. May be operating temperature around 50-70 deg and design in order of 300 deg C. Also there often requirement of minimum frequency to be maintained in flare lines. Analysing lines with very wide temp. diff. is not only difficult but also results in improper supporting. In such cases Analysis Temperature should be established and line should be analysed at analysis temperature and operating temperature. Pipe line should be deigned to withstand these conditions mechanically (material selection, thickness etc) but should not be stress analysed for such conditions. Do you expect plant to operate in fire case ?

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"NO EFFORT IN LIFE GOES UNPAID, HENCE GO AHEAD"

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Tushar K. Rajyaguru
Plant & Piping Engineering,
Larsen & Toubro - Chiyoda Ltd.,

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for stress analysis of such a flare,do you think that fire temp.

(300 c)shall be considered?shall all branches to the flare be considered as hot (300 c)?

> regard's

[Non-text portions of this message have been removed]

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Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ Received on Mon Sep 08 05:44:00 2003