Dear All,

 

API STD 2000 is not applicable to external floating roof tanks is a given. Hence the external floating roof tank working and standing losses cannot be calculated based on API 2000. My understanding is API 42, Chapter 7 needs to be used for tank vapor losses and thus for sizing of VRU irrespective of tank configuration. Also, VRUs are never sized for thermal outbreathing calculations as given in API 2000. Working losses (liquid filling) also need to be calculated as per API 42, Chapter 7.

 

Can somebody corroborate my understanding?

 

Regards,

Ankur.

Hi,

I would recommend you to read the article related to application of flame arresters in the link below. German standard TRbF 20 has explicit guidelines for installing flame arrester application. Refer the links below:

https://www.aiche.or.../20131216_1.pdf

http://www.hemmingfi..._arresters.html

Regards,
Ankur

Hi,

The modern method of placing fire and gas detectors is to generate contours or maps for fire exposure and / or gas leaks for a specific area or unit. This requires a fire and gas mapping study using sophisticated mapping tools such as Detect3D.

Here is a link for Detect3D:

http://insightnumeri...tion-Report.pdf

There are specialist companies who provide F&G mapping studies. You can google these specialized companies involved in various process safety management services including F&G mapping. In India one such company is “Chola MS Risk”.

Regards,
Ankur.

Hi,

 

Refer the link below for what Bobby has suggested regarding checking it against the 2-K method by Hooper. Harvey Wilson's valuable observations are also provided in the thread. A spreadsheet for 2-K method also appears as an attachment for 2-K method in post #4 of the thread.

 

https://www.cheresou...-pipe-fittings/

 

Regards,

Ankur.

Hi,

 

Foam extinguishment is required generally for fires classified as "Class B" fires and the chemicals involved in a "Class B" fire. Refer the link below for firefighting foam system design guidelines:

 

https://www.cheresou...d-calculations/

 

Regards,

Ankur

Hi,

 

There is a specific book: "Process Plant Commissioning" by David Horsley which should be of some guidance.

 

Regards,

Ankur.

Hi,

I understand your dilemma and appreciate your questioning attitude. The chemical process industry has evolved over the last 80-90 years. Some of the guidelines and practices being utilized today have been tested for their efficacy since the early days of the chemical process industry and have been found to be effective and workable even today and hence have become established norms. Now there may be more effective guidelines and precision values of certain process variables such as momentum, approach etc using advanced simulation tools but the fact remains that many of these established norms and numbers are field tested over numerous installations over long years and thus have become the de facto guidelines. The whole idea of using these established norms is not to re-invent the wheel.

Having said that, I would certainly advise young engineers to question the boundaries of the established norms. In fact I have posted a blog post for a very similar topic which I would recommend you to read. Here is the link:

https://www.cheresou...-and-practices/

Regards,
Ankur

Hi,

Refer to my blog post on calculating the dielectric constant:

https://www.cheresou...l-transmitters/


Regards,
Ankur

Ramesh,

 

If the corrected hydrotest pressure for the shell side is lower than the design pressure of the tube side then a PSV would be required considering a tube rupture case for the shell-and-tube exchanger.

 

 

Corrected hydrotest pressure is defined as follows:

P_corrected = P_hydrotest x (σ_scenario / σ_hydrotest)

 

Where:

P_corrected = Corrected hydrotest pressure, kPag

P_hydrotest = Hydrotest pressure, kPag (Current ASME Code for pressure vessels defines as 1.3*MAWP)

σ_scenario= Material stress at the overpressure scenario temperature, MPa

σ_hydrotest = Material stress at the hydrotest temperature, MPa

​

​Hope this helps.

 

​Regards,

​Ankur.