Emergency Venting as per API 2000 3

[takiyasamsama]

As per API 2000, the need of emergency venting is not required provided the rules in 3.4.3 are met. Let say, the roof for the tank is design to be weak roof-to-shell thus the emergency venting is not required. Is this true?

However it also mentioned in API 2000, the emergency venting is required to avoid failure of the weak roof-to-shell joints.

Also can anyone provide me some example calculation for the fire relief requirement. Also what criteria to determine the liquid is hexane type or higher than hexane as mentioned in Table-2 for C-factors.

 

[IFRs]

API 2000 does not require emergency vents if the tank has a frangible roof-to-shell joint, however it says that emergency vents [highlight #8AE234]may[/highlight] be used to if you would like to protect this joint.

 

[takiyasamsama]

Thank you IFR. I had doubt about this matter and thank you for clearing it up.

May I ask you, in API 2000 it mentioned regarding the Hexane like liquid. What is it mean by that?

 

[fegenbush]

"Hexane like" refers to the volatility of the product stored. This is used as a reference to a product which will exhibit a significant evaporation rate at a relatively low temperature. This comparison is considered conservative, as most products do not have such a high volatility as hexane.

 

[tankSnvessels]

If you would have noted, many foot notes in API 2000 refer as, "...by using the latent heat of vaporization of hexane...". So the code wants to clarify that they have considered at the max for hexane. If you have to design for something more severe than this, than you cannot just use the tables and graphs which are meant for products like hexane.