5 replies to this topic

[processengeng]

Dear all,

I have a breather valve installed on a atmospheric tank. Originally, I specified 100% of accumulation. But Based on vendor feedback, they are asking if 105% accumulation is acceptable.

I checked API 2000. Previously in edition 1998, there was a table to mention that normal practice is 100% accumulation for direct acting breather valve. But the table was removed from API 2000 edition 2014. There is no more such statement. Can anyone advise if 105% accumulation is acceptable?

Thank you in advance.

Edited by processengeng, 10 August 2016 - 07:59 AM.

[cea]

With my understanding, 50% over pressure is industrial standard being followed.

 

It is expected that vendor shall indicate his overpressure requirement for closest model. However, I do not find any reference / guideline for specifying over pressure.

[fallah]

Processengeng,

 

You fail to specify the design code of the tank, anyway if it's API 650 one, the main point is: relieving pressure at full lift to be equal to or lower than tank design pressure (or MAWP) regardless of the overpressure percent. Hence there is no rule to specify the overpressure value and vendor should consider the tank design pressure is specifying overpressure in his suggested breather valve... 

[christopherchoa]

Processengeng,

 

From my experience, I always specify the set pressure during FEED to 100 percent accumulation. Then during detailed engineering, vendor may change this set pressure with their product for some reason.

 

Note that when vendor increase accumulation, their valve can permit more flow. There is a factor per Vendor brochure. 

[fallah]

I have a breather valve installed on a atmospheric tank. Originally, I specified 100% of accumulation. But Based on vendor feedback, they are asking if 105% accumulation is acceptable.

Can anyone advise if 105% accumulation is acceptable?
 

 

Processengeng,

 

Actually for an atmospheric tank, it's not allowed the accumulation to be more than 100% hence the answer to vendor question is: no.

[fallah]

 

From my experience, I always specify the set pressure during FEED to 100 percent accumulation. Then during detailed engineering, vendor may change this set pressure with their product for some reason.

 

Note that when vendor increase accumulation, their valve can permit more flow. There is a factor per Vendor brochure. 

 

Hi,

 

You may confuse about accumulation and overpressure. When we say "accumulation" we are talking about the tank itself while when we say "overpressure" we are talking about breather valve. Then, it might you mean overpressure instead accumulation...

For atmospheric storage tank, neither vendor nor somebody else cannot increase the accumulation from 100%