5 replies to this topic

[mido]

Happy new year everybody, We have in my company many crude oil tanks from 70's we don't have sufficient information about it due to poor filling. we work now in update our database, We found that many of them have name plate stated that design pressure of the tank is ATM and the PVRV on them are 3.5 mbarg. My question what is meant by ATM and how to know the design pressure of a tank if i not have sufficient data?
      

[Chemitofreak]

Hi,

 

For me ATM stands for Atmosphere i.e. the tank is designed for atmospheric pressure.

 

What is the Standard used for designing these storage tanks?

 

Generally API 650 or API 620 are used, following is the basic difference between the two standards

 

API 650:

 

• API-650 is a general specification for designing welded steel storage tank for oil storage
• Large size storage tank
• Temperature: -40F to 500F
• Pressure: up to 2.5 psig

API 620:

• Design and Construction of large welded low pressure storage tank
• Large size storage tank
• Temperature: -325F to 250F
• Pressure: up to 15 psig
•  

​In API 650 tanks the pressure in the tanks should never exceed MAWP of the tank.

[fallah]

Happy new year everybody, We have in my company many crude oil tanks from 70's we don't have sufficient information about it due to poor filling. we work now in update our database, We found that many of them have name plate stated that design pressure of the tank is ATM and the PVRV on them are 3.5 mbarg. My question what is meant by ATM and how to know the design pressure of a tank if i not have sufficient data?
      

 

Hi,

 

ATM stands for atmospheric means the tank's design code had mostly been API 650. The design pressure of API 650 tanks is a few mbar's above the atmospheric pressure but less than 18kpag which depends on the tank's roof weight and its mechanical design and manufacture.

[mido]

 

Happy new year everybody, We have in my company many crude oil tanks from 70's we don't have sufficient information about it due to poor filling. we work now in update our database, We found that many of them have name plate stated that design pressure of the tank is ATM and the PVRV on them are 3.5 mbarg. My question what is meant by ATM and how to know the design pressure of a tank if i not have sufficient data?
      

 

Hi,

 

ATM stands for atmospheric means the tank's design code had mostly been API 650. The design pressure of API 650 tanks is a few mbar's above the atmospheric pressure but less than 18kpag which depends on the tank's roof weight and its mechanical design and manufacture.

 

Yes it is designed according to API 650 . So i can assume it is design pressure 2.5 psig??

[Pilesar]

The name plate says the design pressure is ATM. This is 0 psig design pressure. I would not use this tank for anything but low hazard service such as water or non-flammable liquid. The design pressure is too low to connect to a flare system. The pressure relief setting of 3.5 mbarg is reasonable. 

[breizh]

Hi,

Why don't you ask the construction company , they may have the records about your tank ? 

BTW a visual inspection should be a starting point because your equipment is quite old before allocation .

yes ATM = atmospherical pressure or 0 barg

Good luck

Breizh