API Tank Sampling Procedure

[dash81]

Hi everybody, I am wondering if there is any information about sampling procedures of API tanks with N2 blanket, the sample is to be taken from the tank roof through the manhole and during normal operation. I know it might looks kinda weird but my chief is asking me to find information about it.

 

[11echo]

This sample is to be taken from the manway? ...OR through a gauge/thief hatch? Either or you'll lose the N2 blanket once you open to ATM. What are you sampling through the roof?

 

[dash81]

The sample is to be taken through a thief hatch and the product is diesel. Thanks a lot.

 

[11echo]

I've seen diesel tanks there we took samples from different "zones" off the tank, but they were ALL off the side of the tank. That way you won't lost the blanket gas when you do. ...Good Luck!

 

[786392]

Dears;
I don't exactly know from API code(s) reference, but in certain cases

on Vertical API 650 design welded steel petroleum storage tanks

small diameter tapping from different shell level points(duly isolated with block valves)are practiced along with needed reinforcement (doublers)if any,required to ensure shell plate's mechanical withstanding strength.

These points should not make loss of blanket gas normally; but the sampled material(s) come from close vicinity of tapping location and might not be fully representative.

Other forum colleagues(more learned) may guide us better/ further on the issue.

Best Regards
Qalander(Chem)