3 replies to this topic

[lakshmi.narayanan]

In petroleum tank farms, in order to maintain the safe working environment, the hazardous area are classified into different zones.

As per EN60079-10-1, based on the explosive atmosphere and frequency of occurrence, explosive areas were categorized as Zone 0, Zone 1 & Zone 2.

Let us consider the case of cleaning a petroleum tank (Crude tank). The area inside the tank is considered as Zone 0 due to present of explosive atmosphere. Area away from the tanks are classified as Zone 1 & Zone 2. 

My query is as follows,

a. How Zone 1 & Zone 2 areas are distinguished in terms of distance from Zone 0 area?

b. What will be maximum distance of Zone 2 area from the Tank?

c. what will be the zone classification for the access road around tank farm?

A schematic drawing of tank farm with access road is attached for reference.

Please clarify on the above points.

 

 

Attached Files

•  Schematic drawing.jpeg   39.99KB   0 downloads

[breizh]

Hi,

Consider the resource attached.

It should be a good idea to talk to your fire brigade and/or safety bureau. 

Breizh

[shvet1]

Let us consider the case of cleaning a petroleum tank (Crude tank). The area inside the tank is considered as Zone 0 due to present of explosive atmosphere.

Incorrect. No explosives during cleaning. For example see API 2016 and docs attached.

 

Contact an experienced engineering company for proper ATEX zoning. Do you have Ex-zone layout in your Engineering or Design Package?

Attached Files

•  CS15 Tank Cleaning.pdf   762.54KB   8 downloads
•  EI Tank cleaning.zip   3.7MB   7 downloads
•  Foaming.pdf   3.36MB   7 downloads

Edited by shvet1, 05 May 2023 - 06:20 AM.

[seuenergy]

Hi Narayanan,

 

Firstly, you need to identify the zone inside the tank. it depends on how you sealing the tank. if the tank is sealing by continuous N2, and there is no air ingress when N2 failure (no breathing valve), then the zone inside the tank should be non-ex zone, because there is no explosion atmosphere is presented. 

But, if the tank has breathing valve. Then air could ingress when N2 sealing failure. Then zone 2 could be considered.

 

Secondly, for the other area inside the dike, it depends on whether there is potential leaking source(drain/flange e.g.). so there could be zone 2. This needs complete risk assessment depends on facility setting conditions.

 

For the distance of zone, please see respective standards you are going to follow. Different standards has its own requirements.