Zone and Division Classification of a 420# LPG Cylinder

Hi Guys,

Quick question, I have an hard time finding a clear answer in regards to Division and Zone in a 420# LPG Tank application.

Basically we would like to know what would be the Zone and Division classification just above the tank between the collar and the top of the tank.

Thanks!

Pascal
 

rbalex

Moderator
Staff member
The first thing to recognize is it won't be both Division AND Zone. It's an either/or situation. See Section 505.7, especially Subsection 505.7(B).

After that see NEC Section/Table 515.3, NFPA 30, NFPA 497, or API RP500 OR 505 (depending on whether you decide to go with Divisions or Zones)
 
In fact, this is for a product design. It will need to comply to both US and Canada, so, it looks like it will need to comply to both, Zone 0 and Division 1 as
Per NEC Article 505-10(b)(1), a Division classified product may be installed in a Zone Classified location but the reverse is not true.

I partly found the answer in NFPA 58

3-7.2.3 Electrical equipment installed on LP-Gas cargo vehicles shall comply with 6-1.1.4.

--> Tank is outdoor, it looks like electronic equipment needs to comply to Division 1 if product is installed within 1.5m (5ft) in all directions from a point of transfer.

and

Table 3-7.2.2

Thanks a lot Robert!
 

kwired

Electron manager
Location
NE Nebraska
In fact, this is for a product design. It will need to comply to both US and Canada, so, it looks like it will need to comply to both, Zone 0 and Division 1 as
Per NEC Article 505-10(b)(1), a Division classified product may be installed in a Zone Classified location but the reverse is not true.

I partly found the answer in NFPA 58

3-7.2.3 Electrical equipment installed on LP-Gas cargo vehicles shall comply with 6-1.1.4.

--> Tank is outdoor, it looks like electronic equipment needs to comply to Division 1 if product is installed within 1.5m (5ft) in all directions from a point of transfer.

and

Table 3-7.2.2

Thanks a lot Robert!
Looks like you are on right track, tank alone doesn't create a classification, it is where open connections during transfer occurs or possibly an area where venting is intended to occur that a classification may be created.
 
The other thing to clarify is the grounding. Since this device will be a Battery only operated device with a sensor. As per my understanding, the safety barrier's ground (will be using I.S.) will be connected on the battery's negative terminal only as we have no other external "outside connection" apart from the sensor. I went through NEC and CEC regarding grounding chapters and nothing is specifically pointing battery operated devices. At some extend, there is no energy to be diverted to earth ground since it is battery operated...
 

rbalex

Moderator
Staff member
The other thing to clarify is the grounding. Since this device will be a Battery only operated device with a sensor. As per my understanding, the safety barrier's ground (will be using I.S.) will be connected on the battery's negative terminal only as we have no other external "outside connection" apart from the sensor. I went through NEC and CEC regarding grounding chapters and nothing is specifically pointing battery operated devices. At some extend, there is no energy to be diverted to earth ground since it is battery operated...
In that case you now need to become familiar with ANSI/ISA-RP 12.06.01 and ANSI/ISA-12.12.01 (latest editions) for application guidelines.
 
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