Use of x-proof capped elbows as splice location

[kameele]

I am working on a retrofit project that involves changing the connection conduit to a Cl 1/Div 1 solenoid from Div 2 suitable to Div 1 suitable. There are 10 identical SOVs (top of Propane tank farm) The area was originally classified (assumed?) to be Div 2, but several relief valves are within 5' of the SOV which should have required it to be Div 1. The present connection has liquid-tight flex out of a Form 7 T (with one end dead-legged as a support) The rest of the conduit system is built with GUA series bodies and RMC. I feel I have two options for the connection. According to an ASCO white paper, there is no seal required at the SOV, which I also agree with.

Replace the Form 7 with a GUAT body.

1. Replace the liquid-tight with an X-proof flex of the same length.

2. Or, use an MI cable of suitable length. This is where my question (at long last) comes. Can I use an X-proof capped elbow (C-H LBY series or equal)between SOV and MI as a splicing point? It would be cheaper and take up less space. I know only conduit bodies can be used for splicing, but am unsure whether I can define this as a body. I know I have seem splices done in them, but that doesn't necessarily make it right. I am thinking of using the MI because of cost, rather than it being a seal. That's an extra benefit

Any help would be greatly appreciated.

Kevin

 

[don_resqcapt19]

Kevin,
The capped elbow is a conduit body, but is it marked with its volume? You can only make splices in conduit bodies that are marked with its volume and the wire fill must comply with 314.16(B). See 314.16(C)(2).
Don

 

[rbalex]

If you use Option 1 you would still need a boundary seal whether you needed a seal specifically at the SOV or not.

Don's comment on Option 2 is, of course, valid.

Personally, I would look very carefully at that 5? radius. Three feet is more common. If necessary, I?d move the discharge vent (not necessarily the valve itself)

 

[kameele]

Thanks for the responses. I found a Cr-H table of all their body volumes, but there isn't one noted on the actual body. Could be that it's only large enough to have one wire spliced in it, so no terribly useful.

We're constrained to use NFPA 59 for an LPG plant. It says 5' Div 1 for a relief valve with no wiggle room. I believe the 3' comes from AGA recommended practices, which the old-timers here say is not enforceable.

There are boundary seals installed as the main conduit run leaves the top of the tank (and therefore the Div 2 area) and when it goes underground to make its way to the control room. They also put seals at the control room which seems to be extra.

 

[rbalex]

If you are dealing with LPG, I'd use the NFPA 59 dimensions too. The 3' radius is also referenced in both NFPA 497 and API RP500 and its use depends on the application. LPG is an HVL so 5? is the likely application.

If you use Option1 you will still need a boundary seal at the Division 1/Division2 boundary in addition to the one you described.


Now I?d really consider trying to get the discharge vent locations relocated.