NFPA 30 for gensets w belly tanks

[Jeng84]

I'm looking for insight into which NFPA standard and requirements that apply to the diesel tanks for the following scenario: 2 generators (not em or standby), outside (but has enclosures) with each diesel tank stored underneath (belly tank), tank is rectangular shape and ~5,000 gallons of diesel.
Looking at the following code path;
IMC Chapter 13 for fuel oil piping and storage and IFC Chapter 6--> 605.4 Fuel Oil Storage Systems --> storage above ground in quantities exceeding 660 gallons --> NFPA 31; OR
IMC Chapter 9 engine and gas turbine-powered equipment and appliances --> NFPA 37

Reviewing both NFPA 31 and 37 they both seem to be applicable, however when it comes to "outside aboveground tanks" of this capacity they both reference NFPA 30. (see section 6.3.3 for NFPA 37 and 7.9.3 for NFPA 31).

So here's the main question - is NFPA 30 applicable here? :
1. NFPA 30 Scope section 1.1.2 item 9 - it says it is NOT applicable to "liquids in fuel tanks of... stationary engines" ; and
2. All the boundary and tank to tank separation requirements throughout chapter 22 are based on the diameter of the tank.. this leads me to believe this standard was not written for the type of tanks I have, but instead typical giant circular storage tanks.?
3. How to calculate the tank to tank separation for rectangular belly tanks either using NFPA 30 (would you use the width of the tank instead of the diameter?) or is there another method?

Any insight is greatly appreciated!

 

[cdafd]

So the question you have to first ask is

What kind of tank are you looking at

Single wall
Double wall
Protected aboveground tank
Other

 

[Jeng84]

That's a great question, apologies for not including that in the original post! It is a UL 142 listed, secondary containment type tank i.e. double wall. It is not a protected above ground tank.

 

[cdafd]

Hum unprotected

If you have to comply with IFC, it will be in there

I am thinking nfpa 30 applies,

Will have to look at both of those

Should have asked is this a general question or planned install?,, plus in the USA?

If planned do you know what fire code is adopted

 

[Jeng84]

It's a planned install in the USA, the codes followed are the 2021 I-codes.. I've checked IBC, IFC and IMC and I believe the IFC and IMC takes me to NFPA 37 but it's after that I get unsure... NFPA 37 refers to NFPA 30 for "fuel tanks outdoors (aboveground or underground) in 6.3.3.. But does this reference to NFPA 30 "override" the fact that NFPA 30 says it is not applicable to "liquids in the fuel tanks of stationary engines" or does that not apply to generators?

and also that the separation distances in NFPA 30 is only based on "diameter" of the tank, it does not seem to take into account belly tanks which are not round.

 

[cdafd]

Check post 6 and 8

See if that helps a little

Separation Distance Between Generator and Building - NFPA (fire) Code Issues

Hi All, I am trying to establish seperation distance requirements between a Generator (outdoor) and a Building. The 2MVA generator has a 3000L diesel fuel day tank (790 US Gal). The tank is integral to the generator package and located beneath the engine. The building exterior wall does not...

www.eng-tips.com

 

[cdafd]

Would say this does not apply to you::
1. NFPA 30 Scope section 1.1.2 item 9 - it says it is NOT applicable to "liquids in fuel tanks of... stationary engines" ; and

Start with IFC chapter 57

than NFPA 30 chapter 22

How are you connected to this?

Any FPE that can help you

 

[cdafd]

see post 4

Generator belly tank - HVAC/R engineering

How far does a 400 kW with a 300 gallon belly tank of No 2. diesel generator have to be from a building? Looking in NFPA and it's rather convoluted. THANKS

www.eng-tips.com

 

[Jeng84]

This is great, many thanks!
based on these posts I think it's pretty clear how NFPA 30 and the tables for separation distance to buildings and/or property lines apply here.
Shame the shell-to-shell spacing in table 22.4.2.1 is not very helpful for belly tanks