Distance between above-ground propane tank and thermal oxidizer?

We are proposing to install a thermal oxidizer to remediate gasoline-contaminated soil at an existing gas station. The 2007 CFC, CBC and NFPA standards apply.

The burner of the thermal oxidizer uses propane as a supplemental fuel. We intend to install a 500 gallon above ground propane tank to provide fuel for the thermal oxidizer. The thermal oxidizer uses propane at a rate of approximately 400 SCFH.

Question: What is the required minimum distance between the propane tank and the thermal oxidizer?
Original Post
NFPA 58 doesn't give good guidance for the described conditions. CBC does not directly address the described conditions. CMC does not directly address the described conditions. CFC chapter 38 does not directly address the described conditions.
It appears you will need engineering data and a professional Engineer to substantiate your proposal based on sound science and practice standards. Key issues will be;
Since LP is supplementary fuel, what is the primary fuel and how does the fuel type impact codes application to the situation?
What operating temperatures are involved and how much radiant heat is given off by the oxidizer that may affect the LP storage cylinder and surrounding construction?
What is the operating pressure in the tank and delivery piping system?
How does the radiant heat from the oxidizer affect the tank valves, relief devices, and delivery piping system?
Does this oxidizer meet the California air quality emission standards in the geographical area?
Most likely there may be others.
This is a very difficult situation, good luck.
Jim and others---

Here are the answers to the questions raised by Jim Fruit in the post above...see if you can provide me with more specific answers (guidelines) regarding the separation between the propane tank and oxidizer.

1) The primary fuel is gasoline vapor extracted from the soil by a vacuum pump. I don’t know what impact this might have on any codes.

2) The oxidizer operates at 1,700 degrees F. It is well insulated, so the temperature of the outside surface is usually less than 150 degrees.

3) The tank pressure probably depends on the ambient temperature. The pressure of the delivery piping should be about 5 psi.

4) A person can stand next to the oxidizer without any problem, so I don’t believe the radiant heat will have any effect on the tank valves, relief devices, and piping. I believe the summer sun will have a greater effect.

5)The oxidizer will have to be permitted through the Air Pollution Control District, so it will meet their emission standards.

I want to minimize the distance between the oxidizer and propane tank, but the local jurisdiction Building Official and Fire Marshal are not able to provide guidance regarding the separation they are looking for.
Most of these systems have been in used for some time, they the designing company has/should have data to help you. Also get intouch with the lp gas people for the distances they mandate for the tanks with product in them. The unit is just a big stove burner, powered by LPG. The air quality people have already given permission to stack the CO.

By the way the same result can be had by taking the soil turning and fluffing it (adding air) so the bugs stay healthy,
From the answers above, it appears a rational approach is:
The primary fuel will be LP as the gasoline vapor is the pollutant to be "oxidized".
Thermal separation appears to be the main issue; for up to 150 degrees fahrenheit appliance case temperature and ambient air temp up to 100 degrees, 3ft should be adequate for air circulation to provide sufficient cooling.
Radiant shield should be provided for piping control valves rated below 125psig within 3ft of appliance case if they are subject to any unshielded radiant source such as a firebox.
Maintain separation from overpressure relief piping termination from pressure step down regulator to any combustion source.
LP tank should also be positioned in relation to surrounding construction per chapter 38 CFC.
Hope this helps
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