The grease and oils are hydrocarbons and will not mix with water.  The water 
will separate out and depending on where a leak would occur in the tank, your 
spill could be wholly combustible in nature.  Typically these are Class IIIB 
combustible liquids.

IF you are following NFPA 13, I would not do less than EHII.  Also take a look 
at NFPA 30 for indoor storage tanks.

Oil and grease fires can be difficult to control with water alone.  With a 
32,000-gallon tank and 20% (6300 gallons being a combustible liquid) I'd be 
talking with the local fire department to be sure they are equipped for such a 
fire or you may need to provide a foam-water sprinkler system.

Other questions, what is the storage tank made of, steel or plastic?  What 
chemical is used for cleaning the tank and piping systems, any solvent 
materials?  How is the transfer from truck/tank to bldg./tank performed?  What 
is the potential fire hazard there and how is that mitigated?

Craig L. Prahl
Fire Protection Group Lead/SME
Direct - 864.920.7540
Fax - 864.920.7129
Direct Extension  77540
CH2M is now Jacobs.
200 Verdae Blvd.
Greenville, SC  29607<>

From: Sprinklerforum [] On 
Behalf Of James Crawford
Sent: Tuesday, February 13, 2018 1:18 PM
Subject: Tank Storage [EXTERNAL]

I was asked to do a review of a building that collects waste from commercial 
grease traps. They take this waste back to their warehouse and put it in large 
tanks (120,000 liters) to allow separation. 75% water, 20% vegetable oils and 
animal fats, 5% solids.

Once separated the waste materials are then disposed of separately.

I am trying to classify the mixture that is stored in the tanks, but can find 
no direction in NFPA #13, but due to the concentration of water to oils I am 
leaning toward a non-combustible liquid. But that being said I can find no 
direction on tank storage for a non-combustible liquid.

Any help out there

Thank you

James Crawford
Phaser Fire Protection Ltd.
Phone  604-888-0318
Fax 604-888-4732
Cel 604-790-0938

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