secondary containment wall height
secondary containment wall height
(OP)
Does anyone know if there is a minimum height requirement for a concrete wall secondary containment for AGHST's?
I have read that the containment volume should be adequate to contain the volume of the largest tank plus have sufficient freeboard for a 100 year storm event (for a 24 hr period?) & that is typically 110% of the largest tank; but is there any minimum (or maximum) requirement for the wall height (i.e., the sides) of the spill containment area?
I have read that the containment volume should be adequate to contain the volume of the largest tank plus have sufficient freeboard for a 100 year storm event (for a 24 hr period?) & that is typically 110% of the largest tank; but is there any minimum (or maximum) requirement for the wall height (i.e., the sides) of the spill containment area?





RE: secondary containment wall height
I don't have any experience with designing secondary containment, however, I have heard things such as what you propose.
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RE: secondary containment wall height
RE: secondary containment wall height
For us, it is 100% of the larget tank plus the greater of:
- 10% of the largest tank, or
- 10% of the agregate of all tanks (excluding the largest one)
There is no provision for rain.
"Do not worry about your problems with mathematics, I assure you mine are far greater."
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RE: secondary containment wall height
RE: secondary containment wall height
Yes, the wall height has to be engineered to sufficiently do the job (loading, foundation, etc.). If the wall is too high, there is also the possibility of confined space entry requirements, etc.
I interpreted the OP as pertaining to something akin to "... or a minimum of 3 feet" or something.
We are currently putting in 2 different tanks. One by it self, and the other into an exisitng containment area. We do not have requirements for rain.
Seems like each site uses different estimates.
"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
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RE: secondary containment wall height
EPA Region 9 has published one of their usual guidance documents that says hard and fast that the requirement is 110% of the cross-connected volume or the largest tank that is not cross connected. That is the only place I've ever seen the requirement for the cross-connected volume. If three 1,000 bbl tanks have a line to a common pump-suction header then Region 9 would require 3,300 bbl minimum containment volume.
As has been said above, the height of the containment is not mentioned in the SPCC, but the suggestions to use good engineering practices is the way to go since the SPCC plan has to be stamped by a PE.
David Simpson, PE
MuleShoe Engineering
www.muleshoe-eng.com
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RE: secondary containment wall height
we have two lube oil tanks with existing concrete containment which needs repairing. we will likely keep the wall at its current height.
david & ashereng, i am not sure if these two tanks are cross-connected or not. i presume they are, but will verify it later. i was not aware of any alternate to the 110% capacity of largest tank. does "aggregate of all tanks (excluding the largest one)" mean the total volume of all tanks except the largest one? which region does this apply to? i'm in georgia (i think region 4). or is this a national requirement?
jj, i seem to recall having read/heard something about a 3 foot minimum some time ago as well. i thought maybe i read it in NFPA 30, but after reviewing that spec the other day i could not find that in relation to a concrete containment wall. it does make reference to that for berms (i think earthen berms/dikes).
RE: secondary containment wall height
My site is in Alberta Canada.
We have 3 tanks, 100,000 bbl, 60,000 bbl and 60,000 bbl,
Our secondary containment is sized for 112,000 bbl.
1) largest tank is 100,000 bbl
2) 10% of 100,000 is 10,00 bbl, 10% of aggregate is 12,000 bbl so we use 12,000 bbl
"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?
RE: secondary containment wall height
The only time I've seen the largest tank excluded is in the language for calculating the berm capacity after you've determined the volume requirement. Assuming you have several tanks sitting on the ground within your secondary containment that are not cross connected, then the reasoning is that if the largest tank splits wide open you don't have to exclude the volume it occupies from your available berm size, but you do have to exclude the volume of the other tanks up to the berm height because they will not have been be breached.
David
RE: secondary containment wall height
that being said, we will have sufficient capacity using either the largest tank OR both based on the existing wall height. i just determined the capacity for the planned containment area (~1782 c.f.) at that wall height will be way more than the required volume (~1324 c.f.).
so it looks like we'll be covered either way.
thanks all for your guidance.
kahlil