Parking Garage Drainage -Oil/Water Separators

Where are you? What is the average rainfall? If you in Texas, can't expect to have a provision for conditions such as 'IKE' but you should be able to handle a rain storm that bring in about 2" of rain as a worse case without overflow.

If you NEVER want any oil to escape, I suggest you pass on this project. You can only guarantee no escape given so many inches of rain in any 24 hour window.

I'm in Mass, and I know what the 100 year storm is, 4" in 24 hrs, so I know what the flow rate is.

I need to design/size the Oil/Water Separator, how big does the vault have to be to let the oil separate? Are there some rules of thumb?

Fine, but how many floors are below surface grade?

Someone more familiar with current applicable regulations should be consulted to avoid potential legal issues in the future.

Usually, a plumbing engineer, either employed by or subcontracted by, the project mechanical engineer is the one to size the tank as part of the utility systems.

The plan checker in the city where the project is to be built is supposed to be able to tell you if the system is adequate, or how much bigger to make it if the system, as propsped, is not adequate. The city should be providing guidence as to what capacity to make the oil/water separator, unless it's to be in a small-ish city which does not have such expertise on-staff, or otherwise under contract.

Also, a local wastewater engineering consultant should be able to provide more specific guidence, if necessary.

get the retension time by the climate authority

Never mind, I thought this was an engineers forum.

Those answers above are not from engineers, I thought a post here would solicit some technical responses, not just the obvious.

I'll go elsewhere for information.

SteveWell,

I found your response to be that of an ignorant ass.

The people on this forum responded and tried to help you free of any charge or obligation.

They deserve better than to be insulted.

An apology to them is in order.

The next time you want an Engineer's help, PAY FOR IT.

If you're still not satisfied, then you can bitch.

Steve in Massachusetts you need to follow the Mass Plumbing code and if its an open system and doesn't tie into the sewers (sanitary or storm) then it will follow Mass Title 5 requirments which fall into a civil engineers expertise.

As for sizing the Mass plumbing code directs the sizing for their catch basin. If a pre-engineered packaged unit is preffered then teh manufactur has their sizing criteria.

http://www.mass.gov/?pageID=ocaterminal&L=6&L0=Home&L1=Licensee&L2=Division+of+Professional+Licensure+Boards&L3=Board+of+State+Examiners+of+Plumbers+and+Gas+Fitters&L4=Statutes+and+Regulations&L5=Rules+and+Regulations+Governing+Plumbers+and+Gas+Fitters&sid=Eoca&b=terminalcontent&f=dpl_boards_pl_cmr_248cmr1000b&csid=Eoca

http://www.mass.gov/?pageID=ocaterminal&L=6&L0=Home&L1=Licensee&L2=Division+of+Professional+Licensure+Boards&L3=Board+of+State+Examiners+of+Plumbers+and+Gas+Fitters&L4=Statutes+and+Regulations&L5=Rules+and+Regulations+Governing+Plumbers+and+Gas+Fitters&sid=Eoca&b=terminalcontent&f=dpl_boards_pl_cmr_248cmr1000b&csid=Eoca#10.17

If it's directly connected to the sewer than the upper level if exposed will require to be storm drainage and will require a oil/gas and sand sepeartor. The plumbing code has their typical concrete catch basin type but you have other options of an engineered system which could be a prepackaged system.

This was taken directly from teh Mass Plumbing code storm section verbatium.

c. Roof drain assemblies that serve vehicle parking decks or that serve the outside top level of open parking garages shall convey storm discharge to a independent gas, oil and sand interceptor/separator in accordance with 248 CMR 10.09(1)(b) and shall discharge to the storm drainage system or other approved method of disposal.

Oh and yes I am a plumbing engineer!!!!

Read the plumbing code you just referred to. This area is larger than they cover in the code, that's where this question started!

and, I am also an engineer and very familiar with the Mass plumbing code.

Oh another thought I think you meant your a wanna be engineer!!!!! IDIOT!!!!!

Oh and here's another because you know how I keep a jackass in suspense. I'll tell you later!!!! Now if you asked like a professional instead of an a hole... I would have informed you how to break it down to figure out the gpm effluent flows... LOL now your on your own buddy!!!!! Wow I'm LMAO!!!!!!!! To think you could have gotten some free advice? Idiot!!!!

To think I thought Rifle47 was being abit harsh with you stating you were obviously on the wrong site. Your such a dope!!! He was right on the money!!!! RIFLE47 your the man!!!!!!!!

Oh and if you thought this was an engineers forum? Then why the hell are you on it!!!!

Let me preface my question by saying I too am an engineer (civil) in MA, but don't generally deal with the plumbing code that much. I have a similar situation as the original poster, but this is a smaller two-story parking facility. The upper deck is open, and I know that the runoff needs to got through a separator and to the storm drain. My question pertains to the lower level - it is basically covered parking, though not otherwise enclosed and will actually be used for flood storage. There shouldn't be much drainage, but my thought was to treat it the same way as the upper deck. However, Section 248 CMR 10.09 (1)(b) of the state Plumbing Code states that "Except as provided in 248 CMR 10.09(4)(c), there shall be floor drains installed in all commercial motor vehicle parking and storage accommodations …The floor drains shall be conveyed through waste piping …and shall discharge into a gas, sand and oil separator … and be connected to a municipal sewer system." There shouldn't be much flow since it is a covered lot, but I'm confused as to whether the discharge should go to the storm drain or the sewer and, if it's the sewer, what happens when the lot floods. I'd appreciate hearing from anyone who has experience with this.

I've been a plumbing and mechanical engineer for over twenty years. But, that said, its been 16 years since doing any work in Massachusetts so I am not familiar with current Massachusetts code.

Generally, I've seen a number of different approaches to the question.

First off, (I apologize for going back to the original discussion) if your drained area exceeds the limits of your code, who says you have to use only one separator. Separators are usually sized by the area that they drain. I have never seen a jurisdiction that limited you to providing only one separator per garage.

Many jurisdictions now require two separate drainage systems. The top deck goes to storm water while the covered lower decks are connected to the sanitary sewer.

This applies even to jurisdictions that are very restrictive about exactly what discharge can be routed to their sanitary sewers (for example jurisdictions that prohibit connection of HVAC condensate drainage to sanitary).

The reasoning follows somewhat like this: Since covered deck areas are not washed by rainwater, oil from leaking crank cases largely never even reaches a drain. It simply soaks into and stains the concrete. Garage owners then use city water and detergents (that cannot be allowed into the storm sewers) to wash the decks and remove oil stains.

If your garage has no facilities for rinsing or washing down the decks, a number of jurisdictions allow you to delete the sanitary drainage system and connect all the drains to the storm drain system. (On the other hand, I ran into one that required sanitary connections for a garage with no water supply at all. "I know what they are going to do", said the official involved.)

Some jurisdictions, reasoning that the top-deck of the garage is no worse than a parking lot, do not require a separator for the Storm water. This is changing as jurisdictions become more concerned with controlling contamination of stormwater run-off.

In areas subject to flooding (especially on a seasonal or periodic basis) I've seen jurisdictions delete the separator requirement. Their reasoning follows that a trickle of oil entering the sewer system over any set period of time is better than allowing a a large quantity of oil to enter the environment when a separator is "flooded out."

Always check with your local jursdiction. Even if it is not written down as a local code amendment, some jurisictions routinely "waiver" such cases but don't advertise the practice with an amendment.

Hope this helps, Good luck.

Really you are an engineer of what a train? Well enough said. You should refer back to Rifle47's response because you are totally ignorant. You should consider a different occupation. I presented the plumbing code concerning your questions ask, as if you weren't an engineer. As for the area being beyond whats shown in the code and if you are a true plumbing engineer as stated, then you should revert back to your engineering practices since you should know as much as I since I have been in the field for over 25 years. Oh another thought, next time you ask for help try using honey. You won't get anywhere with that attitude and I can see where your on this site, since your collegues dont want to deal with your stuipidity. Have fun with your project, boy do I hope the client knows what an ignorant bastard you are and throw you off the project or atleast your boss finds out soon.

Oh since your name is Stevewell maybe you should stick to wells?

Or Stevewell uneducated?