How Do I Plumb a Food Concession Vehicle?

[Pig Daddy]

Greeting!
LazyPup, first of all, I find your knowledge and drawings simply amazing! You sure sound like you are a true craftsman! I hope you can guide me in the right direction.

My concern is with a food concession vehicle I've been building out of a step-van (like a FedEx or UPS delivery vehicle). I am finishing up the plumbing now and want to make sure I don't have problems with inspectors down the road. The vehicle will me used in different states around the country so I need to get it as close to ideal as is practical.

This URL will show the drawings I am referring to:

http://www.pigdaddys.biz/plumbing_question.html

The CURRENT CONFIGURATION image shows what I have existing now.
The PROPOSED CONFIGURATION image is what I want to do to finish it.

I have a 3-compartment sink and a single bowl hand washing sink. They are both situated over the underfloor holding tank. The stainless steel holding tank tank is fitted with two 1-1/2" ABS fittings - one is MPT and the other is SLIP. The P-traps are typical 1-1/2" screw-together types you find at Menards.

I thought about running the vent line to the roof, but this would be pretty difficult to do, given the current room constraints. Besides, I am not too eager to penetrate the roof on this vehicle!

I've seen the Studor valves discussed before and it looks like it's just the ticket. And if I HAD to, I COULD extend the vent line to the broom closet and elevate the Studor valve above the flood level of the sinks. But again, that would be rather difficult.

Is this proposed configuration going to be OK code-wise, or should I re-think this?

Sorry for the crude drawings but I could not find any plumbing icons for my CAD program.

Any assistance would be greatly appreciated.
Thanks!

Pig Daddy

[LazyPup]

Thank you very much for your kind words of encouragement.

A concesssion vehicle such as you are building would fall into the same general category as a manufactured home, motor home, camper or boat. As such they do not fall under the normal commercial or residential codes but rather they are a code category unto themselves.

If you ever get a chance to examine a manufactured home, motor home or camper up close you should find a small plastic shield looking medallion about 3" high either near the main entrance door or near the front of the vehicle. The medallion says "This vehicle conforms to all applicable codes at the point of manufacture"

In turn, given that this is a non-permanent structure most local jurisdictions have regulations that state they will accept the vehicle if it conforms to the codes at the point of manufacture.

The catch 22 here is that the manufacturers tend to locate their production facilities in areas where there are no codes, therefore they can basically do anything they care to do. In fact, there are a couple states that refuse to enact any codes because they feel it would hinder a vital source of job revenue within thier state.

The problem you may run into as a DIY project is that you cannot get the manufactured home compliance medallion, and many states require all food service equipment to be inspected so it is anybodies guess what they may be looking for. With that thought in mind I think you are on the right approach by trying to comply with the standard plumbing codes as much as possible, especially when you consider the standard plumbing codes are in all cases much stricter than the manufactured home codes. Now let us examine some of the basic code requirements that would pertain to your project.

NOTE: all specifications taken from the International Residential Code.

Kitchen sinks are rated at 3 DFU's (Drainage fixture units) per sink trap. (IRC 3004.1)

One CENTER trap may serve up to three sinks, laundry tubs or lavs of the same type in the same room providing the maximum spacing between the drains does not exceed 30". (IRC 3201.6)

The lavatory bowl is required to have an 1-1/4 drain & tailpiece and is rated at 1 DFU. (IRC 3004.1)

Trap arms less than 3" in diameter must be run with a 1/4" per ft. pitch. IR3002.3.1)

Maximum trap arm lenght from trap weir to vent opening:
1-1/2 trap arm 6'
2" trap arm 8'

Branch sizing:
1-1/2 pipe max DFU's: IRC 3 horizontal 4 vertical
2" 6 hor. 10 vert.

Main Vent MUST TERMINATE above the roof (IRC 3102.1)

All fixture traps require venting (IRC 3101.2.1 & UPC 901.0)

From these facts we can determine that your total combined fixture load is 3 DFU for the kitchen sink trap and 1 DFU for the Lav = for a total of 4 DFU's.

The code will permit an 1-1/2 line to carry 4 DFU vertical but only 3 horizontal, so the solution is to install the riser between the two sinks. The three kitchen sinks connected by means of an 1-1/2 triple center waste kit and an 1-1/2 P-trap. An 1-1/2 horizontal waste arm to the riser. The Lav is then connect by an 1-1/2 waste arm with an 1-1/2 P-rap fitted with a 1-1/2 by 1-1/4 reducer in the slip joint to connect to the 1-1/4 tailpiece. (an 1-1/2/1-1/4 trap is a common off the shelf item at any hardware.)

The horizontal lines are connected to the vertical riser by means of a Back to back sanitary Tee. You could then either extend the center of the back to back vertical up to the roof to form the main vent, or you could install a 4" vertical riser with a threaded cleanout fitting on top and screw in an Air Inlet Valve. The air inlet valve is screwed in so it would also serve as the required cleanout for the vertical line.

The 1-1/2 vertical line would then drop down to the holding tank.

If you install the air inlet valve, which may be desirable to prevent having the vent line run up through the countertop, then you would need to install an 1-1/2 vent line to to the roof from the second tap on the holding tank. Rather than go straight through the roof which could cause a roof leak problem you could run it up close to the roof then offset it out through the side wall of the vehicle and extend it above the roof line. On motor homes they commonly install the vent opening right near the roof grab handle rails which then protects the vent from being damaged by the occassion tree limb when manuevering in tight spots in the RV parks.

The codes prohibit gluing dissimilar plastics together and your holding tank already has an ABS fitting so the obvious solution would be to use ABS pipe and fittings to make the drain system. The alternative would be to use PVC for your DWV system then connect the PVC to the ABS by means of a rubber FERNCO coupling.

The discharge line from the holding tank should be a 3" line equiped with a gate valve and a removable cap on the end of the line. You can get the gate valve and an end fitting with cap that is set up to connect the flexible drain line from any motorhome/camper supply house. They will also have a twenty foot collapsable flex line that is used to drain the holding tank. Motor homes typically have a square hollow rear bumper where the discharge line is stored when not in use. You could do the same thing by hanging an 8ft section of 4" PVC crosswise under the bumper with a threaded cleanout cap on each end. You would then unscrew a cap and pull the line out when you need it.

[Pig Daddy]

Wow!
Now that's what I call a detailed explanation!
Exactly what I was looking for LazyPup!
I thank you very much for your consideration and time.

(You don't happen to be savvy in Electrical stuff for this
same vehicle, do ya? )

Pig Daddy

[HayZee518]

This is hayzee518 - maybe I can be of service to ya!

[LazyPup]

I have the savvy to do the electrical but i would much prefer to differ the answer to Hayzee, who is a Master Electrician and much more familiar with the current codes than I am.

[HayZee518]

Lazypup - isn't there something in the codes that mention a grease trap in the effluent line "before" the holding tank?

[LazyPup]

As I stated before, there really aren't many actual codes regarding these type of vehicles.

I am not aware of any requirement for a grease trap but if they are using deep fryers to make the food product it certainly would be a good idea.

I would also prefer to see a removable access cover on the holding tank so it would be occassionally pressure washed.

[Pig Daddy]

quote:Originally posted by HayZee518

This is hayzee518 - maybe I can be of service to ya!

Thanks HayZee518! Once I get this plumbing stuff squared away I'll give you a post over on the electrical forum.

[Pig Daddy]

quote:Originally posted by LazyPup

As I stated before, there really aren't many actual codes regarding these type of vehicles.

I am not aware of any requirement for a grease trap but if they are using deep fryers to make the food product it certainly would be a good idea.

I would also prefer to see a removable access cover on the holding tank so it would be occassionally pressure washed.

There will be no cooking in this particular vehicle. Only the warming and vending of foods that will be prepared on a separate trailer that will contain all the cooking apparatus. So no need for grease traps.

LazyPup, I have done some head scratching this weekend on my plumbing project. I find at the box stores that ABS stuff is pretty scarce - everything is PVC. As I stated before, I have two ABS fittings already on my holding tank. One is a SLIP fit 1-1/2" termination. The other termination is a 1-1/2" MIPT fitting.

Since PVC is more readily accessible, if I go that way I still have the problem of gluing together dissimilar materials. And I'm not too keen on using the Fernco stuff unless that's my only option.

So I explained this all to the Menards guy today and told him what you said about the code not recognizing gluing together of dissimilar materials and he mentioned the Oatey brand of glue called TRANSITION GLUE. He thought this might be OK for welding together ABS and PVC. So I told him I'd run it by you since he's not all that qualified.

If the answer to this is still no, then here is my plan. What if I come off my holding tanks ABS MIPT fitting with a PVC transition (1-1/2" FIPT x 1-1/2" SLIP), then take off from that point with PVC? Since it's a threaded connection (not welded), is this allowed?

Also, I am going to forget about the Studor valve and just come off my vertical stack with 1-1/2" pipe, go horizontal over to a broom closet, then transition back to vertical to the roof. (See expanded drawing below).

4d 0

Do I still need a clean out on the vertical between the traps and vent?

Thanks again.

[LazyPup]

Oatey does make a glue that they advertise as a transition glue but it has not yet gained code approval.

the codes specifically prohibit glueing dissimilar plastics.

Some local jurisdictions will permit a maximum of one dissimilar glue joint to make a transition, but given that you will be moving from one jurisdiction to another I would be very hesitant to use it. You wouldnt want an overzealous inspector to give you a hard time.

The proper solution would be to use a Fernco which has code approval for this application and they have proven to have a very good service life. The fernco also may prove convenient in future if you ever need to pull the holding tank.

You would still require a cleanout,but fortunately it will be very easy to install. At the point where the vertical from the holding tank is turning 90 deg to the vent line instead of a 1/4 bend as pictured, install a Wye with the side opening going to the horizontal vent line. On the top of the Wye install a cleanout adapter and a screw in cap.

Another point to remember. The codes prohibit using metal hangers or metal strapping to secure plastic pipes. You can get preformed U hangers and J-hooks for each size of pipe or you may use PVC perf strapping. They are all available at Lowes, Home Depot or most local hardwares.

[HayZee518]

when you are ready for the electrical shoot me an email at srf12980@localnet.com and I'll put together a .jpg that you'll be able to view with msn "paint"

[Pig Daddy]

OK LazyPup,
I been making progress on the plumbing project. Finally decided to go with the Fernco fitting. But now I'm ready to run my vent and it's getting very crowded.

What I would like to do is to assemble the vent line (the grey pipe in pix) with threaded PVC connectors from the double sanitary tee, instead of gluing it all together. The reason being is that if I ever had to get the HW heater out of there, I would have to cut out the horizontal vent line. It doesn't look like it from my drawing, but that is indeed the case!

1 - Is it legal to assemble the grey vent line with threaded PVC connectors?

2 - Can I use the tighter VENT ELBOWS instead of SANITARY ELBOWS in the vent's transition from horizontal to vertical?
Thanks again!

[LazyPup]

All fittings on the vent line MUST BE made with DWV Sanitary fittings.

May not use threaded fittings.

may not have a drain and vent back to back.

The easy solution is to replace the sanitary cross with a sanitary Tee with a cleanout adapter on top of the Tee.

You could then screw a air inlet valve (studor vent) into the top of the Tee to make the vent. The AAV also serves as the cleanout cap.

Run the main vent off the second tap on the holding tank.

[Pig Daddy]

Thanks LazyPup.
I really do appreciate your patience with me.

OK, I see what you mean about the back-to-back vent/drain. I also understand no threads on the vent line. But the problem with using the other holding tank ABS fitting to run my vent line from is that it is a 1-1/2" MIPT. So that puts me back in the threaded vent fitting situation again.

What I propose to do now is cut out the offending back-to-back double sanitary tee and plumb it like so. Will this be acceptable?
Grey lines will be new work:

[Pig Daddy]

Can anybody tell me if the above plan is acceptable?
Thanks.

Pig Daddy