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Insulating Outdoor Sanitary Piping in Marine Environment

  • 1.  Insulating Outdoor Sanitary Piping in Marine Environment

    Posted 09-09-2019 11:54
    Hello All,

    I'll start by saying that I am new to this forum and this is my first post.  I do read through posts sometimes and I am impressed with the response times on most topics.

    Anyway, I am working on a project in St. Petersburg, FL which involves routing sanitary piping exposed to the outdoors above a parking garage.  The client is asking about insulating the exposed sanitary piping.  I have been looking through Florida Plumbing Code and have not found any requirements for insulating sanitary piping except for areas subject to freezing.  This project is not in a freeze zone and is only a few hundred yards from the Gulf of Mexico.

    I am assuming the insulation would be to protect the cast iron sanitary piping from corrosion in the salt water environment.  Could it also be just to protect vehicles in the parking garage from condensation dripping from the pipes?  Does anyone have experience with this type of situation?  What type of insulation would be used?  I plan to ask the client for the reasoning but hoping to have some knowledge before asking.

    Thank you,

    Gregory Pearson, PE, CPD
    Mechanical Engineer
    FFE Inc. Engineering & Technical Services

  • 2.  RE: Insulating Outdoor Sanitary Piping in Marine Environment

    Posted 09-10-2019 08:25
    We design and build a large number of parking garages in Florida and we do not insulate sanitary or storm piping within the garage. The piping within a garage should not be lower than 7' to the bottom and at this height it will not be a problem to most people. We typically use PVC for our waste piping so corrosion is not a concern. As far as freeze conditions, we will insulate the water piping, but the waste piping  is never insulated. We have never experienced any problems with condensation from the piping. We have built garages across the street from the gulf and we used PVC piping and galvanized or stainless steel hangers.

    Michael Phegley PE
    Chief Mechanical Engineer
    Finfrock DMC

  • 3.  RE: Insulating Outdoor Sanitary Piping in Marine Environment

    Posted 09-10-2019 08:43

         I agree that freeze protection definitely isn't he concern for this installation based on the location. If the corrosive environment is the main concern, insulating the pipe isn't necessarily going to solve that problem. One could specify​ installing a protective coating over the cast iron, but that would prove to be as costly as insulating the entire system. In both cases, it would require re-application periodically and/or repairs to the covering/insulation.
         An alternative would be to specify Charlotte Pipe and Foundry's new ECOAT cast iron. It is currently only available in 5 foot hub and spigot with plans to expand into the no-hub market. I was fortunate enough to be able to view a sample of this product and I was very impressed.

    To be clear, I am no salesman or product rep., I am a code official so my only stake here is to educate. If you have any questions about the product you should contact Charlotte Pipe and Foundry.

    James Richardson
    Plumbing Inspection Supervisor
    City of Columbus

  • 4.  RE: Insulating Outdoor Sanitary Piping in Marine Environment

    Posted 09-10-2019 18:01
    It amazes me how so many here do not know about the Cast Iron Soil Pipe Institute or CISPI.  The CISPI name is on every piece of pipe.  When you have questions about cast iron sewer pipe or even PVC and ABS DWV, go to

    As as former employee of the Institute, I will answer based on what I remember.  Simply you should pain the pipe and fittings.  Contact CISPi for one of their red books that tells you all about cast iron soil pipe.  They will tell you what kind of paint to use.  What I would recommend you to do is take pictures of the dates and time mark on the pipes.  Once you paint that you will not be able to get that info.  

    As far as Charlotte E-Cote, the coating is not different, just the application process.  The pipe and fittings can only made when the total length is up to 5".  As not one uses 5" cast iron pipe anymore the coating is just used on the fittings.

    Last this, rust on cast iron pipe is not an issue, but corrosion is from low ph contamination.  Rust is good on cast iron, it protects it.  

    Kurt Bramstedt
    Commercial Sales Manager - Wes

  • 5.  RE: Insulating Outdoor Sanitary Piping in Marine Environment

    Posted 09-11-2019 10:04
    Edited by Theresa Hayden 09-11-2019 13:32
    Kurt, you make an interesting observation about why a very specific trade association isn't the first place designers & engineers go to for guidance when it comes to cast iron soil pipe.

    Follow the money and you may find your answer.

    Theresa Hayden
    Plumbing Designer
    Gillan & Hartmann, Inc.