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Structural Lining With Plastic Material In SW Drain

  • 1.  Structural Lining With Plastic Material In SW Drain

    Posted 26 February 2014 16:41
    Hi forum

    I have situation where certain length of SW pipe segment was renewed by structural plastic lining method.

    In theory, this method allow the plastic pipe to fully withstanding independently.
    In fact, the concrete pipe still cover the plastics as baseform.

    I thought to capitalize this segment by disposing the concrete pipe and renewing with plastic because it is no longer required.

    Can anyone advise the right method on how to capitalise this SW asset data?

    Thank you.

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    David Gunawan
    Development & Drainage Engineer
    City of Port Phillip
    ST KILDA VIC

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  • 2.  RE:Structural Lining With Plastic Material In SW Drain

    Posted 26 February 2014 19:25
    Hi David You will most likely get a number of different answers on how to deal with it and there probably is no one correct way. How ever you decide has to be consistent and in your policy and be auditable and logical. At BRC we have decided the asset is now a type of its own....a Relined SW Pipe with its own set of parameters like Useful Life and Unit Rate. We then know what percent of our network has been relined and can view the relined areas in GIS mapping as it generates the line coulour by asset type. Hope that helps. Regards ------------------------------------------- Bruce Janke Maintenance Planner Bundaberg Regional Council BUNDABERG QLD -------------------------------------------
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  • 3.  RE:Structural Lining With Plastic Material In SW Drain

    Posted 28 February 2014 07:48
    Hi there David. We take a very similar approach here at Waipa DC to what has been mentioned by Bruce. It becomes a new asset, the exsisting asset is disposed, and the new pipe capitalised as a Plastic Lined Concrete Pipe. It may be useful to retain some of the original inforamtion in a notes field in your AMS for future reference, but in our system it would be a brand new asset, with a new base life of 80 years. Cheers Jennifer ------------------------------------------- Jennifer Weal Waipa District Council -------------------------------------------
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  • 4.  RE:Structural Lining With Plastic Material In SW Drain

    Posted 03 March 2014 16:27
    Hi David

    To add a little detail we have set a 50% residual on our sewer (similar to SW) pipes in our asset register as in our opinion the cost to reline is about 50% of the replacement cost (obviously varies depending on location e.g. under main street versus outer suburb). This allows us to do a renewal treatment (relining) and keep our asset number (linked to GIS) for a particular length of sewer pipe and adjust the type to now show it is a relined vitreous clay pipe with a new Replacement Value, Useful Life and Consumption Profile.

    Cheers

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    Bruce Janke
    Maintenance Planner
    Bundaberg Regional Council
    BUNDABERG QLD

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  • 5.  RE:Structural Lining With Plastic Material In SW Drain

    Posted 05 March 2014 15:22
    Hi David for the sake of giving you another slightly different yet similar option... Porirua uses structural (CIPP and spiral) liners in much of its sewer renewals programme. We effectively treat the old host pipe as abandoned and the structural liner as a new pipe asset, using the same manhole numbers as endpoints. The old and new lines are differentiated in our AMS by a "parallel line no" which acts like a suffix to the pipe ID string. The advantage of this approach is that the old record is retained and the new pipe is accurately spatially defined in the same location as the old. Identifying / displaying each in GIS is handled by different attributes and in our case feature classes. Regards Anthony ------------------------------------------- Anthony Clarke Porirua City Council -------------------------------------------
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  • 6.  RE:Structural Lining With Plastic Material In SW Drain

    Posted 28 February 2014 07:48
    Hi Bruce, We are using the similar approach to record these relined stormwater pipes at Hobart, but it leads to another interesting question that how you will define the written-off value in such renewal. I believe that the residual value of the stormwater pipe assets should be the value of whole part of the pipe-trench structure including the pipe itself, and all other "things" which ensure the functionality and structure of the trench such as trench structure, bedding materials, etc. Given the relining works will only replace the pipe material itself, does that mean that the value of "other things" actually has not ceased in such activity, and should part of the residual value need to be written off? Let's say 20%? However, it is back to the argument that if the manufactory claims that the lining material would be able to support the structure by itself, is it still necessary to retain the value of these "other things" given they will be not considered as functional in the new lining structure? ------------------------------------------- Frank Chen Stormwater Assets Officer Hobart City Council HOBART TAS -------------------------------------------
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  • 7.  RE:Structural Lining With Plastic Material In SW Drain

    Posted 03 March 2014 17:35
    Hi Frank

    Yes I should have read your post before replying to David again...not to worry..

    Yes there is definitely residual in the existing asset (we believe). Our research showed a variable amount depending on where the pipe to be treated is located. We haven't relined stormwater here that I know of but we do reline sewer each year in a capital works program. We realised it was not relective of what was happening on the ground to dispose of a pipe asset and replace it for one valued at half the cost....One could argue our original unit rate based on digging a trench and relaying new pipes is wrong given we will rarely do that. We will dig up and spot repair but the majority of capital work will be relining. Given our Unit Rate in the register is based on digging up and relaying new pipe we decided last year during a revaluation to add a 50% residual to all sewer pipes suited to relining as our preferred renewal treatment.

    To process capex we do a partial disposal then of the depreciable amount not yet depreciated and add the value of the relining to the remaining 50%.
    I don't want to confuse people but there is still some discussion to be had around how many times we can reline and what is the treatment next time....(how many years does a relined pipe last...we said 80 years...is that correct...not sure...) see how easy this asset management stuff is....all the ducks have to line up...just we haven't spotted all the ducks yet in some cases.

    Enjoy


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    Bruce Janke
    Maintenance Planner
    Bundaberg Regional Council
    BUNDABERG QLD

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  • 8.  RE:Structural Lining With Plastic Material In SW Drain

    Posted 03 March 2014 04:27
    Hi there. Our general approach is determined by the fact that the existing asset had been downgraded to a condition grade 5, and therefore has no remaining life as a pipe asset. However, the liner cannot exist without the casing of the pipe. And so it is s new type of asset- an insitu relined pipe. We therefore use the existing pipe data set, and change the description to relined, assign all costs to the new pipe type, dividing the cost by the lengths renewed. We assign a new life based on the expected life of the lining. 

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    Kathy Dever-Tod
    Tararua District Council

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  • 9.  RE:Structural Lining With Plastic Material In SW Drain

    Posted 06 March 2014 03:53
    Hi ALL,

    We have been successfull in recognising that in by religning a pipe with a structural material it then changes the "life" and "componentry" of the asset originally bought into the finance asset register (FAR).

    We have also had our perspective reviewed by QTC and they are happy to support the extension of the original life of the asset.

    To Expand,
        In relation to Sewer pipe religning,
        The original asset, being the pipe, the formation, base/sub-base etc, has been recognised as one asset with a number of components. 
        The original asset, in total, has a life of say 70 years
    Once the original asset has been religned there are three common themes,
            1/ The liner becomes a new component
            2/ The liner becomes a new asset
            3/ The liner re-news the extisting asset
    In the third case,
        We have capitalised the renewal "work" and recognised the liner as both a renewal treatment and a addition of a new structural componet for the purpose of conveying sewage.

    The original asset, being pipe, formation etc has now been viewed as "formwork" for the installation of the new structural liner and therefor has changed its use/service and life (which could be argued as indefinite).

    So, what does this all mean...I hear you ask...
            The "formwork" has now adopted the Remaining Usefull Life (RUL) of the linner (no one was preparred to adopt an indefinite life), the value of 50 years was snatched out of the ether. 
            
    The outcome is that,
            The original Useful Life (UL) of the original structural compent has had its life extended from 70 to 120 years (ie 70+50 for the added life of the liner). 
       
    Therefore,
            The depreciation (a poor proxy for renewal) is now spread over a longer life, leaving a much reduced Annual Depreciation Expence (ADE).    CRC/UL=ADE
       
    And for those who are saying  .."yes but"... this is a process for satisfying the current ASB116 requirements. the reality is..it is very unlikely that some of these sewer assets will even be required or in use at year 120 and beyond...

    I leave you with this thought..

    If it is unlikely that the asset will require any renewing at year 120...should we be using the depreciation expense as a sustainabilyt/renewal funding indicator at all...


    Cheers


    Darren Moore

       
            

         

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    Darren Moore
    Water Asset Management Program Leader
    Logan City Council
    LOGAN CITY DC QLD

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