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        Urecon | Celebrating 40 Years | 1969-2009

        Design Considerations

        Several factors must be taken into consideration when selecting the core pipe best suited to a particular application, such as:

        TEMPERATURE: the operating temperature of the system must be considered to ensure that the pipe is recommended for operation at the temperature required of it.

        THERMAL EXPANSION:  there is a considerable variation in the expansion and contraction of the various pipe types as can be seen from the following table.  Changes in the length indicated are approximate and may vary depending on the actual resin used by a particular pipe manufacturer.

        Linear Expansion and Contraction of Various Pipe Cores Click for a larger view

        CORROSION RESISTANCE: if the fluid being carried within the pipe is corrosive , the core  pipe must be suitable for the service required.

        ABRASION RESISTANCE: in mine tailings and slurry applications, consideration must be given to the ability of the pipe to withstand the abrasive nature of the tailings being transported.  Pre-Insulated pipes may be flanged at pre-determined intervals to permit the   rotation of the tailings lines, thus increasing the life expectancy of the system.  

        INTERNAL DIAMETER: it must be noted that there is a considerable difference between the internal diameters of the various pipe types of similar nominal size.  This is especially so in the higher pressure ratings.

        JOINT TYPE: care must be taken to ensure that the correct joint is used for the service required.  Some jointing methods are not recommended for above ground use, while others must be secured with thrust blocks when buried.

        WEIGHT: the weight of the pipe can be an important factor when choosing the core pipe, especially if transportation to a remote job-site is involved or in bridge crossing applications.

        PIPE LENGTH: a compromise between ease of handling on the job and the reduction of the number of joints must be arrived at when selecting the length of pipe best suited to the particular application.

        INSTALLATION COST: is any special equipment or personnel required for pipe jointing?  What is the time required to complete each pipe joint?  Is heavy equipment required to lay the pipes?, etc.  These are all factors which must be considered when estimating the overall installed cost of the pre-insulated pipe system.

        Outer Jacket on Pipe Insulation

        Urecon offers several outer jacket alternatives, the choice of a particular outer jacket material depending on several factors, including:

        DURABILITY: is the pipe being buried or is it being exposed to possible mechanical damage above ground?  Is it a mine application where the pipeline may be dis-assembled, moved and re-installed at another location in the future?

        UV RESISTANCE: pipes installed above ground must be resistant to long term UV attack.

        BEAM STRENGTH: is the pipe supported only at intervals as in a bridge crossings or pipe rack applications?

        RESILIENCY: if the core pipe is resilient, is the pre-insulated pipe expected to remain resilient?

        Live Loads

        Note: Urecon's standard jacket is suitable for H-20 highway loading at 600 mm (24 in) bury.  Live H-20 load transferred to the insulation at 600 mm (24 in) depth of bury is 38 kPa (5.51 lbs/in2).  Our system is rated 414 kPa (60 lbs/in2).

        Live Loads on Buried Pre-Insulated Pipe

        HEIGHT
        OF COVER
        LIVE LOAD TRANSFERRED TO PRE-INSULATED PIPE
        Highway H201 Railway E802 Airport3
        mm ft kPa lbs/inē kPa lbs/inē kPa lbs/inē
        300 1 86.19 12.50 - - - -
        600 2 38.34 5.56 181.96 26.39 90.60 13.14
        900 3 28.75 4.17 162.79 23.61 84.67 12.28
        1200 4 19.17 2.78 126.87 18.40 77.71 11.27
        1500 5 12.00 1.74 114.94 16.67 69.57 10.09
        1800 6 9.58 1.39 107.77 15.63 60.61 8.79
        2100 7 8.41 1.22 83.77 12.15 54.13 7.85
        2400 8 4.76 0.69 76.60 11.11 47.78 6.93
        3000 10 - - 52.68 7.64 42.80 6.09
        3600 12 - - 38.34 5.56 32.82 4.76
        1. Simulates 20 ton traffic and impact.
        2. Simulates 119,000 Kg/m (80,000 lb/ft) railway load and impact.
        3. Simulates 81,650 Kg (180,000 lb) gear assembly, 660 mm (26 in) spacing between tires and 1.676 mm (66 in) center to center spacing between fore and aft tires, under a rigid pavement 300 mm (12 in) thick plus impact.
        4. Source: IPEX Inc.

        Weight of UIP Polyurethane Insulation

        Nominal Pipe Size Thickness of U.I.P.® Insulation
        50 mm 2 in 62.5 mm 2.5 in 75 mm 3 in
        mm in Kg/m lbs/ft Kg/m lbs/ft Kg/m lbs/ft
        50 2 1.51 1.01 1.95 1.31 2.41 1.62
        62.5 3 1.82 1.22 2.32 1.56 2.85 1.92
        100 4 2.22 1.49 2.76 1.85 3.35 2.25
        150 6 2.85 1.92 3.47 2.33 4.21 2.83
        200 8 3.46 2.33 4.22 2.84 5.04 3.39
        250 10 4.06 2.73 4.92 3.31 5.88 3.95
        300 12 4.68 3.14 5.68 3.82 6.66 4.48
        350 14 5.35 3.60 6.38 4.29 7.52 5.05
        400 16 5.99 4.03 7.18 4.82 8.38 5.63
        450 18 6.59 4.43 7.86 5.28 9.20 6.18
        500 20 7.20 4.85 8.61 5.79 10.05 6.75

        NOTE: Weight table based on standard 1.27 mm (50 mil) thick polyethylene jacket.