MDPE Gas Pipes
MDPE Gas Pipes
| Gas distribution was among the first application of the medium density polyethene (MDPE) pipe. In fact many of the systems currently in use have been in continuous service since 1960 with greatsuccess. Today , over 90% of the pipe installed for the natural gas distribution industry in the U.S and Canada is plastic, and of the, 99% is polyethylene.
Although the pipe resistance and stiffness increase from the bottom to the top, in contrast, its flexibility and impact strength increase. Because the natural gas pipes are more flexible and their impact strength are higher than the high density ones, they are recommended. |
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Natural gas pipes are in PE80 class. The environmental strength value to be reached in the medium density is 8.0 MPa for now. When this level increases, the wall thickness will decrease and the fluid quantity passing through will increase. When they are used for water, they can be used at 4 bar pressure in the natural gas line by changing the safety coefficient from 1,25 to 2,5 when used in PN 12,5 bar. Because the polymer chain is affected from the hydrocarbon structures, the safety coefficient is selected as high.
C&N Aquatherm HDPE is lightweight, flexible and available in long coils there by making it easy to install and minimizing the number of joints in the piping system. C&N Aquatherm HDPE pipe can be joined by the heat fusion or mechanical fitting and does not corrode like metal pipe. It provides long term resistance to variety of service condition such as , abrasion, temperature and soil shifts, bending, weathering , internal pressure , direct burial point loading and squeeze –off –advantages that give confidence to gas engineers the world over to specify C&N Aquatherm PE pipe for their distribution systems.
MDPE Gas Pipes ADVANTAGES
- It is not affected by the earthquake by its flexible structure.
- It keeps its flexibility when the temperature decreases to – 40 °C.
- Can be used on the building site as coil.
- Show high resistance to chemicals.
- Does not face corrosion by the fluid inside and by the structure of soil outside.
- It is light as 1/8 of steel as its volume being 0.940 gr/cm3.
- It can be combined out of channel and then released to channel. Decreases the excavation amount.
- It dos not require the ground to be sensible excavated progressively.
TEMPERATURE AND PRESSURE
The maximum safe pressure for a given C&N Aquatherm MDPE Pipe is determined by the pipe’s wall thickness and Hydrostatic Design Basis (HDB), the PE pipe Industry’s pressure rating method. The resultant maximum safe pressure is then modified by a design factor of 0.32.
C&N Aquatherm MDPE pipe’s operating temperature range is from – 20F to 140F in pressure service. The system and fitting not be operated above 100F unless components have demonstrated that gas can be safely transported at the higher temperature and expected pressure. Cold ambient temperature does not have an adverse effect on plastic pipe strength or characteristics.
MDPE80 natural gas pipes are used in the 4 bar pressurized regions of the natural gas lines. The natural has lines consist of 20 bar steel pipe, 4 bar intermediary line and 0.4 bar indoor lines
Because the pipes can be produced as a coil, they provide advantages in furnishing. Because the welding quantity decreases, the short lines can be furnished and they provide fitting and workmanship savings. In order to cancel out the natural gas leakage probability from the weld, only electro fusion welding is used which is the most safe welding method. The current is passed from the copper wires which are placed inside the fittings. The wire in which the current is passed is heated. The released energy melts the plastic. The volume of the melted plastic increases and melts the pipe by contacting with it. The molecular welding is performed with the pressure strength which is formed by the compaction in the intermediary region. It does not get harmed in earthquakes with its flexible structure and it eliminates the explosion risk.
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