MPVC Pipes
About Rendifield MPVC Pipe
Rendifield Mining and Industrial Piping Solutions’ MPVC (Modified Polyvinyl Chloride) pipes have been successfully utilised across Southern Africa, Australia, and New Zealand for over 15 years. These pipes are recognised for their cost-effectiveness and energy efficiency in various applications.
Enhanced Material Properties
The unique properties of PVC can be enhanced by adding special additives, resulting in materials like modified PVC (PVC-M). These enhancements create pipes that are both strong and tough, suitable for demanding applications where resistance to cracking and stress corrosion is essential.
Long-Term Safety Factor
The design of PVC pipes incorporates safety factors to predict long-term performance. Materials like MPVC, which exhibit predictable ductile yielding, allow for the use of lower safety factors. This approach balances strength and toughness, leading to more efficient and reliable piping solutions.
Industry Recognition
The 50-year safety factor is a standard consideration in the industry, reflecting the balance between material strength and toughness. For example, while HDPE (High-Density Polyethylene) has lower strength than PVC-U but higher toughness, it is assigned a safety factor of 1.25. This demonstrates the industry’s commitment to ensuring durable and safe piping solutions.
Rendifield’s MPVC pipes exemplify the integration of advanced material properties and industry best practices, offering durable and efficient solutions for various piping needs.
MPVC Pipe Composition and Manufacturing Process
Material Composition
Polyvinyl Chloride (PVC) is a versatile thermoplastic polymer synthesized through the polymerization of vinyl chloride monomer (VCM), derived from common salt (sodium chloride) and hydrocarbons such as coal or oil. Notably, the production of PVC utilizes over 50% salt, contributing to its status as an environmentally friendly plastic by reducing dependence on finite hydrocarbon resources.
To tailor PVC’s properties for specific applications, various additives are incorporated during manufacturing. For MPVC pipes, impact modifiers are blended with the base resin to enhance ductility and resistance to environmental stress cracking. Additionally, heat stabilizers and lubricants facilitate the extrusion process and improve the material’s performance. These additives are thoroughly mixed with PVC resin in a high-speed mixer to create a uniform dry blend optimized for pipe extrusion.
Manufacturing Process
The production of MPVC pipes involves several key steps to ensure precise dimensions and superior mechanical properties:
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Extrusion: The dry blend is fed into an extruder, where it is subjected to controlled heat and shear forces. This process melts and homogenizes the material, preparing it for shaping.
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Forming: The molten polymer is then forced through a die and calibrator, shaping it into a pipe with exacting tolerances regarding outer diameter, wall thickness, and mechanical strength.
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Cooling and Cutting: After extrusion, the pipes are cooled to solidify their structure. They are then cut to specified lengths, ready for quality inspection and distribution.
Environmental Considerations
In recent years, there has been a concerted effort within the industry to replace lead-based stabilizers and lubricants with environmentally friendly alternatives, such as organic and calcium/zinc compounds. This shift aligns with global sustainability goals and enhances the environmental profile of MPVC pipes.
By integrating advanced material formulations and manufacturing techniques, MPVC pipes offer a balanced combination of strength, flexibility, and environmental responsibility, making them a preferred choice for various industrial applications.
MPVC Pipe physical properties
Modified Polyvinyl Chloride (MPVC) pipes are engineered to offer enhanced performance characteristics suitable for demanding applications. Below is an overview of their key physical properties:
Mechanical Properties
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Tensile Strength: MPVC pipes exhibit a tensile strength ranging from 4,500 to 8,700 psi, depending on the specific formulation and manufacturing process.
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Flexural Strength: These pipes possess a flexural strength of approximately 10,500 psi, ensuring resistance to bending under load.
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Impact Resistance: MPVC materials are designed to withstand impact forces, reducing the likelihood of cracks initiating or propagating during handling, installation, or service.
Thermal Properties
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Maximum Service Temperature: MPVC pipes are suitable for continuous service at temperatures up to 60°C (140°F). Exceeding this temperature may affect the material’s integrity and performance.
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Thermal Conductivity: With a thermal conductivity range of 0.14–0.28 W/(m·K), MPVC pipes provide effective insulation against temperature variations.
Durability and Longevity
MPVC pipes are recognised for their durability, with many installations demonstrating a useful lifespan exceeding 50 years without significant loss of capacity. This extended service life is attributed to their resistance to corrosion, weathering, and chemical degradation.
Safety Factors and Design Considerations
In designing piping systems, safety factors are applied to account for uncertainties and ensure reliable performance over time. The 50-year safety factor is a standard used to balance material strength and toughness, influencing the selection of appropriate materials and design parameters.
Conclusion
MPVC pipes combine robust mechanical properties with thermal stability and exceptional durability, making them a suitable choice for various demanding applications. Understanding these physical properties aids in the proper selection and application of MPVC piping systems to ensure optimal performance and longevity.
| PHYSICAL | UNITS | PVC-U | PVC-M |
| Co-Efficient of Linear Expansion | k-1 | 6 X 10-5 | 6 X 103 |
| Density | Kg/m3 | 1.4 X 103 | 1.1.J X 103 |
| Flammability [oxygen index] | % | 45 | 45 |
| Shore Hardness [DJ | 70-80 | 70-80 | |
| Softening Point [Vicat- minimum] | “C | > 80 | > 80 |
| Specific Heat | J/Kg/K | 1.0 X 103 | 1.0 X 103 |
| Thermal Conductivity [D”C-SO”C] | W/m/K | 0.14 | 0.14 |
| MECHANICAL | |||
| Elastic Modulus [long term: 50 years] | MPa | 1500 | 1400 |
| Elastic Modulus [short term: 100 seconds] | MPa | 3300 | 3000 |
| Elongation at break [Minimum] | % | 45 | 45 |
| Poisons Ratio | 0.4 | 0.4 | |
| Tensile Strength [50 year – extrapolated] | MPa | 26 | 26 |
| Tensile Strength [short-term / Minimum] | MPa | 45 | 45 |
| FRICTION FACTORS | |||
| Manning | 0.008-0.009 |
0.008-0.009
|
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| Hazen Williams | 150 |
150
|
|
| Nikuradse Roughness [k] | mm | 0.03 | 0.03 |
MPVC Pipe Applications
Drainage pipes
Above ground drainage
Water supply
Non-potable water pipelines of water between 5 and 50°C in mines.
SEWAGE
Sewerage under pressure
MPVC pipe dimensions
All pipes are manufactured to provide an effective length of 6.0 metres for sizes 50 mm to 250 mm and 5.8 metres for sizes 315 mm to 500 mm after installation. The outside diameters remain consistent across all pressure classes of the same size, with a total of six pipe classes available. The minimum wall thickness and mass per metre are detailed in the table below.
MPVC Features
Environment-friendly & Lead free material
Durability and toughness
Resistant to acids and alkalis
Resistant to abrasion, scouring and modern cleaning methods
Inflammable: Does not support
MPVC Benefits
Excellent flow characteristics: reduces friction losses
Best long-term strength [serves in excess of 50 years)
Long-term strength, toughness and stiffness
Large bore and high flow capacity
Light mass: for easy handling and installation
Elastomeric locked-in sealing ring system