Class 250 ductile iron pipe combines robust pressure capacity with proven longevity, making it a top choice for water, wastewater, irrigation and industrial networks. Engineered to a nominal working pressure of 250 رطل لكل بوصة مربعة (with a 100 رطل لكل بوصة مربعة surge allowance), its nodular-iron body features a shop-applied cement-mortar lining and versatile external protection to achieve an expected service life exceeding 100 years. Installation is streamlined via push-on, mechanical, restrained and flanged joints, ensuring rapid, leak-tight assembly in the trench or at the pump vault. Fully compliant with ANSI/AWWA C150/A21.50–91, C151/A21.51, C104/C105, C110/C111, ISO 2531, EN 545 و EN 598 standards, it delivers a competitive wall-thickness and life-cycle cost profile versus Class 52, 53, 150 and 350 series.

سيناريوهات التطبيق

• Municipal potable water distribution: Class 250’s 250 psi rating supports high-pressure loops and feeders in urban and suburban zones.

• Wastewater and sewer mains: Cement-mortar lining resists tuberculation in gravity and force mains, minimizing cleaning cycles.

• Agricultural irrigation networks: Specialized irrigation ranges of ductile iron pipes deliver low friction losses and exceptional durability in field conditions.

• Industrial process piping: Flanged Class 250 fittings link directly to pumps, valves and metering assemblies in chemical and power plants.

عمر الخدمة

Modern ductile iron pipelines, when coated with cement-mortar and properly sleeved, routinely outlast 100 عام in typical soil environments. Detailed life-cycle analyses confirm Class 250’s low operating costs and minimal maintenance burden yield superior total-cost performance versus PVC and other materials over a century-long horizon.

التركيب والتوصيل

وصلات الضغط والمفاصل الميكانيكية

• وصلات الضغط على الوصلات employ a lubricant-coated gasket for quick, trench-side assembly without bolting.

• الوصلات الميكانيكية use gland-and-bolt restraint gaskets (e.g., Field-Lok®) rated for 250 psi, eliminating thrust-block requirements in many layouts.

Restrained & Flanged Connections

• الوصلات المقيدة lock spigot into bell under pressure surges, safeguarding against separation in bends and dead-ends.

• أطراف ذات حواف bolt to equipment via ANSI B16.1 250 psi patterns or AWWA C207 configurations, yielding rigid, dismantlable connections.

الحماية من التآكل

• Internal lining: Centrifugal cement-mortar per ANSI/AWWA C104 forms a high-pH barrier against tuberculation.

• External coatings: Options include bonded zinc, asphaltic enamel or epoxy; loose polyethylene sleeving per AWWA C105 can be added for aggressive soils.

المعايير الدولية

• ANSI/ AWWA C150/A21.50 – Pressure-class thickness definitions

• ANSI/ AWWA C151/A21.51 – Pipe dimensions and tolerances

• ANSI/AWWA C104/C105 – Lining and encasement specifications

• ANSI/AWWA C110/C111 – Mechanical & push-on joint performance

• ISO 2531:2012, EN 545, EN 598 – International benchmarks for water and sewage applications

Comparative Parameters (Classes 52, 53, 150, 250, 350)

المزايا

• Exceptional Durability: Over a century of proven field performance

• High Strength: Meets AWWA tensile and impact standards under deep cover and surge events

• Corrosion Control: Cement-mortar lining plus coatings/sleeving minimize internal and external degradation

• Installation Flexibility: Multiple joint systems adapt to any trench or above-ground scenario

• الاستدامة: Up to 90 % recycled content; fully recyclable at end-of-life

الأسئلة الشائعة

1. What does “Class 250” mean?
   It denotes a nominal working pressure rating of 250 psi, with a 100 psi surge allowance, per ANSI/AWWA C150 tables.

2. How long will Class 250 pipe last?
   With proper lining and encasement, service lives regularly exceed 100 years.

3. Which joint type installs fastest?
   Push-on joints need only bell-hole prep and no bolting, speeding trench-time.

4. Can it be used in corrosive soils?
   Yes—pair with loose polyethylene sleeving per AWWA C105 or epoxy coating for aggressive environments.

5. What diameters are available?
   Nominal sizes from 3″ to 64″ cover most distribution and transmission needs.

دراسات الحالة

• University of Michigan LCCA: A 1 000 ft, 8″ Class 250 main demonstrated lower total cost of ownership over a 100-year design life versus PVC in a detailed life-cycle cost analysis.

• Louisville Water MRRP: Rehab of early-20th-century iron mains—including Class 250 pipes—in the Main-Replacement & Rehabilitation Program reduced annual break rates by over 70 %, extending system life with targeted cleaning and relining.

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