Asphaltic coating, commonly referred to as seal coat, is a protective layer applied to the exterior of ductile iron pipes. This coating serves as a barrier against corrosion, enhancing the pipe’s durability and extending its service life, particularly in underground installations. Typically, the asphaltic coating is approximately 1 mil thick and is applied during the manufacturing process.
1. Top Manufacturers and Suppliers
Several reputable manufacturers and suppliers offer asphaltic-coated ductile iron pipes. Here are some of the leading companies in the industry:
LuoKaiWei Ductile
LuoKaiWei Ductile provides ductile iron pipes with an exterior asphaltic coating at approximately 1-mil thickness. While this coating offers corrosion resistance, it is not intended as stand-alone protection in highly corrosive environments. For additional protective coatings and linings, LuoKaiWei Ductile recommends consulting with their representatives.
AMERICAN (American Cast Iron Pipe Company)
AMERICAN applies an exterior asphaltic coating approximately 1 mil thick to most of their pipe and fittings per AWWA C151 for ductile iron pipe. This standard coating has provided trouble-free service for decades. In corrosive soil conditions, polyethylene wrap or other appropriate methods are recommended for enhanced protection.
EA
Ea offers R-17-A-73 Asphalt Coating, an asphalt cutback coating engineered for ductile iron and steel substrates. This product can be used universally for the outside and inside diameter of ductile pipe and fittings, meeting or exceeding the performance requirements of NSF Standard 61.
FG
Fg provides Custom Fab 1-2/5 ft. x 6 in. Bituminous Tar Coated Flanged Ductile Iron Pipe, which includes a standard thickness cement-mortar lining with asphaltic coating inside and outside. This product is available for delivery or pickup at Fg stores.
2. Product Specifications and Standards
The application of asphaltic coating on ductile iron pipes adheres to various industry standards to ensure quality and performance:
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AWWA C151: Standard for Ductile-Iron Pipe, Centrifugally Cast, for Water.
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AWWA C115: Standard for Flanged Ductile-Iron Pipe with Ductile-Iron or Gray-Iron Threaded Flanges.
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AWWA C110: Standard for Ductile-Iron and Gray-Iron Fittings.
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AWWA C153: Standard for Ductile-Iron Compact Fittings.
These standards ensure that the asphaltic coating provides adequate protection against corrosion and meets the necessary performance criteria for water distribution systems.
3. Comparison of Leading Brands
| Manufacturer | Coating Thickness | Standards Complied | Additional Protective Measures |
|---|---|---|---|
| LuoKaiWei Ductile | ~1 mil | AWWA C151 | Consult for additional coatings |
| AMERICAN | ~1 mil | AWWA C151 | Polyethylene wrap recommended in corrosive soils |
| EA | Varies | NSF Standard 61 | Suitable for both interior and exterior applications |
| Fg | Varies | AWWA C151 | Cement-mortar lining included |
The application of asphaltic coating involves several key steps to ensure effectiveness:
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Surface Preparation: Clean the pipe surface to remove any contaminants, rust, or scale.
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Coating Application: Apply the asphaltic coating evenly to the exterior surface of the pipe.
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Curing: Allow the coating to cure properly to achieve the desired thickness and adhesion.
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Inspection: Inspect the coated pipe for uniform coverage and any defects.
Proper application ensures that the coating provides optimal protection against corrosion and extends the pipe’s service life.
5. Maintenance and Longevity
Regular maintenance is essential to ensure the longevity of asphaltic-coated ductile iron pipes:
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Routine Inspections: Conduct regular inspections to identify any signs of wear or damage to the coating.
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Repair Damaged Coatings: Promptly repair any areas where the coating has been compromised.
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Monitor Environmental Conditions: Be aware of soil conditions and other environmental factors that may affect the coating’s performance.
With proper maintenance, asphaltic-coated ductile iron pipes can provide reliable service for many years.
6. Environmental Considerations
Asphaltic coatings are designed to be environmentally friendly, offering several benefits:
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Corrosion Resistance: Protects the pipe from corrosive elements in the soil.
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Longevity: Extends the service life of the pipe, reducing the need for replacements.
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Recyclability: Ductile iron is a recyclable material, contributing to sustainability efforts.
Choosing asphaltic-coated ductile iron pipes aligns with environmentally responsible practices in infrastructure development.
7. Frequently Asked Questions (FAQs)
Q1: What is the primary purpose of asphaltic coating on ductile iron pipes?
The primary purpose of asphaltic coating is to provide a protective layer that shields the ductile iron pipe from corrosion, especially in underground installations where exposure to moisture and corrosive soils is prevalent.
Q2: How thick is the typical asphaltic coating applied to ductile iron pipes?
Typically, the asphaltic coating applied to ductile iron pipes is approximately 1 mil thick.
Q3: Can asphaltic coating be applied to both the interior and exterior of ductile iron pipes?
Yes, asphaltic coating can be applied to both the interior and exterior surfaces of ductile iron pipes to provide comprehensive corrosion protection.
Q4: Are there any limitations to using asphaltic-coated ductile iron pipes?
While asphaltic coatings offer corrosion resistance, they may not be sufficient in highly aggressive environments. In such cases, additional protective measures, such as polyethylene wrap or fusion-bonded epoxy coatings, may be necessary.
Q5: How can I purchase asphaltic-coated ductile iron pipes?
Asphaltic-coated ductile iron pipes can be purchased directly from manufacturers like McWane Ductile, AMERICAN, and ErgonArmor, or through distributors such as Ferguson. It’s advisable to contact these companies directly or visit their websites for purchasing options.
Q6: What maintenance is required for asphaltic-coated ductile iron pipes?
Regular maintenance includes conducting routine inspections to identify any signs of wear or damage to the coating, promptly repairing any compromised areas, and monitoring environmental conditions that may affect the coating’s performance.
8. Conclusion
Asphaltic-coated ductile iron pipes offer a reliable solution for corrosion protection in water distribution systems. By selecting reputable manufacturers and adhering to proper application and maintenance practices, these pipes can provide long-lasting service.
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