What is Schedule 80 pipe?
Schedule 80 steel pipe (SCH 80) is an internationally used pipe wall thickness standard and is one of the pipe series specified by the ASME B36.10/B36.19 standard. Its core feature is the thickened pipe wall design, which is suitable for high pressure, high temperature or severe working conditions.
What are Schedule 80 pipes used for?
Sch 80 pipes have higher wall thickness and pressure bearing capacity than Sch 40 pipes, and are mainly used in situations where strength, pressure resistance and durability are required. The following are its typical application areas and selection considerations:
1. High-pressure fluid transportation system
(1) Oil and gas
High-pressure oil and gas gathering and transportation pipelines, wellhead equipment.
Refinery process pipelines: high-temperature and high-pressure media, such as steam and hydrocarbons.
Acidic environment (including H₂S): Corrosion-resistant materials, such as sulfur-resistant materials, are required.
(2) Power and Energy
Traditional thermal power: boiler feed water and steam pipelines, used for high temperature and high pressure conditions, using Sch 80 carbon steel or alloy steel.
New Energy: high temperature brine transportation in geothermal power plants, corrosive medium treatment for biomass power generation.
(3) Chemical and Pharmaceutical
Transport of corrosive media: can be used to transport acids, alkalis, and organic solvents, requiring lining or stainless steel.
High-pressure reactor connection pipeline: withstand pressure fluctuations and high temperatures.
2. Buildings and Infrastructure
Structural Support: heavy scaffolding, bridge load-bearing components.
Underground Pipes: high-pressure municipal water supply and drainage systems, requiring anti-corrosion treatment.
3. Fire and Safety Systems
High-pressure fire main pipelines: fire hydrant systems, fire pump outlet pipelines.
Industrial Fire Systems: chemical plants, oil depots and other high-risk places.
Gas Fire Extinguishing Systems: such as CO₂ pipelines, can use Sch 80 seamless steel pipes.
4. Applications in harsh environments
(1) High-temperature and high-pressure steam
Factory steam main pipeline: Sch 80 carbon steel or alloy steel P11/P22.
Heat network: High-temperature transmission section of central heating system.
(2) Marine and ship engineering
Seawater cooling pipeline: Sch 80 pipe made of 316 stainless steel, which can prevent chloride ion corrosion.
Ship ballast system: Resistant to salt spray and mechanical shock.
5. Special industrial scenarios
(1) Mining engineering
Mud/slurry conveying pipeline: Meet high wear resistance requirements and can be lined with rubber.
Tailings conveying high-pressure pipeline
Mine drainage system (wear-resistant coating)
(2) Heavy machinery
Hydraulic system high-pressure pipeline: Mainly used in engineering machinery and injection molding machines.
(3) Papermaking industry
Black liquor evaporator connecting pipe
Alkali corrosion resistant Sch80 CPVC pipe
SCH 80 steel pipe selection considerations:
Material selection:
Carbon steel (
A106 Gr.B): general high-pressure scenario.
Stainless steel (316): highly corrosive environment (chemical industry, seawater).
Alloy steel (P11/P22): ultra-high temperature steam (＞400°C).
Anti-corrosion requirements:
Buried pipes require 3PE coating or cathodic protection.
PTFE lining is optional for acidic media.
Testing standards:
High-pressure systems require 100% radiographic testing (RT) + water pressure test.
Conclusion:
Schedule 80 pipes are "heavy equipment" under high pressure, high temperature and corrosive environment. When selecting, the three major factors of medium, pressure and temperature must be clearly defined, and high-quality suppliers that meet ASME/API standards should be given priority. For non-critical scenarios (such as ordinary water supply), Sch 40 is more cost-effective.
Read more: ASME B36.10/B36.19 Standard Steel Pipe Dimensions & Sizes Chart
