Schedule 120 Pipe: Specification Analysis and Application Scenarios

Schedule 120 Pipe is specially designed for high temperature and high pressure environments in the industrial and construction fields. This type of pipe has a high thickness and its durability far exceeds that of ordinary steel pipes. This article will provide you with a one-stop authoritative guide from the aspects of definition, application, technical parameters, etc.

What is Schedule 120 Pipe?

Schedule is a pipe number. It is a parameter used to identify the pipe wall thickness grade according to the relevant standards of ASTM (American Society for Testing and Materials) and ASME (American Society of Mechanical Engineers). The larger the value, the thicker the pipe wall and the corresponding pressure bearing capacity.
Core definition: Schedule 120 Pipe has an ultra-thick wall thickness and is specially designed for extreme pressure environments. It is more than twice the thickness of ordinary Schedule 40 pipes.

Common materials: including carbon steel (such as ASTM A106 standard) and stainless steel (such as ASTM A312 standard). In some special environments, alloy steel (such as chrome-molybdenum steel) is also used.

Production process: Schedule 120 Pipe is usually manufactured by hot rolling or cold drawing. In order to ensure the quality of the pipe, it must undergo non-destructive testing during the production process.

Example comparison: Under the same 6-inch outer diameter condition, the wall thickness of Schedule 120 Pipe can reach 0.864 inches, while the wall thickness of Schedule 80 Pipe is only 0.432 inches.

Sch 120 Technical Parameters

Specification table- taking 6-inch carbon steel pipe as an example

Outside diameter (inches)	Wall Thickness (inches)	Weight (lbs/ft)	Pressure Capacity (psi)
6.625	0.864	85.5	3,250

‌Relationship between temperature and pressure‌:

‌For every 50°C increase in temperature, the pressure bearing capacity decreases by about 10%‌ (the design needs to be adjusted according to the ASME B31.3 standard).

Sch 120 Pipe Size

Nominal size [inches]	Outside diameter [inches]	Outside diameter [mm]	Wall thickness [inches]	Wall thickness [mm]	Weight [lb/ft]	Weight [kg/m]
4	4.5	114.3	0.438	11.13	19	28.32
5	5.563	141.3	0.5	12.7	27.04	40.28
6	6.625	168.3	0.562	14.27	36.39	54.2
8	8.625	219.1	0.719	18.26	60.71	90.44
10	10.75	273	0.844	21.44	89.29	133.06
12	12.75	323.8	1	25.4	125.49	186.97
14	14	355.6	1.094	27.79	150.79	224.65
16	16	406.4	1.219	30.96	192.43	286.64
18	18	457	1.375	34.93	244.14	363.56
20	20	508	1.5	38.1	296.37	441.49
22	22	559	1.625	41.28	353.61	527.02
24	24	610	1.812	46.02	429.39	640.03

Pressure of Schedule 120

PANDAPIPE sells all the sizes and types of SCH120 pipe listed above! As a comprehensive piping company, PANDAPIPE is your trusted piping expert! Click below to contact us!

Schedule 120 Pipe Core application

Industrial high voltage systems

Petrochemical: Schedule 120 Pipe is often used to transport high-temperature steam and corrosive chemicals, so the pipe must be equipped with an anti-corrosion coating to resist the strong corrosion of these chemicals.
Energy industry: boiler pipes in thermal power plants, cooling systems in nuclear power plants
Shipbuilding: Responsible for the high-pressure fuel pipelines in the ship’s power compartment.

Large infrastructure

Water pipelines: used for ultra-high pressure water pipelines such as dams and cross-sea tunnels.
Natural gas transmission: used for long-distance high-pressure natural gas pipelines. At the same time, these pipelines need to comply with API 5L standards to ensure normal operation in extreme environments.

Schedule 120 vs 80 Advantages comparison:

parameter	Schedule 120	Schedule 80
Maximum pressure (psi)	3,200+	1,800
Temperature tolerance (℃)	≤450	≤300

Sch 120 Pipe Installation and Maintenance Guide

Key points of welding technology

Groove design: In order to ensure effective welding and a penetration rate greater than or equal to 94%, a V-shaped or U-shaped groove design should be used, which helps the weld metal to fully fuse.
Post-weld treatment: Stress relief must be performed to reduce excess stress generated during welding and reduce welding defects.

Anti-corrosion and maintenance

Coating solution: For buried pipelines, epoxy resin coating is recommended. In addition, it can also be combined with a cathodic protection system to further improve corrosion resistance.
Regular inspection: It is recommended to conduct ultrasonic wall thickness inspection of the pipeline every two years.

Summarize

Schedule 120 Pipe has become a “safety line” in key industrial scenarios due to its excellent pressure bearing capacity. We can provide customized solutions to optimize the performance and durability of the pipeline for the special needs of different industrial applications. Contact us now! We look forward to providing you with professional services and support!

FAQs：

1. What is the maximum pressure of Schedule 120 Pipe? ‌
The maximum pressure of carbon steel pipe at room temperature is 3,200 psi

2. What is the difference between Schedule 120 and Schedule 160? ‌
Schedule 160 has thicker walls, increased weight, and higher costs, and is only used in extreme high-pressure scenarios

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April 21, 2025

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