SCH 80 pipe dimensions and pressure rating chart

Schedule 80 (SCH 80) is one of the most widely used pipe wall thickness schedules defined by ASME B36.10M and ASME B36.19M standards. It is commonly selected for medium- and high-pressure piping systems because its thicker wall provides greater pressure resistance and mechanical strength than Schedule 40 pipe.

SCH 80 does not represent a material grade. Instead, it defines the wall thickness of a pipe. The actual wall thickness varies according to the nominal pipe size (NPS), meaning a 2-inch SCH 80 pipe and an 8-inch SCH 80 pipe will have different wall thicknesses.

What Does Schedule 80 Mean?

The term "Schedule" refers to a standardized wall thickness designation used in pipe manufacturing.

Key points include:

SCH 80 is a wall thickness classification, not a material specification.

The same schedule number corresponds to different wall thicknesses for different pipe sizes.

SCH 80 generally provides higher pressure capacity than SCH 40.

Common materials include carbon steel, stainless steel, alloy steel, and PVC.

For NPS 1/8" through 10", SCH 80 is equivalent to the traditional XS (Extra Strong) wall designation.

Schedule 80 Pipe Thickness Chart

The following table shows common SCH 80 wall thicknesses:

Common SCH 80 Pipe Thickness Examples

SCH 80 vs SCH 40

One of the most common questions is the difference between SCH 40 and SCH 80.

Because SCH 80 has a thicker wall, its internal diameter is smaller than SCH 40 of the same nominal size, resulting in reduced flow capacity but higher pressure resistance.

Schedule 80 Pipe Pressure Rating

SCH 80 pipes generally support higher operating pressures due to their thicker walls. However, the actual allowable pressure depends on:

Material grade

Pipe size

Operating temperature

Corrosion allowance

Design code requirements

Weld joint efficiency

Typical materials include:

ASTM A106 Grade B

ASTM A53 Grade B

ASTM A333 Grade 6

Stainless Steel 304/316

Alloy Steel Pipe

Pressure calculations should always be verified according to ASME B31.3, ASME B31.1, or the applicable project specification.

Common Applications of SCH 80 Pipe

Because of its enhanced strength and pressure resistance, SCH 80 pipe is widely used in:

Oil and gas pipelines

Petrochemical facilities

Chemical processing plants

Power generation systems

Boiler piping

Steam distribution networks

High-pressure water systems

Fire protection systems

How to Select the Correct SCH 80 Pipe Size

When selecting SCH 80 pipe, engineers should consider:

1. Pipe Size (NPS)

The outside diameter is determined by the NPS, not by the schedule number.

2. Flow Requirements

Thicker walls reduce internal diameter, which can increase pressure drop and fluid velocity.

3. Structural Load

SCH 80 pipes are significantly heavier than SCH 40 pipes, requiring proper support design.

4. Design Pressure

Schedule numbers indicate wall thickness only. Final allowable working pressure must be calculated according to the applicable piping code.

Standards for SCH 80 Pipe

FAQ

1. What is Schedule 80 pipe?

Schedule 80 pipe is a pipe with a thicker wall than Schedule 40, designed for higher-pressure applications.

2. Is SCH 80 stronger than SCH 40?

Yes. SCH 80 has a thicker wall and can generally withstand higher pressures.

3. Does SCH 80 affect pipe diameter?

The outside diameter remains the same, but the thicker wall reduces the internal diameter.

4. Which standards define SCH 80 dimensions?

ASME B36.10M for carbon steel pipe and ASME B36.19M for stainless steel pipe.a