Schedule 160 Pipe: Dimensions, Wall Thickness, Weight and Applications

Schedule 160 pipe has a much thicker wall than Schedule 40 or Schedule 80 pipe of the same nominal size. Its outside diameter remains unchanged, but the inside diameter becomes smaller and the pipe becomes heavier.

It is commonly used in demanding pressure and temperature services. However, Schedule 160 is a dimensional designation, not a fixed pressure rating. Buyers sourcing carbon seamless steel pipes must also specify the material, grade and service requirements.

What Is Schedule 160 Pipe?

Schedule 160 is a standardized wall-thickness series for steel pipe. The number does not mean 160 psi, 160 mm or a fixed thickness.

Wall thickness changes with nominal pipe size. For example, NPS 2 Schedule 160 pipe has a 0.344-inch wall, while NPS 8 has a 0.906-inch wall.

For the same NPS, increasing the schedule:

• Keeps the outside diameter unchanged
• Increases wall thickness and weight
• Reduces the inside diameter
• Reduces the available flow area

Schedule 160 dimensions for carbon and alloy steel pipe are generally referenced through ASME B36.10M. ASTM and API specifications separately define the material, grade, manufacturing and testing requirements.

Schedule 160 Pipe Dimensions and Weight Chart

The following chart covers common Schedule 160 pipe sizes. Inside diameter is calculated from the nominal OD and wall thickness.

The inside diameter is calculated as:

Inside Diameter = Outside Diameter − 2 × Wall Thickness

Dimensions and weights are nominal. Actual values may vary with material density, coating and manufacturing tolerances. See BAOLAI’s steel pipe size and schedule chart for other schedules.

How Does Schedule 160 Affect Inside Diameter and Weight?

A higher schedule adds material inward without changing the outside diameter.

For NPS 4 pipe:

The smaller bore can increase fluid velocity and pressure loss at the same flow rate. Greater weight also affects supports, lifting, transport and installation.

Thick walls require more work during cutting, beveling and welding. Schedule 160 should therefore be selected only when the design requires it.

What Is the Pressure Rating of Schedule 160 Pipe?

Schedule 160 pipe does not have one universal pressure rating. Allowable pressure depends on:

• Pipe size
• Material and grade
• Design temperature
• Allowable material stress
• Wall-thickness tolerance
• Corrosion allowance
• Manufacturing method
• Applicable piping code
• Fitting, flange and valve ratings

Two Schedule 160 pipes can share the same dimensions but have different allowable pressures because their materials or temperatures differ.

Engineers first calculate the minimum required wall thickness and allowances. They then select a schedule that meets or exceeds that value. BAOLAI’s guide to selecting steel pipe wall thickness explains the main factors.

Schedule 160 vs Schedule 80 and XXS

Schedule 160 is thicker than Schedule 80, but it is not always thicker than XXS.

XXS is thicker through NPS 6 in these examples. At NPS 8, Schedule 160 becomes thicker. The two designations are therefore not interchangeable.

Schedule 80 is lighter, less expensive and easier to fabricate. Schedule 160 is appropriate when calculations require additional wall thickness despite its smaller bore and higher cost.

Where Is Schedule 160 Pipe Used?

Schedule 160 pipe is used where thinner schedules cannot provide the required wall thickness. Common applications include:

• High-pressure steam lines
• Refinery and petrochemical piping
• Oil and gas processing equipment
• Power generation systems
• Boiler connections
• Chemical process lines
• Compressor and pump connections
• Small-bore vents, drains and instrument branches

It is more common in smaller sizes. Large Schedule 160 pipes are heavy, expensive and less readily available.

Wall thickness also does not replace material selection. Corrosive service may require stainless steel, alloy steel, lining or an additional corrosion allowance.

How Should Schedule 160 Pipe Be Specified?

“Schedule 160 pipe” is not a complete purchase description. A clear specification may read:

ASTM A106 Grade B, NPS 4, Schedule 160, seamless, beveled ends, 12 m length, black finish, hydrostatically tested, with EN 10204 3.1 certificate.

An RFQ should include:

• Material specification and grade
• NPS or DN
• Schedule or required wall thickness
• Seamless or welded manufacture
• Length and end preparation
• Surface finish or coating
• Testing and certificate requirements
• Quantity, marking and packing

ASTM A106 is often used for seamless carbon steel pipe in elevated-temperature service, but it is not the only material specification available with Schedule 160 dimensions. Review BAOLAI’s ASTM A106 seamless carbon steel pipe when this standard is required.

Availability should be checked early. Some sizes, grades and lengths may require a minimum production quantity or longer lead time.

Source Schedule 160 Pipe From BAOLAI

BAOLAI supplies seamless and welded steel pipes for energy, pipeline, boiler and industrial projects. Available specifications include ASTM A106, ASTM A53 and API 5L.

Send the standard, grade, NPS, Schedule 160 requirement, length and quantity through the BAOLAI contact page. BAOLAI can confirm dimensions, testing, production requirements and delivery options.

Conclusion

Schedule 160 pipe provides a thick wall while retaining the standard OD for its nominal size. This increases weight and reduces the bore. Select it through an engineering calculation that considers material, temperature, tolerances, corrosion and connected components.

Frequently Asked Questions

Can Schedule 160 pipe be threaded?

It can be threaded when the material, size and piping code permit it. Because threading removes material at the thread root, verify the remaining wall and fitting rating. Welded connections are often preferred for demanding service.

Does Schedule 160 pipe require Schedule 160 fittings?

Not all fittings use schedule numbers. Butt-weld fittings may use a matching wall or bore, while forged threaded and socket-weld fittings are commonly specified by pressure class. Confirm material, wall, bore and rating for the complete joint.

Is Schedule 160 available as welded pipe?

ASME B36.10M covers dimensions for welded and seamless steel pipe. Actual availability depends on the material, diameter and wall thickness. Smaller thick-wall sizes are often supplied as seamless pipe.

How do wall tolerances affect Schedule 160 pipe?

The chart shows nominal wall thickness. Material standards may permit a negative wall tolerance. Pressure calculations should use the minimum permitted wall after including corrosion and other allowances.

What should a Schedule 160 pipe RFQ include?

State the material standard, grade, NPS, schedule, manufacturing method, length, ends, coating, quantity, testing and certificate requirements. This prevents a dimensionally correct but unsuitable pipe from being quoted.

Official Sources

• ASME B36.10M: Welded and Seamless Wrought Steel Pipe
• ASME Pressure Design Guidance
• ASME B31.3 Design Conditions and Criteria