Schedule 80 Carbon Steel Pipe Size Chart & Pressure Rating

Schedule 80 carbon steel pipe is widely used in industrial piping systems that require higher pressure resistance, greater mechanical strength, and longer service life than standard wall pipes. Compared with Schedule 40, Schedule 80 has a thicker wall while maintaining the same outside diameter, allowing it to withstand higher internal pressure and provide a greater corrosion allowance in demanding environments.

Because of these advantages, Schedule 80 carbon steel pipe is commonly used in oil and gas transmission, chemical processing, power generation, fire protection systems, water treatment plants, and heavy industrial construction. It is available in both seamless and welded forms and can be manufactured according to ASTM, ASME, and API standards to meet different application requirements.

Whether you are selecting piping for a new project or replacing an existing system, understanding Schedule 80 dimensions, wall thickness, pressure ratings, and material grades is essential for choosing the right product.

What Is Schedule 80 Carbon Steel Pipe?

Schedule 80 carbon steel pipe is a heavy-wall steel pipe manufactured with a thicker wall than Schedule 40 while maintaining the same nominal pipe size (NPS) and outside diameter (OD). The additional wall thickness increases the pipe's pressure capacity, mechanical strength, and service life, making it suitable for medium- and high-pressure piping systems.
The term "Schedule" (SCH) does not refer to the pipe material, strength, or pressure rating. Instead, it is a standardized wall thickness designation defined by ASME B36.10M for carbon and alloy steel pipes. Common schedule numbers include SCH 10, SCH 20, SCH 40, SCH 80, SCH 160, and XXS.
For the same nominal pipe size:
The outside diameter (OD) remains unchanged.
A higher schedule number means a thicker wall.
The inside diameter (ID) becomes smaller.
Pressure resistance generally increases.

Understanding Pipe Size Terminology (NPS, SCH, DN & NB)

Pipe dimensions are described using several international sizing systems. Understanding these terms helps avoid specification errors when purchasing or designing piping systems.

Term	Meaning	Common Region
NPS	Nominal Pipe Size	United States, Canada
SCH	Pipe Wall Thickness Schedule	International
DN	Nominal Diameter (mm)	Europe, China
NB	Nominal Bore	UK, Australia, India
OD	Outside Diameter	Worldwide
ID	Inside Diameter	Worldwide

NPS 2
DN 50
NB 2"
all refer to approximately the same nominal pipe size.
However, the wall thickness changes depending on the schedule.
For instance:
NPS 2 Schedule 40
OD: 60.3 mm
Wall Thickness: 3.91 mm
NPS 2 Schedule 80
OD: 60.3 mm
Wall Thickness: 5.54 mm
Although both pipes have the same outside diameter, the Schedule 80 pipe has a smaller inside diameter because of its thicker wall. This design allows it to withstand higher internal pressure while providing greater resistance to wear and corrosion over time.

Schedule 80 Carbon Steel Pipe Dimensions Chart

Schedule 80 pipe dimensions are standardized by ASME B36.10M, ensuring compatibility across different manufacturers and industries. The standard specifies the outside diameter, wall thickness, and approximate weight for each nominal pipe size.

The table below lists the most commonly used Schedule 80 carbon steel pipe dimensions.

Nominal size [inches]	Outside diameter [inches]	Outside diameter [mm]	Wall thickness [inches]	Wall thickness [mm]	Weight [lb/ft]	Weight [kg/m]
1/8" DN6	0.405	10.3	0.095	2.41	0.31	0.47
1/4" DN8	0.54	13.7	0.119	3.02	0.54	0.8
3/8" DN10	0.68	17.1	0.126	3.2	0.74	1.1
1/2" DN15	0.84	21.3	0.147	3.73	1.09	1.62
3/4" DN20	1.05	26.7	0.154	3.91	1.47	2.2
1" DN25	1.315	33.4	0.179	4.55	2.17	3.24
1 1/4" DN32	1.66	42.2	0.191	4.85	3	4.47
1 1/2" DN40	1.9	48.3	0.2	5.08	3.63	5.41
2" DN50	2.375	60.3	0.218	5.54	5.02	7.48
2 1/2" DN65	2.875	73	0.276	7.01	7.66	11.41
3" DN80	3.5	88.9	0.3	7.62	10.25	15.27
3 1/2" DN90	4	101.6	0.318	8.08	12.5	18.63
4" DN100	4.5	114.3	0.337	8.56	14.98	22.32
5" DN125	5.563	141.3	0.375	9.53	20.78	30.97
6" DN150	6.625	168.3	0.432	10.97	28.57	42.56
8" DN200	8.625	219.1	0.5	12.7	43.39	64.64
10" DN250	10.75	273	0.594	15.09	64.43	96.01
12" DN300	12.75	323.8	0.688	17.48	88.63	132.08
14" DN350	14	355.6	0.75	19.05	106.13	158.1
16" DN400	16	406.4	0.844	21.44	136.61	203.53
18" DN450	18	457	0.938	23.83	170.92	254.55
20" DN500	20	508	1.031	26.19	208.87	311.17
24" DN600	24	610	1.125	30.96	296.58	442.08

Quick Reference for Common Schedule 80 Pipe Sizes
The following wall thickness values are among the most frequently requested by engineers and buyers.

Pipe Size	Wall Thickness
1" SCH 80	4.55 mm
2" SCH 80	5.54 mm
3" SCH 80	7.62 mm
4" SCH 80	8.56 mm
6" SCH 80	10.97 mm
8" SCH 80	12.70 mm
10" SCH 80	15.09 mm

Notice：The outside diameter remains the same regardless of the schedule. Only the wall thickness, inside diameter, weight, and pressure capacity change.

What Determines the Pressure Rating of Schedule 80 Pipe?

Many buyers ask, "What is the pressure rating of Schedule 80 carbon steel pipe?" The answer is that Schedule 80 does not have a single fixed pressure rating. Instead, the allowable working pressure depends on several engineering factors.
These include:
Pipe outside diameter
Wall thickness
Material grade
Operating temperature
Design code
Corrosion allowance
Safety factor
For example, a 2-inch ASTM A106 Grade B Schedule 80 seamless pipe can withstand significantly higher pressure than a 10-inch Schedule 80 pipe because smaller diameters generally have greater pressure resistance when wall thickness is comparable.
Likewise, a pipe manufactured from API 5L X52 may have a different allowable pressure than one made from ASTM A53 Grade B, even if both are Schedule 80.
For engineering projects, pressure calculations should always follow applicable design standards such as ASME B31.1, ASME B31.3, or project-specific design codes instead of relying on a single pressure value.

How Much Does Schedule 80 Pipe Weigh?

The weight of a Schedule 80 pipe varies depending on its nominal size, wall thickness, material, and overall length. A commonly used formula for estimating the weight per meter of carbon steel pipe is:
Weight (kg/m) = [OD (mm) − Wall Thickness (mm)] × Wall Thickness (mm) × 0.02466
For example, a 2-inch Schedule 80 carbon steel pipe with an outside diameter of 60.3 mm and a wall thickness of 5.54 mm has an approximate weight of:
(60.3 − 5.54) × 5.54 × 0.02466 ≈ 7.47 kg/m

The values listed in the dimension chart are based on carbon steel with a density of approximately 7.85 g/cm³. Stainless steel grades such as 304 and 316 are generally 1–2% heavier because of their slightly higher density, while most alloy steel pipes have a weight that is very close to carbon steel.

Schedule 80 Carbon Steel Pipe Pressure Rating

One of the most common questions engineers and buyers ask is "What is the pressure rating of Schedule 80 carbon steel pipe?"
Unlike pipe dimensions, Schedule 80 does not have a single universal pressure rating. The allowable working pressure depends on several engineering factors, including:
Pipe outside diameter (OD)
Wall thickness
Material grade (ASTM A53, ASTM A106, API 5L, etc.)
Operating temperature
Design code (ASME B31.1, ASME B31.3)
Corrosion allowance
Safety factor
For the same material, smaller Schedule 80 pipes generally withstand higher internal pressure than larger sizes because the ratio of wall thickness to diameter is greater.
The table below provides typical pressure ratings for Schedule 80 carbon steel pipe manufactured in accordance with ASME B36.10M. These values are for reference only. Final allowable working pressure should always be verified according to the applicable design code and project requirements.

Schedule 80 Steel Pipe Pressure Rating (Typical)

Pipe Size	Schedule	100°F	200°FF	300°FF	400°FF	500°F	600°F	650°F	700°F	750°F
1"	SCH 40	3048	2629	2362	2171	2019	1924	1867	1824	1810
1"	SCH 80	4213	3634	3265	3002	2791	2659	2580	2528	2501
1"	SCH 160	6140	5296	4759	4375	4068	3876	3761	3684	3646
1½"	SCH 40	2257	1947	1750	1608	1496	1425	1383	1354	1340
1½"	SCH 80	3182	2744	2466	2267	2108	2009	1949	1909	1889
1½"	SCH 160	4619	3984	3580	3291	3060	2916	2829	2772	2743
2"	SCH 40	1902	1640	1474	1355	1260	1201	1165	1141	1129
2"	SCH 80	2747	2369	2129	1957	1820	1734	1682	1648	1631
2"	SCH 160	4499	3880	3486	3205	2980	2840	2755	2699	2671
3"	SCH 40	1806	1558	1400	1287	1196	1140	1106	1084	1072
3"	SCH 80	2553	2202	1979	1819	1691	1612	1564	1532	1516
3"	SCH 160	3840	3312	2976	2736	2544	2424	2352	2304	2280
4"	SCH 40	1531	1321	1187	1091	1014	967	938	919	909
4"	SCH 80	2213	1909	1715	1577	1466	1397	1355	1328	1314
4"	SCH 160	3601	3106	2791	2566	2386	2273	2206	2161	2138
5"	SCH 40	1342	1158	1040	956	889	847	822	805	797
5"	SCH 80	1981	1709	1535	1411	1312	1250	1213	1189	1176
5"	SCH 160	3414	2945	2646	2433	2262	2155	2091	2049	2027
6"	SCH 40	1219	1052	945	869	808	770	747	732	724
6"	SCH 80	1913	1650	1483	1363	1267	1208	1172	1148	1136
6"	SCH 160	3289	2836	2549	2343	2179	2076	2014	1973	1953
8"	SCH 40	1073	926	832	765	711	678	657	644	637
8"	SCH 80	1692	1459	1311	1205	1121	1068	1036	1015	1005
8"	SCH 160	3175	2738	2460	2262	2103	2004	1944	1905	1885
10"	SCH 40	974	840	755	694	645	615	596	584	578
10"	SCH 80	1609	1388	1247	1147	1066	1016	986	966	956
10"	SCH 160	3147	2714	2439	2242	2085	1986	1927	1880	1868

Pressure Rating Comparison: Schedule 40 vs Schedule 80

Pipe Size	SCH 40 @100°F	SCH 80 @100°F
1"	3048 psi	4213 psi
2"	1902 psi	2747 psi
4"	1531 psi	2213 psi
6"	1219 psi	1913 psi
8"	1073 psi	1692 psi

How to Read the Schedule 80 Pressure Rating Chart?

When using the pressure rating chart, keep the following engineering principles in mind:
Higher operating temperatures reduce allowable working pressure.
For the same schedule and material, smaller pipe sizes generally withstand higher pressure than larger diameters.
Material grade affects pressure capacity. For example, ASTM A106 Grade B and API 5L X52 have different allowable stresses under design codes.
Schedule number indicates wall thickness, not pressure. Two Schedule 80 pipes made from different materials may have different pressure ratings.

Always verify the final allowable pressure using ASME B31.1, ASME B31.3, or applicable project specifications before installation.

Common Material Grades for Schedule 80 Carbon Steel Pipe

Schedule 80 defines the ：pipe wall thickness, not the material grade. Depending on the application, it is commonly manufactured to ASTM and API standards.

ASTM A53 Grade B
ASTM A53 Grade B is widely used for water, gas, steam, and structural applications. It is available in both seamless and ERW forms, offering reliable performance and good weldability.

ASTM A106 Grade B
ASTM A106 Grade B is intended for high-temperature and high-pressure service. It is commonly used in power plants, refineries, and process piping systems.

API 5L Grade B
API 5L Grade B is designed for oil and natural gas pipeline transportation, providing dependable strength for onshore and offshore pipeline projects.

API 5L X42 & X52

API 5L X42 and X52 offer higher yield strength than Grade B, making them suitable for high-pressure transmission pipelines and demanding industrial applications.

How to Select the Right Schedule 80 Carbon Steel Pipe？

Choosing the correct Schedule 80 pipe involves more than selecting a pipe size. Engineers should evaluate the entire operating environment before making a decision.
Consider the following factors:
Operating Pressure: Higher pressures generally require thicker wall pipes.
Service Temperature: Elevated temperatures reduce allowable pressure ratings.
Transported Medium: Water, steam, gas, oil, or chemicals may require different material grades.
Applicable Standards: Select products manufactured to ASTM, API, or ASME requirements.
Manufacturing Method: Choose seamless or ERW pipe according to pressure and service conditions.
Corrosion Protection: Consider galvanized, painted, FBE, or 3PE coatings for harsh environments.
Connection Type: Verify compatibility with threaded, welded, grooved, or flanged connections.

Working with an experienced supplier can help ensure the selected pipe meets both engineering specifications and project budgets.

Inspection and Quality Control

High-quality Schedule 80 carbon steel pipes should undergo strict inspection throughout the manufacturing process to ensure dimensional accuracy and mechanical performance.
Common quality control procedures include:
Hydrostatic pressure testing
Dimensional inspection
Chemical composition analysis
Mechanical property testing
Non-destructive testing (NDT)
Surface quality inspection
Mill Test Certificate (MTC) verification

For critical industrial projects, third-party inspections can provide additional assurance that products comply with ASTM, API, and ASME requirements.

Schedule 40 vs Schedule 80 Carbon Steel Pipe

Schedule 40 and Schedule 80 are the most commonly used wall thickness classifications for carbon steel pipe. Although they have the same outside diameter (OD) for the same nominal pipe size (NPS), Schedule 80 has a thicker wall, resulting in higher pressure capacity, greater mechanical strength, and a longer service life.

Feature	Schedule 40	Schedule 80
Wall Thickness	Standard	Heavy
Outside Diameter	Same	Same
Inside Diameter	Larger	Smaller
Pressure Capacity	Medium	Higher
Pipe Weight	Lower	Higher
Material Cost	Lower	Higher
Flow Capacity	Higher	Slightly Lower

Which One Should You Choose?
Schedule 40 is suitable for general-purpose applications where moderate pressure and lower installation costs are priorities. It is commonly used for water distribution, gas lines, HVAC systems, and structural applications.
Schedule 80 is the better choice for high-pressure, high-temperature, or mechanically demanding environments. Its thicker wall provides greater durability and corrosion allowance, making it ideal for industrial processing, power generation, oil and gas pipelines, and fire protection systems.
In practice, the best choice depends on your operating pressure, temperature, service environment, and project budget rather than simply selecting the thicker pipe.

Frequently Asked Questions

1. What is Schedule 80 carbon steel pipe used for?
Schedule 80 pipe is widely used in oil and gas, chemical processing, power generation, fire protection, water treatment, and other industrial piping systems that require higher pressure resistance.

2. Is Schedule 80 stronger than Schedule 40?
Yes. Schedule 80 has a thicker wall than Schedule 40, providing greater mechanical strength, higher pressure capacity, and improved durability.

3. Does Schedule 80 have the same outside diameter as Schedule 40?
Yes. Pipes with the same nominal pipe size (NPS) have the same outside diameter. The difference lies in the wall thickness and inside diameter.

4. Can Schedule 80 pipe be threaded?
Yes. Its thicker wall provides stronger and deeper threads, making it suitable for threaded high-pressure piping systems.

5. Is Schedule 80 available in seamless and welded types?
Yes. Depending on the applicable standard and project requirements, Schedule 80 pipe is available in both seamless and ERW welded constructions.

6. Which standards cover Schedule 80 carbon steel pipe?
Common standards include ASME B36.10M, ASTM A53, ASTM A106, API 5L, and ASTM A333 for specific service conditions.