Mechanical Engineering · Fuel-Gas Piping

Propane Pipe Sizing Chart

Select low-pressure Schedule 40 propane pipe from connected appliance input and exact equivalent length, then verify the calculated capacity and governing assumptions.

Fuel: Undiluted propane vapor
Pressure drop: 0.5 in. w.c.
Pipe range: NPS 1/2–4, Schedule 40

JavaScript enables exact-length sizing, unit conversion, first-qualifying selection, copy, share, and reset. The default worked result and complete calculated capacity table remain available below.

Exact-length selector

Size Low-Pressure Schedule 40 Propane Pipe

IFGC 2024 Equation 4-1 · first unrounded capacity that meets the load

At the default 200,000 Btu/h and 50 ft equivalent length, the first qualifying listed size is NPS 3/4 (DN20). With JavaScript enabled, change the inputs to calculate an exact-length preliminary selection.

Safety and scope limit

This preliminary calculation applies only to undiluted propane vapor in the listed Schedule 40 metallic-pipe IDs, downstream of a single- or second-stage low-pressure regulator, on the stated 11.0 in. w.c. inlet and 0.5 in. w.c. drop basis. Verify the adopted code, permitted sizing method, simultaneous loads, available pressure, appliance requirements, equivalent length, regulator capacity, container vaporization, material approval, installation details, and authority having jurisdiction. Propane systems must be installed by qualified personnel.

Calculated reference matrix

Calculated Propane Capacity by Pipe Size and Equivalent Length

Maximum calculated energy capacity in MBH

Read across the equivalent-length row. The first pipe column whose unrounded capacity equals or exceeds the connected load qualifies under this page’s fixed basis. The live “Current input” row uses the exact entered length.

Equation-generated low-pressure undiluted-propane capacity for Schedule 40 metallic pipe at 0.5 in. w.c. allowable pressure drop and 2,488 Btu/ft³. Values are MBH.
	Maximum calculated propane capacity, MBH
	NPS 1/2 DN15 · ID 0.622 in	NPS 3/4 DN20 · ID 0.824 in	NPS 1 DN25 · ID 1.049 in	NPS 1-1/4 DN32 · ID 1.380 in	NPS 1-1/2 DN40 · ID 1.610 in	NPS 2 DN50 · ID 2.067 in	NPS 2-1/2 DN65 · ID 2.469 in	NPS 3 DN80 · ID 3.068 in	NPS 4 DN100 · ID 4.026 in
10 ft (3.05 m)	292	612	1,150	2,370	3,550	6,840	10,900	19,300	39,300
20 ft (6.10 m)	201	420	792	1,630	2,440	4,700	7,490	13,300	27,000
30 ft (9.14 m)	161	338	636	1,310	1,960	3,770	6,020	10,600	21,700
40 ft (12.19 m)	138	289	545	1,120	1,680	3,230	5,150	9,110	18,600
50 ft (15.24 m)	122	256	483	992	1,490	2,860	4,570	8,070	16,500
60 ft (18.29 m)	111	232	438	899	1,350	2,590	4,140	7,320	14,900
75 ft (22.86 m)	98.4	206	388	797	1,190	2,300	3,670	6,480	13,200
100 ft (30.48 m)	84.2	176	332	682	1,020	1,970	3,140	5,550	11,300
125 ft (38.10 m)	74.6	156	294	604	906	1,740	2,780	4,920	10,000
150 ft (45.72 m)	67.6	141	267	548	821	1,580	2,520	4,460	9,100
200 ft (60.96 m)	57.9	121	228	469	702	1,350	2,160	3,820	7,790
250 ft (76.20 m)	51.3	107	202	415	623	1,200	1,910	3,380	6,900
300 ft (91.44 m)	46.5	97.2	183	376	564	1,090	1,730	3,060	6,250
400 ft (121.92 m)	39.8	83.2	157	322	483	930	1,480	2,620	5,350
500 ft (152.40 m)	35.3	73.8	139	286	428	825	1,310	2,320	4,740
Current input: 50 ft	122	256 · selected	483	992	1,490	2,860	4,570	8,070	16,500

Calculated values are not a reproduction of an ICC, NFPA, ASME, PERC, or manufacturer table. They do not establish regulator, container, appliance, material, installation, or jurisdictional compliance. Bulk CSV export is intentionally disabled.

How to Use the Propane Pipe Sizing Chart

Total the connected input. Use appliance nameplate input ratings, not delivered heat output. Determine which appliances can operate simultaneously on the segment being sized.
Establish the permitted length method. Enter the applicable equivalent length from the adopted code or approved design procedure, including fittings when that method requires them.
Confirm the fixed pressure basis. This page assumes an 11.0 in. w.c. inlet reference and 0.5 in. w.c. allowable drop. It does not infer available pressure at the project.
Read the first qualifying size. The calculator compares unrounded capacities, so displayed rounding never decides the nominal pipe selection.
Verify the rest of the propane system. Check regulators, container vaporization, appliance requirements, approved materials, installation rules, local amendments, and the authority having jurisdiction.

Low-Pressure Propane Scope and Safety Limits

Covered by this page	Requires another verified method
Undiluted propane vapor downstream of a single- or second-stage low-pressure regulator	Tank-to-first-stage piping, liquid propane, or elevated-pressure distribution
Fixed 0.5 in. w.c. pressure-drop calculation with the stated 11.0 in. w.c. inlet reference	2 psi, 5 psi, 10 psi, or another inlet/drop basis
Limited Schedule 40 metallic-pipe IDs from NPS 1/2 through NPS 4	Copper tubing, CSST, PE, appliance connectors, or another schedule/material system
Preliminary capacity and first-qualifying nominal-size comparison	Regulator selection, container vaporization, combustion-air design, joining approval, or complete network approval

Natural-gas results are not interchangeable with propane results. The gases have different equation factors, heating values, operating arrangements, and applicable sizing tables.

Equation, Variables, and Length Methods

The page calculates propane flow from connected input and heating value, solves IFGC Equation 4-1 for required inside diameter, and then checks the limited actual-ID set from smallest to largest:

Q = H ÷ H_v

D = Q^0.381 ÷ [19.17 × (ΔH ÷ (C_rL))^0.206]

QPropane flow in standard cubic feet per hour, referenced at 60°F and 30 in. Hg
HConnected appliance input in Btu/h
H_vPropane heating value; default 2,488 Btu/ft³
DRequired pipe inside diameter in inches
LApplicable equivalent piping length in feet
ΔHAllowable pressure drop, fixed here at 0.5 in. w.c.
C_rIFGC undiluted-propane equation factor, 1.2462

Longest-length, branch-length, and equivalent length

The longest-length method commonly sizes applicable segments using the developed length to the most remote outlet. A branch-length method can use segment-specific lengths when permitted. Equivalent-length procedures account for fittings by an approved method. This page asks for the resulting applicable length; it cannot decide which method the adopted code or authority permits for a project.

Worked Propane Pipe Sizing Examples

Example 1: 200,000 Btu/h at 50 ft

Assume undiluted propane, 2,488 Btu/ft³, 50 ft applicable equivalent length, and 0.5 in. w.c. allowable drop. The load is 80.39 SCFH. Equation 4-1 gives a required ID of about 0.750 in. NPS 1/2, with a 0.622 in ID, calculates to about 122 MBH and is short by about 77.5 MBH. NPS 3/4, with a 0.824 in ID, calculates to about 256 MBH and is the first listed size that qualifies.

Example 2: 400,000 Btu/h at 100 ft

Using the same fuel and pressure-drop basis, the load is about 160.77 SCFH and the required ID is about 1.126 in. NPS 1 calculates to about 332 MBH and does not qualify. NPS 1-1/4 calculates to about 682 MBH and is the first qualifying listed size. Both examples remain preliminary because regulator behavior, container vaporization, adopted sizing method, and appliance pressure requirements are separate checks.

Propane Pipe Sizing Mistakes That Cause Bad Results

Using appliance output instead of input: fuel piping is based on the maximum input rating.
Omitting simultaneous loads: each segment must carry the applicable connected demand downstream.
Entering straight-line distance: use the developed or equivalent length required by the permitted sizing method.
Using a natural-gas chart: its fuel factor and heat-content basis do not transfer to propane.
Treating NPS as actual ID: the equation uses actual inside diameter, not the nominal designation.
Assuming 0.5 in. w.c. is always available: confirm supply pressure, regulator performance, appliance minimum pressure, and permissible drop.
Ignoring the container and regulator: adequate pipe capacity does not prove adequate vaporization or regulator capacity.

Schedule 40, Copper, CSST, PE, and Elevated-Pressure Systems

Material systems use different dimensions, installation rules, and sometimes manufacturer-specific sizing methods. Do not convert this result by matching nominal labels.

Schedule 40 metallic pipe: use this page only when the stated fuel, pressure, size, and length scope all apply.
Copper tubing: verify that copper is permitted and use the applicable tubing dimensions, code provisions, and joining requirements.
CSST: use the exact manufacturer’s current sizing tables and equivalent hydraulic diameter system.
Underground PE: use approved PE dimensions, pressure basis, joining rules, tracer requirements, and adopted code provisions.
First-stage or elevated pressure: use the applicable pressure-specific method and complete the required downstream pressure-reduction checks.

Sources, Edition, Calculation Scope, and Data Rights

Original equation-generated capacities for low-pressure undiluted propane; no complete standards or manufacturer table is reproduced.

The calculator and matrix use a limited set of source-controlled constants and pipe IDs to create original calculated values. The adopted local code and authority having jurisdiction control actual design and installation.

International Code Council — 2024 IFGC, Chapter 4Section 402.4, Equation 4-1, propane factor 1.2462, reference conditions, and low-pressure equation scope.
Propane Education & Research Council — Propane Technical Pocket GuideApproximate propane properties, 2,488 Btu/ft³ default heat content, total-load method, and professional-safety context.
ICC CodeNotes — Fuel Gas Pipe SizingLongest-length and branch-length method context; published September 15, 2023.
ASME B36.10-2022 — Welded and Seamless Wrought Steel PipeLimited Schedule 40 NPS/DN and nominal inside-diameter inputs from NPS 1/2 through 4.

Dataset and Source-Check Details

Dataset: LP-SCH40-IFGC2024-EQ4-1-v1.0
Publisher: Turn2Engineering
Source checked: August 9, 2026
Calculated range: 10–500 ft; NPS 1/2–4; 0.5 in. w.c. drop
Reference conditions: SCFH at 60°F and 30 in. Hg; undiluted propane
Rights decision: Limited factual inputs and original calculations; full CSV disabled
Excluded systems: Elevated pressure, copper, CSST, PE, regulators, and container vaporization
Display precision: Capacity about 3 significant figures; selection uses unrounded values

Propane Pipe Sizing FAQs

What size propane pipe do I need for 200,000 Btu/h?

Length and pressure basis control the answer. Under this page’s defaults—50 ft equivalent length, 0.5 in. w.c. allowable drop, and 2,488 Btu/ft³—NPS 3/4 is the first qualifying listed Schedule 40 size.

Is propane pipe sized the same as natural gas pipe?

Does propane pipe length include fittings?

Can this chart size copper tubing, CSST, or underground PE pipe?

Does this chart also size the propane regulator or tank?

Propane Pipe Sizing Summary

Use maximum appliance input and the applicable simultaneous load.
Determine length using the sizing method permitted by the adopted code.
Confirm that the low-pressure propane and 0.5 in. w.c. drop basis apply.
Use the first listed actual ID whose unrounded calculated capacity meets the load.
Separately verify regulator capacity, container vaporization, materials, joining, and appliance pressure.
Have qualified personnel confirm the final design and installation with the authority having jurisdiction.