ASTM A888 / CISPI 301 Hubless DWV True ID: 2.96" (75.18 mm) Gravity DWV Spec

3" Cast Iron Pipe Volume & Capacity Calculator

Standard 3" nominal Hubless DWV cast iron soil pipe has an exact inside diameter of 2.96 inches, holding 0.3575 US gallons (4.438 liters per meter) per linear foot. Part of our Pipe Volume Calculator and Drain Pipe Slope engineering suite.

Presets:

Calculated Result

Total Liquid Capacity

Internal Holding Volume

7.149 US gallons

≈ 27.064 litres

Unit Conversions

US Gallons 7.149 gal

Litres 27.064 L

Cubic Feet (ft³) 0.9557 ft³

Cubic Inches (in³) 1,651.52 in³

Imperial Gallons 5.953 UK gal

Cubic Meters (m³) 0.0271 m³

Filled Water Weight 59.6 lbs (27.1 kg)

Linear Capacity Rate 0.3575 gal/ft

Calculations are based on cylindrical formula $V = \pi r^2 L$. Verify dimensions against manufacturer specs for code submittals.

Pre-Calculated Capacity Table

3" Hubless DWV Cast Iron Quick Reference Chart

Volumetric holding capacity and mechanical dead weight load for 3" cast iron piping filled with wastewater (62.4 lbs/ft³).

Pipe Length (Ft)	US Gallons	Liters	Cubic Feet (ft³)	Water Weight (lbs)	Dry Pipe (lbs)	Total Wet Load (lbs)
1 ft	0.357 gal	1.35 L	0.048 ft³	3.0 lbs	5.8 lbs	8.8 lbs
2 ft	0.715 gal	2.71 L	0.096 ft³	6.0 lbs	11.6 lbs	17.6 lbs
5 ft	1.787 gal	6.76 L	0.239 ft³	14.9 lbs	29.0 lbs	43.9 lbs
10 ft	3.575 gal	13.53 L	0.478 ft³	29.8 lbs	58.0 lbs	87.8 lbs
20 ft	7.150 gal	27.05 L	0.956 ft³	59.6 lbs	116.0 lbs	175.6 lbs
50 ft	17.88 gal	67.6 L	2.39 ft³	149.0 lbs	290.0 lbs	439.0 lbs
100 ft	35.75 gal	135.3 L	4.78 ft³	298.1 lbs	580.0 lbs	878.0 lbs
200 ft	71.50 gal	270.5 L	9.56 ft³	596.2 lbs	1160.0 lbs	1756.0 lbs
500 ft	178.75 gal	676.4 L	23.90 ft³	1490.5 lbs	2900.0 lbs	4390.0 lbs

Engineering Methodology

How to Calculate 3" Cast Iron Pipe Volume

Exact cylinder geometry formulas applied to ASTM A888 standard dimensions.

Step 1

Determine Inside Radius ($r$)

Divide ASTM inside diameter by 2:

r = 2.96" / 2 = 1.4800"

Step 2

Compute Cross-Section Area ($A$)

Calculate circular cross-sectional flow area:

A = \pi \times (1.4800)^2 = 6.8813 sq in

Step 3

Calculate Linear Foot Volume

Multiply cross-sectional area by 12 inches (1 linear foot):

V_linear = 6.8813 \times 12 = 82.576 cu in/ft

Step 4

Convert to US Gallons & Weight

Divide cubic inches by 231 (cubic inches in 1 US Gallon):

Gal/Ft = 82.576 / 231 = 0.3575 Gal/Ft

Technical Specifications

3" Hubless DWV Cast Iron Profile

Physical dimensions, hanger load requirements, and thermal thresholds.

Outside Diameter (OD)

3.3 inches

83.8 mm

Inside Diameter (ID)
2.96 inches
75.18 mm

Wall Thickness

0.17 inches

ASTM A888 Standard

Max Recommended Flow

60 GPM

Gravity drainage velocity

Bare Pipe Weight

5.8 lbs/ft

Unfilled iron load

Max Temperature Limit

212°F

Commercial DWV rated

Common Applications for 3" Cast Iron Soil Pipe:

Water closet toilet soil stacks
Main soil stacks in mid-rise residential buildings
Roof rainwater leaders

Primary Specification Note: The primary soil stack size for residential multi-bath groups where whisper-quiet gravity flushing is essential.

Size Navigation

Compare Related Pipe Sizes & Schedules

Navigate directly to adjacent nominal diameters or alternate pipe materials.

← Smaller Size 2" Cast Iron Soil Pipe Master Suite Universal Pipe Volume Calculator Larger Size → 4" Cast Iron Soil Pipe Compare PVC Alternative ⇄ 3" PVC Schedule 40

Expert FAQ Guide

3" Cast Iron Soil Pipe FAQs

Engineering questions and code guidelines for 3" hubless cast iron.

3 Questions Answered

Q1 How many gallons of water are in 1 foot of 3" cast iron pipe?

A 3-inch hubless cast iron soil pipe holds 0.3575 US Gallons (1.353 Liters) of water per linear foot.

Q2 What is the inside diameter of 3" cast iron soil pipe?

The inside diameter is 2.96 inches (75.18 mm), with an outer diameter of 3.30 inches and nominal wall thickness of 0.170 inches.

Q3 How much does 50 feet of 3" cast iron soil pipe weigh full?

50 feet of 3-inch cast iron pipe holds 17.88 gallons (149.1 lbs of water) and weighs a total of 439.1 lbs including the pipe.

Total Liquid Capacity

Unit Conversions

3" Hubless DWV Cast Iron Quick Reference Chart

How to Calculate 3" Cast Iron Pipe Volume

Determine Inside Radius ($r$)

Compute Cross-Section Area ($A$)

Calculate Linear Foot Volume

Convert to US Gallons & Weight

3" Hubless DWV Cast Iron Profile

Common Applications for 3" Cast Iron Soil Pipe:

Compare Related Pipe Sizes & Schedules

3" Cast Iron Soil Pipe FAQs

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