Standard Pipe Dimensions

Pipe sizes and hydraulic properties for drainage design

Standard pipe dimensions are essential for hydraulic design calculations. The tables below provide dimensions and full-flow hydraulic properties for common pipe materials used in storm drainage and culvert applications. All values are based on manufacturer specifications and ASTM/AASHTO standards.

Hydraulic Properties (Full Flow)

Flow Area (A):

A = pi D2 / 4

For circular pipes

Wetted Perimeter (P):

P = pi D

For circular pipes

Hydraulic Radius (R):

R = A / P = D / 4

For circular pipes

Reinforced Concrete Pipe (RCP)

Precast reinforced concrete pipe with steel cage reinforcement

Manning's n

0.011 - 0.015

Service Life

75-100 years

Specification

ASTM C76

Nominal Dia.ID (in)Wall (in)OD (in)Area (ft2)Wet. Per. (ft)Hyd. Rad. (ft)Weight (lb/ft)
12"12.001.75015.500.7853.140.25079
15"15.001.87518.751.2273.930.313115
18"18.002.00022.001.7674.710.375160
24"24.002.50029.003.1426.280.500270
30"30.003.00036.004.9097.850.625400
36"36.003.50043.007.0699.420.750550
42"42.004.00050.009.62111.000.875725
48"48.004.50057.0012.56612.571.000925
54"54.005.00064.0015.90414.141.1251150
60"60.005.50071.0019.63515.711.2501400
72"72.006.50085.0028.27418.851.5001950
84"84.007.50099.0038.48521.991.7502600
96"96.008.500113.0050.26525.132.0003350
108"108.009.500127.0063.61728.272.2504200
120"120.0010.500141.0078.54031.422.5005150

Material Properties Summary

MaterialManning's nService LifeSpecificationAvailable Sizes
Reinforced Concrete Pipe (RCP)
0.011 - 0.01575-100 yrsASTM C7612" - 120"
Corrugated Steel Pipe (CSP)
0.021 - 0.03025-75 yrsAASHTO M3612" - 120"
Corrugated Aluminum Pipe (CAP)
0.021 - 0.03050-100 yrsAASHTO M19612" - 72"
PVC Pipe
0.009 - 0.01150-100 yrsASTM D30344" - 48"
HDPE Pipe (Smooth Interior)
0.009 - 0.01350-100 yrsASTM F714 / AASHTO M29412" - 60"
HDPE Pipe (Corrugated)
0.018 - 0.02450-100 yrsAASHTO M294 Type S12" - 48"
Ductile Iron Pipe (DIP)
0.011 - 0.01575-100 yrsAWWA C1514" - 64"
Vitrified Clay Pipe (VCP)
0.011 - 0.01575-100 yrsASTM C7004" - 42"

Design Guidance

Material Selection

  • RCP: High strength, long service life, commonly used for large diameter storm drains and culverts under roadways
  • CMP: Flexible, lightweight, good for culverts with varying foundations; consider corrosion protection
  • PVC/HDPE: Smooth interior, excellent corrosion resistance, common for smaller diameter storm drains
  • Elliptical: Low profile, useful where vertical clearance is limited
  • Box Culverts: Large capacity, span long distances, common for stream crossings

Partial Flow Conditions

The tabulated properties are for full-flow conditions. For partial flow, hydraulic properties vary with depth. Peak capacity for circular pipes occurs at approximately 93% full (depth/diameter = 0.93).

Pipe Cover Requirements

Minimum cover varies by pipe material, size, and loading conditions. Rigid pipes (RCP) typically require less cover than flexible pipes (CMP, HDPE). Consult manufacturer recommendations and local standards.

Corrugation Effects

Corrugated metal pipes have higher Manning's n values due to surface roughness. Some HDPE pipes have smooth interior liners that provide lower n values comparable to PVC.

Primary Sources

  • ASTM C76: Reinforced Concrete Culvert, Storm Drain, and Sewer Pipe
  • ASTM C507: Reinforced Concrete Elliptical Culvert, Storm Drain, and Sewer Pipe
  • ASTM C1433: Precast Reinforced Concrete Box Sections
  • AASHTO M36: Corrugated Steel Structural Plate Pipe
  • ASTM D3034: Type PSM Poly(Vinyl Chloride) (PVC) Sewer Pipe
  • ASTM F714: Polyethylene (PE) Plastic Pipe Based on Outside Diameter
  • AASHTO M294: Corrugated Polyethylene Pipe