H2X TOOLS
Pipe Volume
(Dead Leg) Calculator
The volume of water in a pipe 'dead leg' is measured by the area of the pipe multiplied by the length. The 'dead leg' pipe volume can be used to calculate how long you need to wait at a fixture before the hot water is available.

Download our Pipe Volume Calculation App called Dead Leg
Dead Leg helps you to quickly calculate the pipe volume and hot/warm water wait times to ensure compliance with engineering standards and health guidelines.
The Dead Leg app eliminates the risk of oversizing dead legs and ensures plumbers/engineers have a record of the calculations/installations for each dead leg.
To use the app, simply select your pipe size and fill in one of the two below parameters to get your answer:
-
Maximum allowable dead leg capacity
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Length of the dead leg
Also fill in the reference section so you can save the information to your records.
Download for iOS
The Imperial Equation
The following equation can be used to calculate the dead leg pipe volume:
V = L * A
Components of the Equation
V = Water volume inside the pipe (gallons)
L = Length of the pipe (feet)
A = Pipe inside diameter area (in²)
The Metric Equation
The following equation can be used to calculate the dead leg pipe volume:
V = L * A
Components of the Equation
V = Water volume inside the pipe (Litres)
L = Length of the pipe (metres)
A = Pipe inside diameter area (m²)
Pipe Volume Formula
As the pipe size increases, the pipe volume increases too. As the pipe volume (dead leg) can be measured in Litres and/or Gallons, there are two different calculation methods:
Imperial pipe volume formula
Metric pipe volume formula
Using Our Pipe Volume Calculator
This free spreadsheet contains the pipe volume formula
that is used for the H2X dead leg calculations. The spreadsheet calculates the water volume and also includes:

Pipe Volume Charts

Pipe Diameter Data
The objective behind creating H2X was to use modern technology combined with recognised methods of plumbing engineering to automate plumbing calculations, so you can save hours designing each project while reducing errors, rework, and costs.
Using H2X, you won’t need to use a pipe volume calculator as the process is streamlined.
The process that you follow when using H2X is:
Set the parameters for the hot water recirculating system
Draw the pipe layout for the system
The heated water circulating system is calculated - dead leg volumes, return pipe sizes, balancing valves, and the recirculating pump duty
How Can H2X Simplify Manually Calculating the Dead Leg Pipe Volume?
Besides the fact that manually calculating pipe volume is a time-consuming process, any manual calculation opens up the doors for human error.