---
title: Calculate Total Dynamic Head | STH Inc.
description: To calculate the Total Dynamic Head in feet, use our handy free-to-use tools.
---

# CALCULATE TOTAL DYNAMIC HEAD

## **Sump/Sewage/Grinder TDH Calculation Worksheet**

#### Use the tables below to calculate Total Dynamic Head (in Feet) required.

1. Use steps 1-3 and the following chart to calculate TDH from tables A & B below.
2. Enter the TDH, in Feet, in the box under “Design Flow Rate” on the Pump Design Guide.

| **Table A:** |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- |
| Friction Losses through Plastic Fittings in terms of Equivalent Lengths of Plastic Pipe |  |  |  |  |  |  |
|   |  |  |  |  |  |  |
| **Type of Fitting** | **1-1/4″** | **1-1/2″** | **2″** | **2-1/2 “** | **3″** | **4″** |
| 90 deg. Std Elbow | 7.0 | 8.0 | 9.0 | 10.0 | 12.0 | 14.0 |
| 45 deg. Std Elbow | 3.0 | 3.0 | 4.0 | 4.0 | 6.0 | 8.0 |
| Std. Tee | 7.0 | 9.0 | 11.0 | 14.0 | 17.0 | 22.0 |
| Check Valve | 11.0 | 13.0 | 17.0 | 21.0 | 26.0 | 33.0 |
| Union | 1.0 | 1.0 | 2.0 | 3.0 | 4.0 | 5.0 |
| Gate Valve | 0.9 | 1.1 | 1.4 | 1.7 | 2.0 | 23.0 |

| **Table B:** |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Friction Loss per 100 Feet of Plastic Pipe |  |  |  |  |  |  |  |
|   | **Pipe Size (in.)** |  |  |  |  |  |  |
| **Flow Rate (GPM)** | **1″** | **1-1/4″** | **1-1/2″** | **2″** | **2-1/2 “** | **3″** | **4″** |
| 2 | 0.3 |   |   |   |   |   |   |
| 3 | 0.6 |   |   |   |   |   |   |
| 4 | 1.0 | 0.3 |   |   |   |   |   |
| 5 | 1.5 | 0.4 | 0.2 |   |   |   |   |
| 6 | 2.1 | 0.6 | 0.3 |   |   |   |   |
| 7 | 2.9 | 0.8 | 0.4 |   |   |   |   |
| 8 | 3.6 | 1.0 | 0.5 |   |   |   |   |
| 9 | 4.6 | 1.2 | 0.6 |   |   |   |   |
| 10 | 5.5 | 1.5 | 0.7 | 0.2 |   |   |   |
|   |   |   |   |   |   |   |   |
| 12 |   | 2.1 | 1.1 | 0.3 |   |   |   |
| 14 |   | 2.7 | 1.3 | 0.4 |   |   |   |
| 16 |   | 3.5 | 1.7 | 0.5 | 0.2 |   |   |
| 18 |   | 4.4 | 2.1 | 0.6 | 0.3 |   |   |
| 20 |   | 5.2 | 2.5 | 0.9 | 0.3 |   |   |
|   |   |   |   |   |   |   |   |
| 25 |   |   | 3.8 | 1.3 | 0.5 |   |   |
| 30 |   |   | 5.2 | 1.8 | 0.6 |   |   |
|   |   |   |   |   |   |   |   |
| 35 |   |   |   | 2.4 | 0.8 |   |   |
| 40 |   |   |   | 3.1 | 1.0 | 0.4 |   |
|   |   |   |   |   |   |   |   |
| 45 |   |   |   | 3.8 | 1.3 | 0.6 |   |
| 50 |   |   |   | 4.7 | 1.6 | 0.7 |   |
|   |   |   |   |   |   |   |   |
| 60 |   |   |   |   | 2.2 | 0.9 | 0.2 |
|   |   |   |   |   |   |   |   |
| 70 |   |   |   |   | 2.9 | 1.2 | 0.3 |
|   |   |   |   |   |   |   |   |
| 80 |   |   |   |   | 3.7 | 1.5 | 0.4 |
|   |   |   |   |   |   |   |   |
| 90 |   |   |   |   | 4.6 | 1.9 | 0.5 |
|   |   |   |   |   |   |   |   |
| 100 |   |   |   |   |   | 2.3 | 0.6 |
| **For flows over 100 GPM, please contact STH.** |  |  |  |  |  |  |  |