Pedestal Mounted
Single Seal Only
Easy Maintenance
Multi Stage
Single Stage
Self-priming
High-Performance Inline Powder Mixing
Better Mixing in Less Time
Next-Gen Colloid Mill
Quick and Consistent Blending
Low Flow Twin Screw Pump
Pumps Process and CIP Fluids
True CIP, 500 PSI Circumferential Piston
COP Version, 500 PSI Circumferential Piston
Gentle & Efficient Rotary Lobe
Low Pulsation Helical Rotary Tri-Lobe
Food
Beverage & Brewing
Personal Care & Home Care
Meat, Poultry & Pet Food
Dairy
Pharmaceutical & Life Sciences
The place to find all Fristam Pumps USA published material: brochures, maintenance manuals, engineering drawings, etc.
The first Fristam stainless steel pump was manufactured in 1931 – from the very start in compliance with the individual requirements of our customers. Since then the success of Fristam has been based on three principles: Quality, Flexibility and Innovation.
Give us a call at 1-800-841-5001 or send us a message with any questions you might have.
Selecting the right hygienic pump starts long before reviewing performance curves or comparing pump models. One of the most important steps in the process is understanding Total Dynamic Head (TDH).
Whether transferring milk, yogurt, sauces, pharmaceutical solutions, cleaning chemicals, or personal care products, every pumping system creates resistance that the pump must overcome. Understanding this resistance is essential for selecting a pump that delivers the required flow rate while operating efficiently and reliably.
Unfortunately, TDH is often misunderstood or overlooked during the pump selection process. When this happens, the result can be excessive energy consumption, reduced pump efficiency, premature seal wear, and costly downtime.
For engineers and maintenance professionals involved in system design or equipment upgrades, understanding TDH is one of the most valuable skills for ensuring long-term pumping performance.
What is Total Dynamic Head?
Total Dynamic Head represents the total resistance a pump must overcome to move a fluid through a system at a specified flow rate. It is typically expressed in feet or meters of head and serves as one of the primary inputs used for pump selection.
Simply put, TDH answers the question:
“How much energy must the pump provide to move the required amount of fluid from one point in the process to another?”
Many people assume TDH refers only to the vertical height a fluid must be lifted. While elevation changes can contribute to TDH, they are only one part of the equation. In many hygienic processing systems, friction losses throughout the piping network actually represent the largest portion of the total head requirement.
Understanding all of the factors that contribute to TDH is critical to selecting the correct pump for the application.
The Components of Total Dynamic Head
TDH is generally calculated by combining three primary elements: static head, friction losses, and pressure losses created by equipment within the system.
Static Head
Static head is the difference in elevation between the fluid source and destination.
If a product must be pumped to a higher elevation, additional energy is required to overcome gravity. For example, transferring product from a floor-level process vessel to a filler located on an elevated platform requires more head than transferring between tanks located at the same elevation.
Static head remains relatively constant regardless of flow rate and is often the easiest portion of the calculation to determine.
Friction Losses
As fluid travels through piping, energy is lost due to friction between the fluid and the internal surfaces of the piping system.
The amount of friction loss depends on several factors, including pipe diameter, pipe length, flow rate, fluid viscosity, and the overall design of the piping network.
One important concept often overlooked is that friction losses increase significantly as flow rates increase. Doubling the flow rate does not simply double system resistance—it can increase friction losses dramatically depending on system conditions.
This relationship is one reason why pump selection should never be based on flow rate alone.
Check out Fristam’s Friction Loss Calculator
Equipment and Component Losses
Every component installed in a process line creates additional resistance.
Valves, elbows, tees, heat exchangers, filters, flow meters, spray devices, and other equipment all contribute to the total head requirement. While each component may create only a small pressure drop individually, the cumulative effect can be substantial.
In many hygienic processing systems, these losses represent a surprisingly large percentage of the overall TDH.
Ignoring them during pump sizing can result in pumps that fail to achieve the desired operating point once installed.
Why Viscosity Plays a Major Role
The properties of the fluid being pumped have a direct impact on Total Dynamic Head.
As viscosity increases, friction losses throughout the system also increase. A piping system that performs well when handling water may require significantly more head when pumping yogurt, syrup, cream, concentrates, or other viscous products.
Viscosity can also change during production as temperatures fluctuate or product formulations vary. These changes can alter system resistance and impact pump performance.
This is why accurate fluid property information is one of the most important inputs when evaluating a hygienic pumping application.
Why TDH Changes During Production
Many engineers assume TDH remains constant once a system is designed. In reality, operating conditions often change throughout production.
Tank levels rise and fall. Filters gradually become loaded with product. Process equipment is added or modified over time. Product viscosities may change due to temperature fluctuations or formulation differences.
Cleaning processes can create another challenge. A pump selected for transferring a viscous product may also be expected to handle water-like cleaning solutions during CIP operations. These dramatically different conditions can create very different operating requirements.
Understanding how TDH changes during both production and cleaning cycles helps ensure the selected pump can perform reliably across all operating conditions.
Common TDH Calculation Mistakes
Many pump performance issues can be traced back to assumptions made during the sizing process.
One common mistake is focusing only on elevation changes while overlooking friction losses and equipment losses. Another is using water-based calculations for highly viscous products.
Future expansion requirements can also lead to oversized pump selections. While planning for growth is important, selecting a pump significantly larger than current operating requirements often creates efficiency and reliability concerns.
Another frequent issue is relying on estimated piping layouts rather than actual system measurements. Even relatively small changes in pipe diameter, pipe length, or component count can have a meaningful impact on total head requirements.
Accurate information almost always leads to better pump selection decisions.
A Simple TDH Calculation Example
Consider a process application requiring a flow rate of 150 gallons per minute.
The system includes:
The Total Dynamic Head would be:
15 ft + 25 ft + 10 ft = 50 ft TDH
Based on this calculation, the pump must be capable of delivering 150 gallons per minute at 50 feet of Total Dynamic Head.
While this seems straightforward, determining the correct pump requires one additional step.
Using TDH and Flow Rate to Select a Pump
Calculating Total Dynamic Head is not the end of the pump selection process—it is the beginning.
Once the required flow rate and TDH have been determined, these values are used together to evaluate pump performance curves.
A pump curve illustrates how a pump will perform across a range of operating conditions. The horizontal axis typically represents flow rate, while the vertical axis represents total head. By locating the point where the required flow rate intersects the required TDH, engineers can identify pumps capable of meeting the application’s requirements.
However, selecting a pump involves more than simply finding a model that can reach the required operating point.
The ideal pump should operate near its Best Efficiency Point (BEP), where hydraulic efficiency, reliability, seal life, bearing life, and energy consumption are optimized. Pumps operating too far away from their BEP may experience increased vibration, reduced efficiency, higher maintenance costs, and shortened service life.
This is why successful pump selection always begins with an accurate TDH calculation but does not end there.
What Comes After TDH?
Once flow rate and Total Dynamic Head have been established, the next step is understanding how to interpret pump performance curves and identify the optimal operating point for the application.
Partner with Fristam for Pump Selection Support
Every pumping application is unique. Fluid properties, process conditions, cleaning requirements, future expansion plans, and system design all influence pump selection.
Fristam’s application engineering team works with customers every day to evaluate pumping systems, calculate operating requirements, and recommend solutions that maximize performance and reliability.
If you’re designing a new process or looking to optimize an existing system, contact your local Fristam distributor or application engineer for assistance.
