Flow Capacity: What Happens Inside a Hose or Tube

Fluid viscosity, distance required in the application, and other factors affect pressure drop in industrial fluid systems. A new video explains each factor.

This video steps through key factors that influence system pressure drop. We also have a book that goes into detail: The Swagelok Tube Fitters Manual. Edmonton Valve & Fitting is here to help if you have questions: 780-437-0640.

Learn the roles of fluid viscosity, temperature, pressure and distance

Flow capacity — the amount of fluid that can flow through a hose or tube — isn't just a matter of how large the diameter is. Flow capacity is really a matter or pressure drop. And pressure drop is influenced by four key factors.

Let's start with the fluid itself. How viscous is it? The more viscous, the slower the flow (and vice versa). Next consider pressure and temperature. Some fluids flow differently under pressure and at different temperatures. 

Third is the inside surface of the tube or hose. A smooth inner core will mean a smoother flow, while a convoluted core will create turbulence. 

Finally, take into account the distance involved in the application. The longer the distance, the more resistance will build up between the fluid and the interior of the tube or hose, which will create additional pressure drop.  

How we can help

Hose Advisory Services

This service is aimed at applying Swagelok expertise to minimize your hose maintenance, repair, and replacement costs. Learn more here:

Hose Resource Collection

This collection delivers technical briefings, a Quicklook sheet, relevant literature, articles by our local team, and more — all in one step. Free download here:

Hose Essentials Training

Understanding the fundamentals of hose and flexible tubing helps to extend hose production cycles, promote safety, and lower total cost of ownership. View 2023 class dates and get a free PDF with course info here:

Onsite Hose Fabrication

We build hose in our Fremont shop — sometimes with same-day turnaround. We can combine any of 22 types of hose with any of 89 end connections, in almost any length, in small or large quantities. Includes testing. Learn more:

Also see:

• Routing Hose at Manufacturing & Processing Plants: 4 Rules + Damaged Hose Photos, Video
• Using the S.T.A.M.P.E.D Method to Get the Right Swagelok Hose

• New Technical Briefing: Hose Selection & Troubleshooting