Sourcing the correct metal hose

30 October, 2015

When looking to source metal hose for your application it is important to gather all the information you need to select the proper hose assembly for the application. The acronym S.T.A.M.P.E.D can serve as a handy aide memoire for the following guidance:

S.T.A.M.P.E.D

Size – What are the diameters of the hose required? Diameter of the end fittings?

Temperature – As temperature increases, pressure containing capabilities of the hose assembly decreases. The internal and external temperatures, minimum, maximum and operating all need to be taken in to consideration.

Application – How is the how going to be installed and what is its purpose? This includes the overall assembly length and what kind of movement is expected of the hose. Need this information to select proper length and flexibility of the hose assembly.

Media – Identify the all the fluids/chemicals that are exposed to the internal and external surfaces of the hose assembly. The purchaser must make certain that all components are compatible with media and the environment in which the hose is installed.

Pressure – Identify the maximum internal pressure that hose assembly must handle. Also, identify if the pressure cycles, surges or spikes. This information must be considered, since hose pressure ratings are reduced when these conditions are present.

Ends - Specify the end fittings required for installation. Materials and pressure ratings must meet the requirements of the application.

Dynamics – Identify the velocity of the fluid moving through the hose assembly. Since corrugated metal hose does not have a smooth interior, high velocities may cause resonant frequency vibration, causing early failure of the hose assembly.

Selection

Material – Utilise resources, such as National Association of Corrosion Engineers (NACE) and the Compass Corrosion Guides to make your material selection or call our customer service, for their assistance.

Pressure – You must make sure that the hose selected with have a maximum pressure rating that meets the requirements of your application. The stated maximum pressure rating is reduced based on each the following circumstances.

Temperature – As temperature increases, hose pressure capabilities decreases. Use the Temperature Derating Table to determine the factor to multiply the hose working pressure by to obtain the temperature derated working pressure.

Dynamic pressures – Pulsating, surge and shock pressures can damage a hose assembly. If the application has pulsating or surging pressure, the working pressure of the hose needs to be derated to ½ of its original value. If the hose is exposed to shock pressures, the working pressure must be derated to 1/6 of its original value.

Flexibility – Make certain that the minimum bend radius of the hose is less than the bend radius required by your application. See the vibration chart, to determine if the assembly will be exposed to normal vibration levels. If you have an application that involves excessive vibration, contact our customer service department for recommendations.