Selecting a Hose (The ‘S.T.A.M.P.E.D’ Method)

Choosing the right hose and fittings is important as the wrong product can lead to failure from misapplication. To help you make the right choice and increase the lifespan of the hose, we recommend adopting the ‘S.T.A.M.P.E.D’ method:

Note the measurements of the hose you require: the inside diameter (ID), the outside diameter (OD), the length, and the overall length if fittings are to be added. The ID of the hose is important in minimising pressure loss and flow turbulence, whilst the OD may be critical if specific clamps will be used when routing the pipe, or if it passes through a bulkhead.

Temperature has a considerable effect on the working pressure of a hose – as the temperature rises, working pressure reduces. As such, hoses should never be used at the upper limits of both pressure and temperature range. Consider the temperature of the substance conveyed, and whether the cover would be exposed to temperature extremes. The right hose must be able to withstand the minimum and maximum fluid and ambient temperature. Take care when routing past hot components, such as inside engine bays.

Think about the situations in which the hose will be used, as well as how it will be manipulated, installed or handled. A replacement of an existing part will generally be required, but with new or prototype parts, it is advisable to provide as much information as possible about usage of the hose.

We recommend asking the following questions:

  • Will the hose will be subject to surge pressures or repeated cycles?
  • Is there a suction or delivery requirement, or both?
  • Are there specific industry standards that must be met?
  • Does the hose need to be non-conductive?
  • Is the liner or cover subject to abrasive materials or dragging?
  • Is there a specialist fluid compatibility to consider?
  • Did the previous hose perform well, or does it need to be upgraded?
  • Is there a flammability requirement?

Material / Media
Another factor to note is the material that will be passed through the hose – is it wet, dry or gaseous? Is there a chemical present, and if so, what is the percentage of concentration? It is essential to ensure the compatibility of the lining, cover and fittings or couplings with the media being conveyed.

Determining the system pressure is the key factor in choosing a hose, and any pressure spikes must be considered. Is the hose used in a pressure or vacuum situation? What are the maximum pressure or suction ratings? The working pressure of the hose must be equal to, or above, the working pressure of the system, including spikes. Any pressure above working guidelines will shorten the hose’s lifespan. Vacuum ratings follow this rule as well.

Selection of the correct fitting for your system is critical to achieving a good seal and optimum hose performance. An important point to note is the type of fitting, coupling or clamp that is required to connect to the system. Will you need quick release couplings, flanges or adaptors? The type of fitting used must be compatible with all the criteria listed above. If the hose has specific threaded fittings (BSP, metric, JIC, etc) these must be identified correctly. Similarly, quick release couplings need to be compatible with those already on the system.

The final point to consider is delivery requirements. When should it be delivered – is there an urgent need for it? What quantity is required? Does the hose need to be supplied with any specific certification, or must it be tested before use? Are there any other shipping requirements?

If you are replacing a part with a like-for-like hose, remember to note the printed information on the side of the original. This often contains a specification, working or burst pressure and inside diameter (ID), which helps us greatly when preparing a quote. If you find the original text to be covered over or worn away, any fittings would need to be removed to get an accurate measurement of the ID. Before cutting the hose or removing fittings, make sure to measure the overall length if this is critical, and also the orientation of any fittings if required.

It is important to consider that hose products and assemblies have a finite lifespan – providing as much information as possible using the guidelines above will help reduce the incidence of failures in service. The Camthorne team encourages regular inspection and testing of hoses when in use, as proper care will increase service life, and ultimately reduce machine downtime if faults can be rectified before complete failure occurs.