STAMPED Series — Part 4
Proper hose selection is critical in order to realize a safe hydraulic system. The first step in having a safe hydraulic system is selecting the proper components that meet the needs of each individual system. Compromises in hose selection may create situations of danger, as well as affect the performance and durability of the system. The choice may work for the short run, but may not be a good long-term decision. This guide uses the STAMPED process. STAMPED is an acronym for the 7 major information areas required to provide a quality hose assembly. Here we discuss the significance of M for Material.
Material: Fluid being conveyed, type and concentration
Some applications require specialized oils or chemicals to be conveyed through the system. Hose selections must assume compatibility of the hose inner tube and cover material. In addition to the hose materials, all other components, which make up the hose assembly (hose ends, O-rings, and so on), must also be compatible with fluid being used.
Permeation or effusion is the movement of a substance through the hose tube walls which may degrade the hose tube, cause cover blistering, or other undesired effects, and must be considered especially when conveying compressed gasses.
Be sure to select a hose that is compatible and approved by the manufacturer for the fluid conveyed. Concentration, pressure, temperature and other factors may impact the compatibility of the hose and fluid. Depending on the fluid, your hose supplier may lower the maximum temperature or pressure rating of the assembly. When selecting any hose assembly, always consult your hose supplier’s recommendations.
Additional caution must be exercised in hose selection for gaseous applications such as refrigerants and LPG.
NOTE: All block type couplings contain nitrile O-rings which must be compatible with the fluids being used.
The above is an excerpt from NAHAD’s Hose Safety Institute HANDBOOK, which provides performance standards for hose assembly specification, design, handling and management.
For a general overview on STAMPED, check out this post: What does STAMPED stand for?
Hose Safety Institute
http://associationdatabase.com/aws/NAHAD/pt/sp/memservices_hsi
Leave a Reply