STAMPED defines the seven major areas of information required to provide a quality hose assembly for the customer. The acronym stands for size, temperature, application, materials/media, pressure, end and delivery.
Size, I.D., length and O.D. constraints
The overall length should be specified to include fittings, and tolerances need to be specified if special requirements exist. To determine the replacement hose I.D., the layline printing on the size of the original hose must be identified. If the original hose layline is not available, the hose must be cut and measured in diameter from the inside.
The inside diameter must be able to keep pressure loss to a minimum, maintain adequate flow and avoid damage to the hose due to heat generation or excessive turbulence. The hose should be sized in accordance with the nomographic chart in the Hose Safety Institute Handbook v. 1.2. Length tolerances should also be considered for all types of hose assemblies. The flow rate, in conjunction with the inside diameter of the hose, will determine the fluid velocity through the hose. The hose supplier will recommend specific velocity ranges.
Continuous (average), minimum and maximum temperatures should be specified for both the environment and material. If flame resistance or flammability would be an issue, it should be noted.
When routing near hot manifolds, keep in mind that maximum assembly working pressures will decrease as temperatures increase. In extreme cases, a heat shield may be advisable.
Other things to consider are maximum intermittent ambient temperature, fluid temperature, ambient temperature, maximum temperature and sub-zero exposure.
Anticipated movements and geometry of use must be quantified, as well as intermittent or continuous service, indoor and outdoor use, unusual mechanical loads, excessive abrasion, electrical conductivity requirements, equipment type, external conditions, such as abrasion, oil, solvents, acid, ozone and salt water, and if the hose is currently in use.
If the hose is in use, the type of hose, service life being obtained, description of failure, source of customer dissatisfaction, strength, frequency of impulsing, pressure pikes, flexing and non-flexing applications, and vacuum requirements must be noted.
Special requirements for the hose tube, special specifications or agency requirements that need to be considered and whether the material will flow continuously or sit in the hose for long periods of time must be noted.
Media velocity and flow rate, the chemical and concentration, solids, description and size should also be noted. Some applications require specialized oils or chemicals to be conveyed through the system. Hose selection must assure compatibility of the hose materials and components, such as hose ends and O-rings, with the fluid being used.
Hose assembly working pressures must be equal to or greater than the system pressure. Pressure spikes greater than the maximum working pressure will shorten hose life. Temperature implications and vacuum considerations should also be noted.
The maximum operating pressure is the maximum pressure that the system should be exposed to in normal operating conditions. The hose and hose end should not be rated to a pressure less than the maximum operating pressure system. Frequent pressure spikes can reduce the life of hydraulic hose assemblies.
Style, type, orientation and attachment methods, among others, are included in this section. Uncoupled or coupled hoses, hoses with built-in fittings, end styles, materials and dimensions, and conductivity requirements should also be noted.
Deliveries are specific to customer requirements, testing requirements, certification requirements, special packaging and shipping requirements, tagging requirements and can also refer to determined overall length when working with metal hoses.
Filed Under: Hose Assembly Tips