23 July 2003
relief is a small diameter wire cable with eyes at each end for
shackles. The cable is attached to the hose by marlin at regular
intervals. All high-pressure hoses are required to have this
strain relief device except those that are permanently installed.
The safe useful life for each flexible hose in the unmanned
pressure test facility should be specified and inspection
requirements and criteria should be established. Periodic
replacement of rubber hoses should be anticipated. Rubber hoses
used in critical applications should be replaced every five and
one-half years from date of manufacture. Rubber hoses used in
non-critical applications should be replaced at least every 12
years. Metal, PTFE and thermoplastic hoses have no predetermined
life but require annual inspection and testing. In all cases,
hose inspection and replacement criteria should be in accordance
with approved PMS.
All flexible hoses that are not permanently installed should be
provided with suitable end caps that protect the hose end
not connected for use.
The applicant should maintain a hose log for recording the
inspection and test records and the life history of each flexible
hose in the system.
Quick disconnect fittings used on flexible hoses should be
readily accessible and capable of being disconnected under
pressure in an emergency. Provision should be made to prevent
accidental disconnection, i.e., a positive locking mechanism
requiring more than one mechanical action to disconnect.
B.8.2 Piping Components. Care must be exercised when installing
piping components in the system to ensure that gas or liquid flow
is in the proper direction through the component. Most
components have a designed direction for flow and this should be
observed. Where components permit bi-directional flow, they
should be installed to take best advantage of the design. For
example, valves that serve as both inlet and outlet on high-
pressure flasks should be installed so that when they are closed
the flask pressure acts from below the seat and not on the valve
stem packing. Piping components should always be installed in
accordance with the manufacturers' recommendations, unless
deviation is approved by NAVFAC.
accessible and easily operable under normal and emergency
adequate for the most demanding mission conditions expected for
the unmanned pressure test facility. These conditions should be
specified when justifying the selection of a component.