API 574 now covers MI inspection/testing on hoses

Flexible hoses are often used to temporarily transfer hydrocarbons and other process fluids to facilitate turnaround activities (clearing equipment, de-inventorying, purging, etc.) and transfer process fluids/products to rail cars and/or/or tanker trucks for shipment. Flexible hoses may also be installed within process piping systems to mitigate the effects of thermal expansion, vibration, or movement during normal operations. Some sites will maintain several flexible hoses to be used as needed in multiple services. Flexible hoses come in a variety of different construction materials and designs. Owner/users should have appropriate quality assurance systems in place to ensure that each different type of flexible hose is compatible with the process service in which it is used.

The 2016 Edition of API 574 Inspection Practices for Piping System Components includes a section on inspection practices for FLEXIBLE HOSES.  Flexible hoses utilized in hazardous service should be individually identified, including appropriate service (chemical) limitations and acceptable operating conditions.

And yes, I know, API is mostly for refineries, but in the absent of a RAGAGEP that is specific to our flexible hose uses, this RAGAGEP can be the basis of our hose inspection process.

Generally, there are two (2) purposes for flexible hoses utilized in hazardous service:

1. installed instead of hard piping and
2. used for short-term purposes

The flexible hose’s purpose should be considered when determining if the flexible hose should be inspected and how it should be inspected.

Flexible hoses used in PERMANENT INSTALLATIONS should be periodically inspected with the hard piping attached to or more frequently if necessary by the owner/user.

Flexible hoses used in TEMPORARY APPLICATIONS should be cleaned and stored appropriately (per manufacturer’s instructions where available) when not in use to minimize both mechanical damage and exposure to environmental conditions and chemicals that could compromise one or more components of the hose assembly.

Each flexible hose (new and used) should be inspected PRIOR TO BEING PLACED IN SERVICE. This inspection should verify the following:

1. its intended service (process chemicals and temperature/pressure rating),
2. overall condition (looking for mechanical damage to connections, fittings, flanges, etc.), and
3. the periodic inspection has been performed

A complete inspection of the hose should be performed periodically. This inspection should include the following:

1. Ensure the hose has been individually identified (ID tag) and that the records contain appropriate design conditions and service limitations or compatibility.
2. Verify diameter, length, and end fittings for individual assemblies and compare them with existing ID tags and documentation.
3. Verify the hose and fitting pressure ratings are within the design parameters for hydrostatic proof pressure test (generally 1.5 times MAWP), and check the condition of the fittings (thread condition and gasket or sealing surface condition to provide a proper seal). Fittings should also be examined for mechanical damage from the threads’ over-tightening or bolted assembly’s over-torquing, causing flange face rotation. The hose to the fitting attachment point should also be inspected for loose or damaged clamps or compression fittings.
4. Perform a visual inspection of the hose cover for any cuts, gouges, breaches, fraying, or other defects where reinforcement is exposed. The hose assembly should also be inspected for excessive abrasion damage to the outer covering/jacket and for damage from heat (brittleness and/or cracking).
5. Inspect for damage from excessive bending (kinking), which may produce partial crushing/flattening of the hose, crimping, or excessive strain at end connections. Check minimum installed bend radiuses to the manufacturer’s recommendations.
6. To the extent possible, examine the internal condition of the hose, looking for signs of erosion, cracking, or chemical attack/degradation of a nonmetallic liner (swelling, tears, abrasion/roughness, etc.).
7. Additional inspections may include the following:
   1. Visual inspection of the hose tube with a boroscope or video probe for a general condition on the interior liner (looking for blisters, cracks, or other defects).
   2. Perform test to ensure electrical continuity between end fittings and perform electrical conductivity test on fluoropolymer and thermoplastic tube hose.
   3. If the transfer fluid inside the hose is nonconductive, then perform an electrical conductivity test to ensure the grounding/bonding of the hose.
   4. Check for appropriate alloy composition (PMI) per manufacturers and equipment records. Note that this may only be an initial inspection unless hose fittings or other components may be changed or modified.
   5. On-stream inspection using infrared thermography examination may help identify damage to one or more hose components/layers.
   6. Fittings may be examined with dye penetrant, ET, and/or UT methods to identify cracking or other damage.
   7. Perform hydrostatic pressure test in accordance with manufacturers’ recommended design specifications (limited by the lowest pressure rating of included component).
   8. Original equipment manufacturers recommended inspection and testing activities.

As effective inspections of process hoses are difficult, some owner/users stamp and track process hoses, periodically pressure test them, and require replacement after a set amount of service time based on risk and type of hose. Additionally, visual inspection checklists are in use for issues that should be periodically checked to verify the integrity of the hose.