| Industry: |
Refining |
| Specimen Description: |
LPG Product Hose |
| Material: |
Rubber Composite |
| Environment: |
LPG |
| Background: |
Several LPG product loading hoses failed due to
bulging and tearing of the outer rubber layer. The hoses contained LPG
(propane, butane, isobutane) at approximately 150-200 psig. |
| Time in Service: |
Less than 3 months |
| Findings: |
The as-received hoses all contained deflated bulges,
splits and tears to the outer rubber cover. Researching the manufacture
and use of rubber hoses in LPG service indicted that LPG hoses were supposed
to contain pin pricks, holes, or other means of venting gases that permeated
through the hose to the outer cover. As the aneurisms and tears suggested
build up of pressure under the outer cover, a test procedure was devised
to test good sections of the hoses for permeability. A gouge was made
on the I.D. of the hoses to a depth of the outer cover. End caps were
placed on the cut ends of the hoses and they were pressured up using
shop air with the hose under water to facilitate observation of air bubbles.
All submitted hoses bulged indicating that the hose outer covers did
not contain adequate gas venting means. |
