Incorrect installation of a hose assembly will create stresses within the assembly and result in a premature failure. The following guidelines should be followed:
– hose assemblies must not be twisted either during installation or in use
– hoses must not be over flexed or bent into a smaller diameter than the specified minimum bend radius
– hose assemblies should be installed so that flexing always occurs in the same plane
– it is recommended that flanged assemblies have a floating flange on one end for easier installation and to reduce the possibility of twist.
Hoses should be stored in a straight line on solid supports or racks.
Large bore hoses should be carried on a dollie or moved by crane. Hoses must not be supported by a single rope or wire. A wide belt sling should be used, supporting the hose at least every 3 metres. Avoid curvatures that are less than the minimum bend radius of hose.
Do not allow sharp bends adjacent to the end connection fitting – this area is the weakest spot in any type of hose. Support the hose.
Hoses should not be dragged along the ground or over guard rails. Do not allow the hose to chafe (rub) against hard surfaces and/or sharp edges. If unavoidable, consider having the hoses rope lagged.
Before storage, hoses should be drained and flushed with clean water to remove dangerous vapours, the exception being hoses which have been used for conveyants such as sulphuric acid when dilution with water could leave a very corrosive residue. In such instances, drain dry. Hoses must be electrically earthed during cleaning oerations. Hoses may be cleaned using low pressure air, however hoses must be open-ended to avoid excessive pressure build up. Steam is not recommended for cleaning as the excessive temperature involved (over 100°C) will damage the hose fabrics. Also Pigging is not allowed.
Inspect hose for visual damage at least every six months, more often if experience demands it. Look for:
- Weakening of the hose adjacent to the end fitting
- Cuts and abrasions on the fabric cover
- Abrasion of the outer wire
- Displacement of the outer wire – identified by differing widths between each round of wire over the length
- Dents, kinks or twisted sections
Composite hose assemblies should be hydrostatically tested at least once every twelve (12) months and electrical continuity tested, where applicable, at least once every six(6) months. See ‘hose assembly testing’ data sheet.