Portable Utility Hoses used in the energy industry to transfer air, water, steam, condensate, and nitrogen are often subject to heavy usage. If hoses are not properly maintained, safety incidents and, even injuries, can occur. This guideline is intended to provide guidance to ensure that each utility hose is properly maintained.
Portable Utility Hose is an elastomeric hose used only for utility service and is not permanently installed at one location (hoses for hot water mixers are an exception to this). Hose generally consists of three elements: the tube or lining that carries the material being conveyed, the reinforcement (layer or layers) that provides strength to keep the tube from rupturing, and the cover that protects the reinforcement from damage or corrosion. A hose assembly consists of a hose with end connections.
Safety precautions that are unique to utility hoses:
OSHA regulations dictate safe operating practices regarding utility hoses. Safety requirements of OSHA Standard 29 CFR, 1926.302 (partial):
- Pneumatic power tools shall be secured to the hose or whip by positive means to prevent accidental disconnection.
- Safety clips or retainers shall be securely installed and maintained on pneumatic impact (percussion) tools to prevent attachments from being accidentally expelled.
- All pneumatically driven nailers, staplers, and other similar equipment provided with automatic fastener feed, which operate at more than 100 psi pressure at the tool shall have a safety device on the muzzle to prevent the tool from ejecting fasteners, unless the muzzle is in contact with the work surface.
- The manufacturer’s recommended operating pressure for hoses and other fittings shall not be exceeded. [Note that the recommended pressure for a hose assembly is limited to the lowest design rated component.]
- All hoses exceeding 1/2” inside diameter shall have a safety device (locking connection and whip check) at the source of supply or branch line to prevent hose whip in case of hose failure.
The selection of nitrogen hose fittings should be limited to unique fittings having a non-standard thread that cannot be connected to breathing air equipment, or used in other applications where the presence of nitrogen could be a safety hazard. Quick-connect/disconnect couplings should not be used in nitrogen service.
Hot water stations (such as Strahman, etc.) should use the plant steam hose for hot water service due to the potential for live steam to be present in the hose.
Portable Utility Hoses Selections
- Hoses should not be dragged over abrasive surfaces or sharp edges. Avoid pulling hoses around sharp corners or at right angles to the hose fittings.
- Care should be taken to avoid severe end pull on the hose assembly.
- Hoses should not be kinking, nor should they be driven over by vehicles, fork trucks, etc.
- Avoid twisting hoses, especially those with wire reinforcement, as this can cause the liner to separate from the reinforcement.
- Do not allow hoses to contact hot surfaces such as exposed steam lines as this will damage the elastomer.
- Steam, condensate, and water hoses should be completely drained after each use to minimize hose deterioration and to avoid freezing in cold weather.
- Changes in pressure should be made gradually, without subjecting the hose to excessive surge pressure. Pump pulsations and rapid opening and closing of valves should also be avoided as these can cause hose rupture.
- Do not place a hose on a hook, or other support that concentrates strain at a single point.
- Hoses should not be used for lifting or lowering tools.
Portable utility hoses should be inspected annually. Each area of the plant should ensure that a Preventive Maintenance work order is entered in maintenance record for conducting annual inspections of all utility hoses. Inspections should consist of a visual inspection for air, water, and nitrogen hoses. For steam hoses, a visual inspection, a hydrostatic test, and an electrical continuity test is required.
Pre-Use Visual Examination
Prior to each use, the user should be responsible for visually examining the hose for blistering, excessive abrasion, deep cuts, and coupling slippage. The user should also confirm that the hose has a current inspection marking. If the hose does not pass this inspection, it should be removed from service and tagged to prevent any use until repairs have been made.
If the hose is equipped with quick connect fittings, be sure to check that the fitting is securely locked in place before pressurizing the hose.
Annual Visual Inspection of Air, Water and Nitrogen Hoses
Hoses should be inspected in place by the maintenance and operations annually.
- Inspect the outside cover of the hose for blistering, excessive abrasion, deep cuts, excessive weathering, or other damage. Hoses with wear or cuts in the cover that expose or damage reinforcement should be replaced. Hose with bulges, flat spots, kinks, blistering, or loosening of the outer cover shall be replaced.
- Hoses with small cuts, nicks, or gouges in the cover that do not go completely through the cover normally will not be replaced. Uniform pricking (a regular pattern of small holes) of the cover is intended by the manufacturer to relieve pressure due to permeation and should not be cause for rejection.
- Examine fittings for slippage. Slippage is evidenced by the misalignment of the hose, or scored or exposed area where slippage is observed. A factory installed fitting that shows signs of slippage should be cause for rejection of the hose. For clamped fittings, reset the fitting into the hose if slippage is observed. Re-tighten per manufacturer’s specifications, using recommended fitting bolt torques. Make sure that bolted clamps are not bottomed-out by touching the collar or stem of the hose barb; the clamp should be “floating” on the hose OD.
- Couplings and fittings should be cleaned and visually inspected internally and externally for cracks and excessive corrosion. Check couplings for proper fit and operation. Replace defective or missing parts.
Annual Inspection and Testing of Steam Hoses
Portable steam and condensate hoses should be hydrostatically tested at ambient temperature.
- After visual inspection, connect hose to a suitable test pump fitted with a reliable pressure gauge.
- Fit the opposite end with a quick-opening valve. Place hose in a straight line. Be sure hose is secured on both ends and in the middle to guard against whipping.
- Barricade test area, make sure all personnel are clear of hose, and take other necessary safety precautions.
- Be sure all connections are tight and then fill the hose with water keeping the outlet valve open and the end elevated to bleed off air.
- Steam hoses are to be tested at 1.5 x maximum working pressure and held at that pressure for 3 minutes. Visually inspect the hoses for defects and weeping, especially around the couplings.
Because the use of hose in steam service is known to create a static charge build-up, elastomeric steam hoses should receive an electrical continuity test annually. Hoses are to be tested with an ohmmeter to measure the electrical resistance of the hose from coupling to coupling. The maximum allowable resistance should be 100 ohms from coupling to coupling.
If no defects are found, remove pressure, mark the hose with inspection tape and return it to service. If defective, repair if possible. If repairs are not possible, destroy the hose by cutting it into pieces to prevent accidental use.
Outside Contractor Utility Hoses
Each contractor should have a hose inspection program/procedure with adequate documentation, or be able to document the testing of hoses by an outside testing company that meets inspection requirements described above. Contractors should have fittings that are compatible with plant utility hose fittings, and the hose assembly should meet or exceed site requirements.
Non-standard hoses and hoses for working pressures above 150 psi should be specified by the operations and approved by management. Any non-standard hoses must use fittings that are different from the utility hose fittings specified above.