HOSES AND FITTINGS FOR INDUSTRY

Steam has a destructive impact. Steam can cause damage to equipment, serious injuries or even death to personnel.  However, there is a way to avoid this hazard – the hose must be correctly matched with the application, all recommendations given below concerning installation, maintenance, storage, inspection must be obeyed together with H&S guidelines.

While selecting a hose for a steam system, first identify its operating conditions:

• maximum working pressure of steam
• steam temperature
• steam type: wet saturated steam (with water particles), dry saturated steam, superheated steam
• dependence of saturated steam temperature on pressure (overpressure – indicated by pressure gauge) is given below:
  

  press. [bar]	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	22	24
  temp. [°C]	120	134	144	152	159	165	171	175	180	184	188	192	195	198	201	204	207	210	213	215	220	224

• whether the hose will be subject to sudden pressure surges
• whether the hose will be subject to bending while working under pressure
• will it be used constantly or occasionally
• will it be handled manually
• what are the external conditions at the location, where the hose will be employed, risk of mechanical damage, are there any spilled or condensing aggressive chemicals or oils present, which may cause deterioration of hose external layer

• Follow general instructions for flexible hose installation given in the rubber steam hoses handling manual.
• Always check, if the connections (hose fittings) are designed for steam.
• Use only special fittings designed for steam service, mounted with steam safety clamps bolted together on the hose. With these clamps the connection can be re-tightened. When mounting the fittings, follow the instructions concerning selection and assembly provided by the supplier. The bolts of safety clamps must be tightened during the entire period of hose operation. Check if the bolts are tight always before the stem system is started.
• Avoid excessive bending of the hose near the end connections.

The hose must be correctly stored when not in use. Use a rack or a pallet to minimise the risk of hose damage when in storage. Do not hang the hose on a hook, nail or any other device which may cause puncture or damage the hose.

All rubber steam hoses wear out over time.  Therefore, continuous control is of primary importance. The operator must regularly check if deterioration is not so severe as to prevent further safe use.

The operator must pay special attention to:

• rubber lumps or blisters
• cracks that expose the braid
• leakage of steam near the fittings or in any other spot along the hose
• flattening or kinks that may cause hose damage
• decrease in steam flow rates indicating swelling of internal layer

If any of the above occurs, the hose must be shut down from service immediately. This hose must be thoroughly inspected prior to further use. The hoses are usually damaged near the fitting, where they are exposed to excessive bending and deformation. If such damage occurs, cut off the hose fitting and mount it once again. The hoses continuously used at high temperature and pressure should be periodically inspected to check if the internal layer hardens. In most cases, removing the fittings to perform the inspection is necessary.

• Operators must wear appropriate working clothes covering the whole body, including gloves, rubber shoes and eye protection.  Wearing working clothes protects the body from burns in case of steam or hot water burst.
• Always check if the working area is free of hazards and tidy.
• Check if the bolts are tight always before the steam system is started.
• The hose must not be left under pressure when the system is shut. This shortens the service life of the steam hose.