Receiving and Storage > Hoses
Hoses |
Hoses used for loading or unloading ammonia into or from the
refrigeration system have a limited life. The user must be alert to signs of
hose deterioration before failure occurs. This page
describes some inspection and testing procedures, work practices, and hose
selection criteria to ensure the safe transfer of ammonia.
| Hoses |
Figure 1. Unloading a railcar |
Potential Hazards
- Hose failure, leading to a release of
ammonia.
Possible Controls
- Provide information pertaining to the
hazards of ammonia to workers. [1910.119(d)(1)]
- Use hoses that are designed according to generally accepted good engineering practices.
[1910.119(d)(3)]
- Use hoses that are commonly used for
ammonia, such as:
- Stainless steel braided
- Nylon braided
- Use hoses that:
- Indicate suitability for ammonia.
- Have a working pressure of at least 350 psi and a burst pressure of at least 1750
psi.
- Mark at least every 5 feet the manufacturers name, the words Anhydrous Ammonia, the working pressure, and the year of manufacture.
- Make up hose assembly that is capable of withstanding a test pressure of 500
psi.
- Replace hoses according to the manufacturers recommendations.
- Do not use old, damaged, or mistreated hoses.
- Ensure employees are trained in the proper
care and maintenance of hoses. [1910.119(g)]
- Implement the following recommendations
for the use of hoses:
- Do not drag hoses over sharp or abrasive
surfaces, unless specifically designed for
such.
- Protect hoses from severe end loads.
- Ensure the pressure in the hoses is at or
below its rated working pressure.
- Change pressure gradually to prevent
excessive surge pressures.
- Do not run over hose with equipment.
- Do not kink hoses.
- Use dollies to handle large size
hose.
- Storage of hoses
- Protect hose from:
- Extreme temperatures
- Too high or low humidity
- Ozone
- Sunlight
- Oils
- Solvents
- Corrosive liquids and fumes
- Insects
- Rodents
- Radioactive materials
- Avoid stacking hoses in such a way
that the weight of the stack creates
distortions on the hose at the bottom.
- Store hoses in the original shipping
container if possible.
- Conduct routine inspections or testing for hoses as part of a Mechanical Integrity Program. [1910.119(j)]
- Inspect hoses and connectors prior to each
use. Look for:
- Loose covers
- Kinks
- Soft spots, which may indicate
broken or displaced reinforcement
- Perform a hydrostatic test periodically:
- Test for one minute at 150 percent of the
recommended working pressure.
- Test hoses when they are straight, not
coiled, or kinked.
- Flush hoses with alcohol to remove
traces of moisture.
- Never use a compressible gas for the
test due to the explosive action of
the hose should failure occur.
- Bleed air through an outlet valve
while filling it with the test medium.
- Place steel rods at ends and at
approximately 10 foot intervals to
prevent "whipping" should
failure occur.
- Bulwark the outlet end of the hose
to stop blown-out fittings.
- Protect testing personnel from the
forces of the testing media should
failure occur.
- Do not stand in front of or in back
of the ends of the hose being pressure
tested.
- Inspect the couplings or fittings.
Additional Information
- Specifications for Anhydrous Ammonia Hose,
7th Ed. Rubber Manufacturer's Association (RMA) Publication IP-14 (2003), 9 pages. This specification covers hose, three-inch inside
diameter and smaller, commonly referred to as "pressure transfer
hose", used to convey anhydrous ammonia liquid or to convey anhydrous
ammonia gas where the gas is in contact with liquid ammonia.
- Safety Standard for Refrigeration Systems.
American National Standards Institute (ANSI) and American Society of Heating, Refrigerating and Air-conditioning
Engineers (ASHRAE) 15-2001
(2001), 26 pages. Section 9.1, "Materials" contains more information about
acceptable materials for use with ammonia. See the Table of Contents.
- Hose
Technical Bulletin - Manual for Use, Maintenance, Testing, and Inspection
of Anhydrous Ammonia Hose, 4th Ed. Rubber Manufacturer's Association ( RMA)
Publication IP-11-2, (1997), 4 pages.
- A Guide for Developing a Training Program for Anhydrous Ammonia Workers. National
Institute for Occupational Safety and Health (NIOSH) Publication No. 79-119 (1978), 83 pages. This booklet contains more information about hoses.
See the Table of Contents.
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