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2" NPT MULTI-PORT RELIEF VALVE MANIFOLD – SERIES
5. Seat / Coupler Fitting Leakage:
Check for leaks in the seating area using a noncorrosive leak
detection solution.
IF THERE IS ANY INDICATION OF LEAKAGE REPLACE THE
VALVE.
Never force a relief valve closed and continue to leave it in
service. This could result in damage to the valve and possible
rupture of the container or piping on which the valve is
installed.
6. Corrosion: REPLACE THE VALVE IF THERE ARE ANY SIGNS
OF CORROSION OR CONTAMINATION.
7. Moisture, Foreign Particles or Contaminants in the Valve:
Foreign material such as paint, tar or ice in relief valve parts can
impair the proper functioning of the valves. Grease placed in
the valve body may harden over time or collect contaminants,
thereby impairing the proper operation of the relief valve.
DO NOT PLACE GREASE IN THE VALVE BODY; REPLACE THE
VALVE IF THERE ARE ANY INDICATIONS OF MOISTURE OR
FOREIGN MATTER IN THE VALVE.
8. Corrosion or Leakage at Container Connection:
Check container to manifold connection with Marshall Excelsior
leak detection solution.
REPLACE THE MANIFOLD IF THERE IS ANY INDICATION OF
CORROSION OR LEAKAGE AT THE CONNECTION BETWEEN THE
MANIFOLD AND CONTAINER.
!CAUTION!
Never plug the outlet of a pressure relief valve. Any device
used to stop the flow of a properly operating pressure relief
valve that is venting an over pressurized container can cause
severe consequences.
REPLACEMENT OF PRESSURE RELIEF VALVES
!WARNING!
Under normal conditions, the useful safe service life of a
pressure relief valve with LPG application is 10 years from the
original date of manufacture/NH3 applications 5 years after
specified installation date (see DOT regulations effective
7/01/2004). However, the safe useful life of the valve may be
shortened and replacement required in less than 10 years for
LPG/5 years for NH3 depending on the environment in which
the valve lives.
Inspection and maintenance of pressure relief valves is very
important. Failure to properly inspect and maintain pressure
relief valves could result in personal injuries, property damage
or death.
Relief valves are required to function under widely varying
conditions. Corrosion, aging of the resilient seat disc and
friction all proceed at different rates depending upon the
nature of the specific environment and application. Gas
impurities, product misuse and improper installations can
shorten the safe life of a relief valve. The gas dealer must
observe and determine the safe useful life of relief valves in his
systems.
Form #996 Multi-Port Relief Valve Manifold IOM
For Additional Information Read:
1.
NFPA # 58, "Storage and Handling of Liquefied Petroleum
Gases".
2.
NFPA # 59, "LP-Gases and Utility Gas Plants
3.
ANSI/CGA 6.2.1, "American National Standard Safety
Requirements for the Storage and Handling of anhydrous
Ammonia"
Relief valves in service beyond their service life can exhibit the
following degradation in function:
They may leak at pressures below the set pressure.
They may open and fail to properly reseat.
They may open at higher than set pressure.
These failures to function properly are due primarily to four
"environmental" conditions:
1. Corrosion of metal parts (particularly springs) which
result in the component parts failing to perform.
2. Deterioration of synthetic rubber seat disc material.
3. Clogging or "cementing" of the movable relief valve
components so that their movement is restricted.
4. Debris on the valve seat after the relief valve opens,
effectively preventing the valve from resealing.
Corrosion is caused by water, corrosive atmospheres of salt and
high industrial pollutants, chemicals, and contaminants. High
concentrations can attack the metal parts vigorously. No
suitable metals are totally resistant to such corrosion.
Synthetic rubber and seat disc materials can also be attacked by
impurities in the gas and corrosive atmospheres, particularly
those with Sulphur Dioxide. There are no suitable rubber
materials which resist all contaminants.
"Cementing" of relief valve parts can be caused by normal
industrial atmospheres containing particles of dirt, iron oxide,
metal chips, etc. combined with water, oil, or grease. Ice
collecting in recessed valves could cause failure to open. Paint
and tar in relief valves also cause failure to function properly.
Rev B 11/05/15
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