IIAR – Ammonia Refrigeration Technical RAGAGEP Questions

R-717 Show
R-717 Show
IIAR - Ammonia Refrigeration Technical RAGAGEP Questions

IIAR is the world’s leading advocate for safe, reliable, and efficient use of ammonia as a refrigerant.  In this episode Jeremy Willams of ARTS and Eric Smith of IIAR discuss industry prevailing best practices around the design and maintenance requirement of ammonia refrigeration systems. Eric is the Vice President and Technical Director of the association and today we bring you industry prevailing topics such as. 

  • Ventilation requirements of engine/machinery rooms 
    • B2L and A2L refrigerants
    • How much ammonia must be released for ignition?
    • Ventilation Rates from Bulletin 111 to IIAR 2
    • Worst Case Scenario Leaks
      • Shearing off a 1/2” pipe
    • 4% = 25% of the LEL (Lower Explosive Limit)
    • 30 Air Changes per Hour (ACH)
      • (Length X Width X Height) / 2
  • Acceptable ammonia loss rates
    • Expect to lose your inventory due to normal operations and Maintenace
    • Rule of thumb for refrigerants (10% to 20%)
    • Rule for thumb for ammonia (5% – 10%)
    • 2,000 lbs. a year or 5% of system charge you should start to look deeper into the leaks
    • New Technical paper from the IRC
    • Bagging Valves?
    • Tally all residual losses due to maintenance
    • Should IIAR publish in a standard a definite release rate for the industry? 
  • Existing system maintenance – pump down, pump out, LOTO, line break, and welding on the existing system with residual ammonia and oil.  
    • Written procedure must be used
    • Tightening closed isolation valves
    • Should IIAR publish in a standard a definite welding procedure for practices of systems with residual ammonia and/or oil?
  • Testing compressor’s high-pressure cut-out switch.
    • 4 ways applicable is using a pressure transducer
      • Can’t remove switch and test on bench.
      • Can’t turn off, isolate compressor, and pressurize with a gas. 
      • Can manipulate high side pressure by
        • Choking discharge stop valve with machine unloaded
        • Cycle off condenser fans/water with compressors unloaded
        • Reduce cut-out number for a functional test
        • Check valve / block and bleed for new manufactures designs. 
        • IIAR Cut Out Test
  • Low-Side Vessel High Level Protection
    • Testing High Level Floats
    • Regulators want to see that the test is functional and work under the conditions expected to work under
    • 1/2 tests
      • Lifting the float canister
      • Hitting the closing switch
      • Magnets
      • Taking off closing switch
  • If any of the critical safeties trip (activate) during a normal operation due to the system being outside of normal parameters, can a facility take credit for it working and move back the next annual test a year from that time period? Of course, they would want to look into why the system was so far out of normal and do what they can to keep this from becoming norm.  

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