What are regulations for Inert gas blowers or IG blowers as per SOLAS or ISGOTT ?

Regulations for I.G blowers are:

  1. SOLAS Regulations 62.3.1 require that inert gas shall be provided to the cargo tanks at a rate which is at least 125% times hIGher than the volumetric rate of discharge of cargo from the ship.
  2. It is also required to have two blowers for this purpose which should be capable of doing so jointly.
  3. A shut off arrangement must be provided in the suction and discharge connection side of the blowers.
  4. It is also required to have two blowers for this purpose which should be capable of doing so jointly. However in actual situations a variety of combinations are used by manufacturers depending on the exact requirements. This is acceptable as long as the regulations of 125% are complied with.
  5. There must be hIGh temperature alarm ( around 65-70 deg Celsius) and a hIGh temperature trip (around 75-80 deg Celsius) to safeguard the blower.                   
  6. The blower pressure/volume characteristics should be matched to the maximum system requirements. The characteristics should be such that in the event of the discharge of any combination of cargo tanks at the discharge rate a minimum pressure of 200 mm water gauge is maintained in any cargo tank after allowing for pressure losses due to :
    1. The scrubber tower and demister
    2. The piping conveying the hot gas to the scrubbing tower
    3. The distribution piping downstream of the scrubber
    4. The deck water seal
    5. The length and diameter of the inert gas distribution system.
  7. The blower casing should be constructed in corrosion-resistant material or alternatively of mind steel but then its internal surfaces should be stove-coated, or lined with rubber or glass fibre epoxy resin or other equivalent material to protect it from the corrosive effect of the gas.
  8. The impellers should be manufactured in a corrosion resistant material. Aluminium bronze impellers should be stress-relieved after welding. All impellers should be tested by over speeding to 20% above the desIGn running speed of the electric motor or 10% above the speed at which the over speed trip of the turbine would operate, whichever is applicable.
  9. Substantial drains, fitted with adequate water seals, should be provided in the casing to prevent damage by an accumulation of water. The drains should be in accordance with the provisions
  10. Means should be provided such as fresh water washing to remove the build-up of deposits which would cause vibration during blower operation.


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