CASE STUDY-III BOILER TUBE FAILURE

The Incident  Boiler Make: MIURA  Date: March 26, 2010  Place: At sea  Initial Indication: Frequent water being taken into hotwell indicating Boiler High Water Consumption and Boiler Feed pump running frequently  Boiler Furnace checked through peephole, found slight water accumulation inside the furnace  Confirmation: Boiler burner and swirler unit removed, found few tubes on Stbd aft leaking and steam leaking in the form of a jet  Action: Main Engine and Boiler stopped, 6 Nos. leaky tubes plugged by ship staff

Repeat of the Incident  Date: April 11, 2010  Place: At Port  Initial Indication: Frequent water being taken into hot well indicating Boiler High Water Consumption and Boiler Feed pump running frequently  Boiler Furnace checked through peephole, found slight water accumulation inside the furnace  Confirmation: Boiler burner and swirler unit removed. Found 3 major tube leakages and 27 minor tube leakages and steam leaking in the form of a jet  Action: Boiler stopped. 30 Nos. leaky tubes plugged by ship staff

Immediate Causes Identified ROOT CAUSE:  Failure to monitor Boiler water condition INDIRECT CAUSES:  Failure to take proper rounds in Engine Room  Failure in daily monitoring of Cascade tank water quality,  Failure in daily Monitoring of Observation tank on Deck  Failure to test Cargo tank heating Coil at Regular intervals

Design problems  Cascade tank was not fitted with Oil Detecting Sensor or Salinity Sensor to warn operators  Poor material of Plate heaters --- Cracking of plate damages boiler water very fast & by the time, Duty Engineer realizes, Oily Water enters Boiler  Miura Boiler load might reach 100% at High Combustion Mode  Burner has O-rings which require renewal every year  Leaky Burner can cause Violent Combustion – leading to tube burn out

Operational & Maintenance Problems  Lack of interest to protect Machinery  Lack of motivation and complacency by ship staff  Un-Controlled Dumping of excess Steam in Drain Cooler – leading to tube leakage  Burner never pressure tested “OR” Replaced every Year  Cargo Tank Heating Coil not tested at regular interval

Solutions  Attached problem did not happen over-night but over long period of time  Daily Visual Check & Testing of Cascade tank Water, observation tank and gauge glass will give indication  Beyond Doubt, C/E or none of the Duty Engrs or Oilers took regular thorough Rounds of Machinery Space  C/E to witness Boiler water test once every week  Please maintain firing of Boiler at Low Combustion mode, which is good enough for fulfilling Steam requirement onboard including cargo heating  Replacement of Burner every year on exchange basis

Burst water wall tubes in the furnace

Burst wall tubes and plugged tubes with color changed

Horizontal cracks were located in the water tubes of low area

Top view of the water tubes in the furnace room

Deposits in the burst tubes internally (Near bottom tube plate)

Water tubes internal viewing

Take care of your Boilers well!