CASE STUDY-IIIBOILER 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 RoomFailure 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 problemsCascade 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 MachineryLack of motivation and complacency

by ship staffUn-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!