Client : Aggregate Industries , UK.


Date : February / March 2012

Vessel : Yeoman Bontrup


Shipyard : Remontowa, Poland

Project : Vessgard™ Application

Fire Damaged Bulkheads

 



Introduction

The Yeoman Bontrup was the second vessel to have all of her transverse bulkheads applied with CAPPS® Vessgard™, which took place in January 2006 at Lisnave in Portugal. The decision had been made by the owners based on the success of the same application to the Yeoman Bridge in January 2005 which was already demonstrating its huge potential in service. CAPPS® have monitored the performance on the Yeoman Bontrup in the same way over the years, gathering data and building the case studies that are presented to potential new clients to promote the achievements of this highly advanced bulkhead encapsulation process.

In July 2010 the Yeoman Bontrup suffered a major fire in service and the decision was made by the owners to re - build the vessel at Remontowa shipyard in Poland. The primary area of fire damage was at the accommodation end of the vessel which had to be completely rebuilt and replaced. The consequent levels of fire and extreme heat in this area of the ship had caused damage to two of the cargo holds, 4 and 5. Many repairs have had to take place in these holds, the polypropylene plastic sheeting that protects the sloping hogsbacks has had to be refitted, and fire and heat damage had taken place to the Vessgard™ coating system in these two holds.

At the time of inspection in July 2011, the fire damaged accommodation block had been completely removed. The new accommodation block was being built on the dock side and the vessel at this stage had a barge like appearance.

 


Vessgard™ Damage Inspection

In July 2011 CAPPS® carried out surveying of the cargo holds to determine the extent of the damage and the measures that would need to be taken to repair the bulkheads that had been worst affected by the fire. Exposure to flames was one damage effect to consider and then also the intense heat transfer that would have taken place through the steel at this end of the ship.

Upon visual inspection from the deck it was clear that two bulkheads had taken the worst of the fire damage, Cargo Hold 4 Aft and Cargo Hold 5 Forward.

Cargo Hold 5 Forward Bulkhead

On the Cargo Hold 5 bulkhead it was clear that some areas of the Vessgard™ protection had actually caught fire, with blackened charring and signs of melting evident, and evidence of granite cargo that had become encased in the melting coating. The remaining areas were found to have suffered adhesion loss from heat damage - the effect of the heat on the Vessgard™ coating had caused expansion and then contraction with the coating clearly losing its molecular stucture and properties of adhesion, cohesion and elongation.

The intensity of the heat during the fire had clearly caused the bulkhead steel to buckle in the main charring areas shown in these photographs. This level of damage would mean that steel insert work would have to be carried out to these sections of the bulkhead prior to replacing the Vessgard™ system.

An important point noted on inspecting this bulkhead was that it was clear that only the obvious areas of burning had actually caught fire. With heat levels of such an intensity that could buckle steel, the remaining Vessgard™ had not ignited and contributed to the fire at the time. The coating's integrity was ruined by the heat, but it remained intact and had not combusted overall under these extreme heat levels.

 

 

Cargo Hold 4 Aft Bulkhead

On inspection of Cargo Hold 4 Aft bulkhead it became clear that the heat damage was particularly severe to the Vessgard™ coating. All surfaces had suffered blackening and charring, however it was quite apparent that on this bulkhead no areas had ignited or combusted to contribute to the fire at the time. On closer inspection and removal of damaged coating on this bulkhead it became clear how the Vessgard™ had behaved during the fire.

The heat transfer through the steel of the ship had clearly caused this bulkhead to reach extreme levels of temperature. On inspection with an Elcometer DFT gauge readings were found to be 4000 - 5000 Microns on a uniform basis throughout all damaged areas. As the original specification was 2000 Microns to the lower 7m section of the bulkhead it became clear that an expansion process had taken place due to the extreme heat. On removal of some damaged coating and inspection of the cross section it became clear that the initial reaction of the Vessgard™ to the heat was to expand. At the extreme heat levels the molecular structure of the product had clearly changed but it had then cooled and reverted to a new spongy like texture.

The main point to consider here is that the Vessgard™ did not ignite or combust. Once cooling down had taken place it had reverted back to a new form with a thickness of around 4000 - 5000 microns. The product had lost all its properties and clearly had to be removed but the fact that it did not all combust at the extreme heat levels demonstrates the kind of properties that fire proofing materials display in service.

Our lab work with Vessgard™ development has determined its thermostability for in service temperatures. We know the product is thermo-stable to 120 degrees centigrade after which its state may alter, but on cooling it will revert back to its original state, a process known as reverse polymerisation. We have investigated enquiries from coal carriers where the cargo reaches levels of 60 - 70 degrees centigrade where epoxies regularly fail, so therefore we know our temperature threshold has the advantage. It is unlikely that in service conditions from any cargo  would exceed 120 degrees centigrade.

A fire situation is different however, we know we have flammability resistance but reaction to the intense heat of a fire has now been firmly proven in this case study. Whilst we would not claim Vessgard™ to be a fire proofing material it is clear it demonstrates these type of properties. The reverse polymerisation has occured at an extreme level here, with the reverted state nothing like the original state. However, the product has not ignited or combusted and contributed to further damage in the fire situation.

The CAPPS® assessment from these surveys was requirement for complete removal and blasting of all bulkhead surfaces back to SA 2 1/2 75 Micron profile and complete replacement of the original specification.

Apart from the areas where steel inserts were carried out, on blasting removal of the damaged coating the steel was found to be in overall good condition.

 

 

COATING REMOVAL WITH CHISEL SHOWLY CLEARLY EXPANDED CROSS SECTION

 

 

VESSGARD™ APPLICATION PROJECT

FEBRUARY / MARCH 2012 @ REMONTOWA, POLAND.

The decision was made to carry out the Vessgard™ application project to these bulkheads close to the end of the rebuild program, as the rebuilding involved a lot of different works and operations that created considerable logistical challenges for the overall schedule. Shot blasting of the bulkheads to remove all the fire damaged Vessgard™ was carried out in advance of our application project, and a holding primer was applied which could be blast removed prior to Vessgard™ application.

The project was scheduled and took place at the end of February / early March 2012, at this time of year in Poland the cold weather conditions would present challenges that would require efficient sheeting of the scaffolding and heating installation to control the steel temperature and dew point to the correct specification for Vessgard™ application. Steel temperature must be controlled to be at least 5 degrees centigrade above the dew point.

 

VESSEL IN DRY DOCK AND CARGO HOLDS PREPARED FOR APPLICATION

 

 

BLASTED BULKHEADS INCLUDING STEEL INSERT REPAIR SECTIONS READY FOR APPLICATION

 

 

 CAPPS® SPRAYERS IN ACTION - LOWER STOOLS AND UP TO 7 METRE HEIGHT RESTORED TO THE ORIGINAL 2MM DFT

 

 

 ORIGINAL SUBSTRATE ENCAPSULATION RESTORED

 


 

 

 

 














The Yeoman Bontrup is now back in service after a successfull re - building project, with Vessgard™ performance as good as new on the repaired bulkheads.

The bulkheads in the remaining cargo holds will see service until her next dry dock which is due in 2014.

 

2006 VESSGARD™ APPLIED BULKHEAD