A STUDY INTO THE COATING THICKNESS OF SHIP BALLAST TANKS

2021 ◽  
Vol 162 (A3) ◽  
Author(s):  
R Willemen ◽  
D Luyckx ◽  
R Meskens ◽  
S Lenaerts ◽  
K De Baere
Keyword(s):  
Coating Thickness ◽  
Performance Standard ◽  
Coating System ◽  
Ballast Tank ◽  
Coating Performance ◽  
Coating Application ◽  
Flat Surfaces ◽  
Ballast Tanks ◽  
Dry Film Thickness

Ballast tanks are expected to be coated according to the IMO Performance Standard for Protective Coating regulations (PSPC15), in addition to the paint application requirements of the paint producer. In general, a coating system should consist of minimum two spray coats of light-colored epoxy coating on flat surfaces with a Nominal total Dry Film Thickness (NDFT) of 320 μm and 90% of all thickness measurements greater than, or equal to the NDFT and none of the remaining measurements below 0.9 x NDFT (the “90/10 rule”). Allegedly, the value of 320 μm in this PSPC15 rule may be misconstrued as a benchmark for coating application on flat surfaces, eventually leading to a non-PSPC15 compliance due to the resulting variation in coating thickness violating this 90/10 rule. This study indicates that over the years, the arithmetic mean in-situ DFT appears to be 498±18 μm and that too high and low thicknesses, below 288 μm and above 800 μm, were noted in the field. Analysis of a survey of ballast tank coating performance of ships indicates that too low thicknesses appear to be negatively impacting the average theoretical ballast tank performance. However, when an application mean DFT benchmark of 525 μm is used, the coating will almost surely comply to the 90/10 rule and the risk of falling below the 288 μm threshold is small, less than 2% in most cases. Consequently, using 320 μm as a mean DFT benchmark could result in a non-PSPC15 compliance with the in-situ ascertained coating thickness variation as this does not exclude coating thicknesses below 288 μm, which may then result in a significantly less than average theoretical coating performance. If the coating application is performed very evenly, the benchmark may be reduced to 429 μm with a probability of falling below 288 μm reduced to 0.1%. It should therefore be emphasized that the PSPC15 requirement is a coating system framework description, and that the requirement should be broadened to include a mean DFT as a coating applicator benchmark together with a clearly specified minimum and maximum DFT, in order to avoid any misinterpretations.

A Study into the Coating Thickness of Ship Ballast Tanks

2020 ◽  
Vol 162 (A3) ◽  
Author(s):  
B Khan ◽  
F Khan ◽  
B Veitch
Keyword(s):  
Coating Thickness ◽  
Performance Standard ◽  
Coating System ◽  
Ballast Tank ◽  
Coating Performance ◽  
Coating Application ◽  
Flat Surfaces ◽  
Ballast Tanks ◽  
Dry Film Thickness

Ballast tanks are expected to be coated according to the IMO Performance Standard for Protective Coating regulations (PSPC15), in addition to the paint application requirements of the paint producer. In general, a coating system should consist of minimum two spray coats of light-colored epoxy coating on flat surfaces with a Nominal total Dry Film Thickness (NDFT) of 320 μm and 90% of all thickness measurements greater than, or equal to the NDFT and none of the remaining measurements below 0.9 x NDFT (the “90/10 rule”). Allegedly, the value of 320 μm in this PSPC15 rule may be misconstrued as a benchmark for coating application on flat surfaces, eventually leading to a non-PSPC15 compliance due to the resulting variation in coating thickness violating this 90/10 rule. This study indicates that over the years, the arithmetic mean in-situ DFT appears to be 498±18 μm and that too high and low thicknesses, below 288 μm and above 800 μm, were noted in the field. Analysis of a survey of ballast tank coating performance of ships indicates that too low thicknesses appear to be negatively impacting the average theoretical ballast tank performance. However, when an application mean DFT benchmark of 525 μm is used, the coating will almost surely comply to the 90/10 rule and the risk of falling below the 288 μm threshold is small, less than 2% in most cases. Consequently, using 320 μm as a mean DFT benchmark could result in a non-PSPC15 compliance with the in-situ ascertained coating thickness variation as this does not exclude coating thicknesses below 288 μm, which may then result in a significantly less than average theoretical coating performance. If the coating application is performed very evenly, the benchmark may be reduced to 429 μm with a probability of falling below 288 μm reduced to 0.1%. It should therefore be emphasized that the PSPC15 requirement is a coating system framework description, and that the requirement should be broadened to include a mean DFT as a coating applicator benchmark together with a clearly specified minimum and maximum DFT, in order to avoid any misinterpretations.

scholarly journals Practical Difficulties of Sampling Ballast Tanks - What Lessons Can Be Learned?

2017 ◽  
Author(s):  
Paul Evans ◽  
Emma Langley
Keyword(s):  
Ballast Water ◽  
Management Practices ◽  
Time Windows ◽  
Aquatic Organisms ◽  
Small Time ◽  
Performance Standard ◽  
Physical Parameters ◽  
Ballast Tank ◽  
International Convention ◽  
Ballast Tanks

The adoption of the International Convention for the Control and Management of Ships’ Ballast Water and Sediments (BWMC) in 2004 (herewith the Convention) has sought to prevent the spread of harmful aquatic organisms and pathogens in the ballast water and sediments of ships, threatening marine ecosystems worldwide. The Convention sets out the various requirements and the various steps vessels owners / operators and port States need to undertake in order to effectively manage ballast water and sediments. However, there are still open issues and uncertainty, including the scientific and practical challenges of sampling of ballast tanks and monitoring compliance with the Convention’s standards. In order to monitor compliance with the Convention’s standards, documented management practices can be inspected for appropriateness and inspection of vessel log books can give an indication that practices have been implemented. However, sampling is the most effective way to ensure compliance with standards set out in the Convention. To check compliance with the D-1 (exchange) standard, vessel log books should be inspected and sampling can be used to check for anomalies in the composition of the ballast water (e.g. salinity). D-1 compliance is intended as an interim step until treatment systems are more widely available – although, some ports may require exchange as well as treatment in the long term. Compliance with the D-2 (performance) standard following treatment of the ballast water requires the sampling of biological, chemical and physical parameters. Whether checking compliance to the D-1 or D-2 standards, there are significant sampling challenges. These include the logistics of gaining vessel access; having multiple sample methods available to suit ballast tank access restrictions; getting a representative sample; sample analyses; sample interpretation and; what to do if a sample fails? In addition to this, local requirements can present further challenges (e.g. small time windows for bacterial analysis). This paper will highlight the difficulties of sampling ballast tanks in practice, drawing from national and international experiences, and will also comment more broadly on the sampling process and governance – such as regional differences and the role of port State control. Drawing on protocols adopted by other states will help to facilitate a more efficient, consistent and organised implementation of the Convention to the shipping community worldwide.

Coating Life Prediction for Water Ballast Tank

2005 ◽  
Author(s):  
R. E. Melchers ◽  
X. L. Jiang ◽  
K. J. Lu
Keyword(s):  
Life Prediction ◽  
Practical Implication ◽  
Plate Thickness ◽  
Surface Preparation ◽  
Ballast Tank ◽  
Independent Expert ◽  
Key Factor ◽  
Ballast Tanks ◽  
Dry Film Thickness ◽  
Insight Into

Corrosion is the key factor responsible for the degradation of ship structures and in no place is this truer than water ballast tanks. Coating protection system is a continual research interest for classification societies and coating industries. Up to now, most coating performance analyses are qualitative not quantitative. Coating life prediction is almost always based on experience and various assumptions, due to unavailability of practical data support systems. This paper describes a preliminary impartial investigation of coating life carried out with interviewees from the Australian Defence Science and Technology Organization (DSTO), shipyards, coating supplier and an independent expert. Plate surface, edges and welds in ballast tank were considered and the influences of dry film thickness (DFT) and surface preparation (SP) are addressed. The investigation gives some insight into the life of practical coating systems for water ballast tanks. Coating life is proposed to be representable by a normal distribution when corrosion breakdown is below 10% of plate thickness, which is of practical implication.

A New Preservation Protocol for Seawater Ballast Tanks in Naval Applications

1999 ◽  
Vol 36 (01) ◽  
pp. 11-21
Author(s):  
Miles Y. Kikuta
Keyword(s):  
Service Life ◽  
Cathodic Protection ◽  
Surface Contamination ◽  
Protection System ◽  
Coating System ◽  
Ballast Tank ◽  
Critical Elements ◽  
Ballast Tanks ◽  
Cathodic Protection System ◽  
Sacrificial Cathodic Protection

The reality that a smaller force must continue to meet heavy overseas commitments clearly indicates that high maintenance, manpower intensive, and costly repair processes must continue to be improved. One of the most significant maintenance problems identified by the Fleet was the continual and costly requirement to overhaul the coating system in seawater ballast tanks. This paper reports on the research conducted in conjunction with the Naval Sea Systems Command (NAVSEA) to develop a seawater ballast tank preservation protocol which extends the current 5 to 7 year coating service life to one that is expected to last 20 years. The approach to develop the new preservation protocol is discussed, the critical elements of the new preservation protocol are described, and methodologies for the design of sacrificial cathodic protection system for seawater ballast tanks and for the detection of surface contamination are provided.

Taking Care of Ballast Tank Coatings = Green Ballast Tanks Coatings

2014 ◽  
Author(s):  
Kris De Baere ◽  
Helen Verstraelen ◽  
Remke Willemen ◽  
Raf Meskens ◽  
Geert Potters
Keyword(s):  
Environmental Impact ◽  
Complex Structure ◽  
Regression Line ◽  
Age Distribution ◽  
Surface Preparation ◽  
Surface Cleaning ◽  
Ballast Tank ◽  
Coating Application ◽  
Significant Difference ◽  
Ballast Tanks

Shipping plays an important role in the logistic chain. These a worthiness of ships transporting goods world wide is therefore crucial. One element defining these a worthiness of a ship is the condition of her ballast tanks. These tanks are an area of concern for ship owners and crew. They are subject to corrosion; and due to the enclosed environment and complex structure, maintenance is very difficult and costly. This paper gives the results of an “insitu” study of ballast tanks on board of more than 150 merchant ships. No selection criteria were applied from the start and the ships were surveyed as opportunity arose. Most of the ships are worldwide trading and the age varies between brand new and 36years. Figure 1 gives a good idea of the age distribution. Many types of ships are represented in the database amongst others 10oil tankers, 14 liquefied gas carrier, 25 chemical tankers, 28 bulk carriers, 23 full containers carriers, 5 general cargoes, 9 RoRo’s, 8 refrigerated ships. Surface corrosion was assessed, compared and the importance of condition and environmental parameters during coating application recognized. The paper also reveals the significant difference between the average corrosion regression line of the data base and the coating condition in the ballast tanks on board ships to where the operator invested in a superior coating system at new building, with extra attention to surface preparation and coating application. The need to reduce the environmental impact of shipping becomes more and more obvious. Blasting with shot and grit, vast amounts of water used for water jetting and rinsing, surface cleaning and high solvent coatings jeopardize our future generations. Luckily, there duction of the environmental impact has beneficial economic consequences a sit brings down significantly maintenance costs.

In-situ polyurethane/polyacrylate microemulsion formation: the effects of acrylic content in wood coating application

2017 ◽  
Vol 26 (10) ◽  
pp. 753-763 ◽  
Author(s):  
Chengjun Wang ◽  
Xiaorui Li ◽  
Haihua Wang ◽  
Guiqiang Fei ◽  
Huan Wen
Keyword(s):  
Wood Coating ◽  
Coating Application

scholarly journals Extensional Viscosity of Coating Colors and its Relation With Jet Coating Performance

2004 ◽  
Vol 14 (5) ◽  
pp. 240-250 ◽  
Author(s):  
A. Arzate ◽  
G. Ascanio ◽  
P.J. Carreau ◽  
P.A. Tanguy
Keyword(s):  
Euler Number ◽  
Contact Region ◽  
Strain Rate Range ◽  
Extensional Viscosity ◽  
Coating Performance ◽  
Coating Application ◽  
Trouton Ratio ◽  
Number Curve ◽  
The Web ◽  
Key Parameter

Abstract An orifice flowmeter was used to measure the extensional viscosity of several non-pigmented fluids and paper coating colors containing calcium carbonate as pigment in the context of a jet coating application. The orifice flowmeter was first calibrated in terms of a dimensionless Euler number versus Reynolds number curve with Newtonian fluids. The calibration curve was then used to determine the apparent extensional viscosity of coating colors. In the strain rate range investigated, all the fluids were found to exhibit strain-thinning and the Trouton ratio of the coating colors was in the range 5 to 20. Jet coating tests were also carried out in order to evaluate the effect of the extensional viscosity on the jet performance. The extensional viscosity was shown to be a key parameter determining the configuration of the downstream meniscus in the web contact region.

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