Environmentally Friendly “Air Mixed and High-Pressure Water Blasting” (Konki-jet) Developed to Comply with PSPC Requirements

Japan Ship Technology Research Association(JSTRA) has newly introduced the high pressure water-blast system, for surface treatment of the blocks of new-building ships prior to coating application, which will greatly enhance the working environment as well as reducing the industrial waste during new-building.

In the recent years, sophisticated marine coating is more in demand and along with the Performance Standard for Protective Coating for dedicated seawater ballast tanks in all type of ships and double-side skin space of bulk carriers (resolution IMO/MSC.215(82)(PSPC)).  The quality of surface preparation prior to coating has become more and more important.  So far, the conventional systems for surface treatment as represented by sand-blasting to remove the impurities of the steelwork surfaces has presented the problems with respect to dust fumes that deteriorate the working environment, the trouble remove such dust fumes, and the disposal of the used blast material as industrial waste in new-building.

As solution to these problems which is a growing concern in the future from environmental point of view, and also without compromising on the quality of surface treatment for even more stringent standards required for the coatings of the future, the water-blast system machine as decided to be introduced by JSTRA , which is capable of using high pressure as powerful as 100Mpa for cleaning on the intact zinc silicate shop primer surface and compatible to 34Mpa water blasting with media to obtain surface roughness 30-75 micron be used for PSPC as the secondary surface preparation method of new-building production for the first time in the industry.

 With the newly introduced “High Pressure Water-Blast System” it becomes possible not only to remove impurities such as corrosion, salinity, dust and dirt but also to obtain surface profile,   where it is required by PSPC such as welding seams and butts.

 It is not only environmentally friendly by avoiding dust fumes, but it also has the effect of water cleansing, particularly effective removal of salinity, which will improve the adhesion properties.  Further, it is possible to carry out the water cleansing without having to remove the zinc silicate shop primer which is an added benefit of corrosion protection in long run in comparison to dry sand-blasting.

 The countermeasures for flash rust that may occur after water blasting has been carefully studied the project team of JSTRA.  The project has invented how to protect from flash rust after being fully convinced with the result of numerous testing and application of the method to the actual series blocks of new-buildings at IHI AMTEC Co., Ltd. Aioi.