3.6 ANTTPOUTANT PAINT APPIJCATICN AND REMOVAL PRACTICES 



Shipyard and drydock practices typically require specialized painting 

 equipment not available to the citizen boat owner. Use of specialized 

 equipment encourages specialization in job assignments and training in the 

 safe use of the equipment. The availability of this training provides the 

 opportunity for more control over worker exposure and over the amount of 

 organotin compounds released into the environment. There is far less 

 knowledge of and control over the owner painting a boat in his driveway 

 than there is an the commercial yard with a significant investment in 

 equipment and higher public visibility. There have been no studies of the 

 relative contribution of TBT to the environment from individual boat 

 owners vs. commercial ship and boat yards. 



The U.S. Navy requires the use of airless spray equipment by painting 

 contractors painting Navy ships. Studies of the coating efficiency of 

 spray painting found that 5% to 9% by weight of the paint went elsewhere 

 than the hull being painted. Recammended means for preventing this 

 overspray from reaching the environment include plastic film lining of the 

 dry dock area prior to painting, and clean up by vacuum and wash down 

 prior to reflooding the drydock. Developmental studies are being 

 conducted by the Navy at Norfolk to develop a complete spray enclosure on 

 a hi-lifter arm which will have a sealing skirt to the hull, to 

 effectively contain any overspray or grit blasting residue. 



3.6.1 Recammended Paint Application Practices 



The Navy recommends the use of airless spray techniques as the preferred 

 application method but is testing alternatives. The recommended applica- 

 tion rate would be 12 to 16 mils dry film thickness or 12 mg of TBT per 

 square centimeter of hull surface. This would apply approximately 400 kg 

 of TBT on a 100 meter Navy ship having a typical 3.3 x 10 square 

 oentimeter wetted surface. 



The Navy's safety requirements for protecting the health of the 

 applicators is presented below (Chapter 631 of NAVSEA, 1983 Technical 

 Manuals) : 



The basic safety requirements for applying organotin containing 

 antifouling paints are as follows: 



o Workers within 25 feet of paint application or removal, must wear 

 impervious disposable coveralls, taped at the wrists and ankles, 

 disposable shoe covers, plastic or rubber gloves, and 

 NIOSH-approved full face, air supplied respirators; 



o Only protected personnel may remain within the exposure zone (up to 

 100 feet from the spray) ; 



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