(i) Sandblasting Techniques . Sandblasting operations should 

 be carried out to follow particular procedures: 



(1) Strict adherence to the manufacturer's operating 

 instructions; 



(2) careful following of all safety regulations and 

 proper use of safety equipment; 



(3) holding nozzle at proper altitude and angle for 

 surface area being cleaned; 



(4) removing any and all dust after blasting with 



vacuum or brush (the latter is very important to avoid coating 

 adhesion problems) ; and 



(5) particular attention to inside corners, pits, edges 

 bolt threads, nuts and bolts, welds and overblasting; the latter 

 means blasting near an area already coated and allowing the 

 abrasive to hit the coated areas. 



Table 49. Approximate sand usage and labor rates on sandblasting, 





Surf 



ace Preparation to be Achieved 





Condition of 



SSPC-SP-5 



SSPC-SP-10 



SSPC-SP-6 



SSPC- 



SP-7 



Surface to 



White 



Near White 



Commercial 



Bru 



sh 



be Prepared 













S 1 L 2 



S 1 L 2 



S 1 L 2 



S 1 



L 2 





(NHm 2 ) 



(N) (m 2 ) 



(N) (m 2 ) 



(N) 



(m 2 ) 



Loose Mill 



478 11.6 



383 14.4 



192 23.2 



96 



37.2 



Fine Powder Rusting 













Tight Mill Scale and 



575 8.4 



479 10.7 



287 18.6 



96 



33.4 



Little Rust 













Existing Coating 



958 6.5 



766 8.4 



383 13 



72 



29.7 



Which is Failing 













Badly Pitted Steel 



1197 4.6 



958 6.5 



575 9.3 



72 



27.9 



1 S denotes abrasive usage per square meter. 



2 L denotes labor production per hour. 



Note: These figures are approximate and reflect work on large areas 

 such as tanks or large "I" beams. 



340 



