TOWER RENOVATION: GRIT BLASTING
PREPARATION OF METAL SURFACES: Grit Blasting with Platinum Slag
Prior to blast cleaning, all welds shall be free of sla, slag inclusions and pinholes. Adjacent areas shall be free of weld spatter. Which shall be removed by grinding or scraping. All oil and grease deposits shall be removed prior to blast cleaning. In this regard special attention shall be paid to drillings, bolt holes and etc. Blast cleaning shall be carried out on dry surfaces using dry air, free from impurities (in particular grease or oils). All surfaces that are blast cleaned shall be coated with a primer coat within 4 hours. Alternatively, provided the surface cleanliness requirements of ISO 8501-1 or SIS 055900 are maintained, the primer coat may be applied within the same working shift. Under no circumstances shall blast cleaned surfaces be left uncoated overnight.
Blast cleaning may be carried out using grit or slag that shall comply with strict quality requirements - details available upon tender.
Irrespective of the material used for blast cleaning, it shall in all cases be free of foreign matter such as clay, humus, chlorides and bitumen. In all cases, after blast cleaning, all traces of blasting media and dust shall be removed from the steel surface by compressed air or vacuum cleaning. Cleaned surfaces shall not be contaminated with oil, grease, rust or other deposits before coating. After completion of blasting all used and unused blast media shall be removed from site and disposed off at approved disposal facility. Where blasting is performed on towers with exposed cables, tele-communcation antennae equipment, nameplates, and all other equipment that can be damaged by the effects of blasting shall be protected.