SPECIFICATION AND STANDARD FOR STRUCTURAL STEELWORK: GENERAL PART 9 - SURFACE PREPARATION

1.15.1       General

1.15.1.1    All steel surfaces to be painted including welds and connections shall be thoroughly cleaned to remove all dirt, grease and other contaminants.  They shall at no stage have rusted beyond the allowable levels as specified in Swedish Standard SIS 05

5900.    All  rust  and  loose  scales  shall  be  completely  removed  by  mechanical cleaning,  blast  cleaning,  wire  brushing  and any other  approved  method.    After

surface preparation, the surface roughness is to be compatible with the coating to be applied but nowhere exceeding a peak-to-trough amplitude of 80 micrometres. Application of coating, paint and bitumen, etc. shall be carried out as soon as the

surface preparation has been completed.

1.15.2       Mechanical Cleaning

1.15.2.1    Mechanical cleaning, if applicable, shall be carried out by power driven tools, such as carborundum grinding discs and chipping hammers, followed by steel brushing and dusting to remove all loosened materials.

1.15.2.2    Excessive burnishing of the steel through prolonged application of rotary wire brush shall be avoided.

1.15.3       Blast Cleaning

1.15.3.1    Blast cleaning, if applicable, shall be carried out in accordance with BS 7079.  The maximum grade of abrasive permitted is specified in BS 7079.

1.15.3.2    Non-metallic abrasive used for blasting shall be free from harmful contamination and recovered material shall only be reused subject to the approval of SCI.

1.15.3.3    Blasted surfaces shall be brushed or cleaned by vacuum and shall not be touched by hand or contaminated in any other way.