Visual Inspection of Metal Surface.
QC Inspector/Coating supervisor shall visually inspect the condition of internal surface of all pipe fittings for verifying the items suitability for FBE surface preparation.If there is any items which is not meeting the above requirement mentioned in the document shall be identified and informed to the customer for further action.
All weld joints shall be inspected thoroughly,the weld height shall be uniform and within 2mm radius only and should be measured by appropriate equipment.The pipes which are having more than above mentioned height shall be kept aside for repair work by notifying the customer.
The welded surface must be free of defects which may affect the FBE coating.The welds shall be rounded and free of undercutting,excess penetration,spatters,sharp edges and porosity.If the spools found with weld defects shall be rectified prior surface preparation.
Prior to start surface preparation ensure that the surface is free from oil,grease or any other contaminants.If there is presence pf oil or grease,it shall be recommended for solvent cleaning or detergent washing as per SSPC SP-1.
Surface preparation and coating shall not be carried out during rain or wet condition.Climate conditions shall be measured and recorded at every two hours during blasting and coating operations.Relative humidity not to be higher than 85%.Surface temperature of steel shall be minimum 3°C above dew point.
All pipes and fittings which have been in previous oil service or contaminated at large areas shall be burn-Off.The surface shall be employed at a temperature of 350°C -400°C in the oven in order to burn-off oily contaminants by notified the customer/client.
Prior to start surface preparation all imperfections like sharp edges,slivers,weld spatters,scabs,slag etc shall be removed or rectified by wire brushing/grinding.
Garnet should be used for FBE surface preparation.Abrasive materials shall be selected by client approved Venders list and each batch of abrasive materials should be offered for client inspection prior to its use.Abrasive material shall be dry and free from any contaminants or impurities.
The surface profile should be in between 50-100 micron as recommended by coating manufacturer and shall be verified by NACE RP-0287.The frequency of the testing shall be start of shift and every 2 hours.
Dust embedment on the blasted surface should not be greater than Grade-2 in accordance with manufacturer’s recommendation and test shall be conducted as per ISO 8502-3. The frequency of the testing shall be start of shift and every 2 hours.
Chloride contamination on the blasted surface shall be tested in accordance with ISO 8502-6 & ISO 8502-9.The residual chloride content level shall not be more than 2µg/cm² as per manufacturer’s recommendation.
High temperature tape should be used for masking those areas not to be coated.The internal lining will extent 10mm on to the flange face in order to avoid creeping.The remaining flange face should be coated with Phenolic epoxy to maximum DFT of 70micron needed as per client requirement.
Coating shall be carried out within 4 hours from blasting completion.If any flash rusting occurs,the surface will be reblasted.