Fiberglass mat dimensions and application.
Tank internal lining (FGRL) shall be done as per client requirements.There are two types of Fiber glass lining process (two layer and single layer).As per Client recommendation we will do lining application .Normly we are apply single layer with resin and shall achieve a minimum thickness of 1200micron.The Fiber glass mat shall have a minimum weight of 450gm/m2 and a width of not less than 1250mm and shall contain a high solubility binder.
The glass mat shall be cut to conveniently sized pieces and applied in a staggered seam pattern.Each Seam shall overlap minimum of 150mm.Seams on all vertical surface extending to the annular plate shall be overlapped by the mat on the bottom plate.After mat layer is laid down and saturated with resin,it shall be rolled thoroughly to remove all entrapped air and bubbles and to force the mat down smoothly.The direction of trapping air bubbles beneath the mat.
The lowest 600mm on the shell shall be lined only after the completion of bottom plate fiber glass lining application.Connection and man way openings in fiber glass lined areas shall be prepared and coated with epoxy to a minimum thickness of 750micron.The Fiber laminate shall be cut around the shell opening for nozzle and manholes,before the weld joint.
The fiber mat shall be cut just before the weld of gusset plate or any other structure welded to shell or bottom plate.The weld joint and the structures part should be coated with the only resin to a height of 600mm.The intersection area of this resin to phenolic epoxy coating shall be in such a way that phenolic epoxy shall be coated always above the resin.
Roof support legs shall be jacked up and supported to apply the full lining system on reinforcement pads.Temporary supports shall be designed in such a way that it will not damage the roof plates.Only alternate legs shall be lifted.
The resin shall be applied by airless spray machine.Any small area like sump pit,striker plates,RF pads etc. may be applied with resin using roller or brush.The first resin coat shall be tinted a contrasting colour to indicate coverage over the steel plate.The mixed lining shall be spread,uniformly on all area to be covered.
Over the fiber glass mat the surface tissue shall be applied in one layer with resin and shall achieve a minimum thickness of 400 micron.The glass surface tissue shall be a light weight fiber with a minimum weight of 20gm/m2 and minimum width of 1250mm.The surface tissue 400micron layer shall be laid diagonally opposite to the fiber mat as a final additional layer over the laminate.
The fiber glass lining shall be allowed to cure as per manufacture’s recommendation in well ventilated dry condition providing exhaust fans during curing period.Manufacture’s recommendation for curing time required based on ambient temperature shall be followed.
The manual sand papering and dusting on those applied lining with an exceeded redcoat intervals to provide proper adhesion of the subsequent coats.
Final gel coat shall be applied over the laminate system after the complete curing,Inspection,repair and holiday test of the lining and shall achieve a minimum thickness of 200micron.Each individual coat shall be checked for WFT during application and DFT after curing and shall be recorded.
A sample plate shall prepared in accordance with client requirements.The plate shall be blasted and primed on the commencement day of internal blasting.Final mat and gel application shall be done on the last days of each respective layer application.If the upper wall (Above fiber glass lining) are to be lined,the intersection area shall be prepared in such a way that the epoxy shall be lapped over the fiber glass lining at 50mm.