replacement of damaged bottom plate and patch work in digestion vessel 02 in pa plant , fact cd . , replacement of damaged bottom plate and patch work in digestion vessel 02 in pa plant , fact cd . , replacement of damaged bottom plate in digestion vessel 02 in pap . work involves: collect required tools and tackles for the work . make required site arrangement . the existing 12 mm thick ms bottom plates shall be cut removed completely , as required at site to meet with the replacement procedure . temporary re- inforcement members shall be provided to the bottom plate and shell area of the tank . the shell shall be cut at a suitable distance from the top of the shell-to-bottom plate fillet weld such that the launder openings at the top are not misaligned with other vessels . the launder openings/nozzles shall be reworked if required to maintain the alignment by the contractor . the vertical shell bottom edges shall be ground properly with suitable bevel / double vee , where the welding is to be done . new bottom plate shall be fabricated out of 12mm thick ms plate . the plate shall be marked and cut as per relevant drawing to suit with the site condition . inside edge of the new cut plate shall be ground properly with suitable bevel / single vee , where the welding is to be done . the required backing strip plate shall be prepared from 6mm plate . the backing strip plate as required shall be full welded to the new 12mm thick cut plate . all bottom plate connection joint welds shall be full welded . the new 12mm thick cut plate with the backing strip plate shall be inserted / positioned properly with correct root gap . the vertical shell bottom edges shall be full welded [outside and inside] , to the newly replaced bottom plate with required fillet . shell-to bottom plate weld shall be full-penetration fillet weld . the newly welded all areas at inside of the storage tank shall be ground flush to facilitate rubber lining . after replacement of bottom plate , temporary re- inforcement members / plates shall be removed . damaged bottom plates and other scrap shall be transported to scrap yard . , patchwork on digestion vessel 02 shell: work involves: collect required materials from store . make site arrangements for the work including scaffolding . all the hv 09 encasings shall be cut and removed damaged/weak areas of dv 02 shell shall be cut and removed . necessary temporary supports shall be provided . patch work shall be done using 10mm thick ms plate . plates shall be cut , marked and rolled to suit the shell dia . fit up shall be done suitably . proper full welding at inside and out side of the joints and grinding of the welded area shall be done as per the instruction of officer in charge . dp test shall be done on weld joint and defects if any to be rectified . manholes/drain nozzles etc . shall be maintained as per original condition . existing manhole flanges and nozzles shall be used after necessary repair . weak areas near the launder nozzles shall be replaced with new plates . the nozzles shall be cut and removed for patch work . these nozzles shall be reused after repair . all welding joints inside and outside the shell shall be properly ground to facilitate rubber lining . , dismantling and refixing of existing launder between digestion vessel 01 and 03: make required site arrangements for work . the interconnection launder ( moc: ss 904l ) between dv 01 & dv 03 shall be dismantled suitably and removed from position to enable patchwork . the launder shall be cut and removed in segments if required as per site instruction . the cutting shall be plasma cutting only . necessary repairs shall be on the launder and its flanges as per site requirement . once the patchwork is complete the launder shall be erected back in position . the launder if cut , shall be erected with proper fit up and full welding of joints to be done . pad plates on the welding joints shall be provided . any rework on the launder to fit through the connecting flanges of dv 01 and 03 shall be done by the contractor . additional structural supports if required shall be provided . all the flange connection joints shall be properly tightened with gaskets to ensure leak proof joints . 1 no . quantity means dismantling and refixing both included . , dismantle , repair/modify/existing erect interconnection launders between digestion vessels 01 and 02 and digestion vessels 02 and 03: collect the required materials for the work . the launders shall be dismantled from the digestion vessels after site arrangements . the dismantled launders shall be repaired and modifies to suit the new flange orientation between dv 01&02 and dv 02&03 . patch works , repairs on the launder and its flanges shall be done as per site instructions . the modification of the launders shall be in such a manner that these shall be erected without any strain . the launders after rubber / brick lining shall be provided with hv 9 encasing inside with 300 mm extension towards downstream side on dv 02 and dv 03 . the launders shall be erected after getting clearance and serviced without any leak . dismantling of dv01-dv03 interconnection launder shall be in this scope of work . the dismantled launder shall be transported and stacked in earmarked area as per site instructions .