fabrication and erection of discharge duct of fume fan b and dryer fan b with ss material in np plant fact cd , during ata 2020 . , fabrication and erection of discharge duct of fume fan b and dryer fan b with ss material in np plant fact cd , during ata 2020 . , pre fabrication of discharge ducts of fume fan b and dryer fan b with ss material before ata 2020 . work involves: the required ss materials for the fabrication of new discharge duct of fume fan b and dryer fan b shall be transported from cd stores to work site . the measurements for the fabrication of discharge ducts shall be taken from site / existing one . the new discharge duct of fume fan b [duct from fan discharge expansion bellow to the connecting flange to stack b] & dryer fan b shall be fabricated with all its inlet / outlet / required connecting flanges etc . , as per the same dimensions , sizes and shapes of existing one , for proper / convenient erection . [the plate thickness of duct shall be 06 mm to 10 mm . ] . fixed / loose flange arrangements shall be fabricated with ss plates for all flanged connections . required ss pad plates / ss supports / ss stiffeners shall be provided / welded to all connecting flanges , manholes , etc . the ss plate cutting shall be done with plasma / cutting wheel only . ( arc cutting will not be permitted ) . full weld all joints with proper fillet as per arc welding procedure . inside / outside edges of the cut plate shall be ground properly with suitable bevel / single vee , where the welding is to be done . the welding of joints shall be done with full-penetration fillet weld and the root-pass shall be dp tested . ( total weight of the ducts= 06 mt [approx . ] ) . , replacement of rubber lined discharge duct of fume fan b and dryer fan b with ss material , during the ata 2020 period . work involves: the required scaffolding , tools , tackles etc . shall be arranged at site , for the replacement of discharge duct of fume fan b & dryer fan b during ata 2020 . rubber lining shall be removed from the area ( removal of rubber lining is in the scope of contactor ) , where the cutting is to be done . the old rubber lined duct shall be removed and transported to scrap yard after cutting the same into number of pieces for easy handling . temporary supports shall be provided , if required . the newly pre fabricated discharge duct of fume fan b & dryer fan b shall be transported to site and erect the same in position with proper / strong base support . the alignment , level , verticality etc . shall be corrected perfectly . all the flange joints shall be tightened properly and service the duct without any leak . ( total weight of the ducts= 09 mt [approx . ] ) . , fabrication / welding of ms structural support / stiffeners . work involves: the materials , tools and tackles for the fabrication / welding of stiffeners of ms angles / channels structural supports etc . shall be transported to site . the required stiffeners of ms angles / channels shall be welded on the out side surface area / body of the fabricated ss duct . if required , the structural supports for ducts shall be strengthened / repaired .