bids are invited for annual maintenance contract for monitoring and maintenance of corrosion monitoring system for ncr for 02 year- 1 retrieval and reinstallation of internal corrosion coupons using gail retrieval tool. refer schedule of rates or bill of quantity for detailed description of the iitem. 2 retrieval and reinstallation of internal corrosion coupons using vendor retrieval tool.refer schedule of rates or bill of quantity for detailed description of the iitem. 3 corrosion monitoring. refer schedule of rates or bill of quantity for detailed description of the iitem. 4 supply of corrosion coupons same as material of pipeline.refer schedule of rates or bill of quantity for detailed description of the iitem. 5 monitoring or checking or data collecting of existing internal er probe. refer schedule of rates or bill of quantity for detailed description of the iitem. 6 removal of existing internal er probe. refer schedule of rates or bill of quantity for detailed description of the iitem. 7 supply and installation of new internal er probe. refer schedule of rates or bill of quantity for detailed description of the iitem. 8 monitoring or checking or data collecting of existing external er probe ( underground ) . refer schedule of rates or bill of quantity for detailed description of the iitem. 9 supply and installation of external er probe at site ( as & when required ) . refer schedule of rates or bill of quantity for detailed description of the iitem. 10 supply of excess fitting and flush disc coupon holder. refer schedule of rates or bill of quantity for detailed description of the iitem. 11 supply of excess fitting of internal er probe retractable or retrievable.refer schedule of rates or bill of quantity for detailed description of the iitem. 12 new installation by hot tapping per probe or per coupon at site. refer schedule of rates or bill of quantity for detailed description of the iitem. 13 supply & installation of battery operated off-line or online data logger with hand held unit. refer schedule of rates or bill of quantity for detailed description of the iitem. 14 complete service of gails retrieval tool along with service valve.refer schedule of rates or bill of quantity for detailed description of the iitem. total quantity : 592