Objectives

The primary objective of this tender is to establish a contract for the refurbishment of safety valves on the feed heating system at Kriel Power Station, covering Units 1 to 6, over a period of five years. The aim is to ensure the safety valves are inspected, tested, repaired, refurbished, and correctly reinstalled to maintain safe and reliable operation of the plant's pressure systems.

Scope

The scope of work includes:

• Conducting inspections of safety valves by the Contractor, Turbine Engineer, and Turbine maintenance personnel to identify defects and determine corrective actions.
• Transporting valves to the Contractor’s workshop using gagging devices and dampening materials to prevent damage.
• Disassembling valves, inspecting parts for damage and wear, and storing components safely.
• Cleaning valve bodies and components, and conducting visual inspections with photographic documentation for approval.
• Developing a quality control plan (QCP) for each valve, including all inspection and testing activities.
• Maintaining a service book for each valve, documenting all reports, test certificates, spare parts, and calibration data, and submitting copies to Kriel Turbine Engineering.
• Testing spring stiffness using calibrated test benches, comparing results with OEM specifications.
• Executing specific refurbishment activities such as seat lapping, non-destructive testing (MPI/DPI), replacing soft spares, refurbishing components, and serial number stamping.
• Assembling valves, setting lift pressures on certified hydraulic test benches with on-site inspection, and installing tamper-proof seals and pressure setting plates.
• Transporting refurbished valves back to the plant, ensuring protection during transit.

Technical Requirements

The technical scope includes:

• Refurbishment of safety valves listed in the applicable safety valve table, with specific set pressures and sizes.
• Inspection and testing of safety valves, including visual, dimensional, and functional assessments.
• Use of OEM spare parts and adherence to Eskom approval processes for component replacements.
• Execution of non-destructive testing (MPI/DPI) on valves operating above 400°C.
• Calibration and verification of spring stiffness against OEM standards, using SANAS-approved equipment.
• Proper assembly, pressure setting, and sealing of valves, with documentation of all activities.
• Transport and handling procedures to prevent damage during movement of valves.

The scope is limited to the safety valves specified in the provided table, with all activities aligned to relevant standards and regulations, including pressure equipment regulations, safety standards, and quality management systems.