Piping Tie-in List
Template (Excel)

A piping tie-in list is the register of every connection between existing brownfield piping and new revamp piping on a refinery, petrochemical, fertiliser, or power plant modification project. For each tie-in it records the tie-in number, existing line, new line, P&ID references on both sides of the revamp boundary, tie-in type (hot tap, cold cut, spool replacement, flanged tie-in), method (on-stream, shutdown, decommissioned), size, isolation strategy, PWHT and NDE requirements per ASME B31.3, hydrotest method, permit category, shutdown window or hot-tap crew, and the construction sequence number. It is the construction and turnaround planning master.

Required columns: tie-in number, existing line number, new line number, existing and revamp P&ID references with revision, tie-in type (hot tap, cold cut, spool replacement, flanged), tie-in method (on-stream, shutdown, decommissioned), tie-in size and branch configuration (tee, olet, stub-in), existing line service fluid and operating conditions, existing and new PMS class, material compatibility, isolation strategy (double block and bleed, spectacle blind, line blind), PWHT and NDE requirements per ASME B31.3, hydrotest method, permit-to-work category, shutdown window or hot-tap crew tag, civil and structural impact, insulation scope, sequence number, responsible discipline, and status. See the ASME B31.3 standard reference.

Pathnovo, an engineering document intelligence platform, ingests both the as-built and revamp P&IDs and identifies every revamp-cloud boundary crossing as a candidate tie-in. The existing line tag, PMS class, and operating conditions are pulled from the as-built line list; the new line tag and PMS are pulled from the revamp line list. Material compatibility, isolation strategy, and PWHT requirements are applied per project standards. Typical turnaround for a complete tie-in list is 48 hours for the initial pass with 99.5% contractual accuracy on safety-critical fields. See the P&ID extraction workflow.

A hot tap is a tie-in executed on a live line under pressure, using a hot-tap machine to drill the existing line and install a new branch without shutdown. Hot taps require a dedicated procedure (typically per API 2201 for hydrocarbon hot tapping), restricted PMS material categories (no high-hardness or sour service base material above NACE limit), and 100% NDE of the branch weld. A cold cut is a tie-in executed during shutdown with the line depressurised, drained, and isolated, allowing conventional weld procedures and standard NDE percentage per the PMS. Tie-in method drives shutdown window planning and turnaround scope.

The tie-in list drives the shutdown window plan. Tie-ins are grouped by isolation boundary (which existing equipment must be depressurised, drained, and isolated for that tie-in) and by responsible discipline (piping, mechanical, instrumentation, electrical). Critical-path tie-ins (large bore, high temperature, PWHT required, restricted weld access) drive the shutdown window duration. Turnaround planners use the tie-in list to build the level 4 schedule, pre-fabricate spools to the maximum extent, and stage materials at the tie-in location. The Status column tracks each tie-in from identified through commissioned. See the as-built reconciliation template.

On Indian refinery revamps (IOCL Panipat, BPCL Mumbai, HPCL Visakh, RIL Jamnagar) and fertiliser revamps (IFFCO Phulpur, KRIBHCO Hazira, NFL Vijaipur) the tie-in list is reviewed at IFC gate and is a mandatory turnaround deliverable. IBR-scoped tie-ins (boiler-side piping under Indian Boiler Regulations) require Chief Inspector of Boilers approval for the modified scope, and the tie-in list IBR flag drives the IBR Form IIIA register. OISD-118 piping integrity requirements also flow into tie-in inspection scope. See the IBR compliance workflow and the as-built reconciliation template.

Downstream consumers: pre-fabrication packages for tie-in spools (one isometric per tie-in spool, see the piping MTO template), permit-to-work issue (one per tie-in or grouped tie-ins per isolation), inspection test plan (ITP) per tie-in NDE and hydrotest scope, mechanical completion checklist signoff, and pre-commissioning line walk against the revamp line list. The tie-in list is revision-aligned with the as-built reconciliation throughout the construction and commissioning phase. See the isometric extraction workflow.