6" Line Stop
During a routine pump service, the client discovered that key shutoff valves had failed—putting the entire heating-glycol loop at risk. WellFab mobilized a live-work solution: two 6″ line stops were installed to create a safe, controlled isolation window, allowing removal and replacement of the faulty valves without draining the system. The plant stayed online, product stayed in the pipe, and the tie-in area remained stable and monitored from start to finish.
PROJECT OVERVIEW
LINE ISOLATION ON HEATING-GLYCOL MAINS
We executed two 6″ line stops on the active heating-glycol supply and return to replace failed shutoff valves with no shutdown and no drain-down of the system. The work followed a detailed Method of Procedure (MOP) with defined valve line-up and continuous pressure and temperature monitoring to maintain controlled isolation throughout. Execution included branch fitting and temporary isolation valve fit-up, performing the hot taps with verified coupon capture, deploying dual stop heads to establish positive isolation, removing the failed shutoff valves, installing and torquing new replacements, and then retracting the stops and installing completion plugs to restore the mains. Once the change-out was complete, we reinstated service through leak checks, gradual pressurization and flow restoration, and insulation and finish repairs to return the system to a clean, finished state.
SAFETY, QUALITY & DOCUMENTATION
To confirm integrity and compliance, we performed valve integrity and bubble tests, torque and closure checks on the new valves, and weld inspection/NDE on the fittings where required. The project was handed over with a full QA/QC package—including the MOP, test records, photos, redlined as-builts, and formal sign-offs—providing a defensible, well-documented record of the live line isolation on heating for the owner and their operators.
PROJECT IMPACT
This line isolation on heating avoided a full drain-down—eliminating glycol loss, refill time, air ingress, and restart risk—while keeping heating available to occupants throughout. The targeted isolation shortened the workface window and reduced schedule and cost compared to traditional drain/replace/recharge methods. Restored shutoff capability improves maintainability and future shutdown planning, and the QA/QC package supports ongoing operations and compliance.
