Hot Tapping Method for Live Chilled Water Piping

More than a static template

Unlike a downloadable Word or PDF template, this method statement is an AI-assisted editable starting point connected directly to a matching Inspection and Test Plan. Every section is structured, project-adaptable, and ready to export.

AI-assisted drafting — Customize every section with AI for your specific project scope.
Linked ITP — A matching inspection and test plan is generated alongside the method statement.
Multiple export formats — Download as a formatted PDF or editable Excel spreadsheet.
Editable starting point, not a final document — Review, verify, and adjust all content against your project requirements before use.

Static template vs. Quollnet workflow

Feature	Static template	Quollnet
Project-specific content	Manual fill-in required	AI-assisted customization
Linked ITP	Separate document, no link	Matching ITP included
Export formats	Usually PDF only	PDF and Excel
Structured sections	Free-form layout	13 standardized sections
Saved to your account	Local file only	Cloud-saved, reusable
Content accuracy	You verify everything	AI-assisted, you still verify
Cost	Often free but time-intensive	Free to customize and download

What you can customize

When you save this method statement to your account, every section becomes editable. The following 13 sections are included:

Scope — Defines the activity and its boundaries.
References — Standards, specifications, and drawings.
Responsibilities — Roles and accountabilities.
Resources — Labour, plant, and equipment summary.
Materials — Materials and compliance requirements.
Equipment — Tools and equipment details.
Prerequisites — Hold points and pre-conditions.
Method sequence — Step-by-step construction sequence.
Safety controls — HSE risk controls and PPE.
Environmental controls — Environmental mitigation measures.
QA/QC — Quality inspection and test requirements.
ITP — Inspection and Test Plan table (has its own page).
Attachments — Referenced drawings and documentation.

Why this method statement is used

This method statement is used to define and communicate the approved procedure for carrying out method statement for hot tapping tie-in connections on live pressurized chilled water (chw) piping on site. It ensures the work is planned in advance, the correct resources and controls are in place, and all personnel understand responsibilities, sequence, quality requirements, and safety controls before work begins. It aligns site execution with the documented scope and acceptance expectations.

Who uses this method statement

This method statement is used by contractors, site supervisors, project engineers, QA/QC engineers, HSE officers, consultants, and client representatives. It serves as a shared reference for planning, execution, supervision, inspection, and approval of the activity on site.

When it is prepared and submitted

The method statement is prepared before the work activity starts and submitted as part of the pre-construction documentation package for review and approval.

Who reviews or approves it

The method statement is usually submitted to the client representative, consultant, resident engineer, or project management consultant for review and approval before the work commences.

Important approval note

This method statement is an AI-assisted editable starting point, not a pre-approved document. Before use on any project, all content must be reviewed and approved by the relevant parties (superintendent, principal contractor, or client representative) in accordance with your contract and project quality plan.

For example: if your specification requires a departure from a referenced standard, that departure must be documented and approved separately — this method statement will not capture that automatically. Always verify against your applicable drawings, specifications, and regulatory requirements.

Method statement content

Scope

Overview

This method statement defines the engineering, fabrication, installation, hot tapping, and commissioning procedures for creating new branch connections on live, pressurized chilled water (CHW) piping systems using hot tapping. It covers specialized split-tee/reinforcement saddle welding, non-destructive testing (NDT), installation of an isolation valve and tapping machine, coupon cutting under pressure, flange make-up, functional testing, and documentation.

Inclusions

Engineering assessment and calculations for hot tap suitability and reinforcement.
Fabrication of split-tee/saddle and branch spool.
Welder/WPS qualification and control.
Surface preparation, fit-up, preheat, welding, and NDT (VT, PT/MT, UT where applicable).
Valve selection, pressure rating verification, and pre-installation testing.
Tapping machine set-up, pressure equalization, coupon cutting, and retrieval.
Post-tap leak verification, flange closure/branch tie-in, and flushing.
HSE controls for live-pressurized work, hot works, lifting, and water/glycol containment.
QA/QC, ITP, records, and handover.

Exclusions

Permanent system isolation/shutdown (not applicable to hot tap).
Major civil works or supports outside the immediate tap location [Verify per project scope].
Chemical water treatment adjustments post-works [By Client/O&M].

Key Constraints

Work performed on a live, pressurized CHW line at typical 4–12°C and 6–16 bar MOP [Verify per project specifications].
Maximum hot tap branch size, location clearances, and remaining wall thickness as per engineering assessment and applicable codes.

References

Document Type	Reference / Number	Revision	Notes
	ASME B31.3 (or ASME B31.9 for Building Services Piping) – Process/Building Services Piping		Materials, fabrication, examination, testing; select the applicable code based on the facility classification [Verify per project].
	ASME PCC-2 – Repair of Pressure Equipment and Piping (Hot Tapping and On-Line Branch Connections)		Engineering and execution guidance for hot tapping and branch reinforcement.
	API 2201 – Safe Hot Tapping Practices in the Petroleum and Petrochemical Industries		Safety and procedural guidance; adapt to CHW service [Verify applicability per project HSE plan].
	ASME Section IX – Welding Qualifications		WPS/PQR and welder qualification for pressure boundary welds.
	ASME Section V – Nondestructive Examination		General NDE methods, procedures, and calibration blocks.
	ISO 17635 / ISO 23278 / ISO 3452 / ISO 9712		General rules for NDT of welds; MT/PT techniques and personnel qualification.
	ASME B16.5 / B16.47 – Pipe Flanges and Flanged Fittings		Flange classes and dimensions for valve/adapter flanges.
	ASME B16.34 – Valves, Flanged, Threaded, and Welding End		Valve design and pressure-temperature ratings.
	API 598 – Valve Inspection and Testing		Hydrostatic and seat leakage tests for valves.
	ASTM A53 / ASTM A106 – Carbon Steel Pipe; ASTM A234 WPB – Wrought Carbon Steel Fittings		Typical CHW materials; verify per project MTO.

Responsibilities

Role	Responsibility	Name / Party
Project Manager	Project Manager	Main Contractor
Construction Manager	Construction Manager	Main Contractor
Welding Engineer	Welding Engineer	Main Contractor
Supervisor	Hot Tapping Specialist Supervisor	Approved Specialist Subcontractor
QA/QC Engineer	QA/QC Engineer	Main Contractor
NDT Technician	NDT Level II/III Personnel	Approved NDT Agency
HSE Officer	HSE Officer	Main Contractor
Engineer	Client/Engineer Representative	Client/Engineer

Resources

Resource Type	Quantity	Remarks
Manpower	1
Manpower	2–4 [Verify]	Carbon steel SMAW/GTAW
Manpower	2	From approved specialist
Manpower	2	Certified
Manpower	2	IPAF or equivalent
Manpower	1–2

Materials

Material	Specification / Grade	Remarks
Isolation Valve, Flanged	ASME B16.34; API 598 tested; Body ASTM A216 WCB or equivalent; Seat compatible with CHW/glycol	ASME B16.5 Class 150/300 as per design pressure [Verify]
Split-Tee/Full Encirclement Saddle with Branch	ASTM A106 Gr B / ASTM A53 Gr B body; ASTM A234 WPB branch; design per ASME B31.3/PCC-2; with tell-tale/vent holes	Material compatible with run pipe
Flange Adapter/Hot Tap Machine Adapter	ASME B16.5; RF; material to match tee/valve	Class matched to valve/flange
Gaskets	ASME B16.20 Spiral Wound or PTFE sheet [Verify]; potable-water-safe if applicable	Graphite/PTFE per service and temperature
Bolting	ASTM A193 B7 studs / A194 2H nuts or per project	Lubricated with suitable anti-seize
Welding Consumables	SMAW E7018 (low hydrogen) / GTAW ER70S-6 with appropriate flux/shielding	Per qualified WPS
Pipe Insulation and Cladding	To match existing CHW system; vapor barrier; closed-cell insulation	For reinstatement after works

Equipment

Equipment	Capacity / Type	Quantity	Inspection Required
Hot Tapping Machine (e.g., TDW, Enerpac, or equivalent)	Sized to branch; pressure rating ≥ system MOP + margin	1	Calibration certificate
Isolation Valve (Gate/Plug/Ball, full-bore)	ASME Class per design; fire-safe not required for CHW	1	API 598 cert
Temperature Sticks/Infrared Thermometer	0–300°C	2	Calibration
Ultrasonic Thickness Gauge (UTM)	1–50 mm	1	Calibration
NDT Kits (PT/MT), UT if applicable	As per ISO/ASME	1 set	Procedure + NDT personnel certs
Calibrated Torque Wrenches	Up to 500 N·m or as required	2	Calibration
MEWP/Scaffold and Rigging Gear	SWL tagged	As required	LOLER/Thorough exam [Verify per local regs]

Prerequisites

Approved method statement, risk assessment/JSA, and Permit-to-Work including Hot Work Permit [Verify per project HSE plan and local regulations].
Engineering package: tie-in location drawings, isometrics, stress and support check, hot tap size (d), run pipe size (D), branch reinforcement calculations (per ASME B31.3/PCC-2), and minimum remaining wall thickness (t_rem) assessment using UTM corrosion survey.
Confirmation of service conditions: fluid (water/glycol %), MOP, normal/maximum temperature, flow direction and velocity, chemistry/biocide data.
Verification of hot tap feasibility: typical limits d/D ≤ 0.5–0.6; minimum spacing from existing welds ≥ 1.0 × run pipe diameter or ≥ 300 mm, whichever greater; avoid elbows/nozzles by ≥ 3 × branch diameter [Verify per project and PCC-2].
Fabrication drawings and WPS/PQR approved; welders certified to ASME IX for positions applicable (e.g., 2F/3F/4F for saddles, 5G/6G if applicable).
Valve and adapter flange class match; valve API 598 certificates; hydrostatic/seat test records.
Calibration certificates for gauges, torque wrenches, UTM, thermometers, tapping machine indicators.
Access platforms/MEWP erected and inspected; lifting plan; exclusion zones marked.
Insulation removal plan and moisture control for CHW lines to prevent condensation during welding (temporary vapor barriers, localized heating wraps as needed).
Spill response and containment plan for potential CHW/glycol release; drain/collection connections available; environmental approvals in place.
Pre-job briefing and toolbox talk with all crew; emergency plan including rapid valve closure and containment.
Client/Engineer notified and hold/witness points scheduled.

Method Sequence

Step	Activity	Description	Responsibility	Inspection / Hold Point
1	Site verification and marking	Confirm exact tap location on run pipe; verify clearances, supports, and no nearby defects; mark centerlines and orientation of branch.	Construction Manager / Hot Tapping Supervisor	VT of pipe OD; UTM sampling grid set-out
2	Surface preparation & insulation removal	Remove insulation/cladding over adequate area; dry surface; remove coatings to bright metal over weld footprint + 50 mm.	Site Crew / Insulation Subcontractor	VT of prepared surface
3	UT thickness mapping	Conduct 100% UTM over footprint + 150 mm; map minimum wall thickness and corrosion patterns.	NDT Technician	Owner/Engineer witness (W)
4	Split-tee/saddle fit-up	Align split-tee halves; ensure snug fit with max root gap ≤ 3 mm; install temporary clamps; verify branch orientation and level.	Welding Team / Supervisor	Fit-up inspection (H)
5	Preheat and welding (split-tee to run pipe)	Preheat CS to 75–120°C [Verify per WPS]. SMAW E7018 low-H electrode; balanced sequence to limit distortion; interpass ≤ 250°C. Maintain continuous vent/tell-tale opening.	Certified Welder / Welding Engineer	WPS adherence check; temperature monitoring
6	Weld NDT (attachment welds)	After cooling, perform VT 100% then PT or MT 100% of saddle/tee welds. UT/PAUT for full-penetration butt seams of the tee if applicable.	NDT Technician Level II	Engineer witness (W)
7	Tell-tale/annulus leak test	Apply low-pressure air 1.0–1.5 bar through tell-tale; soap-solution check around weld perimeter.	QA/QC Engineer / NDT Technician	Hold point (H)
8	Seal tell-tale and coat	Weld close the vent/tell-tale as specified; PT on seal weld; apply primer/temporary coating to bare steel.	Welder / QA/QC	VT/PT
9	Valve and adapter flange installation	Mount adapter flange to split-tee; install gasket and isolation valve; align bolt holes; torque per pattern in 3–4 passes.	Hot Tapping Supervisor / Rigger	Bolt torque check
10	Pressure equalization and pre-tap checks	Connect pressure gauge; verify zero leaks; open valve slightly to equalize pressure within tapping machine housing once mounted.	Hot Tapping Technician	Functional check
11	Mount tapping machine and set cutter	Attach machine to valve flange; verify travel length > wall + tee thickness; set pilot drill and hole saw to required branch ID.	Hot Tapping Technician	Setup verification
12	Hot tap cutting (live)	Fully open valve; advance pilot and cutter at controlled feed and rpm; use only potable-water-safe lubricant if required [Verify]. Monitor pressure/temp.	Hot Tapping Technician	Engineer witness (W)
13	Retract cutter and close valve	Retract tool beyond valve seat; close isolation valve fully; verify tight shut-off.	Hot Tapping Technician	VT; pressure check
14	Remove machine and install blind/branch piping	De-mount tapping machine; install blind flange or connect branch spool; torque bolts to spec; align piping supports.	Construction Crew	Bolt torque check; alignment
15	Branch pressure test (off-line prior or on-branch as applicable)	Hydrotest the branch/valve assembly off-line before installation where feasible; otherwise, pneumatic/soap test flanged joints post-tap.	QA/QC Engineer	Hold point (H)
16	Flushing and swarf removal	Crack open valve slightly into controlled hose/tank to discharge swarf until clear; sample for particulates.	Hot Tapping Technician / O&M	Visual
17	Coating and insulation reinstatement	Apply corrosion protection coating; reinstall insulation and vapor barrier; seal penetrations.	Insulation Subcontractor	VT
18	Handover and documentation	Compile and submit as-builts, NDT, test certs, torque logs, calibration, coupon custody, and ITP closeout.	QA/QC Engineer	Final walkdown (W)

Health, Safety, and Environment (HSE) – Safety Controls

Key Hazards and Controls

Hazard: Release of pressurized CHW (water/glycol)
Consequence: Rapid flooding, slip hazards, equipment damage, hypothermia.
Engineering/Procedural Control: Validate valve rating and integrity; pre-job verification of pressure/temperature; emergency shut plan; secondary containment and drain paths prepared; limit personnel in exclusion zone; pressure gauges installed before cutting.
Required PPE: Waterproof gloves, chemical-resistant gloves if glycol present, face shield + safety glasses, waterproof boots, arc-rated FR long sleeves for hot work, thermal layer as needed.
Collective Measure: Barricades and drainage trays; spill berms; dedicated suction pump on standby.
Inspection/Permit/Supervision: Hot Work Permit; live system work authorization; HSE Officer present; pre-tap checklist signed by Supervisor and Engineer.
Hazard: Welding on live, fluid-filled pipe (heat sink effect)
Consequence: Cold cracking, lack of fusion, structural failure of saddle.
Engineering/Procedural Control: Low-hydrogen process; controlled preheat 75–120°C and interpass ≤ 250°C; maintain dry electrodes; monitor temps; use qualified WPS/PQR.
Required PPE: Welding hood, leather gauntlets, FR clothing, hearing protection.
Collective Measure: Fire watch with extinguishers; removal of combustibles within 10 m; welding screens.
Inspection/Permit/Supervision: WPS verification; welding parameter logs; NDT hold point.
Hazard: Tapping machine or valve failure under pressure
Consequence: Jetting release, impact injuries.
Engineering/Procedural Control: Use OEM-certified machine rated above system MOP; function test; ensure coupon retention device; double-check flange torque and gasket selection.
Required PPE: Face shield, gloves, hard hat, safety glasses.
Collective Measure: Exclusion zone during cutting; remote position of non-essential staff.
Inspection/Permit/Supervision: OEM maintenance record; pre-use inspection; Engineer witness.
Hazard: Working at height on pipe racks/plant rooms
Consequence: Falls from height.
Engineering/Procedural Control: Certified scaffold or MEWP; harness with lanyard; edge protection; tools tethered.
Required PPE: Full body harness, lanyard, hard hat with chin strap, non-slip footwear.
Collective Measure: Scafftag/MEWP daily checks; exclusion below; toe boards.
Inspection/Permit/Supervision: Working at Height Permit; competent supervisor.
Hazard: Lifting and positioning heavy valves/machines
Consequence: Crush injuries, dropped objects.
Engineering/Procedural Control: Lift plan; rated slings/shackles; tag lines; no standing under load.
Required PPE: Hard hat, gloves, steel-toe boots.
Collective Measure: Designated lifting zone; banksman control.
Inspection/Permit/Supervision: LOLER/Thorough Examination certificates; pre-lift briefing.
Hazard: Electrical hazards from powered equipment
Consequence: Shock, fire.
Engineering/Procedural Control: Use 110V center-tapped or suitable RCD; inspect cables; dry working area.
Required PPE: Dielectric gloves where needed, dry gloves, eye protection.
Collective Measure: RCD testing; cable management.
Inspection/Permit/Supervision: Portable appliance testing; permit.
Hazard: Noise and vibration during drilling
Consequence: Hearing damage, hand-arm vibration.
Engineering/Procedural Control: Limit exposure time; maintain equipment; use anti-vibration gloves.
Required PPE: Hearing protection, gloves.
Collective Measure: Noise signage; rotation of operators.
Inspection/Permit/Supervision: Noise assessment [Verify per local regs].
Hazard: Chemical exposure (glycol/biocides)
Consequence: Skin/eye irritation, environmental harm.
Engineering/Procedural Control: SDS review; sealed drainage; avoid aerosolization.
Required PPE: Chemical-resistant gloves, goggles/face shield.
Collective Measure: Spill kits; containment tanks.
Inspection/Permit/Supervision: COSHH/chemical permit [Verify per project HSE plan].
Hazard: Legionella/aerosolization (stagnant CHW)
Consequence: Respiratory illness.
Engineering/Procedural Control: Minimize spray; use hoses to closed containers; avoid atomizing leaks; coordinate with water treatment vendor.
Required PPE: Respiratory protection if risk identified.
Collective Measure: Ventilation; isolation of area.
Inspection/Permit/Supervision: Hygiene assessment [Verify per project HSE plan and local regulations].

Environmental Controls

CHW/Glycol Containment: Provide drip trays, inflatable pipe seals, and sump pumps. Collect any discharge into IBC tanks. Glycol-bearing water is hazardous to aquatic life; do not discharge to storm drains [Verify per local regulations].
Spill Response: Spill kits (absorbent pads, booms) at point of work; trained responders assigned; immediate reporting and isolation.
Waste Management: Segregate metal swarf/coupon for recycling; dispose of used consumables and PT/MT chemicals as per SDS and project waste plan.
Noise Management: Restrict drilling to permitted hours; use acoustic screens where required.
Air Quality: Use low-VOC cleaners; avoid aerosolizing CHW; control fumes during welding with local extraction where practicable.
Energy/Water: Minimize flushing volume; recirculate through filter bag if approved.
Documentation: Environmental checklist pre/post works; record volumes of any collected CHW/glycol and disposal manifests.

QA/QC

Quality Objectives

Execute structurally sound, code-compliant hot tap with zero leakage and full documentation.

Controls and Tests

Design Calculations: Verify d/D ratio, reinforcement area, allowable membrane stress, and t_rem ≥ required thickness including corrosion allowance.
Materials Traceability: Heat numbers and MTCs for split-tee, branch, flanges, and bolts.
Welding Quality: WPS/PQR approved; low-hydrogen control; electrode ovens (≥120°C) and quivers; interpass monitoring; weld maps.
NDT: 100% VT + PT/MT of attachment welds; UT/PAUT of butt seams where applicable; tell-tale pneumatic leak test; records signed by Level II/III.
Valve Testing: API 598 certificates and off-line hydro/seat tests prior to install where feasible.
Dimensional/Alignment: Branch axis tolerance ±1°; flange face parallelism ≤ 0.5°; bolt protrusion 1–3 threads; torque within manufacturer range.
Pressure/Leak Tests: Hydrostatic for branch at 1.5× design pressure [Verify]; soap test on flanged joints under line pressure; no visible leakage.
Cleanliness/Flushing: Swarf cleared; two consecutive clean discharges confirmed.
Documentation: ITP signed, NCR/CAR tracking, as-built redlines, coupon custody tag, calibration certs, final dossier.

Acceptance

Conformance to ASME B31.3/B31.9 and ASME PCC-2; all ITP hold/witness points passed; zero leaks; Client/Engineer acceptance.

Attachments

General arrangement and isometric drawings with hot tap location.
Calculations: d/D ratio, reinforcement area, t_rem vs t_required, bolt torque values.
Approved WPS/PQR and WPQ certificates.
OEM data sheets: hot tapping machine, cutter, pilot drill, valve.
ITP with signed checklists and hold/witness records.
NDT procedures and reports (VT, PT/MT, UT where applicable).
Hydrostatic/seat test certificates for valves/branch spool.
Calibration certificates (torque, gauges, UTM, IR thermometer).
Pre-job brief/TBT attendance sheet and permits (Hot Work, WAH, Electrical, Live System Authorization).
Risk assessment/JSA.
Environmental checklist and waste disposal manifests.
As-built redlines and final handover dossier index.

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ITP preview

The first inspection activities from the linked ITP for Method Statement for Hot Tapping Tie-In Connections on Live Pressurized Chilled Water (CHW) Piping:

Activity	Inspection / Test	Acceptance Criteria	Responsibility	Record
Design and feasibility review	Check d/D, t_rem, reinforcement calcs per ASME B31.3/PCC-2	Calculations approved; limits within code/company standards [Verify]	Welding Engineer / Client Rep (W)	Approved calc package
Material verification	Review MTCs/heat numbers for tee, branch, flanges, bolts	Materials match specifications/drawings	QA/QC Engineer	MTCs; material log
WPS/PQR and welder qualifications	Verify ASME IX qualifications	WPS/PQR approved; welders qualified for position/process	QA/QC Engineer	WPS/PQR; WPQ certs

Showing 3 of 15 inspection activities. View full ITP →

Related Inspection and Test Plan

An Inspection and Test Plan (ITP) is available for Method Statement for Hot Tapping Tie-In Connections on Live Pressurized Chilled Water (CHW) Piping. The ITP defines the inspection activities, acceptance criteria, hold and witness points, responsible parties, and records required to verify the work described in this method statement.

View the Method Statement for Hot Tapping Tie-In Connections on Live Pressurized Chilled Water (CHW) Piping ITP →

Frequently asked questions

Typical practice limits d/D to 0.5–0.6, subject to engineering calculations, pipe condition, and code/project requirements. Verify per project specifications.

No. The main line remains live. Hydrotesting is done off-line for the branch/valve assembly before installation where possible. Post-tap leak checks are performed on flanged joints under line pressure.

100% visual plus 100% surface PT or MT on attachment welds. UT/PAUT is applied to any full-penetration butt seams. A tell-tale pneumatic leak test verifies saddle integrity.

The pilot drill includes a coupon retention device (e.g., tapped pilot with catcher). The machine log records successful retrieval; the coupon is tagged and stored in the dossier.

Preheat 75–120°C and interpass ≤ 250°C for carbon steel, controlled per qualified WPS. Exact values must be verified per WPS and project specifications.

Method Statement for Hot Tapping Tie-In Connections on Live Pressurized Chilled Water (CHW) Piping – Method Statement