Hot Tapping
Hot tapping, also called pressure tapping or live tapping, creates a new branch connection on a pressurized pipeline, tank, or pressure vessel without shutting down or depressurizing the system. A fitting (often a welded split-tee or mechanical sleeve) and an isolation valve are installed, then a tapping machine cuts a circular coupon from the pipe wall under controlled conditions. The coupon is kept, the cutter is removed, and the valve is closed to place the new branch in service.
Where it’s used: Oil & gas, petrochemical, water, district energy, and industrial plants, anywhere continuity of service matters. Industry guidance (e.g., API RP 2201 on petroleum and petrochemical facilities) exists regarding hot tapping.
Pros
- No service interruptions or product losses.
- Lower environmental impact (no venting/draining).
- Facilitates phased expansions, bypass, or instrumentation tie-in.
Limitations
- Needs expert machinery and qualified and certified staff.
- Tight engineering conditions (materials, pressure/temperature, fluid, wall thickness).
- Live line welding should be in accordance with applicable codes/standards.
Hot Tapping Process
In P water and municipal utilities, wet tapping refers to tapping a pressurized main (often via a tapping sleeve and valve) to add a new service or branch while the main stays in service. The sleeve is clamped or bolted around the main, a tapping valve is mounted, and a machine drills the opening; the valve is closed and the machine removed—no drainage or shutdown required. This approach also minimizes exposure pathways for contamination during potable water work.
Where it’s used: Potable water, reclaimed water, and industrial water systems where public health and service continuity are paramount.
Pros
- Avoids customer outages; helps maintain water quality by limiting intrusion pathways.
- Versatile—accommodates a wide range of pipe sizes and materials with the right sleeve/valve set.
Limitations
- Requires proper sleeve selection and torqueing to avoid leaks.
- Clearance and excavation constraints can impact feasibility.
- Corrosion/condition of the host main must be verified.
Cold Tapping
Cold tapping is performed on a depressurized or drained main, commonly during new main installations, outage windows, or planned maintenance. The crew exercises and taps the hole, connects the connection (corporation stop or branch fitting), and restores the system to service after the test and disinfection (in case of the drinking water).
Where it’s used: Projects where shutdowns are feasible and preferred (e.g., subdivision build-outs, capital replacements).
Pros
- Reduced risk profile as opposed to live work.
- Often, lower direct costs for small service connections.
- No coupon-retention requirement on live product.
Limitations
- Requires outage coordination and customer notifications.
- May trigger flushing/disinfection programs (water) before service return.
Direct Tapping
With direct tapping, threads are cut directly into the pipe wall, and a corporation stop (or similar outlet) is screwed into place, typically for small-diameter service taps. Appropriateness varies based on the material of the pipes, the class/wall thickness, and standards such as guides that limit the maximum outlet sizes allowed in PVC pressure pipe, and direct taps are restricted to certain DR classes, and ductile iron usually allows tough direct taps.
Where is used: Small services (e.g., ¾”–1″)on materials that allow threaded outlets per AWWA/manufacturer guidance.
Pros
- It is Cost-effective and fast for small connections.
- It has minimal hardware with no external saddle when the host pipe qualifies.
Limitations
- Strict outlet size and permitted pipe classes/DRs; not applicable to all materials (e.g., many PVCO pipes). Instead, in such circumstances, use a saddle or sleeve.
Saddle Tapping
A service (or tapping) saddle wrap encircles the main and offers a reinforced outlet boss where the corporation stop is fitted. Where the host pipe is thin-walled, older, or where the local standards forbid direct threads, saddles are used. They assist in the distribution of loads and the minimization of split piping or running threads.
Where it’s used: Older cast iron, asbestos-cement, PVC/HDPE, where direct taps are limited; small branches typically up to ~2″.
Pros
- Enhances the bonded fibre; safeguards the host pipeline.
- Broad product range for different materials and diameters.
Limitations
- More components and installation steps than a direct tap.
- Saddle design and pipe pressure class permit the outlet size to be limited.
Tapping Sleeve & Valve (TS&V)
A tapping sleeve and valve assembly (often known as a tapping tee plus gate valve) can provide larger connections in a branch, even to almost the size of the host main. The sleeve is applied around the pipe with a flanged outlet; a tapping valve is attached to the flange; the cut is carried out under pressure by the tapping machine; the valve is closed. This is the customary system of big wet taps.
Where it’s used: Larger outlets, bad condition of host pipes where reinforcement is necessary, and connections on PVC/HDPE systems where sleeve length augments hoop strength.
Pros
- Handles larger branches than direct/saddle taps.
- Stable, sealed connection across many pipe materials.
Limitations
- Higher material cost and installation complexity.
- Needs to be carefully aligned and sealed with gaskets to prevent leakage.
Line Stopping (Related Method)
While not strictly a tapping method, line stopping (line plugging) is often paired with a hot tap. The process begins with a hot tap and temporary valve; a larger hole allows insertion of a stopping head to isolate a section of the main for downstream repairs, tie-ins, or valve replacements without shutting the entire system. Once work is done, the stopper is removed and the line is returned to service.
Where it’s used: Scheduled valve replacement, emergency leak containment, and intricate tie-in with temporary isolation.
Pros
- Provides bypass creation of a temporary isolation whose flow is maintained.
- Minimizes outage scope and risk, as opposed to complete shutdowns.
Limitations
- Needs special fitting and equipment.
- Engineering care is required to cope with loads and provide a leak-tight seal.
Read more: Hot Tapping vs. Line Stopping: Which Pipeline Shutoff Method Works Best for Your Project?
How to Choose the Right Method
In choosing a tapping method, engineers consider:
- Service continuity: If outages are unacceptable, choose hot/wet tapping or line stopping.
- Pipe material & class: Check allowable direct-tap sizes and DR/pressure limits (e.g., PVC guidance; DI capabilities). Branch size: Larger branches typically require a tapping sleeve & valve rather than direct or saddle taps.
- Host pipe condition: Older or thin-walled mains often need reinforcement via saddles or sleeves.
- Standards & compliance: Follow applicable codes such as API RP 2201 (petroleum hot taps) and relevant AWWA/manufacturer procedures for municipal systems.
Why PTS Group?
PTS Group delivers industry-leading hot tapping, line stopping, power stop, uni-valve, cold cutting, and pipeline maintenance services, combining proven field expertise with equipment engineered to domestic and international standards. We have hot tapping machines (hydraulic or pneumatic) that allow you to safely, accurately, under-pressure drill oil and gas, water, sewage, and chemical pipelines, preventing shutdowns and keeping vital operations online.
If you’re planning a connection, tie-in, or isolation, our team can help you assess feasibility, choose the optimal method, and execute with uncompromising safety.
Key Takeaway
- Hot/wet taps keep systems live for new branches.
- Direct taps are fast and economical for small services when allowed by material and class.
- Saddles and tapping sleeves & valves reinforce the connection and enable larger outlets, especially on PVC/HDPE or older mains.
- Line stopping isolates sections for complex work without full-system shutdowns.
Selecting the right method isn’t just about making a hole; it is about engineering a safe, standards-compliant, and reliable connection that fits your pipe, product, and operations.
