Total Shutdowns vs Under Pressure Drilling: Which Method is Best for Modern Pipeline Maintenance?

Live distribution pipelines are in constant need of repairing, inspecting, and maintaining. They are the service networks that keep us connected to crucial water and gas utilities, so their upkeep is crucial.

Traditional methods of maintaining these pipes meant stopping the flow through them while this essential work could be carried out. This leads to no service for customers for hours on end, and timely work for asset owners.

However, new methods and equipment can now be used to prevent a total shutdown of the entire system. These are much more efficient processes, temporarily isolating sections of a live pipeline instead of disrupting the service and leading to dissatisfaction.

In this article, we will explore why under pressure drilling is outperforming traditional total pipeline shutdowns to maintain the utility networks that keep the nation running.

What is a pipeline shutdown?

Shutting down a pipeline is a purposefully done method to stop the flow of materials running through a pipeline. This is often a scheduled stoppage to allow for routine tests, repairs, and general maintenance for regulatory compliance.

This method of repairing pipelines is usually the chosen operation when an exact size-for-size connection is needed. For example, when branching a new 200mm outlet from an existing 200mm main.

This is a particularly labour-intensive process that involves physically cutting out a large section of the pipe and manually dropping in a standard T-piece to restore line continuity. The connection must be exact to ensure there are no leaks or impacts on the water pressure. Shutdowns are also selected for developments that need specific flows running from their pipes.

The risks of shutdowns

A total pipeline shutdown is becoming less common due to its risks and negative impacts. Here are some of the main ones:

1. Shutdowns can cause transient pressure effects, also known as water hammer. This is a surge of water caused by a sudden change in the pressure within the pipe from the mains being depressurised and repressurised. Studies have highlighted the necessity to limit these water hammer effects where possible as they can lead to other network issues, such as leaks, pipe bursts and water quality issues.
2. A total pipeline shutdown deliberately cuts off  mandatory supply, leading to disruptive service interruptions for both asset owners and customers. Under certain circumstances, asset owners must pay compensation if supply is cut off temporarily.
3. After the maintenance and repair works are done on the shutdown pipe, it must be re-pressurised and restored. This is another costly process that extends the time that the water supply is down for customers and can involve many additional processes i.e. water quality checks, informing customers to flush water systems and run taps.
4. The de-pressurisation from the shutdown process changes the water flow and speed, leading to a disturbance of mineral deposits in the water pipes. This disruption leads to water discolouration, typically leaving a brown or white tint. Changes in the pressure can also trap air in the pipe, creating air bubbles and a cloudy tint to the water.
5. Shutdowns are a very expensive operation, involving large excavations with significant engineering involved including: large/deep excavations, shuttering, reinstatement costs and carbon impact, concrete thrust blocks and other civil engineering works.

What is under pressure drilling?

Under pressure drilling (also commonly referred to as hot tapping or pressure tapping) is a method of completing pipeline work while the system is still up and running by adding connections to the pipes without taking the entire pipeline out of service.

This process involves:

1. Preparing and cleaning the site area, taking measurements, and determining what equipment you’ll need
2. Mounting the correct fitting, under pressure tee and valve onto the fitting of the pipeline where the branch will be added
3. Pressure testing the setup
4. Drilling a suitably sized hole into the pipe, then retracting and isolating the drill safely
5. Attaching the applicable new fittings or assets on to the new branch connection
6. Completing relevant tests before putting the new asset into service

The advantage of under pressure drilling

This method of pipeline maintenance and repair is a strong alternative to shutdowns, specifically combatting the main disadvantages of shutting down an entire pipe system.

Perhaps most importantly, hot tapping minimises service downtime. Due to the nature of the process in adding another connection to the pipeline for the water or gas to flow through, it means that the service can continue while important work is being carried out on the pipe. Customers won’t experience any disruptions or issues to their supply.

The additional branch and continued service from under pressure drilling means there are little to no risks or any water quality or colouration issues, or transient pressures concerns. This keeps the water fresh and safe for consumption.

Under pressure drilling is a much quicker process with minimal excavation works needing to be carried out. With a smaller excavation footprint and less heavy machinery operating on-site, this brings down the total cost of the work to a much lower amount than the total for shutdowns and reduces overall carbon impact.

How can Hy-Ram Engineering help with under pressure drilling?

Using the right tools for hot tapping ensures the success of the process as an alternative to a total shutdown. It’s essential that the pipes won’t be damaged, operate efficiently, and maintain flow while repairs can be carried out smoothly.

At Hy-Ram, we offer a wide range of specialist under pressure drilling equipment for both service and mains branch drilling.

What’s the difference between mains and service under pressure drilling?

• Mains branch under pressure drilling: this refers to drilling into distribution main supply pipelines that carry large volumes of gas or water. Mains pipelines are typically larger in diameter and operate under higher pressure.
• Service under pressure drilling: involves tapping into smaller pipelines that connect the mains supply to individual buildings or properties. These pipes are smaller in diameter and usually operate at lower pressures, therefore they require different tools for hot tapping.

Both types of drilling require precision and safety, but mains drilling tends to involve more complex equipment and larger connections.

The DrillMaster Range

With 50 years of experience in the design and manufacture or equipment for the utility sector, we have refined a range of tools to meet the highest standards of quality and performance needed for under pressure drilling.

The DrillMaster drilling range is a major step forward in mains hot tapping technology, by making the process more efficient, safe, and reliable.

We are delighted to now be sharing the latest branch: the DrillMaster 12.

This product facilitates branch drilling up to 300mm (12”) of flanged connections, allowing for large-scale mains extensions of live pipelines. It features a compact and lightweight design that simplifies operations in tight trench environments.

Our range of quality tools for mains and service branch drilling also includes:

• DrillMaster Service 2.5: particularly useful when making connections through saddle straps, clamps and welded nipples where inserting directly into the main is not possible. For potable water connections up to 16 bar working pressure via 1 1/2″, 2″ & 2 1/2″ BSP threads.
• DrillMaster Branch 4: designed for drilling through 80mm & 100mm under pressure tees on potable water, including the Hy-Ram’s Hi-Flow Drilling Saddles. It’s compact and easy to handle, perfect for operations where space is limited. For potable water connections up to 16 bar working pressure.
• DrillMaster Branch 6: hand-fed and available with a range of cutters to suit metallic, concrete and plastic pipelines, with power source options of either electric/battery or hydraulic, depending on potable water or gas drilling operations. This branch drill is supplied as standard with 3 x flanges to suit 80mm, 100mm & 150mm NP16 connections and has optional Bell Housings where required. With 600mm of traverse, this drill is suitable for a large range of gas and potable water branch connections.

Evaluating pipeline repair methods

Overall, as a proven alternative to shutting down an entire live pipe network, hot tapping offers a better method to pipeline repair and maintenance works without the need for any service disruption.

Where a shutdown poses high risks of water hammer, discolouration, and concerns of pipe leaks or bursts, under pressure drilling masterfully preserves pipeline integrity and causes zero pressure transients.

When further comparing the staggering differences in costs, under pressure drilling is the clear winner for modern utility infrastructure management.

Partner with Hy-Ram for quality under pressure drilling tools

If you’re interested in learning more about investing in or hiring equipment in the DrillMaster range or need support with the calibration, maintenance, or repair of your pipeline equipment, get in touch with Hy-Ram today. Our team of experts is here to assist you with all your pipeline needs!