Bag Off Isolation

Bag and balloon isolation gives you a temporary stop inside a live pipeline using an inflatable bag rather than a mechanical plug. The bag goes in through a fitting, inflates against the bore, and holds the product back while you work. We use it where a mechanical stop or the EZ2 valve system can’t be used.

Call 1800 468 827 with your pipe size, material and what’s in the line, and we’ll tell you whether a bag will hold it.

What is bag or balloon isolation?

It’s a form of line plugging. An inflatable bag, sometimes called a balloon or a bladder, is inserted into the live line through a hot tap fitting and inflated until it seals against the pipe wall. The flow stops, you get your work window, and once the job is done the bag is deflated and withdrawn.

Nothing is drained, and the pipe is left as it was. There’s no permanent fitting left behind unless you want one.

When is a bag used instead of a mechanical stop?

When the pipe or the situation won’t take a mechanical plug. That covers a fair range: sizes outside the EZ2 envelope, pipe geometry that won’t accept a rigid stop, thin or aged wall where a mechanical stop would be a risk, and gas work where a bag is simply the established method.

We can offer balloon or bag off isolations on live pipelines where the EZ2 system cannot operate. That’s the honest way to describe it: the EZ2 is the better answer where it fits, and bagging covers the rest.

Is bagging used on gas lines?

Yes, routinely. Bag insertion is one of the four techniques behind a live gas diversion, alongside live tappings, squash offs and purging. On gas installations we have been accredited to work live since 1998, when Australian Hot Taps became the first company accredited by the Office of Gas Safety, now Energy Safe Victoria, to hot tap and stop off live gas lines.

What pipes and contents can be bagged?

We work on steel, stainless, copper, PVC, HDPE, PE, cast iron, ductile iron, cast and ductile cement lined, AC and most other pipeline materials, carrying natural gas, coke gas, chilled water, heating hot water, potable water, condenser water, steam, compressed air, chemical, petrochemical and various waste product lines.

Every pipeline gets ultrasonic NDT wall thickness testing before we weld or tap it. If it’s too thin to weld on, we’ll tell you before we start.

Bag, mechanical stop, freeze or squash off?

Four ways to stop flow, and they suit different lines. A mechanical line stop inserts a rigid plug through a fitting. Live valve insertion with the EZ2 leaves a permanent valve instead of a temporary stop. Pipe freezing forms an ice plug with liquid nitrogen and puts nothing on the pipe at all. A squash off closes the bore by squeezing the pipe flat.

Bagging sits between them. It’s less permanent than a valve, less invasive than a squash, and it works on lines where a rigid plug won’t seat. Describe the job to us and we’ll tell you which of the four we’d use and why.

What helps us quote it

What the bag has to seal against, and at what pressure, decide whether bagging suits the line at all:

• Pipe size and material
• What’s in the line, and at what pressure
• Whether flow can be reduced or stopped upstream
• How long the isolation needs to hold
• How you get to the pipe. Above ground, in a riser, or buried and needing an excavation
• Any drawings or photos

Call 1800 468 827 or email [email protected]. If you’re not sure whether a bag will hold your line, just give us a call, we’ll ask a few questions and let you know.

Where we work

We operate from depots in Bayswater, Victoria and Currumbin Waters, Queensland, and we have clients in all states and territories of Australia as well as the Pacific Islands and New Zealand. We regularly fly in and out to service our clients.

Bag and balloon isolation is one of the live pipeline services we provide. We also offer hot tapping, live gas diversions, leak repair under pressure, thermowell installation and testing and purging.

Where bag and balloon isolation suits the job