Mechanical isolation tool

Simple. Safe. Smart.

Explore the AOGV in action now and discover how it provides positive isolation while maintaining system integrity.

Postponement of planned shutdowns and required maintenance increases the risk of unwanted incidents and longer shutdowns down the road. Now there is a solution that doesn’t require shutdowns or postponement of maintenance – in fact using Izomax, process and production flow can continue whilst performing critical maintenance!


Isolation without shutdown

The patented AOGV mechanical isolation system installs a barrier/blind and thus achieves positive isolation between a flange pair on a pressurized system whilst in continuous operation. Unlike hot tapping and line stoppling or alternative isolation technologies, the AOGV allows our customers to safely isolate process segments for inspection, maintenance, or repair without a cashflow shutdown!


With the Izomax patented AOGV mechanical isolation system you put the isolation points closer to the problem. By reducing the impacted work area, you reduce maintenance time without the need for hot work. Our approach normally removes the need for drainage, venting, purging, and flushing – with a significant and measurable reduction in environmental emissions – meaning an important reduction in your carbon footprint!

No permanent impact

The AOGV provides positive isolation without any physical modifications or lasting impact to the process plant. Once the operation is complete, the flange pair is returned to its original state with a new gasket, bolts, and nuts. The AOGV mechanical isolation system removes the need for costly and time-consuming redesigns, new plant certification or new facility drawings.

AOGV application versatility

Repair and modifications
of parts of process facilities

Retrospective installation
of equipment

Installation, repair, or
replacement of valves

Emergency plant
and piping repairs

No Hot-Work

No permanent
modifications to plant

AOGV = pure OPEX sense

The Izomax value proposition is easy to see and more importantly, savings are measurable.

Our portfolio of successfully completed projects covers a wide range of shapes and sizes across onshore and offshore facilities – from refineries to LNG terminals as well as offshore platforms and vessels. We regularly receive customer feedback on savings between $2 – $20 million USD per project as a direct result of utilizing the AOGV mechanical isolation system.

Moreover, the AOGV adds flexibility to your maintenance strategy, whilst providing certified lifetime extension for your process plant, refinery, or oil & gas installation.

The AOGV Mechanical Isolation System enables full utilisation of functional plant redundancy to keep the main process running

AOGV Fleet

The AOGV – Add on Gate Value, is a field proven patented technology which
inserts an isolation spade on a live flanged connection thereby reducing down
time and eliminating the need for extensive isolation activities

X-(CL 1500)
X-(CL 1500)
X-(CL 900)
X-(CL 1500)
X-(CL 600)
The AOGV can handle a range of gaskets: Fiber, Spiral Wound, RTJ, CAF..

Check points for choosing AOGV

The AOGV provides positive isolation without any physical modifications or
lasting impact to the process plant.

Positive isolation

AOGV is the most secure method
for energy isolation. It facilitates
both spool removal (“air gapping”)
as well as blind isolation.

Pressure monitoring

The pressure within the AOGV is
monitored and safeguarded
throughout the job. Should an
unsafe situation arise, work can be
stopped at any point.

Reduce risk

Unlike temporary isolation plugs, with the AOGV there is no risk of plugs blowing out.

The AOGV also covers a wide range of materials including at cryogenic temperatures where conventional freeze plugs are less robust

Track record

The AOGV has been successfully used
in the field in sizes from 1” up to 36” and
on pressurized hydrocarbon systems up
to 2,175 psi. Workshop testing has
verified operation at temperature
ranges from -261 F to +392 F.


At what temperature and pressure can the AOGV be used?

  • Temperature range: – 280°F to + 400°F (-173°C to +200°C)
  • Pressure range: up to 2500 psi (175 bar)

For which sizes of pipes and pressure class combinations can the AOGV be used?

We focus on the ASME class 150 & 300 in sizes from 1” to 24” but have tools that can handle sizes up to 36” ASME and up to class 2500. Please see our tool fleet at for available off-the-shelf sizes and class combinations. Our tool fleet is continually expanding, so contact us if you don’t see the size or class you require.

How much clearance does the AOGV need either side of the flange to be installed?

As a rule of thumb, for pipes from 1”to 4” the AOGV needs 2” of clearance and from 5” and upwards a 1/2 pipe diameter is needed. The distance required is measured from the bolts and nut side of the flange.

How does the AOGV seal the full circumference of the flange and bolt holes?

The seal is pre-energised, acts as a plug, and seals directly from the circumference surface all the way inside the AOGV. The bolt holes are also plugged with mechanical plugs bolted to the AOGV kit. The seal is typically an elastomer to make sure uneven surfaces can be sealed properly

Can the AOGV be fitted on the flange of a 3-piece valve?

The AOGV can be fitted on most valve types and nozzles including 3 piece valves.

Does the pipe have to handle the weight of the AOGV?

For some of the smaller sized AOGV’s the pipe can easily handle the weight, but to mitigate any stresses, common practice is it to suspend the weight of the AOGV in chain hoists attached to a superstructure or scaffolding above the AOGV.

What about the condition of my flange?

When the Izomax team set up the AOGV on-site, we remove your old gasket at the beginning of the operation and replace it with a new gasket at the end. So far, every operation has been successfully executed with a new gasket installed and system successfully recommissioned and sealed.

How are the flanges split after the AOGV has been installed?

Either the system pressure is used for splitting the flanges or the pipe is gently moved physically e.g. with chain hoists to pull them apart. The stress tolerances are calculated for the displacements, and we analyze which location is most suitable for minimised displacements.  The movement itself is carefully controlled and monitored by gradually releasing the compression exerted from the integrity clamps.

How is the AOGV different to traditional technologies such as hot tapping and line stopping?

Hot tapping and line stopping typically requires bulky equipment to perform interventions, which can be challenging depending on plant dimensions and access. The AOGV tool can be oriented at any point around a flange to help overcome accessibility challenges. Unlike hot tap and line stop, the AOGV does not permanently modify the plant or piping. When using the AOGV, there is no need for fittings. In addition, the AOGV mechanical isolation system provides a positive isolation whereas traditional methods typically only provide a workable temporary seal.

Does the Izomax AOGV Mechanical isolation system require hot work?

No. The AOGV is a mechanical isolation tool that does not require hot work. This is a major difference to hot tap and line stopping, which normally requires hot work, with the intensive planning, cost and associated risk.

How does the AOGV compare to possible alternatives such as line freezing?

The AOGV approach does not permanently modify plant, and neither does line freezing. However, line freezing does not provide positive isolation or a robust metallic isolation. The AOGV provides positive isolation without the risk of line freezing and in-line isolation.

Is Izomax the only service provider offering positive isolation as an alternative to hot tap and line stopping?

Izomax has a patented mechanical isolation tool which is currently the only system available in the market.

Why is the AOGV considered superior as a technique compared to plugs or smart plugs?

Plugs do not provide a positive isolation. Plug failure is considered a potentially catastrophic risk. The AOGV mechanical isolation system is certified, well proven and provides a positive isolation which can be tested and confirmed, whilst avoiding the risks of plugs becoming irretrievable.

Does the AOGV allow vessel entry?

Yes. The AOGV sets a positive isolation, allowing vessel entry or any other work beyond the positively isolated line. Hot tapping and line stopping does not allow vessel entry in the same safe manner.

Can the AOGV be used on Butterfly and Gate Valves?

Yes – the AOGV is designed to be used as a positive isolation blind on any flanged pair irrespective of whether Butterfly, Ball or Gate valves are in place.

Can more than 1 AOGV can be installed in a system, for example on both sides of a damaged valve?

Yes. Where required, multiple AOGV’s can be installed in a system. A single AOGV can be used to set multiple blinds in a system, but in cases where time or technical constraints need to be considered, several AOGV’s can be utilized to install blinds throughout a system.

Is the AOGV considered best practice as an alternative to Hot Tapping isolation techniques?

Several NOC’s and supermajors have approved the Izomax mechanical isolation system for use in their plants offshore and onshore. The Izomax team work engineered solutions to ensure that the AOGV is the best solution available, and are transparent in their approach. If the AOGV is not the best approach, the Izomax team will communicate this to the customer as part of our standard project evaluation process.

Which inventory/fluid types is the AOGV compatible with?

The AOGV is safe for use with many fluids, including water, sea water, LNG, Oil, Gas, Butane, CO2, Nitrogen, Glycol and several others. The AOGV seals can be tested with non-standard fluid compositions to ensure compatibility. The Izomax AOGV mechanical isolation system has been used with a wide range of fluids at pressures up to 2500 psi, with temperatures ranging from cryogenic to +392 degrees Fahrenheit