Line Freezing & Pipe Freeze Plugging Services
Line Freezing & Pipe Freeze Plugging Services – Keeping Critical Pipe Systems Online and Preventing Unwanted Shutdowns.

For over many years, Seven Seas Machinery’s has made it our business to keep critical pipe systems online and prevent unwanted shutdowns. As part of this commitment, we are proud to offer Pipe Freeze Plugging also known as Pipe Freeze Stopping. Freeze Plugs are an alternative option to our Line Stopping services and are designed to effectively isolate sections of pipe where valves are unavailable or inoperable. Through a combination of Seven Seas Machinery’s Hot Tapping , Line Stopping, and Pipe Freeze Plugging services you can be assured that your pipe systems will stay in service 24 hours a day, 7 days a week. Put us to the test and you will see why at Seven Seas Machinery’s, “We work best ? Under Pressure”.

Pipe Freezing

When no upstream valves are available, the only option for isolation is a freeze plug. Seven Seas Machinery’s well trained engineers and technicians have carried out many freezing projects over the last 15 years without a single plug failure or accident. Our excellent safety record is due to the fact that we constantly monitor all parameters such as temperature during the freezing process in real time to give our engineers a clear picture of what is happening in the line during the freezing process.

How it works

Pipe freezing involves the use of liquid nitrogen in the controlled formation of a solid ice plug inside the pipeline using specialist equipment and techniques. Once formed, the plug is able to withstand very high differential pressures and provide reliable and effective isolation of the line while modifications or repairs are carried out./span>


An effective means of system isolation, freeze plugs are developed within the pipe system through the application of CO2 or liquid nitrogen. The cryogenic process begins with heat being drawn from the product inside the pipe until it reaches a temperature below its freeze point. Once an established freeze plug is formed, the Seven Seas Machinery technicians will monitor the flow of liquid nitrogen to maintain the proper sized plug based on known system parameters.

In order to establish an effective freeze plug, it is critical that the system has no flow and the freeze plug must be an established distance from any flowing pipe branches or headers. In the event that systems can not be blocked in or flow must be maintained, consider Seven Seas Machinery Line Stop Services as a safe and effective alternative.

Can be used to perform any of the following routine system modifications
  • Valve Installations
  • Pipe Section Replacement
  • Equipment Isolation
  • Pipe Branch Terminations
  • Pipe Relocations
Details Application

Pipe freezing has many applications in a variety of industries, including nuclear and fossil power generation, offshore oil and gas production, refineries and petrochemical plants.

Single or multiple freeze isolations can be applied on-line in pipes up to 48″ in diameter, to allow:

  • Valve repair/replacement
  • Pipe modifications/maintenance
  • Miscellaneous intervention procedures
Pipe Freeze plug service benefits

Pipe freezing is widely acknowledged as a safe, reliable and highly cost-effective method of temporary pipe isolation and as a result offers a number of major benefits:

  • No need to drain down systems, thus avoiding costly and time-consuming venting procedures.
  • No need to arrange for the bulk transfer or storage of possibly toxic or corrosive fluids.
  • Cuts losses of expensive liquids, such as treated water and systems inhibitors.
  • Overcomes the problems of handling hazardous materials and enhances safety when working on lines containing contaminated or volatile liquids.
  • In many cases pipe freezing allows maintenance work to be carried out without interruption to continuous process systems.
Freezing can be suitable for the following pipe materials.
  • Stainless steel pipe
  • Carbon steel pipe
  • Copper based alloys
  • Aluminum alloys
Suitable for use on a wide variety of pipe materials and contents, including:
  • Carbon Steel
  • Nickel Alloy
  • Copper-based Alloys
  • Kunifer
  • Aluminium Alloys
  • Stainless Steel
Typical Pipe Freeze applicacion includes:
  • Cooling Water
  • Fire Protection Systems
  • Process Systems
  • Fuel Oil Lines
  • Sludge Lines
  • Hydraulic Control Lines
  • Domestic/Utility Water Systems
  • Hydrocarbon Risers
  • Water Injection Lines
  • Drill Pipe Sea Water Ballast
  • Heat Exchanger Lines
  • Boiler Feed and Condensate Systems
  • Lube Oil/Governor Oil
  • Pressure Vessel Cooling Systems
  • Chilled Water Systems
Controlled Isolation
Seven Seas Machinery’s controlled pipe freeze isolation technique uses gaseous nitrogen and ensures that the equipment is not taken outside its design limits, reducing the risk of embrittlement. The freezing jacket provides an annulus around the pipe into which gaseous nitrogen is introduced, with no direct contact between the gaseous nitrogen and the pipe.
Advantages of Pipe Freezing
  • Avoid massive draining of fluid.
  • System shut down is not required.
  • Minimize manpower is required.
Typical Pipe Contents
  • Water
  • Acids
  • Coolants
  • Paints
  • Alcohols
  • Oils
  • Liquid Food Products
  • Various Chemicals
Quality and Safety
Seven Seas Machinery’s standard pipe freezing procedures specify the use of personal oxygen monitors for all pipe freezing personnel, to guard against the risk of oxygen deficiency due to vented nitrogen gas. The pipe freezing process is fully controlled by formal written procedures which form part of Seven Seas Machinery’s ?fs ISO9001 quality control system. All cryogenic equipment is regularly inspected, maintained and certified, to statutory requirements (and beyond where necessary).
Pipe freezing can be used to perform the following system modification

1. Valves installation on existing pipe line.
2. pipe relocation
3. Line isolation.
4. Pipe line termination.

Seven Seas Group

Prominent at providing full range of services to meet our customer needs.
  • P.O. Box: 36796 Dubai - U.A.E.
  • Tel.: +971 4 2858758
  • Mobile: 508103399
  • Fax: +971 4 2856608