Technical Information
The 'Zap-Lok®' ConnectionThe technology is a mechanical (as opposed to welded) pipe joining system which utilises metal to metal interference fit of the pipes being joined. The pipe joint has excellent structural integrity and will not leak or separate when subjected to the same conditions as a conventional weld.
Pipelines constructed with Zap-Lok® joints have been used to carry a wide range of gas and liquids:
- Crude and refined oil
- Refined petroleum products
- Liquid Petroleum Gas and Natural Gas Liquids
- Natural Gas including sour gas
- Carbon Dioxide
- Water and Steam
- Nitrogen
- Salt Water
- Potable Water
The Zap-Lok® connection is a widely used mechanical interference joint for pipeline use. The joint has pressure, mechanical and fatigue strength suitable for the same service as welded joints, but the cost of making and inspecting Zap-Lok® joints is lower.
Typical applications include gathering and distribution systems, transmission lines and specialized pipe installations on land and offshore. Thousands of miles of pipe have been joined using the Zap-Lok® process under a wide range of operating conditions. Zap-Lok® pipe joining machines have performed on virtually every type of terrain, under severe weather conditions and in hostile environments. They have been used to install portions of offshore pipeline systems and in joining both internally and externally coated pipe.
The Zap-Lok® process begins with a bell, or expanded area, which is formed on one end of a joint of pipe, and a groove which is formed on the opposite end. This part of the process occurs at a Zap-Lok® location, pipe mill, or coating plant. These end preparations are automatically controlled to specifications required for the Zap-Lok® joint. In the field or on the work barge, Zap-Lok® field equipment is used to hydraulically press together the belled end of one length of pipe and grooved end of another with a thin coating of Zapoxy serving as a lubricant/sealant. Once the lubricant/sealant cures the result is a metal to metal interference fit connection made of the pipe itself.
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The Zap-Lok® process produces strong, permanent joints which can be used in the same pressure service as welded lines. This allows the pipeline system design to be based on 100% joint strength. Extensive independent evaluations under varied laboratory test conditions and in-service performance records have proven the Zap-Lok® joint to be strong, reliable and leak proof for onshore and offshore use. Special tests commissioned by several oil companies such as Chevron and Perenco confirm this. The Zap-Lok® method can be used to join thin wall pipe which cannot be easily welded; and the Zap-Lok® joint can carry corrosive fluid without the vulnerability of threaded couplings, or damaged internal coating resulting from high temperature produced by welding.
Pipe ends can be prepared at the pipe mill, coating plant, pipe storage yard, or at the job site and then joined by a hydraulic Zap-Lok® unit in the field. Thin wall pipe can be joined by the Zap-Lok® method in cases where welding would not be feasible. The Zap-Lok® process requires less equipment and labour than conventional welding. It requires no special installation procedures or unusual auxiliary equipment. The Zap-Lok® pipe joining unit (Zap-Lok® Press) is carried by a side boom tractor or mounted on a lay barge. A small field crew is required to lay pipe and only one trained technician is required to operate the Press. Weather delays in construction are minimized because the process can be used in more extreme conditions then welding. All Zap-Lok® equipment is very safe to operate. No hazardous or toxic emissions are made by using Zap-Lok® equipment.
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All of the Zap-Lok® pipe preparation and field joining equipment is easily transported in a standard 40ft container.
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The Zap-Lok® Connection complies with US and Industry Regulatory Codes
- DOT 195 and 192
- ANSI B-31.4
- ANSI B-31.8
- Installations in the US offshore MMS jurisdiction started in May 2004
- NACE MR 0175/ISO 15156(2003) for H2S Service