Lokring is a mechanical method for producing permanent weld equivalent pipe connections, eliminating the need for hotwork and the associated health and safety issues.
Lokring are patented fittings, they are permanently join small diameter nominal pipe size (1/4 thru 3) and tube (1/4" thru 2") without threading or welding.
Following insertion of the pipe or tube end into the fitting, hydraulic tooling is used to advance each swage ring axially over the fitting body, radially compressing (swaging) the fitting body on to the outside diameter of the pipe or tube.
The leak-free seal is the result of LOKRING's ESP installation where the axial movement of the LOKRING driver over the body swages the body onto the pipe's surface. This compresses the pipe wall first elastically and then plastically.
The pipe wall resists this swaging action, generating high unit compressive loads at the contact points between narrow sealing lands inside the fitting body and the pipe surface.
These contact stresses are sufficiently high to plastically yield the tube surface under the sealing lands, forming a 360° circumferential, permanent, metal-to-metal seal between the pipe and fitting body. The driver, which experiences a small increase in diameter (elastic strain) during installation, exerts an elastic, radial pre-load on the metallic seals for the use of the connection.
LOKRING meets or exceeds the following technical specifications, standards and approvals..
American Bureau of Shipping (ABS)
American Petroleum Institute – API-607 Rev 4 Fire Test
ANSI/ASME B31.1, B31.3, B31.4, B31.5, B31.8, and B31.9
Association of American Railroads (AAR)
British Ministry of Defence
California Air Resources Board (CARB)
Canadian Registration Number (CRN) • OA1195
Canadian Standards Association (CSA) Z7396 1-09
DNV TA – Product Type Approval for elastic strain preload (ESP ™ ) SS40, MAS-3000 and CN Product lines
ISO 9001:2015 – Issued by DNV GL – Business Assurance
National Fire Protection Association, standard for health care facilities (NFPA 30)
NSF 61 and 372 Certifications for Potable Water Fittings
United States Coast Guard
NFPA 99: Health Care Facilities Code, 2012, 2015 and 2018 Editions.
Louisiana Department of Environmental Quality (LDEQ)
Source February 1, 2022
Lokring products can bring significant benefits in both new installations and maintenance applications, enabling pipework installations up to 70% faster and cost saving of up to 70% compared to welding.