FAQs – Testing, Inspection and Tools

The following frequently asked questions (FAQs) address situations involving installation.  If you don’t see the question that addresses your concern, we have other FAQs that could assist you.


Does a Lokring installation need to be x-rayed?

Lokring fittings do not need to be x-rayed after installation. The install and inspect marks assure proper fitting installation.


If my specs require the welds to be X-rayed, how about Lokring welded fittings?

In order to provide the best possible product for customer applications, Lokring manufactures many of our “shapes” such as elbows tees and flanges in a modular fashion by welding our proprietary ends to commercially available and approved components. Visual examination of these welded fittings is performed in accordance with the Boiler and Pressure Vessel Code, Section V, article 9. In-process examination is performed by personnel other than those performing the production work according to ASME B31.3, paragraph 342.2. Records of visual examinations are maintained as specified in ASME B31.3 paragraph 344.7.

NOTE: Chapter VI in ASME B31.3, Examination, Inspection, and Testing requires visual examination of welds and 5 % spot radiography. The requirement for spot radiography can be replaced with documented in-process examination in accordance with paragraph 344.7. Chapter VI in ASME B31.1, Examination, Inspection, and Testing allows for visual examination of welds only, for applications under 750 °F (398 °C) and wall thickness below ¾ inch (19 millimeters) thickness. If a customer has an application with stainless steel fittings for use in a temperature range above 750 °F (398 °C), they should specify our stainless steel SS-3300 line of fittings that do undergo 100 % radiographic examination.


How do you know that the Lokring fitting installation is good?

Once the fitting has been installed, you can visually verify that the pipe is located in the correct position within the fitting by viewing the Install and Inspect marks. The purpose of the install and inspect ovals is to establish the correct positioning of the pipe within the fitting. After appropriate pipe preparation and installation of the fitting, there are four keys to verifying a good installation. You should see…

1. the full INSTALL mark
2. a partial INSPECT mark
3. the fitting body protruding from underneath the driver
4. the driver brought up to the fitting body’s flange tool with no more than a small gap between them


What happens if the fitting is complete and the entire “inspect” oval is showing?

This indicates an improper installation. The fitting must be removed or back-welded.


What happens if there is “daylight” showing when the pipe should be bottomed out in the gauge tool?

When daylight is showing in the gauge tool, it indicates that the pipe ends have not been cut within the 5 degrees of square required for a proper Lokring installation.


How often do the tools need to be serviced?

Tools should be maintained on a regular basis. This regular servicing requires lubrication, proper tension on the shoulder bolt, and visual examination of all inserts and moving parts. Proper maintenance of the tools will allow for years of performance. If major repair or servicing is required, contact your authorized Lokring sales and service representative.


Why do you have to “cycle” a hydraulic tool?

In order to verify the proper function of the hydraulic tooling, the equipment should be cycled once; this assures that the tool moves smoothly and that there is sufficient hydraulic fluid in the pump to complete the installation.


What tools are needed to do ¼ to 3-inch fittings?

Lokring offers a variety of installation tools and kits. MTK multiple-size kits or ITK individual kits are available based on fitting size. Tool kit selection can be tailored to customer requirements depending on fitting sizes being installed.


Does the system need to be “hydro-tested” after a Lokring installation? NOTE: “Hydro-tested” refers to hydrostatic testing with liquid (typically water) at 1.5x the rated design pressure.

The systems may require inspection according to ASME standards following a Lokring installation. The standards are located in Chapter VI Examination, Inspection and Testing. The tests for B31.1 and B31.3 vary. Possible tests include but are not limited to:

1. Visual
2. Hydro test
3. Gas leak test using air or helium etc.
4. In-service test

A hydro test specifically calls for water, a specified fluid, or test medium. In some cases, it may not be advisable to introduce water into the system due to the piping service.