FAQs – Installation

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.

Can I use a grinder or a disc grinder to prepare the pipe end?

Do not use a grinder or sanding disc to prepare pipe for Lokring installation. The use of a grinder or disc sander may leave uneven or flat spots on the pipe. This is unacceptable for Lokring pipe preparation.


What happens if the pipe falls through the NO GO slot in the gauge tool?

This indicates that the pipe does not meet typical size requirements. The pipe is either under-sized or oval.


What happens if the pipe does not fit in the GO in the gauge tool?

This indicates that the pipe does not meet typical size requirements. The pipe is either over-sized or oval.


Can there be a gap inside the fitting between the ends of the pipes (or between the pipe end and the stop)?

Yes, it is not necessary for pipe ends to be flush. The Lokring install and inspect marks help to verify the proper installation.


Does the pipe need to be sanded to the metal level if it has paint on it?

Yes. To ensure proper installation, the paint should be sanded and removed from the pipe.


Can you use a pipe mule to cut the pipe like it is done for a weld?

When a pipe mule is used to hold the pipe, care must be taken to avoid grasping the pipe within 1.5 pipe diameters of the ends. This will ensure that the pipe does not have bite marks under the Lokring sealing lands.


Are you supposed to allow for system expansion similar to socket welding?

This is not necessary. Lokring fittings are installed, and hanging requirements are the same as a welded system. Lokring does not require the back-off requirements of a socket welding. Because leaving space is unnecessary, Lokring design has superior flow path characteristics and still meets all hanging requirements similar to welding. Lokring provides a specific document for hanging and stress details. A Guideline for Designing ASME B31 Pressure Piping Using Lokring Elastic Strain Preload® (ESP®) Fittings.

NOTE: Other fittings don’t always meet the hanging requirements thus creating leaks, sagging pipes, and eventually, much higher costs.
How close can I weld/braze to a Lokring™ fitting?
Prior to installation, welding can be performed within 1 pipe diameter of the Lokring connection. To prevent the ESP® technology from compromise after the fitting has been installed, welding should not be performed within close proximity of a Lokring fitting (an exact distance cannot be established due to large process variations). It is important to minimize any differential heating to the fitting-pipe interface.


How much room is needed for the tooling?

See Lokring Fitting Installation Instructions (LP-105), available from your authorized Lokring sales and service representative.


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 if the driver comes off prior to installation?

The fitting can either be returned to Lokring, or the driver can be lightly tapped back in place. Drivers are pre-installed at the factory to simplify the installation. This pre-install is a light press fit that can result in the driver rings dislodging if the fitting is handled roughly. If the driver comes off, it may still be re-installed and the fitting installation may still be completed successfully.


What if the outside of the pipe is pitted?

Proper pipe sanding and preparation can result in an acceptable installation. Pitting is not as much of a concern as long, longitudinal scratches which must be removed prior to installation.

It is difficult to answer this question without examining the exact condition of the pipe. However, if the outside diameter of the pipe/tubing is within specification, and the surface cannot be prepped to proper standards, then the use of an anaerobic sealant such as Loctite® PST® may be used to assist in the sealing. Due to the many variables involved, adequate performance of the assembly cannot be guaranteed by Lokring.


What if the connection leaks?

Lokring’s patented design assures significantly less leakage in its connections (virtually none) than in welded joints. However, if necessary, a Lokring™ fitting can be cut out and replaced. With our patented design, slip-fitting another fitting of longer length or installing a “T” is no problem. In addition, stainless steel and microalloyed steel fittings can be back-welded. Contact your authorized Lokring sales and service representative for support.

NOTE: Repair couplings, made without a center pipe stop, make repairs easier when pipes cannot be easily moved.