6-Steps to Safer Mechanical Squeeze-Offs
Be sure to observe your company’s safety procedures concerning static electricity and controlled release rate for the PE Pipe being used.
Know Your Tools
Before using any manufacturer’s squeeze tool, familiarize yourself with its construction, its design, its special features, and learn how to use it. Operating procedures for mechanical tools differ from hydraulic tools, and also differ between manufacturers. Knowing how to properly operate the squeeze tool you are working with is essential to your safety, and to achieving satisfactory results.
Know Your Pipe
Identify the size and the SDR number of the PE pipe to be squeezed, so you can properly position the lower jaw of the squeeze tool to utilize the correct gapstop needed for that pipe. Inspect the pipe for surface damage. Remove all dirt from around the “squeeze zone” of the pipe. If possible, inspect the inside surface of the pipe. A rough, textured interior surface is much more dificult to squeeze off than a glassy smooth interior surface.
Never position any metal tool on PE pipe, until that tool is properly grounded. Static electricity can exist on the outside surface of a PE pipe, and separately, on the inside of the PE pipe. A static-electric discharge from the inside surface could possibly burn a pin-hole through the pipe and/or spark a dangerous gas fire. All Mustang Tools can be ordered with solid copper grounding rods and static-electric-discharge alarms.
Line It Up
Visually center and square the squeeze tool on the pipe before you start squeezing. Insert the lower jaw until the cross-bar contacts the frame for proper gap stop position. Begin applying a partial squeeze on the pipe by hand-torquing the power screw until you have achieved a 10-15% squeeze on the pipe. Stop and visually verify that the tool’s lower jaw is parallel with the upper jaw, and that equal space exists between the frame of the tool and the sides of the pipe. If the upper jaw is tilted to one side, the tool is not centered on the pipe, and you will not achieve an effective squeeze-off.
Begin Full Squeeze-Off
Hand torque the power screw until it is as tight as you can reasonably make it, then stop. Wait one minute per diameter-inch of the pipe-size, (or two minutes per diameter-inch of the pipe-size, if you are working in temperatures below freezing) for cold-flow relaxation of the PE pipe to occur. After cold-flow relaxation of the pipe has occurred, you should be able to re-torque the power screw approximately one more quarter turn, and achieve an effective squeeze-off.
Secure Saddle Clamps
Saddle Clamps provide additional clamping force next to the squeezed pipe folds, and should be used on larger mechanical tools (DBS-40 and above). If you are using a DBS-40, or larger mechanical squeeze tool, install the saddle clamps immediately upon completion of squeeze-off. Even torquing of the special hex nuts and thrust bearings will result in the ultimate squeeze-off.