The procedure for installing gaskets is simple. However, a large part of the reliability of the seal depends on cleanliness of the joint at the time of installation. Considering the variety of conditions that may be encountered in transit or at the jobsite, it would not be possible to ensure joint cleanliness if the gaskets were pre-installed by the manufacturer. Pre-installation would also expose gaskets unnecessarily to ultraviolet exposure and even vandalism.
For mechanical joints, the gland should be slipped some distance back from the plain end of the pipe with the lip of the gland facing the bell. The inside diameter of the mechanical joint gasket is smaller than the outside diameter of the pipe. Brush the plain end of the pipe and the gasket with an approved pipe lubricant as supplied by the manufacturer. The gasket must then be stretched over the plain end of the pipe with the thinner side of the wedge facing the bell. The lubricant allows the gasket to slide more easily into the bell and become equalized as the gland compresses it to achieve a reliable seal.
The TYTON JOINT® and FIELD LOK 350® gaskets have a stiff rim called the heel bonded to a circular cross section called the bulb. After correct installation, the heel will fit into the first groove just inside the bell. The bulb will enter the bell first and will be compressed between the inside of the bell at the gasket seat and the outside of the pipe to achieve a seal. The gasket diameter is larger than the bell opening, so a technique must be followed to allow the gasket to be properly fitted inside the bell.
For smaller pipe, up to about 20”, draw a loop of the gasket towards its center forming somewhat of a heart shape. While holding the loop with one hand, start fitting the gasket heel into the groove of the bell with the other. Gradually release the loop while pressing the gasket evenly into position around the inside circumference of the bell. It may be necessary to firmly seat the loop with the heel of the hand to ensure it is fully seated.
As pipe size increases, it will be necessary to use an increasing number of loops to facilitate gasket installation. In the largest sizes, it is not uncommon to have as many as eight loops, evenly spaced around the gasket. Regardless of pipe size, if the gasket has been properly installed, the leading edge of the rubber should be slightly below the smallest part of the bell opening all around the inside circumference. If any part of the gasket is sticking up, it must be worked until fully seated, or the gasket must be removed and re-installed.
Once the gasket is properly seated, continue with the assembly procedure to make up the joint.