How to Properly Bury Fiberglass Piping

Beetle Plastics has developed a series of specifications that pertain to buried flexible fiberglass piping where the fiberglass pipe, trench walls, and bedding material work together to form a complete pipe support system. This post outlines the sections covered in our engineering document available for download.

The elements of this system can best be defined by considering a section of buried flexible pipe and the loads acting on it. These loads, the dead load (backfill) and the live loads (vehicle traffic), act downward on the pipe, tending to deflect it into an oval shape. If the bedding material at the sides of the pipe is compacted sufficiently, it will resist the pipe movement and minimize the deflection and ovalization to an acceptable amount. For this reason, the construction of the trench and selection of bedding materials must be closely controlled.

These specifications cover the burial techniques required for the installation of fiberglass pipe under most conditions.

SECTION I: Fiberglass Pipe Storage and Handling

When storing fiberglass pipe directly on the ground, select a flat area free of rocks and other debris that could damage the pipe. Also, when preparing the ends for joining (butt wrap or tapered bell and spigot joints), do not roll the pipe over rocks, debris, or uneven ground that does not fully support the pipe.

SECTION II: Trench Excavation and Preparation

The actual depth of the trench is determined by the final grade, plus the depth required for the initial (bottom) layer of bedding material. The soil conditions and bedding materials being used will determine this additional depth.

Nominal trench widths are listed in the engineering guide available for download.

SECTION III: Bedding and Backfilling

The trench bottom is the first element of the pipe support system. There are many things to consider when building the bedding including pipe diameter, pipe type, soil type and density, and water table.

Schematics and details are contained in the fiberglass pipe engineering document.

SECTION IV: Concrete Structure

Where the fiberglass piping goes through or passes under a concrete structure, precautions must be taken to prevent excessive strain on the pipe due to the differential settling between the structure and the pipe. There are several methods discussed in the engineering document for compensating for settling without straining the fiberglass pipe.

Contact us today about your fiberglass pipe and tank requirements.