Secondary containment flexible underground piping system

A secondary containment piping system, comprising an inner supply pipe, and a flexible, fuel impervious outer secondary containment pipe, within which the inner supply pipe is carried, one of an outer surface of the inner supply pipe and an inner surface of the outer pipe having a plurality of radially outwardly projecting flanges adapted to engage the other of the outer surface of the inner supply pipe and the inner surface of the outer pipe when the pipes are buried to provide a locking engagement of the pipes with respect to each other, and to provide for a flow passage between the pipes, the improvement comprising:

• the inner supply pipe, comprising:
• a first, inner layer fabricated from nylon;
• a second layer comprising a wrap having two opposed longitudinal edges in overlying relationship, the overlying edges forming a first seam, the wrap being fabricated from a metallized polyester film;
• a polyethylene based heat seal adhesive extending between the overlying wrap edges and forming a seamless wrap;
• a third layer comprising a wrap having two opposed longitudinal edges in overlying relationship, the overlying edges forming a second seam, the second seam being rotated 180.degree. from the first seam, the wrap being fabricated from a polyvinyl fluoride coated polyester film;
• a fourth layer comprising a nylon reinforced braid;
• and
• a fifth, outer layer comprising a polyethylene material;
• and
• the outer secondary containment pipe, comprising:
• a first, inner layer comprising a wrap having two opposed longitudinal edges in overlying relationship, the wrap being fabricated from a polyester film;
• a second layer comprised of one of a polyethylene and an ethylene vinyl acetate material, the second layer having a plurality of radially inwardly projecting flanges;
• a third layer comprising a wrap having two opposed longitudinal edges, the wrap being fabricated from a metallized polyester film;
• and
• a fourth, outer layer comprising a polyethylene material.

A secondary containment piping system, comprising an inner supply pipe, and a flexible, fuel impervious outer secondary containment pipe, within which the inner supply pipe is carried, one of an outer surface of the inner supply pipe and an inner surface of the outer pipe having a plurality of radially outwardly projecting flanges adapted to engage the other of the outer surface of the inner supply pipe and the inner surface of the outer pipe when the pipes are buried to provide a locking engagement of the pipes with respect to each other, and to provide for a flow passage between the pipes, the secondary containment piping system further comprising spaced, underground chambers which are interconnected in a fluid tight manner through walls thereof by the secondary containment pipe which passes therethrough, the inner supply pipe having end couplings attached to the ends thereof, the end couplings being disposed within the chambers at a point beyond the termination of the outer secondary containment pipe, the inner and outer pipes being impervious to the fluids to be transmitted therethrough, the improvement comprising:

• the inner supply pipe, comprising:
• a first, inner layer fabricated from nylon;
• a second layer comprising a wrap having two opposed longitudinal edges in overlying relationship, the wrap being fabricated from a polyester film;
• a third layer comprising a nylon reinforced braid;
• and
• a fourth, outer layer comprising a polyethylene material;
• and
• the outer secondary containment pipe, comprising:
• a first layer comprised of one of a polyethylene and an ethylene vinyl acetate material, the first layer having a plurality of radially inwardly projecting flanges;
• a second layer comprising a wrap having two opposed longitudinal edges, the wrap being fabricated from a metallized polyester film;
• and
• a third, outer layer comprising a polyethylene material.

A secondary containment piping system, comprising an inner supply pipe, and a hazardous fluid-impervious outer secondary containment pipe, within which the inner supply pipe is carried, a flow passage being defined between the pipes, the improvement comprising:

• a first, inner layer of the inner pipe being fabricated from nylon;
• a second layer comprising a wrap having two opposed longitudinal edges in overlying relationship, the wrap being fabricated from a polyester film;
• a third layer comprising a nylon reinforced braid;
• and
• a fourth, outer layer comprising a polyethylene material.