Double-containment underground piping system

A piping system for conveying fluid from the outlet port of an underground pump to the inlet port of an above-ground fluid dispenser which comprises:

• (a) a containment chamber installed below grade level containing the pump, said chamber comprising a body capable of containing leaked fluid, a removable cover at about grade level, and a sleeve in communication with the body extending outwardly therefrom,
• (b) a primary pipe of flexible material for conveying the fluid from the pump, the primary pipe having an inlet end and an outlet end and comprising a plurality of primary pipe segments joined together at their ends in sealed communication by fittings,
• (c) means for removably securing the inlet end of the primary pipe in sealed communication with the outlet port of the pump,
• (d) means for removably securing the outlet end of the primary pipe in sealed communication with the inlet port of the fluid dispenser,
• (e) a secondary pipe of flexible material generally surrounding the primary pipe, said secondary pipe having a lower end and an upper end and comprising a plurality of secondary pipe segments, the lower end of the secondary pipe being in sealed communication with the containment chamber sleeve, said inner surface of the secondary pipe and said outer surface of the primary pipe defining an annular space,
• (f) a dispenser pan installed below the fluid dispenser and the fluid dispenser inlet port so as to contain leakage therefrom, said dispenser pan comprising a body and a pan sleeve in communication with the pan in a gravity draining relationship therefrom, the upper end of the secondary pipe being in sealed communication with the pan sleeve, and
• (g) a repeater chamber installed below grade level and comprising a body capable of containing leaked fluid, a removable cover at about grade level and a plurality of sleeves in communication with the body extending outwardly therefrom,
• the primary pipe passing through said repeater chamber sleeves and comprising a plurality of primary pipe segments and a coupling joining in sealed communication each contiguous pair of said primary pipe segments, each of said couplings being generally surrounded by a repeater chamber as recited above in paragraph (g), and
• respective ends of secondary pipe segments being in sealed communication with each of said repeater chamber sleeves, the dispenser pan sleeve, and the containment chamber sleeve, whereby fluid leaked into the dispenser pan or the annular space between the primary pipe and the secondary pipe may travel within the annular space and is contained within the system, and whereby a primary pipe segment may be replaced by removing the cover from the containment chamber, unsecuring each end of said primary pipe segment, and pulling said primary pipe out through the sleeves.

A secondarily contained piping system comprising:

• (a) a flexible inner supply pipe
• (b) an outer secondary containment pipe
• (c) two spaced underground access chambers which are interconnected in a fluid tight manner through the side wall just above the chamber base, by the secondary containment pipe,
• (d) all flexible inner supply pipe couplings and associated fittings being disposed within the access chambers,
• (e) a fluid source providing an originating interface to the flexible inner supply pipe,
• (f) a fluid outlet providing a terminating interface to the flexible inner supply pipe,
• (g) the access chambers being of sufficient size to permit manual or mechanical removal or replacement of the flexible inner supply pipe,
• (h) the flexible inner supply pipe having sufficient bend radius to be removed and replaced through the access chambers,
• (i) all components of the system being chemically compatible with and impervious to the fluids to be transmitted and with the surrounding environment in which they are disposed,
• (j) the flexible inner supply pipe and its associated couplings and fittings being of sufficient strength to withstand internal fluid pressures, and
• (k) the access chambers and secondary containment pipe being of sufficient strength to withstand external loads.

A secondarily contained pipe routing system for fluid fuel dispensers comprising:

• (a) a plurality of flexible fluid supply pipe sections removably interconnected at their ends by coupling fittings to form a linear plural section fluid supply line,
• (b) at least one of the coupling fittings of the supply pipe sections being a fluid tight fitting which provides a connection to a fluid fuel dispenser,
• (c) the terminating coupling fitting being a fluid tight fuel dispenser coupling,
• (d) an access chamber for each coupling fitting which provides a housing through which the plurality of flexible fluid supply pipe sections extend such that each coupling fitting is disposed in an access chamber,
• (e) the flexible supply pipe sections are each capable of being disposed in a continuous curvilinear path,
• (f) a flexible secondary containment pipe enclosing each flexible supply pipe section and providing adequate clearance therefrom to permit movement of its corresponding supply pipe section therethrough,
• (g) each end of all secondary containment pipes being interconnected in tight sealing engagement with the corresponding one of the two access chambers,
• (h) each access chamber having an access opening at the top thereof below which the corresponding coupling fitting joining adjacent fluid supply pipe sections is disposed,
• (i) the access chambers each having a height and width sufficient to permit introduction and removal of the flexible supply pipe sections from their respective secondary containment pipes within the bending radius limits of the supply pipe sections, and
• (j) a fluid fuel dispenser mounted on at least one of the access chambers and positioned immediately above the access opening and above and connected to the corresponding coupling fitting.

A secondarily contained piping system, comprising:

• (a) a series of sealed linearly spaced access chambers which are disposed below ground and each of which has a removable access opening at ground level,
• (b) at least one of the access chambers having a side wall with two substantially opposed secondary containment pipe receiving openings,
• (c) the side walls adjacent each opening having an engaging element adjacent thereof for engaging an end of a secondary containment pipe,
• (d) a flexible secondary containment pipe interconnecting adjacent access chambers and interconnected at each end with a corresponding secondary containment pipe receiving opening and interengaging the adjacent engaging element of the access chamber side walls to thereby provide a sealed linear multiple segmented secondary containment pipe line,
• (e) a flexible inner fluid pipe section disposed within each secondary containment pipe which extends at each end thereof through the corresponding one of the secondary containment pipe receiving openings and into the corresponding access chamber,
• (f) each flexible inner fluid pipe section having a coupling element at each end which interengages another coupling element to thereby provide an inner pipe removal coupling which is disposed within the common access chamber,
• (g) the flexible inner supply pipe sections and their associated coupling elements and fittings being of sufficient strength to withstand internal fluid pressures, and
• (h) the secondary containment pipes each having a substantially larger diameter than that of the associated flexible inner fluid pipe section, whereby the inner fluid pipe sections can be removed from an adjacent access chamber after uncoupling.

A secondarily contained fluid distribution system, comprising:

• (a) a plurality of access chambers;
• (b) a secondary containment pipe having a plurality of segments, a first of said segments extending between a first and a second of said plurality of access chambers and a second of said segments extending between the second and a third of said access chambers;
• (c) a primary containment pipe extending through said secondary containment pipe from said first through said second to said third access chamber, said primary containment pipe being flexible and having a plurality of segments;
• (d) a disconnectable fittings securing adjacent segments of said primary containment pipe together in end to end relationship, at least one of said access chambers having at least one of said disconnectable fittings located therein;
• (e) the flexibility of said primary containment pipes and the configuration of said access chambers being such that, upon disconnection of the two of said disconnectable fittings securing opposite ends of a single segment of said primary containment pipe, said segment may be withdrawn from said secondary containment pipe through one of said access chambers for inspection and/or replacement.

A secondarily contained fluid distribution system for supplying fuel to at least one fuel dispenser, comprising:

• (a) a plurality of access chambers;
• (b) a secondary containment pipe extending in series between said access chambers;
• (c) a flexible primary containment pipe extending in series through said secondary containment pipe;
• (d) a plurality of disconnectable fittings in said primary containment pipe, said disconnectable fittings connecting segments of said primary containment pipe, at least one of said disconnectable fittings being located in a corresponding one of said access chambers;
• (e) the flexibility of said primary containment pipe and the configuration of at least one of said access chambers being such that, upon disconnection of two of said disconnectable fittings, a segment of said primary containment pipe may be withdrawn through an access chamber to an above ground location and a substitute segment inserted through said access chamber;
• and
• (f) at least one fuel dispenser associated with a corresponding one of said access chambers and being in fluid communication with the primary containment pipe within said corresponding one of said access chamber.

A secondarily contained fluid distribution system for supplying fuel to at least one fuel dispenser, comprising:

• (a) at least one liquid fuel dispensing unit for supplying fuel to motor vehicles,
• (b) a plurality of underground access chambers, one of said underground access chambers being disposed beneath said at least one liquid fuel dispensing unit for receiving the end of at least one fuel supply pipe section, each of said underground access chambers having an open top adjacent ground level and at least one fuel line receiving opening,
• (c) an underground secondary containment pipe interconnecting adjacent access chambers, the ends of said underground secondary containment pipe interconnecting the fuel line receiving openings in each interconnected access chamber to provide a fluid tight system,
• (d) the access chambers being interconnected by the secondary containment pipes to form a fluid tight series configured distribution routing line,
• (e) the first access chamber having a fuel line opening interconnected with said underground secondary containment pipe and a corresponding fuel supply pipe section,
• (f) the last such interconnected access chamber having a single fuel line opening, and all of the remaining access chambers having two fuel line openings in their side walls,
• (g) a flexible fuel supply pipe disposed within and extending the length of each interconnecting secondary containment pipe, said flexible fuel supply pipes being sized to provide sufficient clearance to permit them to be readily moved through the corresponding ones of said secondary containment pipes,
• (h) each one of the flexible fuel supply pipes extending through the fuel line receiving openings of the interconnected access chambers,
• (i) a disconnectable fitting disposed on each end of one of the fluid fuel supply pipes and in each intermediately positioned access chamber, said disconnectable fitting interconnecting the adjacent opposed ends of adjacent ones of said flexible fluid supply pipes disposed within each access chamber,
• (j) a disconnectable fitting disposed in the last access chamber for connecting the end of the flexible fuel supply pipe disposed therein to said at least one liquid fuel dispensing unit, and
• (k) the relative dimensions of the access chambers and the containment pipes with respect to the size and minimum bending radius of the flexible fuel supply pipes being sufficient to permit uncoupling of any given flexible fuel supply pipe at its ends and the removal and subsequent replacement thereof.