Secondary containment for liquid

Abstract

In secondary containment of a liquid in a tank which has pipes or posts extending into the ground, a liner covering the ground within a containment wall has a hole surrounding each pipe. Each hole is sealed by a boot which surrounds the pipe and connects from the pipe to the liner and includes a sleeve portion clamped to the pipe and a flange surrounding the sleeve portion at one end which is welded to the liner. A frusto-conical or accordion shape expandable portion is provided allowing longitudinal movement of the flange relative to an upper part of the sleeve of the boot such that the expandable portion allows the liner lies to move downwardly relative to the pipe. The expandable portion is of larger diameter than at the upper part of the sleeve so as to allow the flange to move horizontally with the liner relative to the member.

1 . A method for secondary containment of a liquid in a liquid container, where the liquid container is surrounded by a containment wall and where the liquid container has connected thereto at least one member which extends from the liquid container downwardly into the ground within the containment wall, the method comprising:
 providing a liner covering the ground within the containment wall and extending from the containment wall at least partly under the liquid container;   forming in the liner a hole surrounding the member;   providing a boot which surrounds the member and connects from the member to the material of the liner surrounding the hole;   providing on the boot a sleeve portion and a flange surrounding the sleeve portion at one end;   clamping the sleeve portion of the boot to the member;   sealing the flange of the boot to the liner at the hole;   and providing in the boot an expandable portion allowing longitudinal movement downward of the flange relative to an upper part of the sleeve of the boot such that the expandable portion allows the ground on which the liner lies to move downwardly relative to the member after attachment of the liner to the boot and the upper part of the sleeve of the boot to the member.   
   
   
       2 . The method according to  claim 1  wherein the boot has a portion at the flange which is of larger transverse dimension than at the upper part of the sleeve so as to allow the flange to move horizontally with the liner relative to the member, 
   
   
       3 . The method according to  claim 2  wherein the boot is connected to the flange at the bottom part of the expansion portion. 
   
   
       4 . The method according to  claim 1  wherein the expansion portion is frusto-conical from a lower end of the upper part of the sleeve to the flange. 
   
   
       5 . The method according to  claim 4  wherein the expansion portion can un-fold from a position in which the lower end of the upper part of the sleeve is in a common plane with the flange to a position in which the lower end is raised. 
   
   
       6 . The method according to  claim 1  wherein the expansion portion is frusto-conical with a cone angle in the range 45 to 60 degrees. 
   
   
       7 . The method according to  claim 6  wherein the sleeve above the expansion portion is frusto-conical at an angle less than that of the expansion portion. 
   
   
       8 . The method according to  claim 1  wherein the expansion portion includes an accordion wall between the lower end of the sleeve portion and the flange. 
   
   
       9 . The method according to  claim 1  wherein the sleeve portion is attached to the member by a surrounding clamp and is sealed to the member by a sealing grout. 
   
   
       10 . The method according to  claim 1  wherein in the collapsed position an upper end of the sleeve portion is located above the height of the expansion portion so that sufficient of the sleeve portion is available to attach to the member. 
   
   
       11 . The method according to  claim 1  wherein the collapsed position defines a stable position of the structure in which it holds its position until pulled out of that position in the expansion direction. 
   
   
       12 . The method according to  claim 1  wherein in the collapsed position a component of the expansion portion is in a common plane with the flange to locate the collapsed position.