Tank assembly happens in two stages. Primary tank assembly is the first of two. Each of the primary tank section is pulled together with the joggled lip of one section sliding tightly into the next. Once they are pulled tightly into one another they are stitch welded together. Once all sections are precisely in place and stitch welded the tank heads are secured in place and stitch welded.
Your primary tank is then finished off with high integrity and almost seamless full penetration sub-arc weld on all exterior seems.
The process is then repeated in part for a secondary protective outer tank with the exception of two important steps. After the protective exterior tank section is stitched in place steel spacers are welded in place to ensure the primary tank remains in the center of the secondary tank once it is inserted. Once the secondary tank is inserted and correctly positioned inside the secondary tank, the outer heads are set in place and the exterior tank seems are full penetration sub-arc welded.
The thicker than required steel used in conjunction with joggle fit sections give Envirosafe™ tanks added integrity and smooth outer finish rarely found with any other manufactures tank.