SELF SUPPORTING FLARE STACKS Self-supporting Flares offer excellent alternatives to guy wire supported, or derrick-supported structures, for flares up to 100 ft. tall. Self-supporting stacks are typically larger at the base, then transition to gradually smaller diameters as they ascend. Larger foundations are required at the base, as the wind load on these structures is concentrated in a smaller area. Self-supporting flares are ideal for use with liquid seals, or knock out drum integral in the base of the stack. These vessels can supply the larger, and stronger base ring required to support the stack. Utility flares or smaller steam flares are more commonly self-supporting. The need for large diameter air ducting usually precludes the use of self-supporting structures for air flares. For smaller flare stacks tripod legs can be added for extra support. Many temporary flare systems, or smaller diameter stacks will utilize three point tripod style legs for support. By using tripod bases the foundation load can be spread over a larger area allowing for a more economical foundation. Self-supporting stacks have the following advantages: The "foot print", or area required for installation is very small. The cost of design, manufacturing, and construction is much less than tower supported stacks. No maintenance cost. The only maintenance requirement is to ensure that sufficient corrosion allowance remains. More materials are required for these stacks. The stacks must be larger in diameter at the base, and typically require many transitions to smaller diameters in the upper sections. top