SUMMARY OF PREVIOUS PHASE I WORK
Before discussing the Phase II results, the previous Phase I preliminary design work will first be summarized for reference.
Phase I of this project developed preliminary designs for composite propane tanks for underground service. The designs were based on previous experiences with underground petroleum storage tanks, considering tank design pressure, cyclic pressures due to temperature and filling, and soil loading.
This feasibility design approach for underground composite propane tanks for residential use was based upon a combination of design codes: the American Society of Mechanical Engineers (ASME) Section X (Fiber-Reinforced Plastic Pressure Vessels) for the primary pressure vessel design, and the American Water Works Association (AWWA) Manual of Water Supply Practices M45 (Fiberglass Pipe Design) to account for the buried installation of the tank (ASME, 2004; AWWA, 2005).
The Phase I preliminary design assumed a filament-wound tank using fiberglass and a good quality isophthalic resin for adequate performance in order to help minimize the cost of the tank. The approximate dimensions and marketers’ costs for 250-gallon and 1000-gallon composite tanks, based upon this feasibility design, are shown in Table 1. For comparison, estimated steel tank dimensions and marketers’ costs (from the 2005 report) are also shown in Table 1.
+ $ 75 (1 anode)
+ $ 150 (2 anodes)
Weight Total length Diameter Thickness
484 lbs 5 feet 32 inches 0.20 inch
260 lbs 5 feet 32 inches 0.42 inch
1741 lbs 13 feet 41 inches 0.25 inch
970 lbs 13 feet 41 inches 0.51 inch
Table 1. Estimated Underground Tank Costs – Steel and Phase I Composite Design
Note that the costs for the steel tank in the above table do not include any cathodic protection monitoring costs over the service life of the tank, which are estimated to be on the order of $550. If these costs for periodic inspections are included, the total life-cycle cost of the composite tank may compare favorably to the steel tank. Thus, this Phase I preliminary cost analysis showed
$1125 (appurtenances in side wall)
$2550 (appurtenances in side wall)
Alternative Underground Propane Tank Materials, Phase II—Final Report
September 2009 Battelle and Lincoln Composites