Evaluation of the Hazard of Static Electricity in Nonmetallic Pol Systems-Static Effects in Handling Jet Fuel in Fiberglass Reinforced Plastic Pipe.
Abstract
There is increasing interest in pipe for minimizing contamination in ground handling of aviation fuels. This report presents the results of a litera-ture search and experimental study conducted to determine if static electricity hazards would be increased by substituting FRP for metal pipe in such systems. Experiments were conducted in 6 inch diameter, matched volume, carbon steel and Bondstrand 2000 pipes at four fuel conductivi-ties between 0.2 and 5.5 CU and at flow rates between 200 and 1500 GPM at controlled temperatures. Charge generation in the pipes was low (2.5 micro C/m3 maximum with 0.9 CU fuel at 1200 GPM in steel); generation in FRP was generally less than in steel. Relaxation in FRP pipe depended on fuel polarity; on the average, relaxation was 8 percent faster, with negatively- charged fuel and 30 percent slower with positively-charged fuel than in steel. The slower relaxation should not prevent the use of FRP in Air Force hydrant systems handling JP-4 where a minimum of 2 minutes residence time is available downstream of filter- separators. Voltages up to 55 kv were measured on the FRP pipe and sparks up to 1/ 2 inch long could be discharged from ungrounded metal components on the FRP pipe. These effects should be of no concern in underground installations; methods for eliminating them in above-ground installations are recommended. An evaluation of the A. O. Smith Static Charge Reducer (SCR) showed that it was more efficient with positively-than negatively-charged fuel and that deposit-buildup could reduce its efficiency. Available data suggest that static electricity hazards might exist downstream of an SCR although the average charge level is below 30 micro C/m3. (Author-PL)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1973
- Accession Number
- AD0764358
Entities
People
- J. C. Munday
- Kenneth C. Bachman