||Testing and recommended practices to improve nurse tank safety, phase I.
| Russell, Alan M.; Chumbley, L. Scott; Becker, Andrew; Vennerberg, Daniel; White, Emma
Iowa State University
|| United States. Federal Motor Carrier Safety Administration. Office of Analysis, Research, and Technology
||This research project studied causes and possible remediation inspection strategies to prevent failures for
anhydrous ammonia (NH3) nurse tanks. Nurse tanks are steel tanks used to transport NH3 locally over public
roadways and farm fields. Many of the reportedly 200,000 nurse tanks in use in the United States are 3 to 5 decades
old. Several tank failures have occurred in recent years. Nurse tank failures can injure workers and bystanders by
way of chemical burns, frostbite, suffocation, and physical injuries caused by the catastrophic force of rupture. This
research study addressed this problem by: surveying the technical literature on nurse tank properties and case
studies of tank failures; examination of 20 used nurse tanks by metallography, glow discharge spectroscopy,
neutron diffraction analysis of residual stresses, ultrasound, and fluorescent dye penetrant examination for cracks.
It exposed 56 specimens of the commonly used tank steel, stressed in tension, while either immersed in liquid NH3
or exposed to pure NH3 vapor, for 7 months to study the initiation and growth of stress corrosion cracks. This
research further confirms that stress corrosion cracking is the greatest threat to nurse tank integrity.
Recommendations for best inspection practices are presented on how to reduce the risks associated with nurse tank
|| Tanks (Containers) ; Steel ; Stress cracking ; Residual stress ; Metallography ; Spectroscopy ; Inspection ; Case studies ; Hazardous materials ; Literature reviews
| United States
||DTMC75-07-D-00006; Task order DTMC75-08-J-00017
||NTL Digital Repository