Sizing the Navy's Strategic Reserve of Ozone‐Depleting Substances

Abstract

The domestic production of the most powerful Ozone‐Depleting Substances (ODSs) has permanently ceased and the abundant supplies of a number of refrigerants, fire‐fighting agents, and solvents, once taken for granted, are now a thing of the past. The Navy has adopted a successful strategy for addressing the threat posed by the unavailability of ODSs. That strategy includes relying on a strategic reserve of ODSs. Considering that the strategic reserve will play a critical role in sustained fleet operations well into the next century, it is important to record the history of the reserve and to document lessons learned in order to educate future generations that may be foxed with similar challenges. This is the second of three papers that will cover all aspects of the Navy'S strategic reserve of ODSs. The first paper documented the history of the Navy'S effort to size, establish, and monitor a reserve designed to support fleet operations until the middle of the next century (1). This paper addresses in detail the process used to estimate the required size of the reserve, including the survey method, statistical analyses, and sizing algorithms. The third paper will discuss the development of the plan for monitoring the reserve including the control mechanisms, regression methods, and statistical‐process‐control techniques (2).

Monitoring the Navy's Strategic Reserve of Ozone‐Depleting Substances

“…When the ODS reserve was established, the quantity of ODSs to be acquired was estimated using assumptions about four major factors which affect the drawdown of the reserve (Breslin, Smith, and Toms 2000). Assumptions about these factors, which had to be considered for each ODS, also affect the calculation of projected usage against which the reported issues are compared.…”

“…CFC-12 airconditioning and refrigeration plants are being converted to HFC-134a, and CFC-114 air-conditioning plants are being converted to HFC-236fa. However, because of the technical difficulties associated with the conversion of CFC-114 air-conditioning plants on submarines and the high projected installation costs of the conversions, there are no plans at this time to convert any of these plants (Toms et al 2000).…”

“…As discussed in Breslin, Smith, and Toms (2000), the Navy used an "expected-value" approach to estimate the required size of the reserves. Although this approach provides the best estimate of the required size, the Navy realized that it had to deal with the possibility that the estimate could be too low, resulting in premature depletion of the reserves, or too high, resulting in a surplus.…”

“…Breslin (1999) documented the history of the Navy's effort to size, establish, and monitor a reserve designed to support Fleet operations until the middle of the century. Breslin, Smith, and Toms (2000) addressed in detail the process used to estimate the required size of the reserve, including the survey method, statistical analyses, and sizing algorithms. This paper discusses the Navy's plan for monitoring the Navy's strategic reserves of ODSs and describes the methods used in the monitoring process.…”