in recurring demand. Figure 14-2 illustrates the relationship between the various levels of supply.
Figure 14-2.—Levels of supply.
In expressing the supply level of any stock item, four measurements may be used: operating level, safety level, storage objective, and requisitioning objective.
OPERATING LEVEL.— This measurement indicates the quantity of an item that is required to sustain operations during the interval between requisitions or between the receipt of successive shipments of supplies. The operating level should be based upon the length of the replenishment cycle. For example, if requisitions are submitted every 2 months, the operating level would be the quantity of the item that is consumed every 2 months. This level will vary for different items.
SAFETY LEVEL.— This measurement indicates the quantity of an item, over and above the operating level, that should be maintained to ensure that operations will continue if replenishment supplies are not received on time, or if there is an unpredictable heavy demand for supplies. This measurement simply provides a margin of safety.
STOCKAGE OBJECTIVE.— This measurement indicates the minimum quantity of a stock item that is required to support operations. It is the sum of the operating level and the safety level. For example, if the operating level of an item is 80 units and the safety level is 20 units, the stockage objective would be to maintain 100 units of that item in stock at all times.
REQUISITIONING OBJECTIVE.— This measurement indicates the maximum quantity of a stock item that should be kept on hand and on order to support operations. It is the sum of the operating and safety levels and the quantity of an item that will be consumed in the interval between the submission of a requisition and the arrival of the supplies.
Usage
Data The most accurate guide in determining stock level requirements is past experience as reflected in accurate stock records. Stock record cards, which will be discussed in detail later in the chapter, should be kept current to assist in the material usage notes. Stock records can tell you how much of each item has been used in the past. From this past usage rate, you can make a reasonable projection of future usage rates.
REQUISITIONS
A requisition is an order from an activity that is requesting material or services from another activity. Except for certain classes of material listed in NAVSUP P-485 and P-437, all items ordered from the Navy Supply System, other military installations, the Defense Logistics Agency, and the Government Services Administration (GSA) will be procured using the MILSTRIP system. MILSTRIP requisitioning is based upon the use
