nonstandard material and emergency items. In this section, we will cover supply levels, supply level terminology, requisition, requisition documents, purchase procedures, and the Uniform Material Movement and Issue Priority System (UMMIPS). LEVELS OF SUPPLY There must be some control over the level or quantity of supplies kept by medical departments. Without controls, policy changes or poor ordering procedures may result in some items being in short supply, while other items are stockpiled in quantities that would not be consumed for several years. To avoid such occurrences, it is necessary to develop rules governing stock levels. Supply Level Terminology Supply levels may be expressed in one of two ways: in numerical terms and in terms of months of usage. Numerical is expressed as the total amount of supplies on hand. Months of usage is the most commonly used measurement of supply levels. It is the best method to use in accounting for the amount of items that are used on a monthly basis. 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 the receipt of scheduled 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 unpredictably heavy demand for supplies. This measurement simply provides a margin of safety. STOCKAGE OBJECTIVE.—This measure- ment indicates the minimum quantity of a stock item that is required to support current 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. Figure 13-1 illustrates the relationship between the various levels of supply. Usage Data The most accurate guide in determining supply 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 should tell you how much of each item has been used in the past. From this past usage data, you can make a reasonable projection of future usage rates. SAMS (SNAP Automated Medical System) is an additional management tool. SAMS is the current approved shipboard computer program used to track all aspects of medical supply. 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 D e f e n s e L o g i s t i c s A g e n c y ( D L A ) , a n d t h e Government Services Administration (GSA) will be procured using the MILSTRIP system. MILSTRIP requisitioning is based upon the use of a coded, single-line-item document for each supply transaction discussed in the paragraphs that follow. DoD Single-Line Item Requisition System Document (Manual), DD Form 1348 DD Form 1348 (fig. 13-2) is used as a requisition; requisition follow-up, modification, or cancellation; and tracer request on overdue shipments sent by insured, registered, or certified mail. This form is available in two-, four-, and six-part sets as follows:  The two-part set is used by nonautomated ships for requisition follow-up, modification, or cancellation, and tracer requests;  the four-part set is used for requisitioning from shore activities; and 13-7