MAINTAINABILITY DESIGN TECHNIQUES METRIC - AcqNotes.com

Downloaded from http://www.everyspec.com on 2011-10-29T14:56:01.DOD-HDBK-791(AM)CHAPTER 6IDENTIFICATION AND LABELINGThis chapter emphasizes the importance of the proper identification of parts and the labeling of function toimprove equipment maintainability. basic principles associated with labeling are discussed, and the subsequentpresentations are devoted to the application of these principles. Methods of labeling, positioning, andlabel design to include letter fonts and sizes, colors, and color contrasts are presented. an identificationchecklist is provided.6-1 INTRODUCTIONThere are four distinct aspects of identification andlabeling, namely,1. What marking is required or necessary?2. What information should the mar-king contain?3. How should the marking be applied?4. Where should the marking be applied?These four aspects are covered in detail in subsequentparagraphs.Labels, legends. placards, signs, or markings should beprovided wherever it is necessary for an operator or technicianto identify, interpret, follow procedures, or avoidhazards in the use or maintenance of systems or equipmentexcept where it is obvious to the observer what anitem is and what to do about it. The proper identificationand labeling of equipment components, parts, controls,instruments, and test points simplify the technician’s taskand reduce both the task time and risk of error. However,identification, when considered in isolation, does notconstitute maintainability; the fact that an item is adequatelylabeled does not mean that it can be maintained.Melvin S. Majesty (Ref. 1) states, “... analysis of 600recent rocket engine Failure and Consumption Reportsby Chase and Tobias ( Ref. 2) showed that 35% of thefailure reports indicated equipment failure or malfunctiondirectly attributable to human interaction with theequipment during maintenance.” The study indicatedthat the error rate would have improved (1) by unambiguousidentification of parts and equipment functioning,which would have minimized the need to reference repairmanuals and other data sources. and (2) by properlylabeled positions where equipment is installed. operatingprocedures. and operational limits.Identification can be defined as the adequate markingor labeling of parts, components. controls. and test pointsto facilitate repair or replacement during maintenanceoperations (Ref. 1). Proper identification is present if thecomponent is readily identified for repair, replacement,or service with minimum effort by the technicianIncluded in identification is the process of determiningwhat markings are required to identlify a part correctly orto designate a function; it also determines the best methodfor accomplishing the process. Identification markingsusually are identified with instruction plates, function oroperation information, and caution or warning signs applieddirectly to the item. whereas labels are usually identifiedwith the precise nomenclature or function of theitem, or they are diagrammatic instructions for the operationor maintenance of the equipment. Labels frequentlyare used on the exterior of access locations to describe theequipment or components to be accessed, to help reduceaccess time, and to eliminate possible confusion duringmaintenance operations particularly if the opening providesaccess to several similar components. For example,a circuit diagram on the inside of an access cover caneliminate the need to obtain a manual, which simplifiesthe acquisition of necessary data during maintenance.Regardless of whether the identification is marking orlabeling, the same guidelines apply.Since materiel may be exported or integrated into theNATO forces, markings should conform to appropriateinternational specifications and labeling—i. e., size, color,symbols, and units of measure.The information in this chapter relative to purpose,use, format, and size of labels and identification implementsthe general guidance expressed in pars. 9-3.1 and9-4, Chapter 9, “Human Factors”. Labeling and identificationare not exact sciences; the guidance presented inthis chapter and the referenced documents are the resultof experience, observation, and lessons learned.The referenced Military Standards and Military Specificationsdo not reveal the complete story with regard tolabeling and identification, e.g.. MIL-STD-130 (Ref. 3)refers to many other specifications. To include additionalspecifications with each reference would be cumbersomeand would clutter the text; accordingly, a bibliographyhas been included to augment the references. To gain afull appreciation of the art of labeling and identification,the reader is urged to refer to the references and bibliographyin implementing the guidance contained in thischapter.6-1