MAINTAINABILITY DESIGN TECHNIQUES METRIC - AcqNotes.com

Downloaded from http://www.everyspec.com on 2011-10-29T14:56:01.DOD-HDBK-791(AM)11. Select a lubricant, when possible, that can beused in a given piece of equipment for both operationaland storage purposes. Consider the use of prelubricatedgears and bearings, packaged in plastic. to meet thisrequirement.12. Provide easy access to the equipment for directlubrication if lubrication points are not feasible.13. Design lubrication points with a reservoir areato reduce the frequency of required lubrication.14. Provide guards around lubrication points thatmay require servicing while equipment is operating toprevent accidental insertion of hands or tools into operatingequipment.Lubrication charts should be provided with each pieceof equipment. The material of the chart should be waterproofand oilproof, and the chart should be printed onmaterial suitable for rough handling. All necessary informationfor lubrication, including specification numbers,should be included on the charts in the largest lettersthat the size of the chart will permit. Suggested lubricationtime intervals should also be included. Fig. 8-6 is anexample of a lubrication order.8-4.1.2 Army Oil Analysis Program (AOAP)The policies and procedures governing the Army oilAnalysis Program (AOAP) are described in AR 750-22(Ref. 16). The objectives of the AOAP are1. Improve operational readiness of Army equipment2. Promote safety3. Detect impending component failures in time toavoid more costly and extensive repairs4. Conserve lubricating and hydraulic oils by applyingon-conditional oil changes.All Army aircraft and those nonaeronautical systemsspecified in TB 43-0210 (Ref. 17) are enrolled in theAOAP. Each month thousands of lubricating andhydraulic oils are analyzed at AOAP laboratories at specifiedintervals for contamination and wear-metal concentrations.By means of these tests the technicians candetermine equipment parts that show signs of possiblemalfunction. Water seepage. rust particles. and oil dilutionare additional problems that surface. Detailed operatingprocedures for the AOAP are contained in TB43-0106 (Ref. 18) and TB 43-0210 (Ref. 17). The AOAP isa major contribution for improving preventive maintenanceprocedures.The US Army Materiel Command is charged withexercising staff supervision over the AOAP.8-4.2 FILLING AND DRAINING8-4.2.1 GeneralNo repeated operation of maintenance should be givenmore attention than the details relating to the ease andrapidity of refueling and reoiling. Fuel, exotic fluids andgases, oil, hydraulic fluids, water, and compressed airsystems should redesigned to permit the most rapid, totaloverall inspection. The necessity for opening doors andhatches for inspection or to gain access to service pointsor filler caps should be reduced. Servicing points forchecking, filling, and draining fuel, lubricant. hydraulicfluid, and coolant should be readily accessible, but protected.The need for special tools should also be eliminatedwherever possible.Vehicular fuel tanks should be designed and fabricatedto eliminate or minimize internal corrosion when in use orin storage (empty), and the interiors of tanks should beaccessible for inspection and cleaning.8-4.2.2 Filling RequirementsThe design recommendations that follow should beconsidered:1. The fuel outlet should be located at least 19 mm(0.75 in.) above the bottom of the sump or tank or at thebottom of the sump or tank with a 19-mm (0.75-in.)stand pipe.2. The fuel tanks should be capable of acceptingfuel at 198 min (50 gpm) when tank capacity exceeds189 (50 gal). Tanks having capacities of less than 189(50 gal) should be capable of being filled at the 189- min(50-gpm) rate when using a standard 35-mm (1.375-in.)diameter nozzle that is 406 mm (16 in.) long. The fillerneck should have a flexible seal to fit such a nozzle and anopening other than the filler neck itself for venting displacedair.3. The tank filler should be located to prevent tothe maximum extent possible entrance of dirt, water,and foreign matter into the fuel tank.4. For gravity-filled tanks the tank filler should bewell as forced-nozzle filling. Filler necks should also belocated to permit use of rigid spout fuel nozzles conformingto MS-17967 (Ref. 19).5. Fuel filler neck dimension should be a minimumity or less, and 63.5 mm (2.5 in.) for larger fuel tanks.Water and coolant filler necks should have a minimumdiameter of 38 mm (1.5 in.) and should be located so theyMIL-C-13984 (Ref. 20).6. The type of fuel to be used and the tank capacityshould be stenciled or marked adjacent to the filler openingof the equipment.7. Fuel, oil, and coolant filler caps should be colorcoded as shown in Table 8-1.8. Locate the hydraulic reservoir so that it is visuallyaccessible for refilling. Also the fluid level should bevisible while filling.9. Level indicators of the type indicated by Fig. 8-7for fuels, oils, water, or other liquids should be locatedoutside of the vehicle or tank, when possible, and shouldbe easilu viewed without removal of doors or covers. Forlevel indication of infrequently checkd units, such asgearboxes, dipsticks with integral sealing caps should beprovided. The use of threaded plugs for level indicationshould be confined to such locations as automotive differentialsbecause at such locations other types should betorn off by rocks, mud, or stumps. When such plugs are8-10