UOW ENGG 960 – P Gordon, R Dwight & K El-Akruti 1 PM Task Description Standardisation. Tasks that form part of the Preventive maintenance program should be described in a manner such that the intent of a task is clearly conveyed to the person who has to do it and such that any two qualified people assigned to carry out the task would interpret the requirement in the same way and achieve the same outcome. By way of examining this issue I have selected a number of PM task descriptions from a sample of data supplied and have made some observations of the data and suggested some standardisations. Sample of task descriptions from a pilot study review of PM data with key verbs emboldened: • Ensure bearing hold down bolts are tight. • Check g/box retaining bolts are tight & wired up on all rolls. • With a spanner, ensure the bearing hold down bolts are tight. • Check drive shaft connection bolts to gearbox & to roll for tightness. • Check the tightness of anchor bolts (16 off) • Check brake drum for excess wear, scoring and damage. • Check universal joints for excessive crosshead movement indicating bearingwear. • Check the long travel and hoist brake hinge pins and fastenings are secure • Check universal joint bearing cap bolts for corrosion and tightness • With a stethoscope, check the roll support bearings noise levels • Cycle the table & check table support rolls & side guide rolls rotate smoothly • Cycle the table & check movement time: south( sec) north ( sec). • Visually check spray nozzles are not blocked. • Visually inspect all drive coupling elements for excessive wear or damage. • Check tension on drive chain. • Visually inspect tension on drive chain. • Listen to the eddy current brake, drive motor and main gearbox using the electronic stethoscope for excessive or abnormal noises • Measure gap at South End #2 with feeler gauge • Climb the access ladder into the centre of the turret and listen to the hydraulic rotating union, turret rotation position encoder and turret rotation drive shaft top support bearings for excessive or abnormal noises • With the brake fully lifted, try and lift the thruster up further by hand, to ensure that the thruster is reaching full stroke • Adjust the frame balancing bolt mounted at the base hinge of the west shoe support frame to achieve balance. • Auto teeming hydraulics pump replacement. • Check condition/operation of pressure gauges and operation of regulator. Observations • The same verbs are used with different meanings • The same tasks are described with different verbs and sentence structures. • Sentence structures are varied. • It is quite likely that some of these activities would be interpreted differently by different tradespeopleUOW ENGG 960 – P Gordon, R Dwight & K El-Akruti 2 • It is noted that “acceptable limits” associated with the tasks are specified in a different field. From consideration of the small sample the majority of tasks aimed at determining equipment condition could be specified with the 3 verbs in the table below. The table gives a standardised meaning for use in PM tasks but also the dictionary meaning to show that the proposed standard aligns closely with common meaning attributed to the words. It is recommended that a standard sentence structure be adopted. Ie Verb Noun or noun phrase Verb Qualifiers Action Item action focuses on What / How /When Verb Meaning Inspect Visual or simple sensory examination to determine condition. Specifying what to look for may be necessary in some situations. (Dictionary - to examine closely especially for faults or errors - from Latin specere – to look.) Check Simple test or physical procedure to determine condition. May involve measurement and comparison against acceptance criteria. Does not require recording of the measurement. Where a check is specified the procedure or method of checking needs to specified as well. (Dictionary – to examine, investigate or make an enquiry into (facts, product) for accuracy, quality, or progress esp. rapidly or informally – From C14 Old French - eschec (chess “check”) – hence a pause to verify something) Measure Measurement of a parameter to determine condition through comparison against acceptance criteria and to estimate the rate of deterioration and remaining life. Procedure for measurement needs to be specified. (Dictionary - to determine the size, amount etc of by measurement) Rewriting a number of the sample tasks with these verbs and the proposed sentence structure would yield the following: • Ensure bearing hold down bolts are tight. = Check bearing hold down bolts are tight using ?. “Check” implies the bolt security is tested and the statement would thus need further qualification on how this would be done. If the method envisaged was visual examination then the task could read “Inspect bearing hold down bolts for tightness” • Check g/box retaining bolts are tight & wired up on all rolls. Same as above. Standardisation requires specification of how the assessment is to be made. Intention may be “Inspect” • With a spanner, ensure the bearing hold down bolts are tight. = Check the bearing hold down bolts are tight using a spanner • Check drive shaft connection bolts to gearbox & to roll for tightness. Standardisation requires specification of how the assessment is to be made. Intention may be “Inspect” • Check the tightness of anchor bolts (16 off) Standardisation requires specification of how the assessment is to be made. Intention may be “Inspect” • Check brake drum for excess wear, scoring and damage. = Inspect brake drum for excess wear, scoring and damage • Check universal joints for excessive crosshead movement indicating bearingwear. Requires specification of how the assessment is to be made.UOW ENGG 960 – P Gordon, R Dwight & K El-Akruti 3 • Check the long travel and hoist brake hinge pins and fastenings are secure. Standardisation requires specification of how the assessment is to be made. Intention may be “Inspect” • Check universal joint bearing cap bolts for corrosion and tightness. Intention is probably to inspect for corrosion. Unclear on tightness • With a stethoscope, check the roll support bearings noise levels = Check the roll support bearing noise levels with a stethoscope. • Cycle the table & check table support rolls & side guide rolls rotate smoothly = Check table support rolls & side guide rolls rotate smoothly by cycling the table. • Cycle table & check movement time: south( sec) north ( sec). = Measure table cycle movement time using ?? south( sec) north ( sec). • Visually check spray nozzles are not blocked. = Inspect spray nozzles for blockage • Visually inspect all drive coupling elements for excessive wear or damage. = Inspect all drive coupling elements for excessive wear or damage. • Check tension on drive chain. = Check drive chain tension by ?? • Visually inspect tension on drive chain. = Inspect drive chain is adequately tensioned. • Listen to the eddy current brake, drive motor and main gearbox using the electronic stethoscope for excessive or abnormal noises = Check the eddy current brake, drive motor and main gearbox for excessive noise using an electronic stethoscope. • Measure gap at South End #2 with feeler gauge = Check ?? gap at south end #2 (what)?? meets criteria ?? using a feeler gauge. What I think this illustrates is that standardisation of wording not only demands more precision in writing the task descriptions but also requires more careful thought of how a task is to be done. It also suggests a hierarchy in the actions. Inspecting is simpler than checking which is simpler than measuring. The task should be specified at the simplest level that is effective in achieving the task objective. It is also evident that some tasks recur very frequently and there is an opportunity to review or discuss the options for how these are done. For example, checking that bolts are tight – some tasks are suggesting that this be done with a spanner. This may be appropriate in some situations depending on bolt size and locking method used but I don’t believe it is generally applicable. Checking with a hammer is a simpler and more efficient method for larger bolts and simple visual inspection for evidence of joint movement can also be considered in many situations. Strategy review can challenge why we expect certain failures but decisions on practices may be better debated in advance or in parallel.