Major   repairs   that   involve   welding   of   pressure parts  of  the  boiler  are  done  by  Steelworkers  in strict  adherence  to  the  procedures  in  section  IX of   the   ASME   (American   Society   of   Mechanical Engineers),   “Boiler   and   Pressure   Vessel Code.”   This   section   is   concerned   with   operator and   preventive   maintenance   and   major considerations   for   the   maintenance   and   care   of firesides   and   watersides.   Procedures   for   laying up idle boilers are also discussed. OPERATOR   MAINTENANCE Operator  maintenance  is  the  necessary, routine,   recurring   maintenance   work   performed by   the   operators   to   keep   the   equipment   in such  condition  that  it  may  be  used  continuously, at   its   original   or   designed   capacity   and efficiency   for   its   intended   purpose.   The operator  is  actually  the  most  important  member of   the   maintenance   team.   A   well-informed   and responsible  operator  can  do  the  following: 1.  Keep  equipment  in  service  for  maximum periods  of  time. 2.  Detect  any  flaws  so  equipment  can  be removed  from  service  in  time  to  prevent  serious damages. 3.   Perform   minor   repairs   on   equipment removed  from  service  to  minimize  outage  time. It  is  sometimes  difficult  to  determine  where operator   duties   end   and   maintenance   crew work   begins.   However,   the   operator   must realize  that  he  or  she  has  the  keenest  interest  in the  condition  of  the  equipment.  A  well-kept  plant not  only  reflects  the  operator’s  interest  (and  the desire  to  better  his  or  her  position)  but  it  also  is vital  to  the  safety  of  equipment  and  personnel. It  is  essential  for  every  person  in  the  operating aisle  to  perform  the  following  duties: 1.  Clean.  Dirt  is  the  principal  cause  of equipment  failure.  Whether  it  is  fly  ash  in  the switch  gear,  oil  on  the  deck,  cloth  lint,  or  dust,  it causes  trouble.  No  matter  the  form  in  which dirt  appears,  it  should  be  removed  immediately by   the   operator. 12-38 2.   Lubricate.   Any   two   surfaces   brought together   develop   friction.   If   not   properly lubricated,   these   surfaces   wear   one   another down,   change   clearances,   and   cause   equipment breakdowns.  A  well-placed  drop  of  oil  or  a  thin layer  of  grease  can  go  a  long  way  toward keeping  a  much-used  piece  of  equipment  in  good condition. 3.  Cool.  Every  piece  of  equipment  has  an operating   temperature   range.   The   operator should  be  informed  on  this  matter.  An  unusual change  in  temperature  that  the  operator  cannot correct  should  be  reported  immediately  to  the plant  supervisor.  When  the  temperature  of  a piece  of  equipment  rises  rapidly,  an  immediate shutdown  is  recommended, 4.   Tighten.   Vibration   is   another   major source  of  equipment  failure.  A  simple  step  taken in  time,  such  as  tightening  of  bolts,  can  prevent a  serious  failure.  Equipment  that  is  not  secured properly,  vibrates,  causes  an  unbalance,  vibrates further,  and  compounds  a  cycle  that  can  only lead   to   further   trouble.   In   making   rounds,   the operator   should   put   his   hand   on   the   bearings, touch  the  fan  housing,  and  feel  the  motor casing.   When   any   unusual   sound   is   heard, vibration  felt,  or  motion  seen,  the  proper  steps should  be  taken  by  the  operator  to  correct  the condition. PREVENTIVE    MAINTENANCE Preventive  maintenance  inspection  (PMI)  is  a system   of   routine   inspections   of   equipment recorded  for  future  reference  on  some  type  of inspection   record.   The   purpose   of   PMI   is   to anticipate and prevent possible equipment failures by  making  periodic  inspections  and  minor  repairs in  advance  of  major  operating  difficulties. Preventive   maintenance   directed   specifically toward   maintaining   boiler   efficiency   is   the exception,  rather  than  the  rule.  Rising  fuel  costs have   placed   an   increasing   emphasis   on conscientious   maintenance   because   it   results   in higher   boiler   operating   efficiency.   Preventive maintenance practices are easily justified from an economical and safety standpoint. Tables 12-4 and 1 2 - 5     r e f l e c t     N A V F A C E N G C O M recommendations  for  PMI.