through  sources  contained  in  the  Ship’s  Store Contract Bulletin.  These bags are easy to install and remove and should be cleaned once every 4 hours. STEAM  COILS Steam  coils  are  located  at  the  top  of  the  dryer. The   configuration   of   steam   coils   as   heat   ex- changers makes them collectors of lint and dirt, which slows down the transfer of heat and reduces airflow. Steam coils should be examined daily for the  presence  of  lint;  any  lint  present  must  be removed. TUMBLER DRYER FIRES Before we get into the actual operation of the tumbler   dryer,   let’s   discuss   the   potential   fire hazards  involved  in  drying  clothing  and  other textile  materials  in  standard  shipboard  tumbler dryers. The principal cause of shipboard laundry fires  is  spontaneous  combustion  of  residual  soil in  clothing  (particularly  paint  and  drying  or  edible oils)  and/or  polymeric  elastic  waistband  materials. Most  laundry  dryer  fires  are  caused  by  human error or negligence. Many of the causes are listed below: In Leaving clothing or linen unattended in the dryer Not   properly   washing,   rinsing,   or extracting  clothes Overdrying   because   of   imbalance   in loading  (heavy  items  included  with  light items) Placing divisional laundry bags in the dryer Not   cooling   down   dryer   loads   for   10 minutes with dampers set to deliver room temperature after drying Improper   cleaning   of   primary   and secondary lint traps Improper  use  of  the  timer  on  the  dryer Unclean  steam  coils  on  the  dryer addition, operators must be familiar with safety   devices   and   report   faulty   equipment to   maintenance   personnel.   Investigations   of shipboard   fires   have   revealed   the   following conditions in laundry tumbler dryer safety devices: Clogged,  damaged,  or  missing  lint  traps Missing  or  inoperative  thermometers Thermometers  that  do  not  indicate  tem- peratures   above   220°F,   although   the equipment   can   be   operated   above   this temperature No  automatic  temperature  control No   automatic   timing   device   to   control drying  time No   automatic   cool-down   cycle No  fire  sensing  and  smothering  device When  the  above  conditions  exist  on  board your  ship,  be  extra  careful  when  operating  the tumbler  dryer. A Prevent Laundry Dryer and Hamper Fires placard (fig. 5-29) should be posted on the front of each dryer. Placards are available through the supply  system  and  should  be  mounted  on  the  door of  every  dryer. OPERATING  THE  TUMBLER DRYER The procedures for operation of the dryer are as  follows: 1.   Load   the   dryer,    not   exceeding   rated capacity. 2. Set dampers to the desired position. Most loads  can  run  in  the  HOT  position. 3.   Set   thermometer   regulator   to   desired temperature    (140°-160°F).    The    actual    dryer temperature will be indicated on the thermometer. 4.  Set  drying  time  for  approximately  20 minutes. 5. Set the cool-down timer for 10 minutes to cool the load to approximately 120°F during the cool-down  cycle. 6.  Push  the  start  button.  Drying  time  depends upon  steam  condition,  weight  and  texture  of  load, and the amount of moisture left in the load after it was extracted. Standard tumbler performance should  not  exceed  1  minute  per  pound  (dry weight).  NOTE:  During  the  cool-down  cycle, move  dampers  to  the  cool  position. 5-36