some  remedial  actions  are  discussed  in  the following   sections, Automatic Sprinklers Conditions  that  indicate  the  need  for maintenance for automatic sprinklers include the following: .  Mechanical  injury  such  as  bent  or  loose deflectors  or  bent  frames.  Where  sprinklers  are subjected to continual damage, provide approved sprinkler guards. l Corrosion such as marked discoloration or hard   deposits.   Use   lead-coated   or   wax-coated sprinklers  to  prevent  corrosion. .   Overheating   causes   soldered   joints   and cracked  quartz  bulbs  to  give  way.  Temperature ratings for soldered link sprinklers should be 50 “F above  (for  quartz  bulb  sprinklers  25  ‘F  above) normal  room  temperature. .   Freezing   produces   reduced   tension   in soldered  links,  bent  struts,  and  distorted  caps. .  Loading  is  deposits  of  paint  or  other foreign  materials. . Need for replacement or relocation. Major construction and occupancy changes and changes to heating, lighting, and air-conditioning systems may   require   relocation   or   replacement   of sprinklers or additions to the system. Changes in sprinkler location and pipe sizes should be based upon  an  engineering  evaluation. .  Where  sprinklers  are  installed  in  areas where  there  is  stockpiling  of  materials  a  clearance of  at  least  18  inches  under  the  sprinklers  is necessary  for  proper  water  distribution. Keep  a  supply  of  extra  sprinklers  for  the various  types  and  temperature  ratings  required and a sprinkler wrench. Outside Open Sprinklers When   you   are   servicing   outside   open sprinklers,  you  should  do  the  following: .  Visually  check  the  general  condition  of sprinklers. 8-20 . Close windows and doors and take proper precautions  to  avoid  water  damage  to  property before  making  flow  tests. .  Conduct  the  flow  test  by  opening  the control  valve. After  making  flow  tests,  remove  and  clean  any plugged  or  obstructed  sprinklers. Piping and Hangers In  servicing  piping  and  hangers,  check  for mechanical injury and corrosion. Replace bent or damaged  piping  and  fittings  and  replace  or  repair missing or loose hangers. Make sure that piping is not used to support stock, equipment, or other material. Make sure wet pipe system piping is properly protected  against  freezing.  Before  and  during freezing  weather,  check  piping  of  dry  pipe  systems for  proper  drainage.  During  freezing  weather, open drains for outside sprinkler systems. Drain water from low point drains and drum drips on dry pipe systems before freezing weather occurs. Obstructed Piping When  evidence  of  obstruction  of  piping  has been  found,  check  for  the  following  sources  of obstructing  material: Improperly  screened  inlets  from  open bodies  of  water Poorly maintained elevated gravity tanks Dead end of extensive water distribution systems Poorly  installed  underground  mains Highly  acid,  alkaline,  or  saline  water Active  chemicals  in  water  supply Use  of  secondhand  materials  in  the sprinkler   system Frequent operation of systems (especially dry  pipe  systems)  introducing  additional foreign  material  and  free  oxygen Alarm  Check  Valves Perform a 2-inch drain test quarterly to test alar m check valves. Open the 2-inch drain valve