NOTE:    Whenever possible, the RFR burn source should  be  replaced  with  a  nonmetallic  substitute  or relocated or reoriented to eliminate the hazard before resorting to a type 3 sign for personnel protection. A type 3 sign should be installed on the RFR burn source or in the immediate vicinity where it can be seen easily. When used on cargo handling running rigging, type 3 signs should be mounted on the hook insulator. Personnel   should   be   warned   to   not   touch   the wire/rigging above the insulator. More than one type 3 sign should be installed on larger burn sources that can be approached from multiple directions. Type 4—“WARNING RADIO FREQUENCY HAZARD . . . FUELING OPERATIONS” The   type   4   sign   advises   of   the   hazards   of electromagnetic   radiation   to   fuels   (HERF).   These signs   are   normally   used   only   on   ships   that   carry aviation   gasoline   (AVGAS)   or   automotive   gasoline (MOGAS). Marine diesel fuel and JP-5 jet fuel are not considered  to  have  a  HERF  problem  and  require  no special   electromagnetic   safety   precautions   during fueling.  Most  naval  ships  do  not  carry  gasoline.  An exception   to   this   is   amphibious   ships   carrying gasoline-powered landing vehicles. Aboard ships that carry AVGAS or MOGAS, personnel should observe the   following   precautions   during   fueling   or   fuel transfer operations: 1.   Secure all transmitting antennas located within the quadrant of the ship in which fueling is being conducted. 2.   Ensure  that  RADHAZ  cutouts  for  microwave radiators   are   not   overridden   during   fueling, which  could  result  in  the  illumination  of  the fueling areas. 3.   Do  not  energize  any  radar  or  communications transmitter on any aircraft or vehicle. 4.   Do   not   make   or   break   any   electrical,   static ground  wire,  or  tie  down  connection,  or  any metallic   connection   to   the   aircraft   or   motor vehicle   while   it   is   being   fueled.   Make   the connections   before   the   fueling   commences. Break them afterward. Type 5—“WARNING RADIO FREQUENCY HAZARD (SPECIAL CONDITION)” The  type  5  sign  has  a  blank  area  for  filling  in special   safety   precautions.   Its   purpose   is   to   advise personnel   of   procedures   to   follow   when   other RADHAZ   warning   signs   are   not   appropriate. Examples of directions that can be filled in on a type 5 sign include:    “Inform OOD before placing system in radiate.”    “In manual mode, do not depress below horizon between ______ and _______ degrees relative.”    “Ensure   temporary   exclusion   barriers   are   in place before radiating.”    “Do   not   stop   antenna   between   _______   and _______ degrees while radiating.” A type 5 sign is normally installed below decks in a system  operating  room.  It  should  be  installed  in  the vicinity of controls such as a radiate switch or antenna control switch, where the person operating the gear in normal operation can see it. When mounted on system cabinets or control panels, RADHAZ signs should not obscure switch labels, meters, indicators or nameplate data. Type 6—“WARNING RADIO FREQUENCY HAZARD . . . HAZARD TO ORDNANCE” T h e    t y p e    6    s i g n    a d v i s e s    o f    h a z a r d s    o f electromagnetic   radiation   to   ordnance   (HERO). NAVSEA   OP   3565   explains   the   purpose   of   HERO signs and where to place them. ROTATION HAZARD WARNING Rotating   directors   present   a   serious   danger   to personnel near them. To guard against this hazard, be sure the topside area near the directors is cleared of all personnel before you energize a director. “DANGER ROTATION   HAZARD”   warnings   should   also   be posted or painted in conspicuous places to alert unwary personnel. Q7. What   OPNAV   instruction   gives   the   OOD guidance for the Working Aloft Check Sheet? Q8. What   size   RADHAZ   signs   should   be   used   on ships? Q9. What type of RADHAZ warning signs should be used   when   other   RADHAZ   signs   are   NOT appropriate? OTHER RADAR HAZARDS The  hazards  we  discussed  above  occur  primarily on  the  exterior  of  the  ship.  We  now  need  to  discuss 3-14