the following is the preferred embodiment or best mode for carrying out the invention . it should be noted that this invention is not limited by the discussion of the preferred embodiment , but that skilled artisans may easily recognize that certain modifications may be made without deviating from the spirit of the invention . now referring to fig1 a and 1b which depict the shielding system of the unit in a closed and open position , respectively . the shielding material comprises a canopy 1 and leg cover 2 . typically , canopy 1 and leg cover 2 comprise polycarbonate material that includes a one - way mirror effect such that an occupant sees out while an intruder cannot see inside the closed unit . this effect may be achieved by coating the polycarbonate material with a dark window film that may be bought at auto supply or other such stores . the canopy 1 and leg cover 2 are hingedly affixed to back headboard plating 5 and foot frame plating 4 as shown in fig3 and 4 . thus , the shielding system may be opened as shown in fig1 b such that the occupant can sleep with the shielding in an open position . the shielding system also includes side frame plating 3 , foot frame plating 4 , back headboard plating 5 and side headboard plating 6 . the plating may comprise polycarbonate material or other alternative materials , some of which are listed above . the plating is affixed to the frame of the protective bed unit by fastening devices such as rivets or bolts . a sealant may be applied between the plating and the frame for assuring that an effective seal is created . doors 7 comprise shielding material and are hingedly affixed to side headboard plating 6 for gaining access to the interior of the unit . the matting surfaces of the canopy 1 , leg cover 2 and doors 7 include grooves with rubber seals 8 inserted therein . the seals 8 are compressed when the unit is closed to create an airtight seal as shown in fig5 . [ 0053 ] fig2 through 4 are perspective views of the protective bed unit . hinge 56 attaches door 7 to side headboard plating 6 . external hinges 56 also attach the canopy 1 and leg cover 2 to the headboard and foot frame plating respectively . filters 24 and 25 are also attach to back headboard plating 5 . outlet ducts 23 a allow filtered air to exit the air tight chamber . now turning to fig6 a - d which show perspective views of the frame that supports the shielding system and bedding . the frame comprises side bed frame elements 9 that are formed in a box - like structure on either side of the unit as shown . bed frame brace members 11 connect the two box - like structures together via fastening devices such as rivets . the box - like structures are fastened at one end to the foot bed frame elements 10 and at an opposite end to the headboard 12 . hex head bolts and nuts 46 affix the side bed frame elements 9 to the headboard 12 . a mattress base 50 sits atop the box - like structures and is shown in phantom in fig6 b . box spring 49 and mattress 48 rest atop the mattress base 50 . actuator bases 13 are arranged as shown to provide support surfaces for lifting the canopy 1 and leg cover 2 . [ 0055 ] fig7 a depicts cover actuators 14 in the open and closed position . an end of a cover actuator includes an actuator mounting base plate 18 that is affixed to actuator base 13 . an opposite end of the actuator 14 attaches to an actuator mounting lift plate 19 that attaches to canopy 1 . likewise , an actuator is coupled to leg cover 2 for raising it to an open position or lowering it into a closed position as shown . each door 7 includes a door actuator 15 for opening and closing the doors . the door actuator 15 includes a quick release link 20 for manually disengaging the actuator 15 . bolts 57 secure the halves of the quick release link 20 to the actuator 15 . a spindle 20 d having a key notch and projecting from first half 20 a couples the halves 20 a and 20 b together . half 20 b includes a female complementary receptacle ( not shown ) for accepting the spindle 20 d . now turning to the ventilation system shown in fig8 a through 8c , the ventilation system includes two filters a hepa / dust filter 24 and a bio - chemical filter 25 . the hepa / dust filter 24 is used during ordinary venting operations . in emergency situations such as during a gas attack , the bio - chemical filter 25 filters the air supply entering the unit . the unit may automatically switch from the dust filter 24 to the bio - chemical filter 25 when the bio - chemical agent sensor 32 detects the presence of an agent . vent fans 21 pull external air through the filters 24 and 25 . arrows shown in these drawings indicate the direction of air as it flows through various parts of the ventilation system . vent solenoid valves 22 control whether the air will be circulated through the rebreather 26 . valves 22 a and 22 b control the flow of air through either of the filters 24 and 25 . these valves are electronically controlled by the control panel 34 and may be switched over automatically in response to warning sensors . as can be seen in fig8 a , air flows into one of the filters 24 or 25 and through duct 23 through valve 22 a and into the unit . the air is then pushed out of the unit through valve 22 b . these valves 22 a and 22 b are closed when the rebreather 26 is being operated . as shown in fig8 b , when the rebreather 26 is in operation , air is pulled through valve 22 d into the rebreather 26 and is scrubbed to remove carbon dioxide and replenish oxygen . the air is pushed through valve 22 c and re - circulated into the interior of the unit . [ 0059 ] fig9 shows a block diagram of the electrical system of the protective bed unit . a motion detector 27 detects motions in the area around the protective bed unit . the operator may place the control panel in a mode that either an alarm may sound or the unit may automatically close should motion be detected around the unit . the controller may also include a feature for detecting glass breakage and acting according to preprogrammed directions . a smoke detector 29 alerts an occupant when smoke is detected . oxygen sensor 30 sounds an alarm when the oxygen content of the air becomes too low for safe breathing conditions . an lel sensor 31 detects the presence of natural or lp gas . bio - chemical agent sensor 32 senses the presence of biological or chemical agents . other such sensors and detectors may be included such as pressure sensor 55 . sensors may include those sold by figaro such as a carbon dioxide sensor model number tgs4160 , and oxygen sensor model ke - 25 . the control panel 34 allows the user to select from a wide variety of modes . an external key pad 35 provides a means for locking the door 7 of the unit when away . a user then enters a numerical password to gain entry into the unit . cabinet lights 33 are included in the unit for providing a user with a light source . the unit may include a remote unit 37 for remotely controlling the unit . a heating and air conditioning unit 38 provides climate control for the interior temperature of the unit . the unit may be equipped with a refrigerant gas sensor 39 for detecting the leaking of coolant gas into the unit , which may lead to a dangerous condition . the heating and air conditioning unit 38 to maintain a desired temperature uses a thermostat 40 or temperature sensor . the unit includes a backup power source 42 for operating the unit when the primary power source has failed . the system might include visual warning lights such as led 43 . an audio amplifier 51 amplifies external sounds such that the user can hear them being broadcast through speakers 52 . a communication system 53 is provided as discussed above . entertainment system 54 may include a stereo , dvd player , television or the like .