FIG. 34 is a schematic representation of a processing system for monitoring personnel according to one embodi- ment of the present invention.

FIG. 35 is a flow diagram for operating the processor/ transmitter of the SCBA according to one embodiment of the present  invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 generally illustrates a Self-Contained Breathing Apparatus (SCBA) as typically used by inpiduals. The SCBA10 has a mask body portion 100 that snugly fits to the face of an inpidual. The SCBA10 also incorporates a clear shield portion 15 through which the inpidual sees. The SCBA also incorporates a source of bottled air 12 connected to the mask portion through a breathing tube 13. The equipment includes a harness 18 which holds the air tank at the workers back and a personal alert safety system 20 that is held on the worker by, for example, mounting it on the harness. The PASS senses an emergency situation such as lack of worker motion for a period of time. The PASS activates an alarm if the worker remains motionless for a predetermined period. It is common that after twenty sec- onds of detecting no motion, the PASS sounds a chirp to remind the worker that it will activate the full alarm in ten seconds if the worker remains motionless, so the worker can move to avoid a false alarm. The alarm usually includes a device that produces a loud sound. As illustrated in FIG. 2, the SCBA also includes a radio transmitter 14 that transmits through antenna 16 an emergency signal to a command station that may be on a nearby fire truck to alert others that a fireman is in danger.

FIG. 3 illustrates the mask body 100 of the SCBA in the present invention. The mask body includes a viewing win- dow 20 and an inner half-mask 30 which, in turn, includes an exhale valve 40. The mask body 100 is surrounded about the periphery by a sealing rim 50 which accommodates sensors 20, 22 in the forehead region of the wearer of the mask. The sealing rim 50 of the mask can include two mutually adjacent sealing beads 60 and 58 which extend around the peripheral region of the mask. The mutually adjacent sealing beads conjointly define a cavity therebe- tween and the sensor 6 is seated in the cavity so as to be in contact engagement with the wearer of the mask when the mask is worn. An additional contact thermometer 70 can be mounted on the side of the sealing rim 50 opposite sensor 20 in order to detect the body  temperature.

Sensor 20 monitors carbon monoxide and sensor 22 monitors heart rate and oxygen saturation levels in an inpidual’s bloodstream. The mask also incorporates sen- sors 26, 28 and 30. Sensor 26 monitors external temperature, sensor 28 monitors cyanides or other potential constituents of smoke and sensor 30 monitors exhaled carbon dioxide. Sensor 30 is conveniently constructed to be in the respira- tory path of the SCBA. The sensors 20 and 22 shown as in FIG. 3 are illustrated  in more detail in FIG.  4.

The oxygen saturation sensor 22 measures the percentage of blood cells that are occupied with oxygen (SEO,) versus empty. Sensor 22 is capable of distinguishing between blood cells occupied by oxygen and blood cells occupied by carbon monoxide. Carbon monoxide makes a stronger bond to blood cells than oxygen does, and thus, prevents the exchange of oxygen and carbon dioxide causing hypoxia in the person. A carbon monoxide sensor 20 can be used to determine the concentration of carboxy-hemoglobin (COH,) in  the body. True  oxygen  saturation  can be  determine by

subtracting COH, from SEO,. A carbon dioxide CO, sensor is placed in the exhaled respiratory path of the SCBA. This device measures End-Tidal CO, (EtCO,), or the amount (partial pressure) of CO, in exhaled breath. If the amount of

5 EtCO, drops significantly below 5 o (or about 35  mmHg), the person wearing the mask is not achieving good oxygen- carbon dioxide exchange.

A processor  160,  which  is  mounted  on  the  mask 100,receives the data signals from the carbon monoxide  sensor 10 20, oxygen sensor 22, temperature sensor 26, cyanide sensor 28 and carbon monoxide sensor 30. The processor 160, in turn, creates at least one condition signal indicating a hazard condition.