Document QqmXZRqqXXDZ0N9j5J0MzOQ8

Chemical Section carbon monoxide to carbon dioxide, would appear as one outstanding American con tribution, along with potassium superoxide and refinements in chemical oxygen sources). A number of impregnated actuated carbons have been developed for certain vapors and gases. A recent advance of the British seems very significant. "Schlicrc" is the German word for "streak" or "shadow". When one has the proper light source, lenses, and mirrors, it is possible to see as well as photograph shadows representing different densities of air or vapors. In one ease, a man was intro duced into the Schlicrcn system and very clear pictures were made of the air move ments during inhalation and exhalation, as well as the normal upward air flow of the air closest to the body. This technique could be useful in studying respiration and respira tory devices. Already, it has suggested why we can expect dust and bacteria from cloth ing, such as coveralls or nurse's uniforms, to be transferred to the breathing zone due to the upward movement of air close to the body. There is much need for more creative initiative in the field of respiratory protec tion. If we want a supply of oxygen in a selfcontained device of some type, an interest ing question arises as to the most effective and light-weight source. Here is an interest ing comparison between the three possible oxygen sources -- gaseous, liquid or solid: Oxygen Sources Volume of Weight Free/ Unit + Stored 02 Cont. Space cu. in. Gas Solid Liquid Ref: Miller 126 44.5 2,160 630 28 460 860 19 1,355 All three have application; it should be obvious which offers the greatest potential for the future development of light-weight, long-life, self-contained breathing apparatus or hoods of some type if certain technical problems can be resolved. As one practical illustration, a photo taken in Toronto a few years ago shows 72 fortycubic-fcct air or oxygen cylinders, part of the supply emptied by firemen in their at tempts to control a fire. Large numbers of cylinders are needed, and few fire depart ments or plants have instant refill capability. This is certainly a serious limitation of the cylindcr-snpplicd air or oxygen mask; chemi cal-oxygen self-generating masks have a similar limitation which is all too often over looked. There are many instances of fires where many dozens of cylinders or canisters were expended. To illustrate the importance of this problem of masks as it affects the real world, here arc some figures recently received from a state fire coordinator relat ing to the volunteer firemen in that state. Active Firefighters......... 2,966 No. of Devices Type N Masks Self-Gen. 0, B. A. Demand-Air-Oj 233 123 351 Spares SO men -- 20 hrs. -- alarm 483 Mask / Man 1-15 1-30 1-12 Time Mask 1 hr? 1 hr? Yt hr Man Hrs. 233 123 175 'Add. Hrs. 50? 246? 241 Tot. Hrs. 283 369 416 1068 Two-thirds time at actual exposure = 14 hrs. real "working time", for 2,966 men. From this, the very real limits of opera tions of the firemen imposed by breathing apparatus and spare cylinders and canisters, become apparent. There are certain fundamental limitations of any breathing equipment. These have not been widely appreciated. 1. Some substances highly toxic by skin absorption require skin, as well as breathing protection. Examples arc: liquid HCN, ani line, other nitro and amino aromatic com pounds, phenol, cthylcnimme, and certain organo-pliosphatcs. There arc others. 2. Maintenance. There is no excuse for poor or inadequate maintenance of breathing apparatus, masks, or respirators, but in fact, 9