Document zo67VVNgQxVJj7L12YMBOoML0

XXVUl CONTENTS V. Poisoning from Radioisotopes.................................................................................. 722 A. Radium Poisoning................................................................................................ 722 B. Thorium Poisoning.............................................................................................. 739 Handbooks of the National Bureau of Standards on Radiation Protection.... 742 XX. Lighting for Seeing. By Sylvester K. Gdth and E. A. Linsday. ....................... 743 I. Lighting Terms and Units...................................................................................... 744 II. Visibility............................................................................. 745 III. Ease of Seeing. .......................................................................................................... 751 IV. Quality of Lighting................................................................................................... 752 V. Color.............................................................. 755 VI. The Human Element................................................................................................ 755 VII. Light Sources................................................................. 769 A. Filament Lamps................................................................................................... 759 B. Mercury Lamps.................................................................................................... 759 C. Fluorescent Lamps.............................................................................................. 760 D. Germicidal Lamps............................................................................................... 760 E. Infrared Lamps.................................................................................................... 761 Vni. Lighting Benefits....................................................... ................... ............;. .. 761 IX, General Lighting..........................'.......................... ..................... ;..!.................... 774 A. Maintenance......................................................................................................... 778 X. Supplementary Lighting........................... 780 XI. Infrared Radiation................. 787 XII. Ultraviolet Radiation............ ................................................................................... 787 XXL Heat Control in the Hot Industries. By T. F. Hatch.......................................... 789 I. Effects of Heat on Man................................................................ .......... .............. 790 II. Physiological -Limits of Heat Exposure................................. ........... .................. 791 A. Haldane's Wet-Bulb Temperature Limits................................................. ... 791 B. Exposure Limits in Terms of Effective Temperature. .................................. 792 C. Physiological Limits Based on Performance Ability...................................... 792 D. Maximum PermissibleSweat Rate..................................................................... 793 E. Calculated Limits of Heat Exposure to Maintain Thermal Balance............ 794 F.TPhyrical Basis of Toleranoe Lines....... .............................. ............ 795 G. Limits of Heat Exposure Fixed by Thermal Balance and Maximum Per missible Sweat Rate............................................................................................ 798 III. Physical Evaluation of Hot Environments................................................... 799 IV. Heat Control. ......................... '................ .............. .................. .......... 801 A. Control at Source...................... 801 B. General Building Ventilation............................................................................. 804 C. Localized Ventilation and Cooling at Fixed Work-Stations....... .... ............. .-804 V. Su^eirviiiphtpf Employees in Hot Industries..................... .............................. 805 A. 'Safe Tolerance Limits and Intermittent Rest Periods................................... 806 B. liiSdical Supervision................................................................. 807 Sm CHAPTER I Industrial Hygiene--Retrospect and Prospect FRANK A. PATTY Historical accounts down through the ages are replete with allusions to the unattractive lot of the man who has earned his livelihood by manual labor. In ancient times a considerable portion of such work was done by slaves, a practice that has been extended in instances even into the twentieth century. Where slave labor has been employed there has not been sufficient incentive or opportunity to study the adverse effects of occupational environments. Early beliefs that unhealthful conditions are inherent in certain trades have now been disproved and are no longer generally expressed; when plant operators today are presented with clear-cut evidence of unhealthful working environments they are almost universally ready to institute any practical control measures. One of the industries that rather recently joined the modern trend toward providing clean as well as healthful environments was the foundry industry,, and even today -some-foundryoperators still believe that considerable dirt, dust, and fumes are inherent in the industry. This is not an expression of conservatism among foundry management, but rather the result of the failure of the layout man, the industrial hygienist, and the ventilation engineer to provide information on the correct design of foundries and foundry equipment as well as on correct ventilation practices. No one wants a dirty work place if it is easy, practical, andieconomically feasible to have a clean one. Neither does management want to spynd huge sums, for dust control only to find that it does not do what it was intended to do. Although there may still be isolated employers who regard labor as a commodity purchasable on the market and more easily replaced than preserved, the.vast.majority of workmen in the United States today are in a very enviable position with respect to the -safeguards taken-to-protect-them from occupational diseases and accidents. I. Historical Resume A. MEDICAL AND INDUSTRIAL HYGIENE LITERATURE ' Lead poisoning is the oldest recorded occupational disease. Hippocrates, who lived in the fourth century b.c. and is credited with lifting the practice of medicine from its basis of superstition and giving it a scientific foundation, has also been credited by some with being the first to record adverse effects upon miners $nd metallurgists from exposure to lead. i 1