OSHAOCCUPATIONAL SAFETY AND HEALTH ADMINISTRATIONU.S. DEPARTMENT OF LABOR OCCUPATIONAL SAFETY & HEALTH STANDARDS ) (Working Safely in Confined Spaces : ) ( Confined Spaces (OSHA) 22400 7.2 5000 . . :- - - - - - - - - - - :1 . Atmospheric Hazards2 . Mechanical & Electrical Hazards3 . Physical Hazards4 . Engulfment Hazards 1 - : 1 :- 19.5 % 23.5 % . :- : .......- .- 10 .% : : . : 10 (10 ppm) . : 35 (35 ppm) . 2 - : : ..... . 3 - : ) ( . 24 - : . . . :1 . : 19.5 5 : 2 . : :- 19.5% 23.5%- 10 %- . 3 . : . 344 . : 19.5% 10 % . . . 5 . : . . . . ********************************************************