Hazard from Engines Rebreathing Exhaust in Confined Space.
NTIS: PB 228 667 :16 pages
The Bureau of Mines conducted a series of experiments to determine the influence of exhaust rebreathing on emissions from various gasoline and diesel engines. Tests were conducted that simulated operation of engines in nonventilated spaces as well as in spaces with partially restricted ventilation. Results of these tests showed that exhaust rebreathing can have a marked effect on exhaust emissions and thus on the composition of the air in the working space. For the case of restricted ventilation, unaccaptably high (greater than 50 ppm) levels of CO in the air of the working space resulted from exhaust rebreathing rates as low as 8 pct exhaust in the engine's intake. Operation in a nonventilated space resulted in highly critical CO levels (fatal in a few minutes) at times corresponding to 1 to 3 pounds of fuel consumed per 1,000 cu ft of space. Tests involving space of various sizes showed that volume of the air spaces per se is not important--the primary variable is fuel consumed per unit volume of air space.
IH; Report of Investigation;
NTIS Accession No.
NTIS: PB 228 667