According to NIOSH’s PWC norms (1991), for an average civilian worker, how much seated rest (in minutes/hour of work) should be allotted for a floor-level lifting task that is only performed less than one hour per work day and requires an oxygen consumption rate of 1.5 liters/minute?

37min/hour

Explanation:

% of rest with respect to work time=  (PWC-Ejob)/(Erest-Ejob)

According to NIOSH 1991, PWC= 3.7kcal/min

E job= 1.5 litre/min of oxygen × 4.9 kcal/litres of oxygen

E job= 7.35 kcal/min

Taking E rest= 1.5 kcal/min

% of rest with respect to work time= (3.7-7.35)/(1.5-7.35)×100

                                                             = 62.4%

62.4 % of an hour or 37min/hour.