We want to evaluate the usage of nitrogen in the ISU Unit Operations laboratory. We are concerned that if a release of nitrogen occurs, the oxygen level will be reduced below the 19.5% allowed by OSHA. The laboratory has a floor area of 4800 ft2 and a volume of 74,300 ft3 . The ventilation rate is 1 ft3 /min for each square foot of laboratory floor space. A. We currently use a gas cylinder to deliver nitrogen. This cylinder contains a volume of 1.76 ft3 of nitrogen. The nitrogen in a full cylinder is pressurized to 2500 psig. Nitrogen behaves as an ideal gas under these conditions. Calculate the concentration of oxygen in the room if the cylinder fails catastrophically. Assume that the nitrogen released by the cylinder displaces the air in the lab. Is the oxygen concentration acceptable for this case?
B. We are proposing to replace a gascylinder with a small nitrogen plant. The plant is capable of producing 19.3 SCFM of nitrogen. If the nitrogen is all released into the laboratory instead of into the process that uses it, estimate the concentration of oxygen in the lab due to this continuous release of nitrogen. Is this acceptable? What about the local concentration around the vicinity of the leak?