Please answer (b) and (c)

(a) Fifty-five-gallon drums are being filled with 2-butoxyethanol. The drums are being splashfilled at the rate of 30 drums per hour. The bung opening through which the drums are being filled has an area of 8cm2. Estimate the ambient vapor concentration if the ventilation rate is 3000ft3/min. Also, calculate the concentration range of 2-butoxyethanol vapor for subsurface filling. The vapor pressure of 2-butoxyethanol is 0.9mmHg under this conditions. Data: For splash filling (filling from the top of a container with the liquid splashing to the bottom), =1. For subsurface filling (by the dip leg to the bottom of the tank), =0.5. Molecular weight of 2-butoxyethanol =118,1ft3=7.4805gal=28.317L,1ft=30.38cm =0.3048m (7 marks) (b) Make a comparison of different types ventilation techniques. (5 marks) (c) A block valve is not installed as required on the upstream of an acid tank which may cause difficulty during maintenance. As a safety engineer what will you do? Give practical solution to prevent this situation happen again in the future? (8 marks)