Select suitable valve types for the following applications:

a. Isolating a heat exchanger.

b. Manual control of the water flow into a tank used for making up batches of sodium hydroxide solution.

c. The valves needed to isolate a pump and provide emergency manual control on a bypass loop.

d. Isolation valves in the line from a vacuum column to the steam ejectors producing the vacuum.

e. Valves in a line where cleanliness and hygiene are an essential requirement.

State the criterion used in the selection for each application.