Select suitable valve types for the following applications: 

1. Isolating a heat exchanger; 

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

3. The valves need to isolate a pump and provide emergency manual control on a bypass loop; 

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

5. Valves in a line where cleanliness and hygiene are an essential requirement. State the criterion used in the selection for each application.