Varibles in a steam system include :

1. use:  is it being used for heating / cooling, for process, or a combination

2. operating pressure

3. load characteristics:  peak demand, steady state demand, etc.

4. quality (dryness):  100% steam quality refers to zero saturated steam (dry steam)

5. degrees of superheat:  amount of heat added to the steam above its saturation temperature

6. condensate return requirements (temperature, pressure, flow rate)

7.  make-up water requirements

8.  fuel used for combustion in the steam generator
clean steam is used where it may come into contact with ingested products, or where it is used to heat WFI water or clean devices in an autoclave