Appropriate PRPs for the manufacture of food grade liquid co2

HI, I've read the thread on  FSSC Certification for CO2

Manufacturing from Natural Fermentation 

i just want to know which PRPs are appropriate in the manufacture of food grade liquid co2, 

from ISO 22000 : 2005

clause 7.2.2 a): The PRP(s) shall be appropriate to the organizational needs with regard to FOOD SAFETY

and from ISO 22000 : 2005

clause 7.2.3: 

The organization shall consider the following when establishing these programmes:

a) construction and lay-out of buildings and associated utilities;

b) lay-out or premises, including workspace and employee facilities;

c) supplies of air, water, energy and other utilities;

d) supporting services, including waste and sewage disposal

e) the suitability of equipment and its accessibility for cleaning, maintenance and preventative maintenance;

f) management of purchased materials (e.g. raw materials, ingredients, chemicals and packaging), supplies (e.g. water, air, steam and ice), disposal (e.g. waste and sewage) and handling of products (e.g. storage and transport);

g) measures for the prevention of cross contamination;

h) cleaning and sanitizing;

i) pest control;

j) personnel hygiene;

k) other aspects as appropriate.

thanks in advance 

Look at your process and identify all of the hazards....this is step 1 of HACCP.

As you work your way through your process you should be able to identify what PRPs apply and those that do not