I think you have brought up some important points here (for example, between isolation and non isolation, which action is the most reasonable based on risk involved?) but I am simply not sure how such an item can be incorporated together with any other construction activities (imagine the ranges) in a form of procedure. Maybe the idea of the isolation will vary from one activity to another, the availability of resources, etc. I really don't know. In any event, I think it would be wise to have the food safety expert's input on this before going any further.
As I mentioned I am not drafting a procedure, not will be providing a form. I am documenting guidelines how to assess each situation. There a many contributing factors, that make each situation very different. The document defines who may be involved in the risk assessment (depending on the scope of the activity) and provides some examples of what measures may be considered if the risk is identified.
I like your policy Jan; I was thinking similar to you e.g. what, where, who, when, how is a risk assessment that leads to informed and adequate control measures. In answer to your question on ‘Means for isolation the construction zone’ usually a containment tent with dust extraction or collection is effective. Not sure what you mean about ‘Specific procedures for preventing contamination of pipes’ – do you mean internal or external?
My question concerns the cases where closed processsing systems need to be opened, e.g. replacing/adding pipes, filters, pumps, etc. How do you ensure that the new component are delivered clean? How do you prevent contamination from entering the system?