27 replies to this topic

[RMAV]

Hi RMAV,

 

Out of curiosity, why do you not run the ("CCP") steps in sequence ?. Seems the most logical control procedure.

 

There are analogous processes elsewhere in which the control of 2 variables "boosts" the reduction (= synergy),  but IMEX, as per Trubertq, the activities are usually closely "combined" eg see the short attachment in this post -

 

http://www.ifsqn.com...indpost&p=85830

Yes, they usually are very "close" step-wise.  For my process, it is impossible to run my "CCP steps" in sequence as once I have mixed it I have to fill it, package it, label it, box it, then store it (plus other steps in between). 

[RMAV]

Just a thought, since the actual control is being at the correct pH for the specified time you could call the mixing step a control point (CP) and the holding time the CCP? 

I'm going to look into this further - I might just do that.  I can make recording of the CP (I'll likely call it CM) as stringent as if it were a CCP.  My initial thought of "tying the two together into CCP1" might, perhaps, draw more scrutiny (confusion) than doing it this way.

 

By the way, I am very grateful for all the comments here.  I'm really struggling with this one.

[Charles.C]

Hi RMAV,

 

The obvious theoretical difficulty is that yr process is not the same as yr (sole ?) guideline reference. I'm surprised the difference has not been already remarked upon.

 

But as long as your validation is OK, i doubt that auditors will worry too much about about a single(combined)/double CCP format.

 

For me, yr Post 8 characterises synergy. If so, afaik it is customary (and logical) to include both control functions in the CCP. If the mixing/holding were literally combined, would equally logically be a one step CCP with no ambiguity.

 

The choice also relates to the number of critical limits to be implemented.