Analysis of contamination before design stage and definition of need
This part aims to highlight a number of issues that need addressing in order to best define which washing procedure should be implemented:
First, it is necessary to know precisely the input data, to clearly know what requires the use of the washing procedure.
Contamination: is it?
- Known, controlled (chemically, size, source, vector …)
- Regular or infrequent (What is the frequency of occurrence and kinetics)
- Multiple or single
- Chemical, organic or both
- Dry or liquid
- Uniformly distributed in quantity or in thin layers on surfaces (problem: corners and pre-cleaning)
- Amount of tackiness caused by a possible preliminary treatment: embedded deposits / Aerosol, reaction (laboratory equipment), cooking (glassware), ….
Next comes the definition of output data:
Identify and formulate in writing, from the design stage, the objective of cleanliness, which means :
- The quantifiable results WITH its pass / fail criteria (operational ranges, alarms and shutdowns)
- The probable Cleanliness Assurance Level (NAP) and not the average
To reduce or eliminate? All or part:
- of particulate contamination? (Which – Size – Threshold …)
- of microbiological contamination? (disinfection up to sterilisation – endotoxins)
- of the risk of cross contamination?
Is it necessary to have the same threshold for all items? Guidelines, operators, products
Which air classification :
- no traces visible to the naked eye or to the specific sensor
- <1 particle / 1 µm
- <2 particles / 2.5-20 µm
- no particles / 25 µm
Are the objectives:
- Technically realistic?
- Qualitatively quantifiable?
- Economically profitable?
- And consistent according to risk / criticality?(CI = GPxFPxND)
Only after addressing these questions can we focus on the means and their own parametres.
Any investment in knowledge and upstream analysis would remain a latent economy for output and quality in terms of the anticipated risks for process monitoring.