ISO 14644 – What it is.


ISO is the International Organization for Standardization, based in Geneva Switzerland1. You may have heard of ISO 9000/9001 certification, which covers general quality management systems, but there are many more ISO standards – more than 10,000 total standards available at the time of this writing (September 2013), covering everything from IT systems configuration to milk production to statistical methods.2

A bummer, to me at least, is that the standards are not free, and they are not cheap. Copies of standards in electronic (PDF) or paper form can be purchased from the ISO website ( in Swiss Francs, or from ANSI3 or IEST4 in American Dollars. The 18 page ISO 14644-1 will cost you around $100. Note that the copy is for individual use only, not to be shared. Needless to say, to get yourself a complete set of ISO standards would cost you a pretty penny. Continue reading ISO 14644 – What it is.

Cleaning Validation – Visual Inspection

Visual Inspection

Visual inspection is actually a method used to collect data against an acceptance criterion.

Per PDA’s Technical Report 29 “Cleaning Validation” (2012) you only need a quantitative visual limit if visual examination is the only method used and visually clean is the only acceptance criterion. According to the report, if you are using visually clean as an acceptance criterion in conjunction with swab or rinse sampling, you do not need to quantify the visual limit and what “visually clean” means.
If you do need to quantify the visual limit, you can do so by spiking coupons with solutions at different surface densities (e.g. microgram/cm2 or ppm) and having a panel of qualified personnel determine at which level the residue ceases to be clearly visible. Distance, lighting, and viewing angle need to be considered.

URS for Purified Water Systems

WFI Still
WFI Still

Hello good people of the world! Today’s post deals with the User Requirements Specification (URS) for a Purified Water System. It may be RO/DI, Purified Water, or WFI, but it should probably have a URS. As with any URS, make sure requirements are specific, measurable, accurate, repeatable, and testable. Considerations specific to purified water systems include: Continue reading URS for Purified Water Systems

Creating a User Requirements Specification (URS)

Life without a good URS

Purpose of a URS:

  • Specify guiding regulations and industry and site standards the system must meet
  • Specify deliverables


  1. Ensure each requirement has a unique number. This is for ease of traceability and referencing in other documents
  2. Evaluate the impact to quality in the URS itself. This will allow agreement up front for what requirements will need to be tested as part of qualification/validation, and which can be safety ignored.
  3. Each requirement should be specific and measureable so that it can be easily tested. While it’s tempting to include statements like “The XYZ system shall comply with applicable regulations” this statement really becomes meaningless because it is not specific enough, and is not testable. Continue reading Creating a User Requirements Specification (URS)

The Basic Validation Approach


You need to understand your process, define what the acceptance criteria is, and then challenge the process. The idea is once you have a validated process, you don’t have to look at the acceptance criterion each time, just monitor that the process is under control.

Monitor process while performed under controlled conditions
Define successful results beforehand
Challenge the process
Determine efficient ways to monitor the successful process
Document the process testing