Please forgive the pun but it’s a fair question. What is the value of validating your control system or process historian? Many industries don’t bother and leave it to the domain of the regulated manufacturers such as the Pharmaceuticals, Aerospace and Nuclear industries as it is often considered to be a very time consuming and expensive process which offers little in return.
But could other industries such as food, textiles, paper, oil and gas etc benefit from this approach? I would say definitely!
It’s true to say that, initially at least, computer system validation will add work-load to a project while staff come to terms with the process. However, the benefits thereon are manyfold – not least that you will end up with a properly documented system built to the relevant standards which you can then use to fault find and diagnose faults or manufacturing issues and when upgrading or changing the system. The validation process also leaves a documentation chain newcomers can use to understand how the software system works so it can be effectively and efficiently supported and modified in the future.
How many times have you heard, “I don’t know how it works – Joe wrote the software originally and he’s the only one who understands it”. Never helpful, especially if Joe left the company 18 months ago!
It also has the benefit of making you think during the design process as validating a system does not only involve the prospective design of a computer system but also as to whether it will work by virtue of a comprehensive testing regime. In this sense it is often argued that both design and test processes should be run in parallel – in other words when you design a piece of software have you considered whether you can you test it? If the answer to this is no, then you will struggle to get the software to work in the first place! In fact if you can’t test it you can’t be sure it works!
So what is Computer System Validation? The text book definition is ‘the process of ensuring a software system meets specifications and requirements so it fulfils its intended purpose’.
I went to a computer system validation conference years ago and heard this definition for Computer System Validation, which I prefer:
Say what you are going to do – Write the relevant specifications.
Do what you said you would do – Build the system according to the specifications you’ve written.
Prove you did what you said you would do – Test the system according to the specifications you’ve written.
For help getting started with computer system validation I recommend taking a look at the ISPE’s (International Society of Pharmaceutical Engineering) excellent publication called GAMP5 (Good Automated Manufacturing Practice) which explains this recognised methodology for computer system validation. It also provides a comprehensive list of documentation type templates (e.g. URS, FDS etc).
The website is: ispe.org/publications/guidance-documents