Functional Design Specification - The supplier's response to URS

In previous articles, I wrote mainly about the User Requirement Specification, which is the Alfa&Omega of the Control System Validation, and overall the Alfa&Omega of #Computerized #Software #Validation.

Then you should proceed through the #supplier selection, where multiple audits should be done to verify that the supplier can manufacture your machine in terms of the #ISO/ #NISTR/ #EN, capabilities, knowledge, etc.

But, it is done? What's next?

The Functional Design Specification (#FDS) is the cornerstone of the #IQ and #OQ qualification phases of an Automation Control System. It is a high-level document, that is written by the supplier and describes briefly and clearly how the intended Automation Control System will meet the purchaser's requirements/needs as set out in the #URS.

The Functional Design Specification can be developed jointly by the purchaser and supplier. It is not unusual, particularly when the Automation Control System is large and complex.

The Functional Design Specification is the basis for the development of the #Qualification Phases as was mentioned above, therefore FDS should identify all measurable or determinable parameters, which may affect the system performance, and include the acceptable values or characteristics of each critical parameter. Critical parameters/functions/devices are those, that will affect the state of control of the Automation Control System/Quality of the final product or patient safety. These #critical parameters/functions/devices should be defined in the User Requirement Specification.

The important part of the FDS is to describe the #interfaces between the Automation Control System and Operating Environment. It can be a part of the FDS, or it can be referred to the documents, such as construction drawings, equipment manuals, or #SOPs for more detailed information.

Once the Functional #Design Specification is produced, there will be a formal verification if it addresses properly all #requirements, and functions of the User Requirement Specification that are to be implemented by the system.

What we should avoid in #professional Functional Design Specifications?

• Vague or ambiguous statements,
• Each function should have a unique reference,
• Specification of functionality should not be duplicated,
• Each function defined should be testable. This is particularly important for Automation Control System to validate because Factory and Site Acceptance Testing is carried out against the FDS/URS.
• FDS should be understood by both the purchaser's representatives and suppliers,
• Jargon should be avoided.

What should you do, when you have some Non-Conformance?

Any non-conformance, due for example to time constraints or costs, should be resolved between the supplier and purchasers before approval. Any technical non-compliance must be fully documented as a supplement or update to the URS. This is very important as the FDS is normally the base document for the System Integration Tests, and also Factory and Site Acceptance Tests.

You are welcome to subscribe to the #newsletter about the #CSV / #CSA, where more articles will be uploaded, following the validation of the #software.