Glossary · Engineering, integration and validation
Requirements specification
Also known as: Technical specification, Supplier specification
German: Pflichtenheft
In German engineering practice, a requirements specification (Pflichtenheft) is the contractor's document describing how and with what means the requirements of the client's user requirements document (Lastenheft) will be met. In English usage, requirements specification can also refer more generally to any document that states system requirements.
- Validation
In one sentence
A requirements specification (Pflichtenheft) describes how the contractor will meet the client's requirements stated in the Lastenheft.
Example
The system integrator's requirements specification answers each point of the customer's user requirements, for example by naming the controller platform and the redundancy concept.
How it applies
- Project management: The Lastenheft states what the client wants; the Pflichtenheft states how the contractor delivers it. Once approved, it is often part of the contract and the basis for acceptance.
- Engineering: The specification is refined into Functional specification and Design specification; each point should be verifiable against an Acceptance criterion.
- Testing: Test cases for the Factory acceptance test (FAT) and Site acceptance test (SAT) are traced to the specification.
- Documentation: Requirements for documentation, such as languages, formats and delivery dates, belong in both documents. The documentation team should review the specification for promises about manuals and training.
Requirements specification vs. user requirements specification
The User requirements specification (URS), similar to the German Lastenheft, is written by the client and describes needs. The requirements specification (Pflichtenheft) is written by the contractor and describes the solution. Because English uses "requirements specification" loosely, projects should state which document is meant.