Requirements and Design Specification

All requirements for Requirement Management refer to the specification of requirements in ISO 26262, Part 8, clause 6 (Specification and Management of Safety Requirements). Requirements for Design Specifications could hardly be found in norms and standards at all. Most likely, the only requirement on Design Specifications in this case is that the content needs to be understood. The challenge is to find a healthy mix between requirements and design and specify it correctly and sufficiently (Fig. 3.14). 

The example with the image of the Mona Lisa shows that a mere statement of requirement can become pretty extensive. The recipient of this statement of requirement will have a hard time creating this image with the given information. A good mix of requirements and clearly stated design characteristics, which are also illustrated respectively, can be helpful. 

For a mechanic design it would not be suggested to specify a M6 screw with requirements specifications. Furthermore, one would not voluntarily write requirements specifications for a resistance with 100 and a tolerance of 1 %. Now the question is if this is so obvious for electronics and mechanics, how do we define the limit for a system or software The example of Mona Lisa shows clearly that requirements specifications alone are not enough. Now how do we structure specifications and to whom do we assign them The specification of a vehicle 

Objective Copy the image of the Mona Lisa by Leonardo Da Vinci 

Color and detail to the frame can be taken from this image. 

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Functional/operational tests versus user requirements and design specifications Continuous measurement of environmental control... 

Boehm, B. W. 1979. Guidelines for verifying and validating software requirements and design specifications. In Euro IFIP 79, ed. P. A. Samet, 711-719. Amsterdam North-Holland Publishing Company. 

Contamination. Manufacturers of cosmetics must be careful to guard against chemical and microbial contamination. Chemical contamination, which may result from the presence of undesirable impurities in raw materials, is avoidable by adhering to rigid specifications for raw materials. Compendial specifications and pubHcations by the CTFA and other professional societies form the basis of most intracompany raw material specifications. Moreover, all packaging components must meet not only physical and design specifications but also such chemical requirements as extractables and absence of dust and similar contaminants (see Packaging, cosLffiTics and pharmaceuticals). 

In addition to withstanding some minimum load or loads (sections titled Load Capacities and Design Specifications ), derricks and masts that satisfy API standards must also satisfy certain requirements regarding materials, allowable stresses, wind, dynamic loading, earthquakes and extremes of temperature. 

User requirement specifications (URS) for the computerized system are provided by the pharmaceutical firm to the computer systems vendor. The vendor generates functional and design specifications as a basis for designing and coding software for the computerized system. The system is then built, together with all the interfaces to the hardware, and tested by the vendor. After installation of the computerized system, IQ, OQ, and PQ are performed at the pharmaceutical facility to verify that the system is able to meet the URS and design and functional specifications. 

ISO 8829 1990 Aerospace - Polytetrafluoroethylene (PTFE) hose assemblies - Test methods ISO 8913 1994 Aerospace - Lightweight polytetrafluoroethylene (PTFE) hose assemblies, classification 204 degrees C/21000 kPa - Procurement specification ISO 9528 1994 Aerospace - Standard-weight polytetrafluoroethylene (PTFE) hose assemblies, classification 204 degrees C/21000 kPa - Procurement specification ISO 9938 1994 Aerospace - Polytetrafluoroethylene (PTFE) hose assemblies, classification 204 degrees C/28 000 kPa- Procurement specification ISO 10502 1992 Aerospace - Hose assemblies in polytetrafluoroethylene (PTFE) for use up to 232 degrees C and 10 500 kPa - Procurement specification ISO 13000-1 1997 Plastics - Polytetrafluoroethylene (PTFE) semi-finished products -Part 1 Requirements and designation... 

The installation should be documented. The accuracy of software installation should be verified, and for networked systems, drawings with diagrams should be generated. The instrument should be tested for compliance to user requirements and functional specifications, as defined during the design qualification. Critical parameters should be tested before and during routine analysis. System suitability... 

Use case specifications document functional requirements. The next step is to design the partial system that the current iteration is supposed to deliver. The gap between requirements and design is not trivial, and a bridge between the two is desired. This bridge is what object-oriented analysis is about. The domain analysis object model is not the final design. However, it provides a starting point for the design process. 

The first step in the scale-up process is the selection of a suitable preliminary formula for more critical study and testing based on certain agreed-upon initial design criteria, requirements, and/or specifications. The work is performed in the development laboratory. The formula selected is designated as the (lx) laboratory batch. The size of the (lx) laboratory batch is usually 3-10 kg of a solid or semisolid, 3-10 liters of a liquid, or 3000 to 10,000 units of a tablet or capsule. 

Hardware evaluation tends to be less complex than software evaluation, and unless hardware is being designed and built specifically for the application it will generally comprise standard components with defined performance detail that can be evaluated relative to the functional requirements and operational specifications. This also applies to the measurement and control instrumentation. 

Complete A Requirements Traceability Matrix (RTM) should be developed to confirm that all relevant aspects of the URS have been brought forward into the Functional Specification and Design Specifications. This includes both positive and negative requirements (the latter often overlooked), i.e., what the software is snpposed to do and what it is NOT supposed to do ... 

It is not typical to receive a separate functional and design specification these are often included as part of the building s environmental control package. If this proves to be the case, then it is not necessary to rewrite these specifications. The recommended approach is to create a matrix that references those parts of the environmental control package that are relevant to the computer system validation requirements for the critical functions. Also, ensure that this matrix is mapped back to the URS in order to ensure that the URS is met. This matrix will form the basis of the Requirement Traceability Matrix (RTM), which is intended to assure that all requirements have been addressed, that the functionality is appropriate, consistent, and meets predefined standards, and that the system is appropriately tested. The functional/design specification or the relevant sections of the environmental control package should typically address ... 

FIGURE 33.3 Traceability Example All of the Functional Specifications and Design Specifications in This Table are Derived from the User Requirement Labeled URS-1. 

Abstract Software and computer systems are tested during all development phases. The user requirements and functional specifications documents are reviewed by programmers and typical anticipated users. The design specifications are reviewed by peers in one to two day sessions and the source code is inspected by peers, if necessary. Finally, the function and performance of the system is tested by typ-... 

These guidelines are intended as a basic guide for use by GMP inspectors. They are not intended to be prescriptive in specifying requirements and design parameters. There are many parameters affecting a clean area condition and it is, therefore, difficult to lay down the specific requirements for one particular parameter in isolation. 

The Operational Qualification is performed in accordance with a preapproved written protocol. The specific Operational Qualification attributes to be verified during the performance protocol will be developed from the design specifications, manufacturer documentation, cGMP requirements, and other specific documentation. They, along with the acceptance criteria, will be approved as part of the protocol approval process. 

In many problems, there are recycle loops and design specifications. Recycle loops require convergence blocks. Explicit iterations occur to satisfy material, temperature, and pressure agreement in a given recycle stream. Design specifications require control blocks. Implicit iterations occur to satisfy a specification by adjusting an input stream variable or equipment parameter. 

User requirement specifications (URS) for the computerized system are provided by the pharmaceutical firm to the computer systems vendor. The vendor generates functional and design specifications as a basis for... 

If the language used at level 3 is formal (rigorously defined), then it can play an important role in system validation. For example, the models can be executed in system simulation environments to identify system requirements and design errors early in development. They can also be used to automate the generation of system and component test data, various types of mathematical analyses, and so forth. It is important, however, that the black-box (that is, transfer function) models be easily reviewed by domain experts—most of the safety-related errors in specifications will be found by expert review, not by automated tools or formal proofs. 

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