June 15, 2016

Tender Specification - E-1

Express needs in terms of functions and constraints

A. Scope

Important foreword. Some of the text in this section, dedicated to the Tender Specification, is taken from AFNOR Standard "NF X 50 151 Value Analysis, Functional Analysis - Expression of need and tender specification", and has been adapted to the context of scientific projects.

The Tender Specification (CdCF) is a document by means of which a caller (or his representative) expresses his needs (or those which he is assigned to express) in terms of services that the product is expected to provide and not in terms of solutions and means of performance. Expected services, usually referred to as service functions in a Tender Specification, are expressed in a technically neutral and negotiable manner.

Through the technical neutrality of the service functions, the Tender Specification favours innovation and guarantees competition between solutions. The level of negotiability associated with each descriptive element of a service function also encourages optimisation between performance and costs.

The Tender Specification therefore gives a lot of scope to the designer's initiatives in finding a range of solutions and proposing the optimum solution with respect to defined objectives which are usually based on performance, costs and schedule.

B. Fundamentals

Based on an external functional analysis, the preparation of the Tender Specification shall result in a pertinent expression of the need and give the best possible representation of this need in terms of service functions and constraints.

The Tender Specification is prepared in four phases :

  • defining the context of the study,
  • setting up a working group,
  • validating the need and external functional analysis,
  • writing the Tender Specification.


1. Defining the context of the study

The first objective of this phase is to situate the project within in its general context, and to position the expected product in the system for which it is intended. The definition of the characteristics of the expected output of the analysis, the lead-time allowed and the assigned resources, constitutes the second objective of this phase, which determines the success of the activities of the subsequent phases.

2. Setting up a working group

A Tender Specification must take into account the interests of all the partners concerned. For this reason, cooperative working and a wide range of skills are essential. It is therefore strongly recommended that a working group should be set up to carry out the study, and led by a specialist in functional analysis. The skills of the working group members must be complementary and include all fields covering the definition of needs, the use of the product and the various interfaces between the product and its operating environment, without forgetting the fields of installation, maintenance, etc., where applicable. Designers may also take part in the analyses of the working group, in order to fully understand the needs to be met.

The working group set up in this way carries out an external functional analysis in order to produce a Tender Specification for which it provides rationale for all the expected service functions.

In the case of a Tender Specification for an instrument produced by a scientific laboratory, the working group shall include :

  • the Scientific Manager (or his/her representative), who is the initiator of the need,
  • the Technical Project Manager of the laboratory (or his/her representative),
  • the CNES Project Manager (or his/her representative),
  • the Manager of the spacecraft which will carry the instrument,
  • a CNES Product Assurance and/or Dependability Manager,
  • specialists in specific technologies, as applicable.


3. External functional analysis

This is the essential phase in the development of the Tender Specification. It includes:

  • validation of the need, which consists in checking that the need is clearly identified and correctly formulated, and in assessing its stability over time. This validation can only be established by asking the following questions: For whom or what does the product provide a service ? On what does it have an effect ? What was the purpose of its creation ? Why does this need exist ? What could cause it to change ? Be modified ? Be deleted ?
  • the functional analysis, which includes :
    • identification of the elements that make up the environment of the product (people, equipment, environment, etc.); this favours an exhaustive research into the service functions and the constraints ;
    • an inventory of the service functions and constraints, which respectively describe the services expected of the product and the limitations imposed by the caller or by the environment of the product ;
    • characterisation of each service function and each constraint; this consists in identifying the criteria that enable performance of the function or compliance with the constraint to be assessed, defining their levels (or performance), and stating the negotiability (flexibility) of each level in order to optimise the cost/performance ratio ;
    • determination of the relative importance given to the service functions and constraints, by means of a simple classification or grading.


4. Writing the Tender Specification.

The results of the external functional analysis are written into the Tender Specification by the working group, which is jointly responsible for its content with respect to the decider of the study.

C. Typical content

1. Scope

This section gives a brief outline of the objectives of the Tender Specification and of the product concerned.

2. Product overview

2.1 The product and its environment

The general concept of the product is presented here, and also its general environment, in order to understand its integration level and the main services that are expected of it and for which it is to be designed (abstract of the description of need or terms of the fundamental need).

The objective is to make it easier for the designer to quickly obtain a clear understanding of the product.

2.2 Context of the project, objectives

The purpose of this paragraph is to provide the designer with all the useful information concerning the general context of the project :

  • position of the project in a larger programme ;
  • "earlier" design work already completed ;
  • design work carried out in parallel on similar subjects, if such work can be disclosed ;
  • parts concerned by the duration of the project and its results (caller's product manager, departments or people who will be the real users of the product) ;
  • type of service required (is it a feasibility study, a definition analysis, a mock-up creation study, a prototype study, etc..) ;
  • level of interest for new, original solutions ;
  • confidential character, where applicable.


3. Functional description of the need

The functional description of the need is the result of an external functional analysis based on the elements of the "general presentation of the product". It is the essential part of the Tender Specification, and it provides a reference for the need to be met for all the parties concerned.

3.1 Identification of the product environment

This is defined by an exhaustive list of the elements (people, equipment, materials, environments, etc.) that make up the environment of the product while it is being used. These elements are in a situation where they can have an effect on the product or can be affected by it.

The environment in the operating situation is then completed by the non-operational environments that occur during development, production, transport, storage, handling, integration, maintenance, etc.

3.2 Description of the service functions and constraints

This paragraph establishes :

  • the list of service functions that convey the actions expected of the product in order for it to meet all or part of the need expressed by a given user (or any element of the surrounding environment) ;
  • the list of constraints that are either restrictions in the freedom of design choices imposed by the caller, or limits imposed by the environment of the product.


The service functions and constraints are generally expressed in the form of a verb followed by several complements.

In order to convey the relative importance of the functions, the Tender Specification may include either a classification or a grading of the functions.

3.3 Characterisation of the service functions and constraints

For each service function and constraint, this paragraph :

  • establishes the list of criteria that enable creation of the function or the observance of the constraint to be assessed ;
  • defines, for each criterion, the required assessment (or performance) level and its flexibility, which indicates the negotiability or the range of negotiation for the assessment level.


General assessment criteria applicable to all functions or constraints can also be defined. The decisive criteria which enable the solutions to be assessed are specified.

Three examples of characterised functions are given below.


FunctionsAssessment criteriaLevelsFlexibility ratings
Produce images of the EarthSpectral domain[4.2 µm - 7.5 µmF0 (Essential)
 Number of channels54 to 7
 Field60 km x 60 kmF1 (Little negotiability)
 Return frequencyTwice a dayAcceptance limit: Once a day
Comply with the allocated resourcesWeight< 120 kgF1
 Power consumption< 75 WF2 (Negotiable)
Transform the characteristics of the gamma photons received from the target source into digital dataEnergy field measurement range[20 keV - 8 MeV]F0
 Measurement resolution> 2 keVF1




RisksNeeds and solutions do not match
Tender Specification (CDCF)
Technical Specification (STB)


Activities / documentation

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