The four most important systems engineering standards (2025 update)

Standards play a particularly important role in the safety-critical area and are required by the client or legislator. I would therefore like to provide an overview of the most important standards below.

There are a number of organizations that publish standards. In addition to the well-known ISO (International Organization for Standardization), there are many others that often cooperate with ISO or even publish standards together. These include DIN, IEC, DOT, IEEE and many more.

In the following, I abbreviate the names of the standards and choose only one organization and leave out the year, language and the like. So "ISO 15288" instead of the actually correct designation "ISO/IEC/IEEE 15288:2023(en)".

There are also many domain-specific standards, for example the well-known ISO 26262 "Road vehicles - Functional safety". Instead, I prefer to describe the domain-neutral standard (if it exists), in this case IEC 61508.

And finally: the list is not complete, and "important" is subjective. And there is of course a lot of literature on the subject. A good starting point is any relevant standard, as these always cite other related standards. INCOSE also has a Overview of SE standards and a special issue (Insight Connect, April 2014). Research is also being conducted in this area. For example, the paper "A review of systems engineering standards and processes" (2008) provides an exciting historical outline.

Everything clear? Then let's go!

ISO 15288 is so important that I have already written a separate article about this and will certainly do so even more frequently in the future, because this is actually the entry point for serious systems engineering. INCOSE has already recognized this, which is why the INCOSE SE manual also places great emphasis on conformity with ISO 15288. Therefore, my recommendation is to study the SE manual as well as ISO 15288, which is somewhat easier to digest.

The title actually already says what the standard says: It is primarily about the processes that must exist in order to be able to carry out systems engineering. And there are a lot of them: 25 processes, 123 artifacts and 403 activities (refers to an older version). As not all projects require this scope, the adaptation of the process is an important aspect that is also described.

It is also important what it does not say. In particular, there is hardly any mention of methodology. This makes sense, as there are many different development methods. Furthermore, the topics of quality and project management are only touched on, as there are separate standards for these.

Finally, there are a few "related" standards. Interesting here is the ISO 29110which covers the same topic for small organizations. And the ANSI/EIA-632 (Processes for Engineering a System) is an older standard that now coordinates with ISO 15288. And ISO 12207 corresponds to 15288 for software (and not systems). It has been harmonized so that software development according to ISO 12207 is also compliant with ISO 15288.

Of this series of standards, ISO 9001 is probably the best known. It defines the minimum requirements for an organization's quality management. It is hard to imagine that an organization can develop complex systems without having implemented the requirements of 9001. For safety-critical developments, however, the requirements go far beyond ISO 9001. This is where IEC 61508 comes into play (see below).

The series of standards is initially designed to be neutral. There are usually other standards for the various domains and sectors, such as ISO 10006 for quality management in projects.

This standard forms the basis for a number of industry-specific adaptations. ISO 26262 from the automotive sector is certainly one of the better known.

Nowadays, safety is becoming increasingly important, both in terms of functional safety and security. Recently, I have been hearing more often that the standard is not (or no longer) adequate for today's developments. This is also clear from the name (electrical systems): modern systems typically consist of mechanics, electronics and software. The standard lacks precision and a high level of detail, particularly with regard to the continuous safety check across these three areas.

Not all functional safety standards are derived from IEC 61508. DO178 (aviation) is independent. Here is a Overview of safety standards in various industries.

Professional project management is also essential for successful systems engineering. For this reason, references to the project manager and the project plan are also regularly found in the other standards. However, project management is so extensive that there is a separate standard for it.

As a guideline, ISO 21500 refers to a number of other standards. DIN 69901, which covers not only processes but also methods, is particularly important in Germany.

Is something missing? Discuss with us!

We have now familiarized ourselves with the most important standards and gained a rough overview of the jungle of standards. Have I forgotten anything important? Or do you have any suggestions or further information? Then Just start a discussion.