Plain answer

Is ISO 29148 certifiable?

No. ISO/IEC/IEEE 29148 is a process and information item standard, not a management system standard with a certification scheme. A project can claim conformance and an assessor can examine the evidence, but no certificate is issued against the standard itself.

The distinction

A certifiable management system standard, such as ISO 9001, sets requirements for a management system and has an accreditation and certification infrastructure. 29148 sets requirements for requirements processes and for the content of information items. It has no such infrastructure and the text does not create one.

What a claim means

A project can claim full conformance under clause 4.2, a process claim under 4.3, an information item claim under 4.4, or tailored conformance for information items under 4.5 and Annex C. The claim is a statement about the named provisions and the evidence, not a certificate.

What an assessor does

The assessor reads the claim, then tests it: the process records, the information item index, the content checklist and the evidence for Annex A where full conformance is claimed. The claim and the evidence have to match. A claim with no index or no process record is a statement of intent.

What this site does

It states the requirements, the evidence and the gaps, and it helps a project build the register and the plan. It does not certify, audit or give legal advice. It does not promise that a project will conform.