Self-certification, formalised
FENSA for windows, Gas Safe for boilers, NICEIC and NAPIT for electrical, HETAS for solid fuel — each is a competent-persons scheme that allows a trade to certify its own work as compliant.
Why they exist
Building Control cannot physically inspect every electrical socket or every window. Competent-persons schemes outsource that confidence to the trade itself, against a certification body that audits them.
What they prove
Only that the issuing trade believes their work complied at the moment of issue. They are not a guarantee of quality or longevity, and they do not cover anyone else's work on the same project.
Frequently asked
No. They sit alongside it. Both are usually needed for a complete paperwork pack.