Importance categories A, B, C and D are gone. Article 370 paragraph (1) says that from the code’s entry into force the importance-category system is replaced by the consequence-class system, an approach built on the risks associated with a building being damaged.
The change is not vocabulary. The class decides whether someone else has to check your project, how long a guarantee you can require from the contractor, and how far the technical memo has to go.
The old categories did not disappear, they were translated
Paragraph (5) gives the equivalence, and it is the one thing in the article worth memorising:
- CC1 corresponds to category D
- CC2 corresponds to category C
- CC3 corresponds to category B
- CC4 corresponds to category A
So a single-family house that was category D is now CC1, and a hospital that was A is CC4. The order runs against instinct: the small number means small consequences.
The designer assigns the class, and cannot round it down
Paragraph (14) is short and strict. Assigning the class is the designer’s obligation, and assigning a class lower than the one the code and its subsequent legislation indicate for that type of building is forbidden. That is a prohibition, not a recommendation.
Paragraph (6) also says how to choose: the class follows the most severe of the consequences assessed, not an average. There are five of them, in paragraph (3): loss of life, economic loss, loss of cultural or natural heritage, social consequences and environmental consequences. A modest building that houses something of heritage value moves up a class on one criterion alone.
Until the methodology arrives, annex 6 governs
Paragraph (16) settles the practical question. Until the classification methodology takes effect, buildings are classified exclusively under annex 6. Where a building is not listed there, paragraph (17) requires the designer to assimilate it, by the number of lives, of injuries, by economic loss or by cultural loss, to the building in the nearest class.
The same paragraph (17) allows something useful on interventions: on a change of use, a refunctioning, an added storey or an extension, the initial class may be changed with reasons. The word doing the work is reasons.
What the class actually changes
The verification level follows the class one to one. Articles 441 to 444 tie NVP1 to CC1, NVP2 to CC2, NVP3 to CC3 and NVP4 to CC4.
The bottom of the ladder is the surprising end. Article 440 paragraph (3) says technical checking is not necessary for projects in CC1, and that responsibility for compliance with design rules rests exclusively with the architects and engineers who drew it. There is no checker, so there is no second pair of eyes. When the obligation to have one starts is in the project checker.
At the top, article 445 paragraph (8) requires the NVP4 verification report to come with the calculation and sizing notes.
And in the middle sits the detail designers miss most often: article 442 paragraph (4) letter a) lists, among the input data the checker controls at NVP2, the correctness of the consequence-class assignment itself. Your first decision is also the first thing checked.
The class outlives the file, too: the minimum guarantee you can require from the contractor is set by it, at 5 years for CC3 and CC4, 3 years for CC2 and 1 year for CC1, as the page on reception at completion of works sets out.
Where it shows up in the file
The class has no box of its own in the permit documentation, but it shows in what you are asked for. We wrote about the threshold at which building services come in with their own drawings in DTAC installations, and about the memo’s content and the annex it is taken from in the memo model. On existing buildings the starting point is usually an expert report, the subject of the technical expert report.
The first line of the project
The consequence class is assigned once, at the start, by the designer, and verification, guarantee and part of the file’s content follow from it. It is one of the few design decisions the code frames as an obligation, caps from above, forbids rounding down, and then puts on the list of what somebody else controls.