Product and system certification

Two separate levels

The product level

What the material can do: how strong it is, how combustible, how well it insulates. The manufacturer declares this, and it is the subject of the declaration of performance.

The system level

What the assembled structure can do: how much load it carries, how long it resists fire, how much sound it keeps out. This cannot be derived from the data of the components, because the way they are assembled determines it too.

Why it cannot be added up

The fire resistance of a wall is not the sum of the fire classes of the layers. The capacity is not the sum of the capacities of the sections. The sound insulation is not the sum of the masses of the layers.

In every case the connection decides: how the board is fixed, what the screw spacing is, where the joints are, what the detail is. Two walls built from identical materials can differ significantly in performance.

Where this goes wrong in practice

“There is paperwork for it”

For the materials there is; for the structure there is not. That is the most common situation, and not necessarily a problem — you just have to know the verification of the structure is still to come.

The similar system’s verification

A test report issued for another, similar build-up cannot be lifted across. Extended application has rules. The routes to verification.

Substitution

A board or insulation swapped during construction changes the system, not just one material. If the system verification rested on a test, the substitution invalidates it.

What verifies the system

• Testing and its regulated extension,
• technical assessment (NMÉ, ETA), which applies to a fixed arrangement,
• design, produced and signed for the project.

There is no off-the-shelf system certificate for a load-bearing light gauge steel wall — it has to be commissioned, or verified by design.

The point

Collecting product paperwork is necessary but not sufficient. The question is always what verifies the structure — and who signed it.