Cavity barriers installed to issued details

What is installed

A cavity barrier closes a hidden path at a compartment line or at the spacing the fire strategy has already set. On the packages we are asked to price, that usually means a barrier in a masonry cavity, a closer at a rainscreen or cladding line, or a void barrier in a roof or ceiling void where the issued detail shows one. We install the system named on that detail — the product, the fixing, the line.

The same rule as for penetrations applies: we install what is drawn. We do not survey a façade or a roof void to determine where barriers ought to have been provided. If a barrier line is missing from the issued details, that is a design query. Installation of that line waits until a detail is issued. That may be a variation.

Typical packages

On new-build and fit-out, cavity barriers often sit with the envelope or with the drylining / ceiling package rather than with the M&E penetration run. We take them as a defined install package when the main contractor issues the elevations, sections and product specification. Horizontal and vertical lines are installed to the setting-out on those drawings. Open-state or closed barriers are used only as specified — we do not choose between them on site.

Access is the practical constraint. A rainscreen closer may need a MEWP, a scaffold, or a programmed envelope window. A void barrier may need the ceiling open. Tell us how the line is reached and whether the envelope contractor will still be on site. We quote labour and certified materials against that access, not against an assumption that we can open a finished façade.

Evidence

Each barrier is tagged to the seal register where the specification requires it. Photographs are taken against those IDs for the Assigned Certifier. Product evidence — data sheets, Declarations of Performance, and the test / ETA documents named on the specification — sits in the handover file with the construction ancillary for installation to issued details only. Irish TGD B / Part B / BCAR. Not a design certificate.

What is out of scope

A façade survey. A cavity inspection to locate missing barriers. Selecting open-state versus closed, or setting out lines that the fire strategy has not drawn. Design responsibility and design ancillaries. We do not hold professional indemnity for design. If a survey or design partner already holds that work on a separate contract, we can quote the installation that follows.

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