by Siderise
Siderise RH ‘Open State’ horizontal cavity barriers comprise a non‑combustible stone wool lamella core with reinforced aluminium foil facings. The primary seal has a reaction to fire classification of Class A1. The exposed leading edge is also sealed with aluminium foil.
The stone wool core is water repellent and non‑hygroscopic. In this predominantly enclosed configuration, the barrier provides additional protection to the core material under normal service conditions.
RH ‘Open State’ horizontal cavity barriers incorporate a continuous reactive intumescent strip bonded to the leading edge. The intumescent material has a reaction to fire classification of Class E. In the event of exposure to fire, the intumescent expands to seal the ventilation gap formed between the barrier and the rear face of the cladding at the time of installation.
The range includes products for nominal air gaps of 25 mm (RH25) and 50 mm (RH50). Both options are available with either galvanised mild steel (G) or stainless steel (S) fixing brackets as part of the system, designated RH25G, RH25S, RH50G and RH50S. Bracket selection is typically determined by the rainscreen system designer in relation to project exposure and location.
The leading edge of the horizontal cavity barrier is encapsulated in a weather‑resistant polymer film. As standard, the film is black to provide a shadow‑line appearance behind open‑joint cladding.
For product identification, the upper edge of the film on RH25 and RH50 cavity barriers is colour‑coded and labelled to indicate the product fire performance rating.
Features and benefits:
Fire performance:
Product fire performance:
Siderise RH25 ’Open State’ horizontal cavity barrier for maximum 25 mm air gap.
Siderise RH50 ’Open State’ horizontal cavity barrier for maximum 50 mm air gaps:
System fire performance:
Please read the below in conjunction with the manufacturer's RH Technical Data Sheet.
Brackets:
Screw fixings:
1 Revision
29/01/2025

Compliant
Compliant
Not Available
This data is based on generic material data.
There are no EPDs.
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Bimstore on 15 May 2026
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