SP Firestop VRB
Cladding Solutions

SP Firestop VRB

Close protection for open states 

Rainscreen cladding is a widely specified finish for many high rise buildings, facilitating creative and aesthetic designs. But balancing the breathability of these constructions with effective fire protection can be a challenge. To help overcome this, ROCKWOOL SP Firestop VRB has been specifically designed to form an effective open-state cavity fire barrier.


ROCKWOOL SP Firestop VRB provides essential fire resistance for external cladding systems and forms an important part of the comprehensive range of ROCKWOOL’s fire protection products. Designed to allow for ventilation and drainage of the cavity under service conditions, it has been rigorously tested with ROCKWOOL RAINSCREEN DUO-SLAB to ASFP TGD 19. It ensures that moisture is allowed to escape from within the façade system whilst maintaining adequate airflow. The important combination of non-combustible mineral wool insulation and an effective intumescent strip supports the design of safe façade systems and, when combined with RAINSCREEN DUO SLAB, works to prevent fire risk in tall buildings above 18m. SP Firestop VRB has been developed for use as an ‘Open State’ cavity barrier for drained and ventilated rainscreen systems. The Firestop allows moisture to drain from within the façade system whilst ensuring the flow of air. In the event of a fire the Firestop will react to create an effective smoke and fire seal.


Fully tested to ASFP TGD 19 

  • Highly responsive - in the event of a fire the firestop will react effectively to create an essential smoke and fire seal.
  • Fire integrity – it ticks the right boxes by satisfying the NHBC and CWCT guidance for ventilation gaps at fire barrier locations, offering 60 minutes fire integrity.
  • Industry proven – the product is fully tested to ASFP TGD 19: “Fire resistance test for ‘open-state’ cavity barriers used in the external envelope or fabric of buildings”, ensuring complete compliance on a build.
  • Weather resistant – SP Firestop VRB is ideal for exposed buildings as it comprises of a stone wool barrier with a continuous intumescent strip to its leading edge, encapsulated by a polythene sleeve to keep moisture out.
  • Easy site storage and handling - installed horizontally and designed to ensure an appropriate open air space is maintained, the SP Firestop VRB is suitable for cavity widths up to 300mm. 

Product Properties

Reaction to fire Fire performance Up to 60 minutes integrity

Product range and ancillaries

Item number External item number Country Thickness (mm) Width (mm) Length (mm) Pieces Per Pack
2482486 2482486 UK 75 75 1000 22
243750 243750 UK 75 100 1000 17
242617 242617 UK 75 125 1000 13
248963 248963 UK 75 150 1000 11
220189 220189 UK 75 175 1000 9
220193 220193 UK 75 205 1000 8
220194 220194 UK 75 225 1000 7
220195 220195 UK 75 250 1000 6

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SP Firestop VRB
SP Firestop VRB

SP Firestop VRB Datasheet

Routes to compliance - In high-rise buildings above 18m
Routes to compliance - In high-rise buildings above 18m

Meeting the guidance within the Requirements of Approved Document B Volume 2