Fire, Acoustic and Thermal Effective Edge Sealing for timber walls

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1 commercial connections LIMITED Sound and thermal insulation specialists Fire, Acoustic and Thermal Effective Edge Sealing for timber walls in conjunction with Building Solutions Ltd 1

2 The Party Wall Thermal Bypass Explained Establishing what constitutes a suitable effective edge seal around cavity party walls, as demanded by Part F for zero U-values and Part G 2012 to resist acoustic transmission, is a complicated issue. Traditional fire barrier systems are not necessarily effective edge seals, or generally have proven tested performance to resist acoustic transmission. Part F1 and G states that, on their own, traditional fire barriers may not be effective in restricting air flow. This was also confirmed via BPAC Hangar 17 tests. Recent studies on test structures at BPAC Hangar 17 by the Institute demonstrated that even tight compression of mineral wool within the cavity still lead to air leakage. It is clear that effective edge sealing, which does not conflict with Part G, is required around the cavity s perimeter. But what is an effective edge seal? By now, most architects and house builders will be aware of the need to fully-fill and effectively edge seal the cavity, as the penalty of a 0.5 U-value for not doing so is just too harsh to contemplate. Therefore, architects and house builders should understand that Part F1 does not expand upon definitions it only states that the edge seals must be effective in restricting airflow. So the onerous responsibility of selecting the correct product fit for purpose is left to the architect and developer to demonstrate that: A. It is robust both to normal site installation and has longevity throughout the lifetime of the building B. It has a tested performance to resist acoustic transmission for compliance with Part G 2012 C. It has a fitting and installation system to demonstrate effective vertical and horizontal edge sealing D. Has a tested fire performance to comply with the relevant section of Part E E. It has been independently tested to an appropriate Effective Edge Seal Criteria 2

3 Specification Clause for effective edge seals and pitched roof fire barriers: Effective Edge Seal General Effective edge seal shall have been independently tested at 250l/m for pressure differential CO 2 ratio concentration expressed as a percentage in the external wall compared with the rise in CO 2 levels in the party wall to prove air exchange resistance effectiveness. It shall be designed to resist acoustic transmission for compliance with Part G 2012, and have been tested for fire performance to comply with the relevant sections of Part E ARC T-Barrier Fire, Acoustic and Thermal Solution for Timber Party wall edge seal specification: 1 FATT CC/CB T profile vertical fire acoustic and thermal party wall thermal bypass or per Technical Booklet F1 Conservation of Fuel and Power (October 2012). Effective edge seal to be T profile design to allow for secure compression fitting to party separating wall and effective friction fitting to external cavity wall. Achieves U values of 0.0 W/m 2 K when fitted within a fully filled cavity and 0.2 W/m 2 K in an unfilled cavity when installed around all exposed edges and in line with insulating abutting elements. Party wall width mm (1 hour fire rating) External cavity width (1 hour fire rating) Download ARC Timber CAD 3

4 Party wall & roof edge seal specification 2 FATT CC/CB T profile pitched roof (to satisfy NHBC7.2D13): Cavity barrier to provide an effective perimeter edge seal and fire stopping between the roofing membrane and party wall. The T profile design is fitted along the length of the roof pitch from soffit to apex and is held in place by compression between the leaves of the party wall blockwork. This ensures an effective consistent barrier to the underside of the roofing membrane and continuity of the edge seal. NHBC 7.2 Fire Stopping Details recommend that the separating wall should stop about 25mm below the adjacent roof trusses or rafters to ensure that a 50mm design gives a 25mm compression to a level roof line. Party wall width mm Void depth from raking wall tight to underside of slaters felt mm 4

5 Section through complete system 3 ARC Tile Batten Barrier to be used in conjunction with FATT CC/CB pitched roof seal at the party wall between the roof tiles and the roofing felt. Tile battens nailed on the top of the barrier compressing it where the two cross. A knife is used to score the tile batten barrier releasing the compression and allowing the barrier to recover the full width of the tiling batten. 1 FATT CC/CB T profile vertical fire, acoustic and thermal 2 FATT CC/CB T profile pitched roof fire, acoustic and thermal 3 ARC tile batten barrier 4 ARC soffit slab 5

6 Ancillary Products supplies a range of ancillary products from ARC for non-standard junctions, such as stepped semi-detached/apartment plan layouts. ARC Party Wall DPC The ARC Party Wall DPC fits the design of a mineral wool closer for acoustic insulation under building regulation requirements. Up to four hours fire integrity Specified in semi-detached, apartments and major projects Part E Robust Detail compliant Vertical and horizontal applications Available to fit cavity widths from 50 to 300mm Manufactured from rockfibre mineral wool lengths bonded to a polyethylene DPC, it is suitable for closing an external cavity at both the junction with a party wall and horizontally at separating floors. L-Shaped Barrier internal corner, DPC on short leg 6

7 ARC Party Wall DPCs have an A+ Green Guide rating, with all of ARC s rockfibre mineral wool classed as zero ODP and zero GDP, as well as no CFCs or HCFCs involved in manufacturing. L-Shaped Barrier external corner, DPC on long leg ARC Spandrel Barriers ARC Spandrel Barrier, when used alongside ARC T-Barrier, can achieve zero U-value, by sealing the top of the party wall cavity. Up to four hours fire integrity around edge of party wall Up to one hour fire integrity between the spandrel panel and block work Use in conjunction with ARC T- Barrier vertically to create an effective edge seal around the party wall cavity Zero U-value can be achieved Minimises thermal bypass Easy to install ARC Spandrel barrier creates an effective fire and thermal break, compressed between the top of the 7

8 party wall block work and underside of the spandrel panel. 8

9 Traditional Cavity Barriers supplies ARC Cavity Stop Socks and TCBs, designed to restrict smoke and flame spread within external masonry and timber frame walls. ARC Stop Socks and TCBs ARC Stop Socks and TCBs help restrict smoke and flame spread, and minimise the effect of flanking noise pollution at wall junctions. Up to four hours fire integrity Specified in semi-detached, apartments and major projects Compiles to Robust Detail Part E and Building Regulations Available without flanges (CSS) or with flanges (TCB) Can be manufactured to suit cavity widths up to 300mm They are produced from low resin, non-combustible rockfibre mineral wool, and are sleeved in 50 micron polythene for on-site weather protection. Cavity Stop Sock installed vertically in traditional masonry construction 9

10 ARC Cavity Stop Socks and TCBs have an A+ Green Guide rating, with all of ARC s rockfibre mineral wool classed as zero ODP and zero GDP, as well as no CFCs or HCFCs involved in manufacturing. TCB installed horizontally in timber frame construction commercialconnections.co.uk 10