Sealant specification sorted

A range of Dowsil sealants, including Dowsil’s Firestop 700, were specified for use on the atrium elevations and glazed partitioning within The Sorting Office, a new commercial property in Dublin’s Cardiff Lane.

All the sealant products were specified and distributed by the Sherwin Williams Company.

The Sorting Office is a seven storey, flexible use office building in the Irish capital’s Silicon Docks district. Fitted between October and December 2019, sub-contractor Walls to Workstations (W2W) installed glass elevations totalling 1,944m2 in area around all seven floors of the atrium using a variety of Dowsil glazing sealants depending on the properties required.

The highest specification sealant product selected was Dowsil Firestop 700 low modulus sealant in black, which was required for the top two floors. On these levels, an Optima Technishield 65 system was used, glazed with Pyroguard EI 30-32-2 SWS glass and featuring mitred corners to avoid having to include metal posts at the edges. The completed installation achieves a barrier load rating of 1.5kN/m.

“The Pyroguard glass was originally tested with a light glazed product which we really didn’t like, as it presented a grainy appearance,” W2W contract manager Peter Durand said.

“Being in regular contact with our local Sherwin Williams’ technical consultant, Alan Griffin, we had the glass manufacturer retest with the Dowsil Firestop 700. It is a world recognised product with the performance characteristics we required in terms of fire rating. When tested with the glass it passed successfully and we were happy with the appearance of the sealant so we specified the use of that instead.”

Dowsil Firestop 700 is a one-part, low modulus neutral curing and fire-rated silicone sealant. It possesses an excellent un-primed adhesion to a wide range of common construction substrates including stone, brick, wood and metal, the company said. It is ideal for preventing the spread of smoke and flames through expansion joints in facades and partitions, as well as through pipe and cable penetrations. It can provide up to four hours’ protection and accommodate movement of +/-50%.

Another Dowsil sealant product was also used across the remaining atrium floors. Unlike the top two floors, the first to fourth floors of the atrium did not require fire rated glazing and as such are enclosed by non-fire-rated partitions manufactured by W2W, with 21.5mm heat soaked, toughened laminated glass. These partitions were assembled using Dowsil 895 Black Structural Glazing Sealant, again achieving a load rating of 1.5kN/m.

On the ground floor, W2W was also responsible for creating the three-sided enclosures to the scenic lifts, which have a total area of 33m2 and use the same glass specification as the lower levels of the atrium, including the use of Dowsil 895 Structural Glazing Sealant in Black.

Dowsil 895 Structural Glazing Sealant is a one-part neutral silicone specifically designed for bonding a wide variety of substrates, including metal and glass, with excellent adhesion. With an odourless and non-corrosive cure system, it is resistant to ozone and extreme temperatures so can also be used externally.