Posted October 23, 2016
‘The fire curtains became a feature on this job as the metalwork and control panels were exposed’.
What was the technical problem?
The Hub fit-out comprises of seven floors of office use connected via an open circulation stair and will accommodate approximately 1535 people. The interconnection of the 7 levels created a single fire compartment.
The Hub refurbishment connected multiple floors. However, the base building stair pressurisation system is only able to deal with two interconnected floors in order to maintain the required airflow (1m/s) across each fire stair door. As such, each two interconnected floors are to be designed as separate fire compartments thus staying within the design limitations of the base building.
There are a number of stairs and voids that connect through all levels and these were separated using a mixture of horizontal and vertical fire curtains, glazing, wall wetting, and fire rated construction.
The fire compartment size exceeded the limits imposed by the DtS Provisions (>8,000m2). Based on a combination of active and passive fire rated construction, the fit-out was separated into fire compartments in fire mode with the largest fire compartment approximately 4700m2 which satisfies DtS requirements.
The contractor was able to select between fire curtains (where the drop of them will not likely be interfered with), fire rated glazing, and conventional fire rating to fire rate around the void.
Greene Fire solution
Greene Fire installed a horizontal fire curtain underneath the level 6 stair void. This was a the largest simplex horizontal curtain supplied to date of approximate size 9.5 metres wide x 9.5 metres long. The main challenge however, was not the installation but actually getting this product into the building.
For other large installations on this job, like the stairs for example, they came into site in small pieces that could fit into the goods lift and were welded on-site. We did not have this option with the horizontal fire curtain as it was manufactured in the UK and the fabric roller and side guides could not be cut down.
The only solution was to set up a boom lift and remove a window on the Pitt Street side of No. 1 Martin Place. Then a 90 tonne crane was used to lift the 9 + metre long crate into the building and the window was re-instated. Due to its location right outside the door of The Westin Hotel and in the heart of Sydney, this process required a lot of planning before we could get approval for the crane lift.
Again, getting the fire rated glass to its installation location on Levels 3, 4 and 5 was a challenge due to the size and weight of each piece of glass. The Contraflam 31mm thick glass consisted of 5 layers and the 1300mm wide x 2740mm high panes weighed between 200 and 230kgs each.
We delivered the glass to the loading dock and used manpower/mechanical aids to get each pane into the goods lift/to its final home.
For the wide single rollers fire curtains which were on Levels 3,4,5 and 6, we mounted the curtain onto the barrel on site. As the curtains were each 13 metres wide, this was our only option here but it worked well as the builder gave us enough room to get this work done close to where the curtains had to be installed.
Greene Fire worked closely with the builder and design team from early design concept stage right through to hand over to provide the optimal solution of openness, security, fire protection, functionality and architectural design that is expected from such a high profile client.
- Using fire curtains throughout the fit out allows for wide open spaces to be created but still provides the occupants with a safe workplace.
- In fire mode, occupants are able to evacuate by retractable fire curtains & doors in the fire rated glass walls.
- The use of a horizontal fire curtain underneath Level 6 separates the two floors above from the fire compartments below.
- The use of wide single roller vertical fire curtains allowed the existing walls to be used as a structure for fixing the fire curtain to as well as providing the greatest floor area & open space available.