15 Stout St

General building description:

This former Departmental Building, built in 1939, is located in the Wellington City Council Stout Street Precinct Heritage Area, the building is an “H” shaped plan configuration around a central interior courtyard andlightwell. Constructed in theart moderne style, many Wellingtonians consider it a favourite, with bold granite cladding and curved bronze corner windows. As a Category 2 listed heritage building the project has ensure the survival and rejuvenation of a previously vacant building.The building has been completely transformed into a modern 5 Green Star office space with an integrated fit out for a single tenant, all new services and central plant, new core risers and toilets as well as additional lifts. A collaborative team approach was undertaken that allowed for clear communication across all parties and ensured a superior build

A series of full scale load tests were conducted where selected beams were isolated and then jacked cyclically using hydraulic rams in order to determine the joints’ true moment/rotation characteristics. As a New Zealand first, this onsite structural testing allowed the redevelopment work to proceed without the requirement for seismic strengthening. The existing building wascomplete striped back to a bare shell including removal of all services and plant. The existing internal courtyard underwent significant structural demolition followed by the addition of a new structure creating an additional 3,000 square metres to the building’s gross floor area.

The glazed internal atrium is one of the key elements of the buildings composition, allowing visual connection between floors and offering sea views to the upper stories. The atrium features acoustic panels made from damaged timber taken from the existing roof structure. The ground floor holds a variety of meeting and conference rooms along with a public cafe and is a key space for social and collaborative work. 15 Stout Street won Best in Category and two Excellence at the 2015 New Zealand Property Council, Rider LevettBucknall Awards, as well as Gold at the New Zealand Commercial Property Awards.

Levels 1-6 GFA= 2500 m2, NLA=2300 m2

HVAC system overview

  • 3 No main heat recovery air handling units to be installed within the rooftop plant room. The air handling units shall be furnished complete with fan section, coil section with internal hot water heating coil, rotary heat exchanger and filter section. The air handling units shall provide ventilation air to the building.
  • 2 No. smoke clearance supply fans. These fans shall be installed in parallel to the main air handling units and utilize the same supply riser duct.
  • 3 No air cooled chillers located outside on level 8 roof. Chilled water shall be circulated through the chiller by 3 No. primary chilled water pumps.
  • 3 No secondary chilled water pumps supplying a single set of main chilled water risers running vertically up the building with branches and distribution piping on Ground floor to Level 8.
  • 3 No. gas fired condensing boilers installed within the rooftop plant room. The boilers will be furnished complete with individual low loss vertical headers, primary hot water circulating pumps and cascade controller.
  • 2 No main supply air riser ducts with branches and distribution ducts on Ground floor to Level 8.
  • 3 No Atrium smoke exhaust fans with attenuators.
  • 2 No. toilet extract fan systems. One will serve the toilets within the core area on all floors and basement shower and locker rooms. The other will serve toilets in the south-east corner of the ground floor.
  • 1 No. utility exhaust fan system consisting of fan, extract ductwork, attenuators and exhaust grilles to serve tenant defined areas.
  • 1 No. cleaners’ cupboard extract fan system consisting of fan, extract ductwork and exhaust grilles.
  • 309 No4-pipe (heating and cooling) fan coil units installed throughout the building, generally located within a central bulkhead, complete with distribution ductwork and diffusers.
  • 8 No. electric radiant heaters serving the space at the bottom of the atrium. Heaters shall be located around the perimeter of the atrium.
  • 2 No. standalone VRF systems serving the building’s communications rooms. One will serve the Comms rooms from Ground floor to Level 3 and the other from Level 4 to Level 8.
  • 2 No. exhaust fans serving the basement transformer room.
  • Car park ventilation system.
  • On-floor condensate piping and connection to existing vertical riser pipes within columns around the perimeter of the building.
  • Building automation system complete with desktop workstation.
  • Fire fan control and indication panel (FFCP).
  • Building fine tuning.

Equipment specifications:

Heat recovery air handling units: 2 no. Swegon Gold model 80D2RX, supply air=9.5m3/s, extract=7.5m3/s. 1 no. Swegon Gold model 120D2RX, supply air=12.5 m3/s, extract=7.0m3/s

Condensing boilers: 3 no. Rendamax R604 each with capacity of 350kW

Air cooled chillers: 3 no. Swegon Tetris 37.4 LN (low noise) each with capacity of 400kW

Primary chilled water pumps: 3 no. Grundfos NBG80-65-160 with capacity of 16 l/s @ 150kPa head

Secondary chilled water pumps: 3 no. GrundfosNBG150-125-250 with capacity of 16 l/s @ 300kPa head

Primary HW pumps:supplied with boilers

Secondary HW pumps: 3 no. Grundfos NBG65-230 with capacity of 6 l/s @ 300kPa head

EC multizone fan coil units: Temperzone IXDL-various sizes

EC single zone FCU’s: Temperzone IMDL-various sizes

Smoke extract fans: 90 m3/s total

Fans: Fantech-various models

BMS: Automated Logic as installed by Building Automation systems (BAS)

Unusual Features

  • Has heat recovery air handling units that recover heat from extract system to preheat incoming fresh air
  • First Project to use Temperzone EC fan multizone fan coil units. They didn’t even have printed brochures available at the time of design.
  • Plant had to have ability to deliver twice the normal supply air in Fire mode. This necessitated having supplementary fire supply air fans in parallel with the AHU’s.
  • Atrium served as vertical exhaust air shaft with exhaust chamber at the roof

Challenges

  • Low floor to floor heights combined with deep structural beams made reticulation of on-floor services difficult
  • Working with Developer who’s primary concern was cost
  • Client decided to go for 5 star rating late in the design piece which required a total redesign of the plant
  • Very aggressive design/construction programme
  • Building’s beam arrangement created difficulties in locating FCU’s/supply air diffusers
  • Heat recovery ducts from top of the atrium had to cross the chiller mounting platform to get into the plantroom.
  • AHU’s have common supply air“header” so that in the event of a single AHU failure-a reduced amount of supply air can be delivered to each riser. Fitting this into the plantroom was a big challenge.
  • First project “kick-off” meeting was in September 2012. Client moved into building in July 2014.