Healthcare Design - September 2017 - 43

and tracks the system's ongoing energy use,
solar thermal collectors deliver 100 percent of
the campus' hot water needs, and a grey water
system treats sewage for cooling tower re-use.
Additionally, the campus features rainwater
harvesting; T5 and LED lighting; daylight and
occupancy sensors; and a building management system with monitoring, occupancy levels, and sleep modes for energy conservation.

RORY
ED
HOK
LACASSE
DANIEL/CPG CONSULTANTS

O P T I M I Z I N G B U I L D I N G L AY O U T

Providing every bed on the NTFGH and JCH
patient floors with a view and natural ventilation began with a floor plate geometry that
staggers the headwall of the inpatient wards
in a sawtooth shape to create a space for each
patient to have their own window (see diagram
on page 44). "Departing from a linearly arranged communal ward layout, the wards are
installed in a fan-shaped design with the beds
rotated at an angle, creating a window with
a view for every bed," says Juby Koshy Varghese, senior architectural associate at CPG
Consultants Pte Ltd. (Singapore), the architect of record. This unique aerodynamic form,
coupled with single-loaded corridors and a
funnel-shaped floor profile, maximizes wind
flow and more effectively draws the wind in
and out of the windows through the floor plate.
Additionally, delivering natural ventilation for
70 percent of the buildings was achieved by
the design team taking advantage of unique
prevailing breezes, which reverse from one
direction to another during Singapore's two
yearly monsoon seasons. By keeping the shape
and layout of the patient floors as narrow as
possible and providing enough distance between the window openings on both sides of
the rooms, the wind can easily travel across a
floor and escape from both directions.
As a result, 82 percent of the inpatient areas
are passively cooled and naturally ventilated,
with a small percentage of mechanical fanassisted ventilation coming from ceiling and
exhaust fans. In the event of seasonal haze in
Singapore, caused by illegal agricultural and industrial fires in southeast Asia and exacerbated
during the dry seasons, the windows will close
and both NTFGH and JCH make use of a centralized air filtration system to filter the polluted air,
Varghese says. "The impure air will be effectively
filtered out before it even enters the room."
To address infection control, the team used
computational fluid models prior to construction to accurately map out the wind flow direction to make sure that the wind would not flow

Louvered jalousie
windows located
near a nurses' station
provide the staff with
access to natural
ventilation, while
sunscreens help control
heat gain and glare.

across multiple patients and spread germs before exhausting, says Mara
Baum, sustainable design leader at HOK. The positioning of the layout
and the size and placement of the windows ensure that the wind passes
over only one patient bed before leaving the building.
While the layout allowed the team to achieve natural ventilation, it also
created a challenge in transferring the structural load from the irregular
shape in the upper floors to the more traditionally shaped floorplate at the
building's base. In other words, the structural system holding up the building has a significantly different shape at the base than the higher floors. The
project team, including CPG Consultants Pte. Ltd. and the building envelope consultant Studio 505 (Melbourne, Australia), identified the issue
early on and designed structural connectors in an interstitial floor between
the towers and base building to transfer the structural load between the
two floor plates.
S U S TA I N A B L E S T R AT E G I E S

With lots of daylighting and ventilation coming into the building, properly shading openings to prevent solar heat gain and glare was key. Fortunately, Singapore's location near the equator means that the sun's position at any given time of day changes only slightly throughout the year,
making the exterior sun shading plan relatively easy to create, Baum says.
Overall, three levels of sun shading were built into the design, including
large overhangs extending from the concrete floor slab to provide shading
from the ceiling plane to the floor below. Smaller horizontal and vertical
sun shades were installed in louvered jalousie windows. Custom external
shading devices, including sliding sun screens and light shelves, deliver
shading to at least 60 percent of the critical façades where patients and
staff reside. Even green roof vegetation, located next to windows on multiple floors of both buildings, is considered a tertiary shading element, with
the added benefit of evapotranspiration helping to lightly cool the ambient temperature inside the buildings while absorbing and trapping a small
amount of pollutants. (For more on the building's green façade, read "Healing Oasis" on page 45.)

SEPTEMBER 2017

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