California Academy of Sciences - D+H Mechatronic

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California Academy of Sciences - D+H Mechatronic

® Tim Griffi th / California Academy of Sciences

WORLD OF D+H

Overview of further North American reference objects:

BILL & MELINDA GATES

FOUNDATION

Seattle, USA

Showroom »California Academy of Sciences«

THE BOW

Calgary, Canada

KENDALL SQUARE

Cambridge, USA


2

WELCOME,

We appreciate your interest in our reference booklet »World of D+H«.

As one of the leading companies in the fi eld of smoke and natural

ventilation we already realized a multiplicity of projects worldwide. To

obtain a better impression of us and our products, we are providing

more details from one of our reference objects on the following pages:

The California Academy of Sciences, Renzo Piano´s ecological work of

art building in San Francisco.

One of the biggest challenges in this area threatened by earthquakes was

the development of the large glass architecture which was needed to

provide the entire building with natural ventilation and air conditioning.

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With pleasure we would like to introduce you to the project »California

Academy of Sciences«, based on the scientifi c paper of XIA architect

magazine (press excerpt, page 3 to 15) which was published at the end

of 2009. Enjoy the »World of D+H – Showroom California Academy

of Sciences«.

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ISSUE 01/09

01/09 smart buildings - materials - technologies

Renzo Piano

Building Workshop

Ove Arup & Partners

Barkow Leibinger

Transsolar

VJAA


Golden Gate Park San Francisco with De Young Museum and California Academy of Sciences

East-West Building Section

North side with main entrance Living roof

Photographer: Tom Fox

Photographer: Tom Fox

Photographer: Nic Lehoux

CALIFORNIA ACADEMY OF SCIENCES

SAN FRANCISCO, CA, USA

RENZO PIANO BUILDING WORKSHOP / STANTEC ARCHITECTURE

The California Academy of Sciences in San Francisco is one of the few

Natural Science Institutes where the public experience is directly related

to in house scientific research, done in the same building, since its

foundation. The primary goal of building a new Academy was to provide

a safe, modern facility for Exhibition, Education, Conservation and

Research under one roof. The new building will become one of the

world’s most innovative and prestigious scientific and cultural institutions.

The new Academy is designed on the same site of the previous

facility in Golden Gate Park. This project required the demolition of

most of the 11 existing buildings, built between 1916 and 1976.

Sustainable Design

The mission statement of the Academy, “To Explore, Explain and Protect

the Natural World”, (combined with the mild San Francisco climate)

made this project ideal to incorporate sustainable design strategies.

Not only energy efficient heating and cooling, but also a more holistic

approach was agreed to, involving a serious effort in the choice of

materials, recycling of the materials of the old Academy and the way in

which they are put together. The location of spaces in relation to daylight

and ventilation, the efficient use of water and the run-off from the

roof, as well as the generation of energy are integral to the building

design.

Sustainability is also part of the exhibition design, the exhibition philosophy,

and its day-to-day operation. As a functioning demonstration the

public will be able to see and understand many of the principles of sustainable

design.

The Design

The new building retains the former location and orientation, and like

the original Academy, all functions are organized around central Piazza,

or courtyard. Three historic elements of the previous Academy have

been maintained in some fashion, as a memory and a link to the past:

African Hall, North American (California) Hall and the entrance to the

Steinhart Aquarium.

Two spherical exhibits, the Planetarium Dome and the Rainforest Bios-

phere, are located adjacent to the Piazza. Together with the reconstructed

entrance of the Steinhart Aquarium, these elements represent

the Academy: Space, Earth and Ocean.

These 3 icons ‘push’ the roof up, and thus create the undulating roofscape.

This roof, floating at the same height as the roof of the original

halls, formally unifies the institute. It is landscaped with native plant

species which are drought resistant and do not require irrigation once

established. The green roof extends beyond the perimeter walls and

becomes a glass canopy providing shade, protection from the rain and

generates energy through more than 55,000 photo voltaic cells in the

glass.

In the center of the Living Roof a glazed skylight covers a piazza. Much

smaller skylights distributed over the surface of the roof, allow natural

light into the exhibit space and can be automatically be opened for the

natural ventilation of the space below.

The Research activities and the storage of scientific specimens (a collection

of 18 million specimen in jars and special containers) will be

concentrated on the 5 floors facing south to the park. Additionally the

exhibit halls and the public entrance, will be oriented to the other wind

directions on the ground level. In the basement, below this floor, a large

aquarium has been located together with back for house functions of

the museum and the life support system for the tanks.

The Piazza

The piazza is the focal point of the new institute and is covered partly

with a glass roof, its structure recalling a spider web, while the center is

open to the sky. The two main aquarium tanks are positioned adjacent

to this space and connect the groundfloor with the aquarium in the

basement.

During opening hours the piazza will be used as a lunch and break-out

space, in the evening for concerts, diners and parties. A sophisticated

system of retractable fabric screens under the glass skylight assures

the comfort level in this event space. Sun and rain screens, as well as

special screens to improve the acoustics, are important features that

help to control the microclimate in the space.

Client

California Academy of

Sciences

13 5

Architects

Renzo Piano

Building Workshop, architects

in collaboration with

Stantec Architecture,

San Francisco

Design team: M.Carroll,

O.de Nooyer (senior partner

and partner in charge) with

S.Ishida (senior partner),

B.Terpeluk, J.McNeal,

A.De Flora, F.Elmalipinar,

A.Guernier, D.Hart, T.Kjaer,

J.Lee, A.Meine-Jansen, A.Ng,

D.Piano, W.Piotraschke,

J.Sylvester; and C.Bruce,

L.Burow, C.Cooper, A.Knapp,

Y.Pages, Z.Rockett, V.Tolu,

A.Walsh; I.Corte, S.D’Atri,

G.Langasco, M.Ottonello

(CAD Operators);

F.Cappellini, S.Rossi,

A.Malgeri, A.Marazzi (models)

Consultants

Ove Arup & Partners (engineering

and sustainability);

Rutherford & Chekene

(civil engineering);

SWA Group (landscaping);

Rana Creek (living roof);

PBS&J (aquarium life support

systems);

Thinc Design, Cinnabar,

Visual-Acuity (exhibits)

General contractor

Webcor Builders


614

Exhibit Spaces

The exhibit design in concept was developed parallel with the building

design resulting in a large, flat, 34 feet high flexible exhibit space on the

ground level which benefits from the natural light and ventilation

through the facades and the roof. (the space is ventilated by means of

operable vents in the glazed facades and openings at the large undulations

of the roof, where warmer air is allowed to escape during the day)

This exhibit space continues outside of the building envelope, and is

first protected by the glass canopy and then continuing in the park in

which the Academy is situated. A new aquarium exhibit is realized in

the basement, taking advantage of the absence of light for better visibility

into the tanks. The large open tanks adjacent to the Piazza are

connected to the aquarium exhibits, thus allowing natural light to penetrate

through the water into the aquarium below. Because of the need

for a highly controlled environment in the tanks they are positioned next

to the life support system spaces.

African Hall was restored and continues to display its historic dioramas,

while California Hall was replaced by a similar volume which houses the

new Auditorium as well as the Academy Restaurant.

Public Entrance

The main entrance on Music Concourse Drive was shifted about 80

feet to the northeast, to center the facility on the site. This new configuration

achieves a more compact footprint and in doing so returns one

acre of land to the Golden Gate Park.

The elimination of one driveway and landscaping the area between the

Concourse bowl and the Academy, the original formal stairs accessing

the Academy have been eliminated creating a gentle slope that leads

up to the entrance.

The new parking garage under the Music Concourse Drive has a protected

exit under the glass canopy, adjacent to the entrance doors of

the Academy.

A second entrance, from Middle Drive, passes through the Research

and Administration block, thus becoming mainly the staff entrance with

a possibility to allow public access also here in the future.

Cross section of the RCA Building

The Research, Collection and Administration Building

Only three of the five floors of the RC&A building are above grade. The

two lower floors are under the main exhibit floor level, directly adjacent

to ‘back of house functions’, such as the aquarium life support, the

loading dock, workshops etc.

The scientific library occupies the upper floor and the research departments

most of the lower 4 floors, mixed with Administrative functions.

The entire scientific specimen collection is stored between these

research and administration spaces at the facade and the flexible

exhibit floor.

The Research and Administration facility will be naturally ventilated and

naturally illuminated by employing operable windows and automatic

sun blinds, which will balance the natural light in the workspaces.

Materials

To emphasize the roof and the building as a whole, the materials used

for the new Academy are minimal. The use of color is sporadic, (e.g.

only to indicate circulation of visitors), leaving the spaces neutral in

color intentionally. The material palette is “frugal”, not rich, to make the

space strong and essential.

Light gray architectural concrete is the main material for the walls and

closed facades, apart from the restored the African Hall which features

the original limestone. The formwork tie holes have been left visible and

are used to fix exhibits.

The floors are polished concrete and the exhibit hall soffit consists of a

series of individual white acoustic panels, mounted horizontal under the

undulated roof, thus creating a “fish scaled” surface

The four glazed facades in between the more solid blocks are executed

with extra white glass, to enhance their transparency and to

improve the visual transition of the interior into the Golden Gate Park.

The roof is a hybrid concrete\steel structure with vegetation on top,

including a water “storage” layer. The roof transforms towards the

exterior into a light steel structure supporting glass panels with PV

cells.

OdN, Genoa, 28 July, 2008

Photographer: Nic Lehoux


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2

3

4

5

6

7

8

9

10

11

12

RCA Building East

RCA Building West

Planetarium

Piazza

Rain Forest Hall

Africa Hall

Cafe

Retail

Exhibit

Labor workroom visitors

Side entrance

Main entrance

Rrainforest exterior: Inside the four-story rainforest dome, visitors can meet live rainforest residents from Borneo, Madagascar, Costa Rica, and the Amazon.

Ground floorplan

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1 2

10

11

4

9 3

5

9

6 7

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Photographer: Tim Griffith/ARUP

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Rainforest interior: A winding

ramp allows visitors

to explore the different

levels of the rainforest.

A 100,000-gallon

Amazon Flooded Forest

tank graces the bottom of

the exhibit.


10 18

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CALIFORNIA ACADEMY

OF SCIENCES

Engineering

and sustainability

by Ove Arup & Partners

Text

Janette Lidstone

Peter Lassetter

Eric Ko

Jean Rogers

Armin Wolski

Paul Switenki

Founded in 1853, the California Academy of Sciences is the largest

cultural institution in the City of San Francisco, one of the ten largest

natural history museums globally, and has a mission to explore and

explain the natural world.

The Academy’s new $484 million home located in Golden Gate Park

opened to the public on 27 September 2008 and its completion marks

the end of a seven year collaboration between Arup, and the architects

Renzo Piano Building Workshop and Stantec.

The visually-striking building features an undulating 2.5 acre living roof

with a perimeter steel canopy supporting photovoltaic cells, a large

glass skylight supported by a tensile net structure, a freestanding 90foot

diameter planetarium dome, five separate iconic aquarium tanks

and a 90-foot diameter glazed dome housing a rainforest exhibit.

Come inside and learn about the engineering and consulting solutions

that made this new San Francisco icon a reality.

STRUCTURAL SOLUTIONS

From the ground floor up, the Academy appears as four, rectangular

cornerstone structures reminiscent of the old Academy arrangement.

These structures contain the research, collections and administrative

areas, exhibits, retail, dining and conference facilities.

The main structure of these buildings consists of concrete shear walls

and columns with concrete flat plate floors on a 24-foot x 24-foot grid.

From the main podium level, two 90-foot diameter domes rise to house

the planetarium and rainforest exhibits. Glass walls and an undulating,

2.5 acre, native green roof - representing the seven hills of San Francisco

- enclose the volume between the cornerstone structures. Included

within are the two large spherical volumes (the rainforest and planetarium),

a 6,000 square foot glass piazza and 38,000 square feet of flexible

exhibit space. As the executive architect Renzo Piano described it,

the green roof design is like lifting up a piece of the park and putting a

building underneath it. The rainforest and planetarium form two of the

seven mounds that represent the topography of San Francisco.

The living roof

The undulating 2.5 acre ‘living roof’ blanketed with 1.7 million native

California plants is one of the key building features. With seven ‘hills’

mimicking the seven hills of San Francisco, the roof structure consists

of a grillage of curved steel beam sections – some spanning up to 96feet

- that support a contoured concrete slab. The curved steel beams

form a structural skeleton whose concrete skin was applied from

above (with the aid of temporary timber formwork) to achieve a carefully

contoured finished surface.

The combination of complex geometry, architecturally exposed steel

and necessary seismic detailing made the steel connection design a

challenge. Three-dimensional computer modeling techniques were

used extensively to create connection details that were both structurally

and aesthetically acceptable. Once developed, these computer

models were provided to the steel fabricators who then prepared their

own computer models for final detailed shop drawings.

The piazza skylight

At the center of the roof is a curved 72-foot x 98-foot glass skylight

supported by a steel tensile structure. This structure consists of two

nets of threaded stainless steel rods, each with a 6-foot x 6-foot grillage.

Vertical steel pipe struts connect the two nets at the nodal points.

The connections at these nodes are made by an articulated cast stainless

steel connector. This allows for all connections with varying geometry

to be made with a single connector type and allows for required

rotation.

The tensile structure is then supported by a perimeter ring truss which

transfers lateral forces into the surrounding roof structure. The glass

panels in the skylight are 6ft x 6ft triangular panels with three-point

support, using both patch and point support. These triangular panels

provide for a faceted geometry which allowed for a significant cost

reduction as compared with the alternative using doubly curved glass.

The exhibit tanks

The museum features five new aquarium tanks, including a Philippine

coral reef tank containing the largest living coral reef exhibit in the

world, a California coast tank featuring native California marine life, a

swamp tank including a flooded Amazonian rainforest floor with walkthrough

acrylic tunnel, gar tank and a penguin tank. The relative complexity

of the tank geometry and openings to receive acrylic panels

provided for extensive concrete detailing. Concrete water tightness is

addressed by using a mix design with a Xypex crystalline admixture

and by careful detailing of construction joints. Corrosion resistant

MMFX-reinforced steel was used in all concrete that is in contact with

water.

The rainforest exhibit

The rainforest exhibit features a 90-foot diameter glazed dome (bolla)

and a series of winding ramps which lead visitors through various rainforest

habitats. The bolla structure consists of an interior glazed dome

approximately 90-feet in diameter. Glass panels are point supported by

cast spider brackets, which are supported by a grillage of steel pipes.

Lateral stability is provided by tension rod bracing. A concrete ring

transfer beam at the first level supports the dome structure.

The rainforest ramp construction consists of a central steel pipe with

concrete fins that support the walkway. The ramp pipes are filled with

concrete to improve vibration performance. The sinuous geometry of

the ramps lent itself to fabrication by a steel fabricator that specializes

in fabrication of roller coasters.

The planetarium

The planetarium dome structure consists of a truncated sphere

approximately 90-feet in diameter. An inner projection screen dome is

75-feet in diameter. The planetarium will include an extremely precise

digital projector that will not only present the typical star displays, but

also provide live feeds from NASA’s planetary missions and other

space ventures. The outer dome structure is made up of steel pipe and

wide flange sections acting as both meridian and parallel elements.

The dome supports a GFRG exterior cladding system as well as the

inner projection dome. The lateral system consists of chevron diagonal

bracing.

SEISMIC INNOVATION

The site of the California Academy of Sciences lies within 10 miles of

the San Andreas Fault, and in its lifetime is likely to be subject to very

strong ground shaking. A standard building code approach required

the use of ground anchors on the building to prevent the Academy

from overturning during a seismic event.

Pushing the boundaries of conventional design, Arup structural engineers

agreed that instead of the building aggressively resisting an

earthquake by tying it down, the structure should work with the seismic

forces, dissipating the energy in an elegantly simple manner – through

rocking at the foundations.

This is not a new idea. Many engineers have hypothesized the benefits

of allowing buildings to “rock”, but few have implemented it. The seismic

concept for the Academy can be considered similar to the structure

of a table. The four wings of the building act as table legs and the

roof as the table top. The roof and ground floor slab tie the table legs

together to ensure the building acts as a whole. This roof comprises a

5 inch concrete slab over steel beams typically supported on a 48-foot

x 24-foot column grid, except in the dome areas, where beams arch

up to 96-foot intervals in the north-south direction. During an earthquake,

lateral forces will be transferred through the roof and floor slabs

in to 18-inch reinforced concrete shear walls in the four wings and

basement.

The interaction between the four wings and the roof was essential to

the seismic design. The roof structure is reasonably flexible, largely due

to the curved dome structures with glazed penetrations and the large

central space for the elegant piazza glass canopy.

Photographer: John McNeal

Cross section Piazza

Cross section Rain Forest Hall, ventilation, day- and artificial light

CFD model with ventilation openings

Piazza


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The living green expanse of the roof must roll and expand with an

earthquake to accommodate any differential movements between the

wings without compromising its stability.

Arup’s seismic concept was keenly embraced as it was in tune with the

green philosophy of the building design. The idea of the Academy

‘dancing with nature’ was appealing, but first it had to be thoroughly

investigated. A performance-based approach was undertaken to validate

the design concept and quantify the performance of the new

Academy without ground anchors. Non-linear dynamic time history

analyses were performed on a three-dimensional finite element model

using advanced simulation software, CEAP (2004). Essentially the new

Academy was ‘virtually-tested’ for an earthquake.

The performance of the building was shown to meet code level standards

and was improved through allowing the building to rock at its

foundation. Approximately $2 million was saved from the construction

budget by alleviating the need for ground anchors.

SUSTAINABILITY AT ITS BEST

Close collaboration between Arup, the California Academy of Sciences

and the architect, Renzo Piano Building Workshop, has yielded innovative

strategies to help preserve the natural integrity of Golden Gate

Park, conserve water and energy, reduce pollution and maximize natural

ventilation and light.

Arup has also taken a leading role in assisting the Academy with its

application to achieve a Platinum rating in Leadership in Energy and

Environmental Design (LEED) from the U.S. Green Building Council.

While many museums turn their backs on nature, the Academy is

embracing and attempting to embody it in both form and function.

With a projected 1.6 million visitors annually, the building itself will be an

exhibition - an educational tool for the general public.

The living roof

The new roof of the Academy comprises more than two and a half

acres of California native plants. Due to the undulating nature of the

roof, the 1.7 million plants occupy a diversity of exposures, slopes and

biological interactions. To assess which plant species could thrive in

the climate regime of northern California - including a variety of exposures

- slopes and nutrient/water combinations, the roof of the former

building on the site of the new Academy was used to assess the viability

of three dozen different plant species and several systems for soil

mixtures and stabilization and drainage.

A full-scale mock-up of a section of the roof was constructed to prototype

and demonstrate not only the techniques required to bend the

steel to achieve the significant degree of slope necessary for the roof’s

form, but then to plant the section to study plant species growth and

associated fungi below ground, and the native insect and bird species

attracted to the plants. The undulating roof aims to mimic the seven

hills of San Francisco. Functionally, it helps to serve as a chimney so

when hot air in the Academy rises; the public spaces will be naturally

ventilated. It will also serve to save energy (keeping the interior temperature

10 degrees cooler than on the roof), conserving water through

the use of reclaimed water in a micro-irrigation system. By addressing

storm water management issues, 3.5 million gallons of rainwater won’t

flow into the storm drains of San Francisco, but will be captured on the

Academy’s roof.

Renewable energy

The perimeter of the roof is bordered by 60,000 photovoltaic cells. This

system will not only provide cover and modulate light for visitors, but

provide over 220KW of energy annually. That is the equivalent of preventing

400,000 pounds of greenhouse gases emissions entering the

atmosphere, and would be the equivalent of planting 340 trees.

The photovoltaic cells will generate 5% of the building’s total energy.

The energy produced by the photovoltaic cells will be highlighted and

demonstrated on the publicly-accessible roof deck. In addition, tours of

the building will be offered to highlight and demonstrate how the building

works, the materials used and performance of conservation

approaches.

Indoor environmental quality

By employing natural daylighting and ventilation, high-efficiency electric

lighting, and commissioning, the Academy will use 30% less energy

than federal and state requirements. The glazed transparent facades

and roof sections of the building will allow daylight to be filtered into the

office, research and exhibition spaces, helping to reduce energy use

and heat gain from electric lighting. Operable windows, daylight and

views in 75% of all regularly occupied research and office spaces

ensure thermal comfort, and the health and productivity of staff and

volunteers. The public spaces have 90% with daylight and views.

Lighting controls include dimming - linked to the external light level - to

ensure that a minimum of electric light is used at all times. As part of

the low energy design strategy, the Academy plans to minimize the use

of mechanical systems for ventilating and cooling internal spaces. The

exhibit area will be naturally ventilated.

The roof shape in the form of ‘hills’ provides the height differences

required for stack driven (warm air rises) ventilation on calm days. On

days with some wind, the roof hills generate a negative pressure at the

top, to provide driving pressure for airflow. The open offices will be naturally

ventilated. The building shape and materials are designed to be a

climatic filter, limiting the solar gain and cooling/heating requirements.

Easy to open windows will be used so that occupants still have control

over their local environment. Natural daylight will be accomplished with

the glazed facades, the roof design, and lighting controls.

Water

Use of reclaimed water and low-flow fixtures will mean that the Academy

will use 20% less water than required by code, and reduce reliance

on municipal potable water for wastewater conveyance by 85%. The

building is plumbed for the use of recycled water, which will be provided

by the City of San Francisco. Recycled water will be used in the

bathrooms and in the life support systems to backwash the aquarium

filters.

Arup has also developed water systems for the aquarium so that energy

and potable water use are minimized. A number of strategies have

been employed for the ‘greening’ of the life support system of the

aquarium. They include:

• Emulating natural systems with removal of waste

• Adjusting water clarity to approximate nature (versus having ‘gin

clear’ water)

• Minimizing energy use through mechanical design (with big pipes,

small pumps, equipment locations following pipe layouts, use of variable

speed pumps etc)

• Minimizing the use of potable water by using reclaimed (gray) water

to backwash recovery filters; minimizing water discharge to sewers

with backwash recovery systems; and closed versus flow-through systems.

The entire aquarium industry will benefit from the technologies being

employed at the Academy.

Building resources

The Academy’s original building was taken down, except for outer

walls of Africa Hall. More than 80% percent of the materials in the original

building have been recycled, including stone, wood, concrete and

glass.

The stone was crushed and included in a number of public building

and construction projects around the Bay Area. More than 9,000 tons

of concrete went to the Richmond Roadway project site, 1200 tons of

metal were recycled and 120 tons of green waste were recycled for

landscaping on-site.

Building materials including non-virgin or renewable resources that feature

high recycled content, low embodied energy, long life span, and

no or low VOCs were used in the construction of the new Academy.

PROTECTING THE ACADEMY FROM FIRE

Innovative suppression system

The Research Collections & Administration (RC&A) storage for the California

Academy of Sciences includes approximately 6 million scientific

specimens in small containers, many of which are ‘archival’, and more

The 90-footdiameter planetarium dome is cantilevered out over the Philippine Coral Reef tank-the world's deepest

living display of corals.

Photographer: Tim Griffith/ARUP

Air movement and temperature as ribbon model

Evacuation model for Rainforest Dome

Fire modelling for Rainforest Dome

Protecting the academy from fire

13

Exhibit Hall

CFD Model Geometry


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than 100 years old. A majority of these specimens are preserved in a

70% - 75% alcohol solution. The total amount of flammable liquid is

estimated at 100,000 gallons. This volume of flammable liquid in a

large assembly building can be a cause for concern. In addition, the

specimens are stored in a special high-density shelving system (compactors)

that slide on tracks for access.

Since the Academy is a ‘working’ scientific facility, it was important that

the specimens remain readily available to the researchers. Off site storage

was not an option. In order to allow an unlimited amount of flammable

liquids to be stored in the Academy, separate buildings (flammable

liquid storage warehouses) were created within the main building

with the help of area separation (fire) walls.

Due to the special hazard and configuration (flammable liquids in compactor

shelving units), the design of an appropriate automatic fire suppression

system was a particular challenge for Arup’s fire engineers. In

addition, a secondary containment of spills and the fire suppression

water were required. Since no published protection guidance existed

for this special arrangement (high-density storage, low ceiling clearance,

flammable liquids in glass and plastic containers), full scale fire

testing was proposed using a mist deluge system.

Perfect timing

The Academy also contains a unique multi-level rainforest exhibit. This

exhibit is enclosed in a glass sphere and will create a humid Amazonian-like

environment with a water-filled pond on level one and trees and

vegetation extending through level two up to the third level. The visiting

public will be able to enter the glass sphere at level one and circulate

throughout the three levels via a spiral open ramp system.

The building code does not normally permit three levels to be atmospherically

interconnected without a smoke exhaust system. Since the

glass sphere is located within a building, a smoke exhaust system was

not feasible. An alternate method of construction design was developed

by Arup using performance based fire engineering.

With the help of computer modeling, a timed egress analysis was conducted

to verify the safety of the egress system of the rainforest exhibit.

The available safe egress time was established based on computer fire

consequence modeling and compared to the required safe egress time

determined using a computer egress model.

The quantitative tenability criteria and the probable fire scenarios were

established, and then computer fire consequence modeling was conducted

to determine the available safe egress time. The required safe

egress time was determined by performing a timed egress analysis.

This included an estimation of the time at which the occupants

become aware of the fire incident, as well as the delay time for occupants

to start evacuation and the time involved (including travel time

and queuing) after the decision is made to evacuate.

The latter was determined using the computer egress model STEPS

(Simulation of Transient Evacuation and Pedestrian movementS). The

required safe egress time included a safety factor that accounts for the

uncertainty inherent in human behavior and movement. Mobility

impaired occupants were also modeled.

MECHANICAL ENGINEERING

The California Academy of Sciences is a major cultural and environmental

icon within the city of San Francisco and Arup’s mechanical

design was strongly influenced by the sustainable strategies laid out for

the building. However, minimizing energy consumption while providing

superior indoor environmental quality was a difficult challenge. Arup

needed to research and specify a diverse suite of mechanical solutions

and equipment to condition and ventilate the many spaces within the

Academy while meeting the performance criteria to achieve a Platinum

LEED rating.

Main exhibit floor climate control

The 38,000 square-foot, main exhibit space was a challenge for Arup

to ventilate and condition. The goal to maintain monolithic, sheer surfaces

coupled with the desire to display the geometry of the green roof

above meant Arup’s mechanical engineers could not use traditional

overhead air systems.

Instead, Arup’s approach was to take advantage of San Francisco’s

mild climate, using natural ventilation with supplemental heating and

cooling via a radiant floor slab. Solar gains are minimized by the roof

overhang and by motorized sun shades protecting some of the glass

walls and canopies.

Natural ventilation does the majority of the space cooling, while the

radiant floor delivers all space heating requirements and also provides

supplementary cooling. The massive exposed concrete surfaces serve

as a thermal capacitor, reducing peak heating and cooling loads and

assuring space comfort is maintained. Sun shades on the east and

west glass walls and on the north canopy are activated when solar

intensity is high, unless wind speed is excessive.

High and low level ventilation openings are located in the glass walls

surrounding the exhibit areas. During cold weather high level openings

provide background ventilation and minimize low level drafts. During

warmer weather, high and low level openings work in tandem to maximize

air flow and limit space temperatures. Roof vent hatches are also

provided at the high points above the rainforest and planetarium

exhibits. All openings are automatically controlled to adjust space airflow

and temperature.

On a still day, airflow is generated by stack-effect (warm air rising) generated

by the height difference between facade openings and the roof

vents above the rainforest and planetarium. On a day where some

wind is present a negative pressure is generated at the roof vents and

drives the airflow, regardless of the wind direction.

Exhibit space temperatures and wind conditions drive the ventilation

sequence. Wind direction determines which banks of dampers operate,

and the space temperature dictates damper position. Vents can

be overridden by several means. They move to a more fully open position

when CO2 concentration exceeds the space setpoint or when

the humidity level exceeds its allowed upper limit. Some or all of the

vents close if conditions are right for floor condensation, if wind speeds

are excessive, or if rain or fog is present.

High level vents are kept open at night if the previous day’s temperature

was high if the nighttime air is cool and if the slab is warm.

Powerful exhibit lighting is located above the coral reef and rainforest. If

the vents cannot be opened due to one of the override conditions, high

level temperatures rise and trigger the lighting control system to shut

off lights, thereby preventing overheating of the space and nearby

glass.

Complex analyses were necessary to hone the system design and

prove that comfort conditions would be maintained throughout the

Academy’s operating hours. Using Computational Fluid Dynamics

(CFD), Arup proved that on a summer’s day (79°F), with the floor slab

at 68°F, the occupied zone’s operative temperature is expected to be

in the mid-70s and the average air velocity to be 35 feet per second.

Likewise, the CFD studies proved the exhibit area will be maintained at

an average temperature of 69°F and air velocity of 60-feet per minute

in the winter. For both design conditions, these parameters fall well

within comfort requirements.

The radiant floor

Approximately 100,000 linear feet of tubing runs within the 38,000

square feet of concrete slab. Manifolds are located at the first level of

the three-level basement. The system is broken into nine independent

temperature control zones, so nine sets of valves, pumps and accessories

have been located in the mechanical rooms on the first basement

level.

The floor operates in cooling mode only when the exhibit area temperature

is above setpoint or when the outdoor air temperature is above

77°F and rising. In cooling mode, the return water temperature is fixed

at 68°F. When the outdoor air temperature falls below 64°F the radiant

floor switches into heating mode.

The water temperature modulates between 75°F and 90°F as the outdoor

temperature drops to the winter design condition. The system

changes over from heating to cooling via simple modulation of two-way

valves – one at the tertiary chilled water (radiant) loop and one at the

associated hot water heat exchanger.

The Water Planet exhibit features an ever-changing array of aquarium tanks set into curvilinear

walls that evoke ocean waves.

Summer temperature contours - section through Exhibit Hall, Detail Summer velocity vectors - section through Exhibit Hall, Detail

Summer temperature contours - Plan view at 3.6ft above floor level

Summer temperature contours - Section through Exhibit Hall Winter velocity vectors

Exhibit Hall without Piazza

The new African Hall closely resembles the original hall, a longtime San Francisco favorite.

It is now also home to five live animal displays, including African penguins at the

end of the hall.

Summer velocity vectors - Plan view at 3.6ft above floor level

Planetarium Rainforrest

Photographer: Tim Griffith/ARUP


D+H Mechatronic AG

Georg-Sasse-Straße 28-32

22949 Ammersbek

Germany

Tel: +49 40 60565 0

Fax: +49 40 60565 222

E-Mail: info@dh-partner.com

WWW.DH-PARTNER.COM

© 2011 D+H Mechatronic AG, Ammersbek_99.701.28; 1.0/08/11

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