The St.
Louis region’s creative engineers are making better buildings.
By Peter Downs
Buildings just aren’t what they used to be, and that is a good thing.
Innovative St. Louis region engineers and architects are changing
the rules of building design to help children learn, help businesses
cut costs, and help make users more comfortable.
At the Central Institute for the Deaf (CID), the architects of Mackey
Mitchell Associates faced the challenge of designing a school that
is quiet enough for deaf children to learn in, with classrooms substantially
quieter than most existing “quiet” classrooms. That may seem paradoxical,
but CID is an oral school that teaches children how to interpret
audible cues to help them decipher what a person is saying. Seventy
percent of the children have cochlear implants, so it is important
not to have noise interfere with hearing the teacher.
The typical solution to the problem of making someone heard over
noise is to make the speaker louder. Amplifiers do also increase
noise, however, so that was not a good choice for CID. Mackey Mitchell
architects chose a different, and ultimately cheaper path, and it
is a choice that is garnering national attention. They chose to
design out noise.
The first step in designing out the problem was analyzing where
noise comes from. According to Marcus Adrian, an associate architect
at Mackey Mitchell, there are four sources of noise in any room:
outside noise, including traffic noise from the highway abutting
the site and from helicopters carrying patients to Barnes-Jewish
Hospital; noise from the heating, ventilating, and air conditioning
system; building noise from halls and other rooms; room noise from
talking, desk sliding, reverberations, etc.
With so many sources of noise, no one solution was possible. Instead,
designers considered the need for quiet in every decision they had
to make about the building, such as where to put it on the site;
how to arrange interior spaces as offices, classrooms, and halls
with respect to each other; what building materials to use; the
height of interior walls; where to place ductwork and how big it
should be; and so on.
No one thing was new, Adrian says. What was new was integration
of all of them. “Our silver bullet was good planning,” he says.
The CID solution has applicability for more than just schools for
the deaf. There is a growing awareness that noisy classrooms can
retard learning in normal children. National Public Radio’s Diane
Rehm Show has taken note of the movement for quiet classrooms, and
a board in Washington, D.C. is drafting standards for acceptable
background noise levels in public schools.
Up to now, acoustical treatments in classrooms are the second things
cut from school construction budgets, after only landscaping, Adrian
says, but “our budget [for CID] was not much greater than for a
normal elementary school.”
At Donald Danforth Plant Science Center, the problem isn’t noise,
it’s heat and reliability. Scientists at the center will have environmentally
controlled growth rooms and growth chambers to study plants in all
kinds of environments by controlling temperature, humidity and light.
To avoid contaminating one experiment with airborne particles from
another, the growth chambers use all outside air. In the typical
office building, 90 percent of the air in the building is recycled,
and only 10 percent of the air that flows through the ventilating
system comes from outside. The ventilating system for the growth
rooms takes 100 percent of its air from outside, and exhausts all
of it. That means they need a mechanical system and ductwork that
are bigger than would be needed for a similar amount of office space.
That’s expensive. Running it is even more expensive. The Danforth
Plant Science Center purposefully expels all the energy used to
heat, cool, or dehumidify air from the building and expends new
energy to heat, cool, or dehumidify unconditioned air approximately
every four minutes.
To help reduce costs, the team of Icon Mechanical and C&R Mechanical
put a coil in the exhaust air stream to recapture some of the energy.
In the winter, the exhaust warms the coil, which transfers heat
to a similar coil in the intake air stream to warm incoming air
before the mechanical system expends new energy to bring it up to
the desired temperature. In the summer, the exhaust cools the coil,
which cools incoming air before it enters the chillers. Based on
1999 energy costs, the energy recovery coil will pay for itself
in only three years, says Mike Bieg, president of Icon Mechanical.
Since plant experiments can last for as long as three years, it
also was important that the system operate without interruption.
To accomplish that goal, the mechanical contractors connected the
office building mechanical system to the growth room system so that
one backs up for the other.
Above Left: The Central Institue for the Deaf Building
is designed to be quiet enough for deaf children to learn. In designing
the building, Mackey Mitchell "designed out noise."
Above
Right: Nidus Center for Scientific Enterprise, a 40,000-square-foot
plant and life sciences incubator, officially opened in April
2000. William Tao & Associates designed a unique air system
for the Nidus Center that combines the labs and offices into one
integrated system.
At Nidus Center, William Tao & Associates (WTA) faced a similar
challenge, but took a very different approach. Where the mechanical
engineers for the Danforth Center designed in two heating, ventilating,
and air conditioning systems, one for the offices and another
for the growth rooms, WTA combined the labs and offices into one
integrated system at the Nidus Center.
“I have a basic conceptual disagreement with the way labs are
usually done, which is to segregate systems for both labs and
offices,” says Richard Janis, president of WTA. “Labs need all
this air, why not run it through the office first and then through
the lab without throwing it away? It doesn’t increase your risk
of contamination, but it saves money and improves office air quality.”
Nidus system uses 100 percent fresh air, just like the growth
room system at the Danforth Center, but the air goes through the
offices first, which makes for much better air quality in the
offices.
As the air is exhausted from the labs, a thermal wheel recaptures
energy. The wheel recovers 80 percent of the energy used to condition
air, which is a lot better than a coil does, Janis says. As a
result, “you get great air quality at an economical price,” he
says.
This integrated system design won an Engineering Excellence Award
from the Missouri Consulting Engineers Council. The Engineers
Council estimated that it uses only half the energy of a conventional
laboratory building system. The Engineers Council also concluded
that If research organizations adopted it as they built new facilities
or renovated existing ones, they would save more than $500 million
over 20 years.
Innovative heating and air conditioning solutions aren’t just
for exotic biotechnology research centers, however. St. Louis-based
Aedifica Case tackled a more prosaic problem: chilly aisles in
the frozen food sections of supermarkets.
Shop ‘n Save prefers to use open freezers in its frozen food sections
so customers can get unobstructed views, and access, to the items
they might want. The drawback: consumer complaints of cold air
and drafts.
The problem, according to Aedifica Case president Darrell Case,
is that typical supermarket ventilation systems delivered heat
near the ceiling, while cold air rolled out of freezer cases at
waist level.
Case designed a system for Shop ‘n Save’s Fenton store that captures
waste heat from the freezer compressors, dehumidifies it, and
supplies warm air to the aisle from underneath the freezer cases.
That warm air mixes with the cold air rolling out of the cases
to provide a comfortable temperature for customers. Since installing
the system, customers at the Fenton store have ceased complaining
about cold air in the frozen foods section.
This system won a Technology Award from the St. Louis Chapter
of the American Society of Heating, Refrigerating and Air-Conditioning
Engineers for improving air quality and energy efficiency while
cutting installation and operating costs
Peter Downs is a free-lance writer and editor of Construction
News & Review.
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