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44 Engineering Fundamentals
It turns out that the temperature gauge on your
oven is not accurate, and you have been baking
the cookies at 425° even though the gauge says
350°. In buying a new cookie sheet, you have
solved the wrong problem. The real problem was
that the temperature gauge was broken, and not
that the cookie sheet was of low quality. Untold
time and money is spent by design engineers
who fail to properly identify the true problem
before designing a solution.
In order to defi ne the problem, engineers
must do as much research and gather as much
information as possible on the problem. Engi-
neers must be willing and able to ask a lot of
questions and look at problems from all angles.
Engineers are often handed a problem by some-
one else. In industry, the problem, or need, can
be generated by market forces. A company may
see an opportunity to make money selling a
given product if it can be designed, built, and
brought to market. Engineers are often called on
to solve problems with equipment that breaks
down or parts that fail. They could be called on
to design new parts or systems to meet a given
need. If the engineer was not the person who
identifi ed the problem, the engineer should
seek out the person who did identify the prob-
lem to make sure the engineer understands the
true problem.
The engineer must develop a problem state-
ment. The problem statement outlines the prob-
lem in clear terms, but it is not so specifi c that it
limits creativity in design. For example, a prob-
lem statement could be:
Student lockers fail to adequately meet the needs of
students and custodial staff.
Problem Constraints
Once the problem has been identifi ed and
a problem statement has been written, it is
time to defi ne the constraints of the problem.
Constraints are the limitations of the design,
such as materials, costs, size, and time. Using
our locker example, students report that their
lockers are diffi cult and time consuming to lock
and unlock, lack adequate ventilation, and do
not allow for easy storage of common student
materials. Custodians fi nd the lockers diffi cult to
clean. The outsides are cleaned weekly and the
insides are completely cleaned out each summer.
School administrators require the lockers to be
upgraded on budget, occupy the same amount of
fl oor space, and be completed on time (before the
start of school year).
Lockers should be redesigned to meet the following needs:
• Ample storage.
• Good airfl ow.
• Reasonable security.
• Convenient student use.
• Easy cleaning for custodians.
• Privacy.
• No fl oor space increase.
• Cost.
The engineer creates a document called the
design brief, which guides the design process. See
Figure 3-5. The design brief includes constraints,
Design Brief
Redesigning Student Lockers
Anyone who has ever tried to use a
school locker knows that they are very
small and difficult to use. Many lockers are
too narrow for large books to lie flat and to
store full backpacks.
Your challenge is to redesign common
school lockers without taking up more
floor space to improve the following:
Amount of storage
Airflow
Security
Convenience of use
Ease of cleaning
Privacy
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Figure 3-5. 
The design brief guides the design process.