Designing for Safety
In this
section, you will learn about some of the way in which designers plan safety into structures and the factors they consider when designing and monitoring
them.
No one can
design a structure to be 100% failure
proof. The materials may wear down
over time. A person may use it incorrectly
and break it. Unexpected forces
might come into play
Engineers
use the techniques of risk management
to reduce the risk of failure as much as possible.
They deal
with known risks in one of three ways:
Ignore the risk
Avoid the risk
Design for the risk
When a risk unlikely to occur, it can be ignored. E.g., an elephant sitting on a
classroom chair.
Building a
bridge with no supports in the water
is a way to avoid the risk of boats
colliding with the bridge supports.
When
designers design for risk they often
over-compensate for the various
risks. They often make the structure stronger
than really needs to be; e.g., stronger bridge supports in the water in case of
a boat collision.
They also
build in back-up and warning systems that may use sensors.
Designing for Loads
When designing
a structure, the designers must calculate the load it will support. They design the chair to support more than itself plus the biggest occasional load. Some structures have warning
notices about the maximum load they
are designed to support, e.g., an elevator.
The Ontario Building code gives minimum standards
for all aspects of building, including load
bearing design and materials. This
assures the public of a certain level of safety.
The Ontario Fire code is a law in Ontario that
states that every home in Ontario must have working smoke alarms on every floor and outside all sleeping areas. Properly installed working alarms can warn people to get out of a burning building. This reduces
the number of fire-related injuries
and deaths.
Designing for Efficiency
Something
described as “efficient” operates
well without a waste of time, effort, or expense. E.g., if two students build bridges that support the same load, the bridge that uses the least
amount of materials (usually by
weight) is considered more efficient.
Sensors
A sensor is any device that can detect or
measure real-world conditions. Different
sensors can detect heat, lights, pressure, or sound, as well as changes in the amounts of these things.
Make a list
of sensors found in your home:
Smoke alarm
Carbon-dioxide
alarm
Thermostat
Motion
sensing lights
Motion
sensor alarm
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