Designing for Safety
In this section, you will learn about some of the ways in
which designers plan safety into structures and the factors they
consider when designing and monitoring them.
Risk Management
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 is highly 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 it really needs to be; e.g., stronger bridge supports
in the water in case of a boat collision.
They also build in back-up
systems 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 maximum occasional load. Some structures have warning notices about the maximum load they are designed to support e.g., an elevator.
Designing for Safety
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 sleeping areas. Properly
installed smoke 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 can support the
same load, the bridge that uses the lesser 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, light, pressure, or sound;
as well as changes in the amounts of
these things.
Make a list of the sensors found in your home:
Smoke detectors, carbon monoxide detectors and thermostats
How are sensors used in entertainment?
Wii, and Xbox connect, dance video game.
Where are motion detectors used?
Automatic doors, automatic lights, automatic taps, motion
sensors for alarms, reverse sensors, garage door sensor,
How do engineers use sensors to make people safe?
Security cameras that sense noise, traffic lights, vibration
sensors for weaknesses in the building.
