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Risk
The total risk (R т + R SЕ )

Social and economic risk
The region of acceptable
(R SЕ )
risk
10 -6

Technical risk (R Т )
10 -8

Expenses on security

Figure 2.1 - Determination of acceptable risk (Explains the concept of
"acceptable" risk)

By increasing spending (expenses) on improving technical systems, we can
significantly reduce the value of technical risk. And increasing the expenses for
reducing the technical risk cause harm to the social sphere (reduced spending on
health, culture, education, etc.). The economic opportunities of any society are
limited, as result, social and economic risks increase.
Acceptable risk include the technical, economic, social and political sides
and this risk is a compromise between the level of safety and opportunities to
achieve it.

Value of total minimal risk can be determined analytically by using the
theory of the function extremum.

After differentiation of function R=f(E) (where R – value of the total risk; E
- expenses for occupational safety) the resulting expression is equated to zero:
dR
 , 0 (2.7)
dЕ
then we can determine the optimal expenses E and minimum total risk R min .
opt

4 TASK OF CLASS
4.1 Before meeting on class, students should study basic theory of the
engineering method of risk determination. All students are expected to come to
class alert and ready to participate in discussion.
4.2 Students in the classroom at the request of a teacher give answers on the
questions.
4.3 Then the students should solve the problems and tasks (should determine
the risk by engineering method, determine the value of acceptable risk) according
to the variant given by teacher. They may use references [1, 2] and theoretical data
from basic theory.

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