Environmental Engineering Reference
In-Depth Information
R
= D
Tt Tf
( ) /
(
),
[2.5]
T
where R T is technical risk; ∆ T is the number of failures per unit time t of
the identical technical systems and facilities; T is the number of identical
technical systems and facilities, subject to general risk factor f .
Sources and technical risk factors are listed in Table 2.1.
The process of formation and development of risk is affected by a
variety of factors and conditions specified on Fig. 2.8. The diagram show
a range of underlying causes of risk: malfunction sites and equipment due
to their structural deficiencies, poor manufacture or technical violations
of maintenance, deviation from normal operating conditions, human error,
external influences, etc. Because of these reasons, industrial facilities are
constantly in an unstable state which in relation to production safety is
especially critical for emergency situations at the facilities.
The risk occurs when the following necessary and sufficient conditions
are fulfilled:
• The existence of risk factors (source of danger);
Table 2.1 Sources and technical risk factors
Source
Most common factors
Wrong choice of directions of technological develop-
ment and technologies for safety criteria
Low level research
Selection of potentially hazardous construction schemes and
principles of technical systems. Errors in the determination
of operating loads. Wrong choice of construction materi-
als. Insufficient margin of safety. The absence of technical
security measures in projects
As above, experimental
and design studies
￿ ￿ ￿ ￿ ￿
Experimental production
of new machinery
Poor finishing construction, technology, documentation for
safety criteria
Variation of the chemical composition of constructional
materials. Insufficient accuracy of structural materi-
als. Violation of thermal and thermochemical treatment of
parts. Violation of regulations of assembly and installation
of structures and machines
Series production of
unsafe equipment
Inappropriate use of technology. Violation of the passport
(design) operating modes. Untimely prevention inspections
and repairs. Violation of requirements for transportation and
storage.
Violation of the rules of
safe operation of techni-
cal systems
Poor skills in a difficult situation. Inability to assess the
status of the process. Poor knowledge of the nature of the
ongoing process. Lack of self-control under stress. Indisci-
pline.
Human error
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