Archives of

1. Introduction
Despite the relative comfort and welfare brought to humankind, today’s modern technology and advancements have also been the basis for risks and threats having the potential to cause accidents and cause harm, injury, and damage to people’s lives, property, equipment, environment, and other physical and intellectual assets. Therefore, human reason dictates that these risks and risk factors be controlled. In order to control the risks, they must be identified first and then prioritized according to their magnitude and probability of occurrence. The systematic process of identifying risks, determining their magnitude, and prioritizing them is called risk assessment. Risk assessment is one of the basic stages of the risk management program, which should be performed by experts and experienced people based on efficient methods and techniques so that its results can be used as an acceptable criterion to guide managers in decision-making regarding the allocation of financial resources and other facilities for safety and risk control, according to the cost-benefit analysis [1,2].
Numerous techniques and methods have been developed to analyze the risks, the number of which reaches more than one hundred, and are classified into three general categories: Quantitative techniques, semi-quantitative techniques, and qualitative techniques [3,4]. Among these techniques are quantitative risk assessment, Dow’s fire and explosion index, failure mode and effects analysis (FMEA), hazard and operability study, fault tree analysis (FTA), and dozens of other techniques, which are selected according to the type of system under study and access to sufficient data, and are used for risk assessment [5,6]. Each of these techniques has its own strengths and weaknesses [7].
One of the system risk analysis techniques, which is among qualitative techniques and identifies and analyzes
Safety Risk Assessment in the Tile Industry with a New Approach
Mohammad Khandan1ID, Mohammad Reza Jafari2ID, Alireza Koohpaei3ID, Zeinab Hosseinzadeh4ID, Abbas Sadeghi5*ID
1PhD Student in Ergonomics, Department of Occupational Health Engineering, School of Public Health, Tehran University of Medical Sciences, Iran
2MSc Student in Safety and Hazard Defence, Department of Water, Environment, Construction and Safety, Hochschule Magdeburg-Stendal, Magdeburg, Germany
3Associate Professor, Occupational Health Department, Health Faculty, Qom University of Medical Sciences, Qom, Iran
4Occupational Health Department, Health Faculty, Qom University of Medical Sciences, Qom, Iran
5Department of Health, Safety and Environmental Management, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran
*Corresponding Author: Abbas Sadeghi, Email: sadeghi_osh@yahoo.com
Abstract
Background & Aims: Despite the relative comfort and welfare today’s modern technology has brought to humankind, it has also been the basis for the emergence of risks and threats. These risks and risk factors should be assessed and controlled using systematic risk assessment and management methods. Numerous techniques and methods have been developed to analyze risks, each of which has its own strengths and weaknesses. One of the system risk analysis techniques, which is among qualitative techniques and identifies and analyzes system risks inductively, is the functional hazard analysis (FuHA) technique. The present study aims to identify and control risks that occur due to technical defects or system dysfunctions and can lead to an unpleasant event, as occurred in an industrial unit in 2016.
Methods: In this cross-sectional analytical study, the functional risks of an industrial unit were analyzed using the FuHA technique. By implementing the FuHA technique in the investigated industrial unit, 17 functional defects were identified.
Results: In general, according to the level of severity of different consequences caused by the identified defects, 60 functional risks were identified, of which 7 cases (11.67%) were assessed as unacceptable, 17 cases (28.33%) as unfavorable, and 36 cases (60%) as acceptable but needing revision.
Conclusion: The results of this study showed that the FuHA technique had a favorable ability to identify and analyze system and subsystem functional risks, especially software subsystems.
Keywords: Safety, Risk, Risk assessment, Functional hazard analysis
Received: March 28, 2022, Accepted: April 13, 2022, ePublished: March 18, 2023
https://jhygiene.muq.ac.ir
10.34172/AHS.12.1.10.36
Vol. 12, No. 1, 2023, 7-11
Original Article
Khandan et al
8 Arch Hyg Sci. Volume 12, Number 1, 2023
system risks inductively, is the functional hazard analysis
(FuHA) technique. In inductive techniques, unlike
deductive techniques, the analysis is from part to whole,
which means that risk analysis starts from the system
components and ends with the whole system [8].
The primary goal of the FuHA technique is to identify and
control risks that occur due to technical defects or system
dysfunctions and can lead to an unpleasant event [8,9].
FuHA is a powerful tool for identifying functional
defects, system risks, and their effects [10] and is
especially suitable for identifying and analyzing the risks
of any system, including software and functional tasks,
and is broadly used for analyzing the risks associated
with the performance of systems and subsystems of
aircraft, spacecraft, and satellite systems [10-12]. In this
regard, in a research in 1998, Wilkinson and Kelly, while
explaining the principles and process of implementing the
FuHA technique, expressed the problems and difficulties
of using this technique in analyzing the functional risks
of integrated aircraft systems and suggested solutions to
overcome these problems and difficulties [11]. In another
research in 2010, Hai-feng proposed the FuHA technique
based on a safety-critical application development
environment model. The researcher used this model
to form the functional structure and functional defect
structure, integrated these two structures, and used it to
identify the functional risks of safety-critical systems. As
a case example, the researcher implemented the presented
model on the computer signaling system in railway tracks;
the results showed that the proposed model could increase
the accuracy and completeness of the FuHA technique
[13]. In another research in 2014, Khosravirad et al used
the FuHA, FMEA, and bowtie analysis techniques to
analyze the root causes of process accidents in natural
gas pressure reduction stations and showed that the
combined method used in this study could be suitable for
identifying root causes and controlling process risks [14].
The FuHA technique can be implemented in all phases
of the system life cycle. However, if it is used in the initial
phases of system development, such as the initial design
phase or the detailed design phase, its results will be more
beneficial and will result in maximum benefits because
the fewer changes needed to improve the system and its
functions, the less cost imposed to the system. Another
advantage of implementing the FuHA technique in the
initial design phase is to identify the main event used
in the FTA technique because when the main event is
defined and specified, the fault tree can be designed for
each fault condition or event related to the system [8,15].
The FuHA technique is a predictive technique that
tries to discover and identify the effects of functional
defects of system components [11]. The outputs of the
implementation of this technique include functional risks,
safety-critical functions, causative risk factors (defects,
design errors, human errors, etc), system risks, and safety
requirements to reduce risks [8,14].
The present study was conducted to assess the risks of a
tile production industrial unit using the FuHA technique.
2. Methods
The present study is a cross-sectional descriptive study
conducted in a tile production industrial unit. The
required data and information were collected through
observation, checking the list, creating a flow diagram
of system and subsystem functions, and interviewing
experts.
The general process of implementing the FuHA
technique is shown in the flow diagram of Figure 1.
The system studied in this research is the roller furnace,
which is used for baking and preparing tiles and consists
of different parts and systems, such as the driving
system, the combustion system, the pre-furnace section,
the baking section, and other sections (Figure 2). Each
of these systems includes a number of functional and
software subsystems. Some of these subsystems include
the furnace computer subsystem to adjust the speed
of the furnace motor and the burner temperature, the
manometer subsystem to adjust the air pressure entering
the burner, the exhaust fan subsystem to suck air, the
Figure 1. The flow diagram of the process of implementing the FuHA
technique [8].
Specifying the operation
Collecting the required information
Listing the functions
Implementing the FuHA technique
The system risk assessment
Identifying safety-critical function
Suggesting corrective measures
Monitoring corrective measures
Following up risks
Documenting the FuHA technique
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Safety Risk Assessment with New Approach
thermometer subsystem to measure the furnace internal
temperature, and the servomotor subsystem along with
the thermocouple to adjust the air in the rapid cooling
section. Defective and wrong function at any time other
than the appropriate time by any of these subsystems
can lead to defects, breakdowns, and accidents in the
furnace system. The FuHA process usually starts with
preparing a list of functional operations of the system or
subsystem, especially software systems, and then risks are
identified based on defects or the possibility of defects in
each of the mentioned functions [15]. In the next step,
all the possible effects of the risk on the system and its
components are determined based on the guide Table 1.
After that, according to the records of past accidents and
risks of the system and its subsystems and using the
opinions of system experts, the probability of occurrence
of the desired risk or accident is determined using the
guide Table 2. Then, with the help of Table 3, the initial
mishap risk index (IMRI) for each functional risk is
calculated using the proposed standard method (MILSTD-
882E) and Equation 1. Finally, by using Table 4, the
decision-making criterion on the risk level of each hazard
is determined [16]. In order to control the identified
risks, corrective solutions are proposed, and then the final
mishap risk index (FMRI) is also calculated if corrective
solutions are applied [8].
(Risk = Severity of accident occurrence × Probability of
accident occurrence)
Risk = Probability × Severity Eq. (1)
3. Results
By implementing the FuHA technique in the furnace
system of the investigated industrial unit, 17 functional
defects were identified, and in general, according to the
severity of the different consequences caused by the
identified defects, 60 functional risks were identified, and
IMRI and FMRI were determined for each one. Among
these probable risks, the IMRI indices of 7 cases (0.12%)
were assessed as unacceptable, 17 cases (0.28%) as
Figure 2. A view of the tile firing furnace in the studied process.
Table 1. Risk severity level
Definition Category Risk Type
System death or crash 1 Catastrophic
Injuries, occupational diseases, or damages to the system are severe 2 Critical
Injuries, occupational diseases, or damages to the system are small 3 Marginal
Injuries, occupational diseases, or damages to the system are very small 4 Negligible
Table 2. Risk probability level
Risk description Risk level Probability of occurrence
It happens frequently. A Frequent X > 10-1
It occurs several times during the system life cycle. B Probable 10-2 < X < 10-1
It occurs from time to time during the system life cycle. C Occasional 10-3 < X < 10-2
The probability of its occurrence during the system life cycle is very low. D Remote 10-4 < X < 10-3
The probability of its occurrence during the system life cycle is zero. E Improbable X < 10-4
Table 3. Risk assessment matrix
Probability of occurrence
Severity of risk
Catastrophic (1) Critical (2) Marginal (3) Negligible (4)
Frequent (A) 1A 2A 3A 4A
Probable (B) 1B 2B 3B 4B
Occasional (C) 1C 2C 3C 4C
Remote (D) 1D 2D 3D 4D
Improbable (E) 1E 2E 3E 4E
12
Khandan et al
10 Arch Hyg Sci. Volume 12, Number 1, 2023
unfavorable, and 36 cases (0.6%) as acceptable but needing
revision. Among the identified risks, non-operation of
the ventilation system of the furnace with the IMRI of
2B (unacceptable) was identified as the most critical risk
in the studied system, which can lead to the poisoning
of individuals and personnel due to inhalation of the gas
exhausted from the furnace. Among the causative factors
of this incident (the failure of the ventilation system)
are the power cut, the fan’s unintended operation, and
the gas outlet channel breaking. On the other hand, the
lack of flame and non-operation of the furnace with the
IMRI of 4A were also identified as the functional defects
with the least importance in the studied system. Power
cuts, non-operation of the sparker, premature operation
of the detector, failure and defect in the flame spreader,
and breaking of the gas or air inlet pipe are considered the
causative factors of this event.
Table 5 shows a part of the table of the results of
implementing the FuHA technique in the investigated
industrial unit.
4. Discussion
Out of the 60 functional risks identified in this study,
the IMRI indices of 7 cases (11.67%) were assessed as
unacceptable, 17 cases (28.33%) as unfavorable, and 36
cases (60%) as acceptable but needing revision. In order
to reduce the IMRI of the identified risks, controlling
solutions and measures were proposed, and the FMRI of
each functional risk was also estimated. Some corrective
suggestions and solutions include timely planning and
implementation of preventive maintenance, purchasing
higher quality parts, creating a container for the mechanical
valve and manometer, calibrating the manometer, using
gearbox motors instead of gear motors, and using rollers
with a higher modulus of elasticity, which by applying
and using these corrective measures, the risk index of all
hazards will be reduced to a lower level. For example, the
FMRI of non-operation of the ventilation system improves
from 2B to 2C after implementing measures such as the
implementation of inspection and regular maintenance
programs and the use of good quality parts, or the risk of
breaking the furnace gear wheels due to non-operation of
the operating system improves from 3A to 3B.
In this study, the functional risks of an industrial unit
were analyzed using the FuHA technique, which is one
of the powerful techniques to identify and determine
the effects of functional risks of systems and subsystems.
In order to assess the risk of hazards using the usual
method of risk assessment, the risk index of each hazard
was obtained from the product of the two components
of the probability of the hazard in the severity of its
consequences. The results of this study showed that the
FuHA technique had a favorable capability to identify and
analyze the functional risks of systems and subsystems,
especially software subsystems. Also, the results of the
FMEA technique can be used as the input of the FuAH
technique.
In general, the FuHA technique can be used in different
phases of risk management in different industries.
Khosravirad et al used this method to identify and
determine the risk priority number of hazards in natural
gas pressure reduction stations [14]. Another study [17]
in the industry conducted using the FuHA technique
also showed that about 11% of cases were unacceptable,
which is similar to the present study, both of which were
the lowest among different risk levels. On the other hand,
in the previous study, most risks were at an average level,
but in the current study, most risks were obtained at an
acceptable level, which can be due to the type of industry
and the conditions of the equipment used.
Table 4. Decision-making criteria based on the risk index
Risk classification Risk criterion
1A, 1B, 1C, 2A, 2B, 3A Unacceptable
1D, 2C, 2D, 3B, 3C Unfavorable
1E, 2E, 3D, 3E, 4A, 4B Acceptable but needs revision
4C, 4D, 4E Negligible
Table 5. A part of the table of the results of implementing the FuHA technique in the tile production industrial unit
System Subsystem System Component Defect State Causative Factors Effects IMRI Controlling Measures FMRI
Roller
furnace
Baking
section
Furnace
gasification system
Fueling the
furnace less
than enough
1. Creating a leak in the gas tank
1. Creating holes
and quality defects
in the product
4A
1. Timely planning
and implementation of
preventive maintenance
4C
2. Clogging of the filter openings
3. Malfunction of manometer
2. Purchasing higher
4. Leakage of gas transmission pipes quality parts
3. Creating a container for
5. Regulator failure the manometer
6. Clogging of gas transmission
pipes
2. Failure to bake
the tile
4A
4. Calibrating the
manometer
4C
3. Possibility of
explosion
1D 1E
4. Emission of gas
to the outside of
the furnace
2D
5. Increasing the quality
of incoming gas by using
a CNG tank
4D
Abbreviations: FMRI, Final Mishap Risk Index; IMRI, Initial Mishap Risk Index.
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Safety Risk Assessment with New Approach
5. Conclusion
In the end, it should be noted that since the FuHA
technique deals with functions and functional risks,
other risks of the system, including risks related to energy
sources, risks of sneak circuit paths, risks of dangerous
substances, etc., may be ignored. As a result, one should
not only be content with implementing this technique and
using its results in system risk assessment, but other types
of risk analysis techniques, such as preliminary hazard
analysis or subsystem hazard analysis, should also be used
as a supplement [8].
Acknowledgments
The researchers of this study would like to thank the management
and all personnel of the studied industrial unit for their cooperation
and assistance in conducting this study.
Authors’ Contribution
All authors contributed equally in all phases.
Competing Interests
There has been no conflict of interest.
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