A fuzzy-based occupational health and safety risk assessment framework and a case study in an international port authority

Figures & data

Table 1 Previous OHSRA studies for port operations.

Study	Objectives	Methods used	Approach used
Mokhtari et al. (2011)	Risk management of seaports and offshore terminals	Fault Tree Analysis (FTA), Event Tree Analysis (ETA), Fuzzy Set Theory (FST), Fuzzy Possibility Score (FPS)	Used FTA and ETA to analyse the risk factors associated within the ports and offshore terminal operations and management and used fuzzy methods to deal with the vagueness of the data
Mokhtari et al. (2012)	Risk management of three Southern Iranian ports	FST, ER	Used FST to describe and evaluate the associated risk factors within the ports and terminal operations and management and used ER to synthesise the information produced
Yang et al. (2014)	Risk quantification in port facility security assessment	Fuzzy Evidential Reasoning (FER)	Used FER to facilitate the quantitative analysis of port facility security assessment
Alyami et al. (2014)	Risk analysis for container port safety evaluation	Failure Mode and Effects Analysis (FMEA), Fuzzy Rule-Based Bayesian Network (FRBN)	Used FRBN to evaluate the criticality of the hazardous events (HEs) in a container terminal
Zhang et al. (2016)	Maritime transportation risk assessment of Tianjin Port, China	Bayesian Belief Networks (BBN)	Used BBN to express the dependencies between the indicator variables and accident consequences
Alyami et al. (2016)	Assessing the safety performance of a Container Terminal Operational System	FMEA, FRBN, Evidential Reasoning (ER)	Used FRBN for prioritising HEs individually in a container terminal then used ER to aggregate the HEs’ risk estimations collectively
John et al. (2018)	Seaport security assessment	FAHP, ER	Used FAHP to analyse the complex structure of the system and determine the weights of security systems/measures and used ER to synthesise the risk analysis
Ozturkoglu et al. (2019)	Sustainable and preventative risk management for ship recycling	Fuzzy Decision-Making Trial and Evaluation Laboratory (FDEMATEL)	Used FDEMATEL to analyse causal link between occupational health and safety factors
Cao and Lam (2019)	Fast reaction-based port vulnerability assessment	FER, Fuzzy Technique for Order Preference by Similarity Ideal Solution (FTOPSIS)	Used FER to fuse vulnerability indicators and used FTOPSIS to gain bottleneck coefficients for each assessment unit in the port
Efe (2019)	Operational safety risk analysis in shipbuilding	FMEA, Intuitionistic fuzzy numbers-based quality function deployment (QFD), VIsekriterijumska optimizacija i KOmpromisno Resenje (VIKOR)	Used intuitionistic fuzzy numbers to weight FMEA parameters, used QFD to weight design requirements and used VIKOR to rank the occupational accidents-related failure modes in shipbuilding

Figure 1 The proposed risk assessment framework.

Table 2 Hazards list and their descriptions.

Code	Station	Activity environment	Hazard description
D1	Dock	Loading and unloading	Not use of safety shoes
D2		Loading and unloading	Working without helmet
D3		Loading and unloading	Working at height
D4		Loading and unloading	Standing under load
D5		Loading and unloading	Working with unsuitable crane
D6		Working with magnesite	Intense dusting of magnesites
D7		Working with magnesite	Not opening of magnesite vessel covers
D8		Work on the docks	Affecting employees of soda powder
D9		Working with crane	Lack of safety catch in the crane hooks
D10		Working with crane	Loading too much strain on the lifting equipment
O1	Offices	Use of computer	Fire
O2		Use of computer	Looking at the screen for a long time
O3		Use of computer	Long-term use of keyboard and mouse
O4		Use of computer	Long-term sitting
O5		Use of computer	Electric shock
O6		Printer, Copier and Fax usage	Fire
O7		Printer, Copier and Fax usage	Electric shock
O8		Printer, Copier and Fax usage	Working with toner ink
O9		Air conditioning use and maintenance	Conditioning fluids contamination
O10		Office work	Office furniture
O11		Cleaning works	Wet floor
O12		Working with the pressure tube	Working with the pressure tube
P1	The whole port	Manual handling jobs	Heavy and unstable lifting
P2		Working with forklift	Hitting and To be hit
P3		Visitors	Not identifying areas where visitors should wait and rules they should obey
P4		Passenger car traffic	Lack of dual carriageways and non-determination of speed limits
P5		Whole work	Absence of danger and warning signs
P6		Closed areas	Fire
P7		All works	Noise
P8		Work on electrical panels	Electric shock
P9		Work on electrical panels	Firefighting
P10		Working with electrical machinery	Leakage current
W1	Workshop	Working in the Lathe	Burr leaping
W2		Working in the Grindstone	Grindstone burst, Burr leaping
W3		Working in the Angle grinder	Grindstone burst
W4		Stacking materials	Overthrowing, collapsing
W5		Workshop-General	Oil slick floors
W6		Compressor use	Air tank explosion
W7		Working with the pressure tube	Working with the pressure tube
W8		Working with the pressure tube	Oxygen cylinders

Table 3 Linguistic terms and corresponding fuzzy values for risk factor weighting.

Linguistic term	Fuzzy value
Absolutely strong (AS)	(2, 5/2, 3)
Very strong (VS)	(3/2, 2, 5/2)
Fairly strong (FS)	(1, 3/2, 2)
Slightly strong (SS)	(1, 1, 3/2)
Equal (E)	(1, 1, 1)
Slightly weak (SW)	(2/3, 1, 1)
Fairly weak (FW)	(1/2, 2/3, 1)
Very weak (VW)	(2/5, 1/2, 2/3)
Absolutely weak (AW)	(1/3, 2/5, 1/2)

Table 4 Linguistic terms and corresponding fuzzy values for hazard rankings (Chen 2000).

Linguistic term	Fuzzy value
Very poor (VP)	(0, 0, 1)
Poor (P)	(0, 1, 3)
Medium poor (MP)	(1, 3, 5)
Fair (F)	(3, 5, 7)
Medium good (MG)	(5, 7, 9)
Good (G)	(7, 9, 10)
Very good (VG)	(9, 10, 10)

Table 5 Evaluations of expert team members in linguistic variables and weights of the risk factors.

Evaluation of ETMs	Likelihood	Severity	Weight
Likelihood	E, E, E	SW, VW, VW	0.379
Severity	–	E, E, E	0.621

Table 6 Linguistic assessment for the most important hazards in the observed port.

Station	Hazards	Likelihood	Severity	Station	Hazards	Likelihood	Severity
Dock	D1	(MP, F, MP)	(MP, F, MP)	Offices	O1	(P, P, VP)	(G, VG, VG)
	D2	(MP, F, MP)	(VG, G, VG)		O2	(MP, P, VP)	(MP, F, MP)
	D3	(MP, F, MP)	(G, VG, VG)		O3	(P, P, VP)	(MP, F, MP)
	D4	(MP, F, MP)	(VG, G, VG)		O4	(MP, P, VP)	(MP, F, MP)
	D5	(P, P, VP)	(VG, VG, G)		O5	(MP, F, MP)	(VG, G, VG)
	D6	(MP, P, VP)	(MG,MG,F)		O6	(P, P, MP)	(G, VG, VG)
	D7	(MP, F, MP)	(VG, G, VG)		O7	(MP, F, MP)	(VG, G, VG)
	D8	(P, P, P)	(G, VG, VG)		O8	(MP, F, MP)	(P,P, MP)
	D9	(P, P, MP)	(G, VG, VG)		O9	(P, VP, VP)	(MP, F, MP)
	D10	(P, VP, MP)	(VG, VG, VG)		O10	(P, P, P)	(MP, F, MP)
The whole port	P1	(MP, F, MP)	(MP, F, MP)		O11	(P, P, MP)	(MP, F, MP)
	P2	(MP, F, MP)	(MG, MG, F)		O12	(P, VP, MP)	(VG, G, VG)
	P3	(MP, P, VP)	(VG,G,VG)	Workshop	W1	(MP, F, MP)	(MG, MG, G)
	P4	(MP, F, MP)	(G,VG,VG)		W2	(MP,F,MP)	(MG,MG,G)
	P5	(P, P, VP)	(VG, G, VG)		W3	(P, P, VP)	(MG, MG, F)
	P6	(MP, P, VP)	(G, VG, VG)		W4	(MP, P, VP)	(VG, G, VG)
	P7	(P, P, VP)	(MG, MG, F)		W5	(P, P, VP)	(MP, F, MP)
	P8	(MP, P, VP)	(VG, G, VG)		W6	(MP, P, VP)	(VG, G, VG)
	P9	(P, P, VP)	(G, VG, VG)		W7	(P, P, VP)	(G, VG, VG)
	P10	(MP, F, MP)	(VG, G, VG)		W8	(MP, P, VP)	(VG, G, VG)

Table 7 Aggregated crisp ratings, the best and the worst values of likelihood and severity (for risk assessment of the observed port).

	Crisp ratings of hazards
Risk parameters	D1	D2	D3	D4	D5	D6	D7	D8	D9	D10	fj*	fj-	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	fj*	fj-
Likelihood	3.78	3.78	3.78	3.78	0.94	1.72	3.78	1.17	1.94	1.72	3.78	0.94	3.78	3.78	1.72	3.78	0.94	1.72	0.94	1.72	0.94	3.78	3.78	0.94
Severity	3.78	9.28	9.28	9.28	9.28	6.22	9.28	9.28	9.28	9.83	9.83	3.78	3.78	6.22	9.28	9.28	9.28	9.28	6.22	9.28	9.28	9.28	9.28	3.78
	O1	O2	O3	O4	O5	O6	O7	O8	O9	O10	O11	O12	fj*	fj-	W1	W2	W3	W4	W5	W6	W7	W8	fj*	fj-
Likelihood	0.94	1.72	0.94	1.72	3.78	1.94	3.78	3.78	0.72	1.17	1.94	1.72	3.78	0.72	3.78	3.78	0.94	1.72	0.94	1.72	0.94	1.72	3.78	0.94
Severity	9.28	3.78	3.78	3.78	9.28	9.28	9.28	1.94	3.78	3.78	3.78	9.28	9.28	1.94	7.61	7.61	6.22	9.28	6.22	9.28	9.28	9.28	9.28	6.22

Figure 2 S_i, R_i and Q_i values for the hazards in four stations of the observed port.

Figure 3 The compromised rankings for the hazards in four stations of the observed port.

Table 8 Control measures for the hazards in the dock of the observed port.

Clusters	Hazards	Control measures
Cluster-1	D2, D3, D4, D7	Providing the use of helmets for all employees Ensuring the use of appropriate scaffolding, platforms and mobile vehicles during works at height Hanging of a warning sign as ‘Do not stand under suspended loads’ in the workplaces Providing the magnesite caps gains open easily by making consultation with the manufacturer
Cluster-2	D9, D10	Replacing of no safety latch hooks with safer ones To be known of the amount of the load to be removed and noting of the maximum amount to be carried on all lifting equipment by a sheet
Cluster-3	D8, D5, D6	Warning of the manufacturer about the influence of dust Non-use of cranes that have not undergone periodic maintenance without making inappropriate parts appropriate Using the staff working with magnesite of appropriate masks and activating of dock cleaning tool immediately
Cluster-4	D1	Ensuring the use of steel-based steel-toed work shoes by all employees

Table 9 Control measures for the hazards in the offices of the observed port.

Clusters	Hazards	Control measures
Cluster-1	O5, O7	30 mA leakage current relays installation and periodic monitoring of grounding suitability of all electrical installations for each year
Cluster-2	O6, O12	Performing periodic control of electrical installations, implementation of fire alarm systems and detection systems and training of employees Renewing of the broken glasses in the manometers of compressed gas cylinders and worn hose end fittings (therefore preventing gas leak and explosion of tube)
Cluster-3	O1, O11, O2, O4, O10, O3, O8, O9	Performing periodic control of electrical installations, implementation of fire alarm systems and detection systems and training of employees Providing a non-slippery ground against fallings Taking periodic eye examinations and providing a minimum illumination of 500 lux Providing ergonomic chairs and completion of employee ergonomics training Fixing the furniture longer than 150 cm Completing the training of employees Using protective gloves Ensuring the use of gloves preventing the liquid touch

Table 10 Control measures for the hazards in the whole port.

Clusters	Hazards	Control measures
Cluster-1	P4, P10	Non-loading of forklifts by blocking the operator’s view and loading of pallets individually Determination of parking area of passenger cars in the workplaces, not allowing to situate the vehicles chaotically, determination of the speed limit for vehicles with loading and notifications of subcontractors, and design of areas where pedestrians can be in the dock
Cluster-2	P3, P6, P8, P2, P5, P9, P7	Non-use of forklifts beyond the scope and training of forklift operators Use of forklifts safely and make a scientific examination once every 3 months Installing the exhaust flame arrester for used diesel forklift or using tow truck Prohibit riding of workers to the load-bearing fork of the forklifts Installing a rear-view mirror on the forklift, always being active of reverse voice signal Availability of visitors waiting areas, prohibition of entry into the workspace Determination of forklift route across the port with yellow lines
Cluster-3	P1	Providing training for manual handling

Table 11 Control measures for the hazards in the workshop of the observed port.

Clusters	Hazards	Control measures
Cluster-1	W4, W6, W8	Stacking of materials on the ground which sustain on load Performing hydraulic control of the air tank and periodic pressure test of the compressor by technical staff at least annually Put into practice of required notices and warnings in order to prevent touching of workers to the oxygen tubes with oily hands
Cluster-2	W1, W2, W7	Making a proper glare shields against sawdust in the lathe Prevention of workers against grinding equipment Storage of compressed gas cylinders, such as oxygen and LPG properly
Cluster-3	W3, W5	Installing the housing of angle grinder and avoiding working without glasses and unshielded Cleaning of slippy floor due to oil

Figure 4 Results of the sensitivity analysis.

Table 12 Weights of the risk factors with respect to the considered cases.

Parameters	Current Case	Case 1	Case 2	Case 3
Likelihood	0.379	0.400	0.350	0.500
Severity	0.621	0.600	0.650	0.500

Figure 5 Results of the sensitivity analysis according to v value in fuzzy-based VIKOR.

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