Innovative management for Occupational Safety and Health: A tower engineering project

. Risk is very attached to every activity. Potential risks also occur in antenna installation projects at telecommunications company vendors, which create hazardous work. The aim of the research is to identify the causes of accidents at the Base Transceiver Station (BTS) tower and make recommendations for ways to reduce the accident rate for tower workers by using Failure Mode Effect and Analysis (FMEA) and Fault Tree Analysis (FTA) method. The results based on the FMEA method used indicate that: the highest work accident rate is obtained from being hit by heavy material (RPN = 128), with a percentage of 31%. Whereas in the FTA method, the most fundamental factor in the occurrence of material overlap work accidents is technical factors where the antenna installation is not perfect, the tools used are not based on standards, supported by the results of data verification by the internal control team which found 6% of engineers do not have proper helmets. Improvements were made by eliminating the existing failure modes, namely by equipping PPE for workers who do not yet have PPE and training certificates to work at tower heights.


Introduction
The main hazard of working at heights is falling workers or objects falling on workers and people below them [1].This can occur as a result of inadequate protection, or from improperly maintained items used.Table 1 presents that based on data from the Social Security Administrator for Employment, there has been an increasing accident rate in the last 5 years [2].This can be seen from 123,040 cases in 2017 to 234,270 in 2021, an increase of 47.48%.For this reason, research was carried out at Telecommunications Company vendors engaged in antenna installation projects.
In Figure 1, work accidents increased from 3 cases in 2020 to 5 cases in 2021 based on data of accident record within company.
In the previous study [3], 26 hazards and 30 risks were found in the 7 steps of antenna installation with a lifting device, namely 13 mechanical hazards, 11 physical hazards, 1 ergonomic hazard and 2 biological hazards.For this reason, this study aims to minimize the risk of hazards working at height with the FMEA and Fault Tree Analysis methods.

Occupational Health and Safety
The definition of Occupational Health and Safety (OHS) according to WHO is an effort to maintain and also improve the physical health of our bodies, improve the mental health of workers and also improve the social health of every existing worker [4].With OHS, the degree of all workers must be raised as high as possible and this applies to all types of work.Companies must take action for prevention in the event of health problems that occur in workers caused by the work in the workplace.Another definition of Occupational Safety and Health according to OHSAS 18001:2007 are conditions and factors that impact the safety and health of workers and other people who are related to or around the work [5].

Safety working at tower height
Regulation of the Minister of Manpower No 09 of 2016 requires employers and/or administrators to implement OHS when working at heights [6].The application of OHS can be done by ensuring the following things [7]

Fault Tree Analysis
The Fault Tree Analysis (FTA) method is a method for analyzing, displaying and evaluating failures in a system, thereby providing a mechanism for an effective system at a risk evaluation level [8].This technique is useful for describing and estimating events in a system.Fault Tree Analysis (FTA) pinpoints a variety of problems.By having the advantages of Fault Tree Analysis (FTA), which is easy to read and understand, using two main symbols, namely event and gate [9].This FTA illustrates the relationship between basic events (basic failure causes) and top events (failures that occur which are depicted graphically.The FTA depiction symbols are presented in Figure 2 [10].

Failure mode and effect analysis
The failure mode is a manner in which an item or operation has the potential to fail to meet or deliver its intended function and related requirements [11].Depending on the definition of failure established by the analysis team, failure modes may include failure to perform a function within specified limits, the inadequate or poor performance of a function, the intermittent performance of a function, and/or performing an undesired or undesired function.

Field study
In this research, the authors conducted a field study to telecommunications company vendors.Support the causal factors, interviews were conducted using questionnaires with 15 tower cluster workers in the Bandung area.The OHS risk event is given a risk assessment using the FMEA (Failure Mode Effect and Analysis) method.The assessment given consists of S (Saverity) based on Severity with a value that can be assigned 1-10, O (Occurance) based on the level of frequency, a value that can also be assigned 1-10, and D (Detection) based on detection or prevention that is currently available.this, with a value that can also be assigned 1-10 for each identified risk event.
Then look for the Risk Priority Number (RPN) value of each risk event by multiplying the S, O and D values [12] : RPN values are then sorted based on the highest value.The risk factor that has a risk event with the highest RPN value is defined as the dominant risk factor.To make an FTA model from the highest RPN, we need to identify the intermediate event and basic event risk variables, so interviews are conducted with workers to get agreement on the potential causes of accidents according to experts who are considered to have experience.
The interview here was carried out in three stages, stage I to determine the intermediate event, stage II to determine the basic event and stage III to establish the relationship between the top event, intermediate event and basic event.In Figure 3, that shows the steps and activities carried out by the author in conducting research.

Data collection
The data collection is data obtained from the Internal Control Team's report, debriefing with coordinators in the field and questionnaires distributed to workers.The accident data during past 2 years is shown in Table 2. Table 2 shows the occurrence total of 8 cases of work accidents in the two years.From the audit conducted by Internal Control, the following presentation can be obtained in Figure 4.It can be seen that 3% of employees did not have WAH (Working at Height), Electrical, and First Aid certificates.

Accident factor data based on Severity, Occurrence, and Detection
Accident factor data based on Severity were presented in Table 3 based on the criteria in the Severity rating criteria of a failure in FMEA [13]  Accident Factor data based on Occurance were presented in Table 4. Accident Factor data based on Detection were presented in Table 5.

Analysis the causes of accidents with FMEA
The results of the questionnaire that has been carried out, the RPN results are obtained as follows in Table 6 [14].Based on the FMEA theory, the highest accident rates were obtained from: 1. Crushed by Heavy Material (RPN = 128) 2. Fall from a height (RPN = 66) 3. Electric Shock (RPN = 65) So that we can see the presentation diagram as presented in Figure 5. Based on Figure 5, the biggest accident factor is the incident of a "crusher by heavy material, which is equal to 31%.

Identify improvement with Fault Tree Analysis (FTA)
The following are the procedure steps and approaches using FTA as a tool to analyze and evaluate failure modes as follows [15]: -Identification of the main events (top events) that may occur which have been obtained based on calculations with the previously calculated FMEA method.-Identify first-level contributors by adding conditions or events that may contribute to or cause the top event to occur.-Set logic gates according to events occurring at the same time and place (AND) or one of the events that may occur (OR).Movement forms a branch in the fault tree showing the effect of the top event -second-level contributors and specify logical symbols to relate events that may be the cause of failure modes of first-level contributors.-Define second-level contributor logic gates.Repeat or continue.Develop a strategy to improve the combination of events to prevent the events above from happening again.The FTA Crushed by Heavy Materials was presented in Figure 6.The FTA fall from a height was presented in Figure 7.The FTA cause Electric Shock was presented in Figure 8.

FTA identification with the Method for Obtaining Cut Set (Mocus)
The results of the FTA diagram will be analyzed by determining the Cut Set.Cut Set is a combination of various basic events that can cause accidents.Mocus is a method for obtaining cut sets and minimum cut sets [16].The combination of basic events is obtained from the FTA that was previously drawn.The result of MOCUS was presented in Table 7.To reduce the rate of work accidents that occur, all workers are required to wear appropriate PPE and complete certificates, as seen in figure 9.

Conclusion
Factors causing the highest risk of work accidents based on the method used, namely the FTA method, are: 1.The most basic factor of work accidents falling on material, namely technical factors where the antenna installation is not tight and the tools used are not according to standards, supported by the results of data verification by the internal control team which found as many as 6% of engineers did not have proper helmets.where there is a lack of OHS training, supported by the results of data verification by the internal control team which found as many as 3% of engineers did not have a valid electrical certificate and as many as 6% of engineers did not have suitable electrical gloves.
Improvements made by eliminating the existing failure modes, with: 1.

Fig. 1 .
Fig. 1.Graph of work accidents at Telecommunications Company vendors.

Table 2 .
Work accident data of Telecommunications Company vendors.

Fig. 7 .
Fig. 7. Chart of FTA Fall from a Height

2 .
The most basic factor of work accidents falling from height is from a human factor perspective where technicians are not yet certified, supported by the results of data verification by the internal control team which found as many as 3% of Engineers did not have a valid Working at Height (WAH) certificate.3. The most basic factor of work accidents being electrocuted is in terms of management factors

Table 1 .
Work accidents in Indonesia.

Table 3 .
Risk assesment based on Severity.

Table 4 .
Risk assesment based on Occurrence.

Table 5 .
Risk assesment based on Detection.

Table 6 .
Results of OHS Risk Event assessment.

Crushed by Heavy Materials MOCUS 'Fall from a height' MOCUS Electric Shock
To reduce cases of work accidents that are crushed by material, namely by completing 6% of standard helmets or 2 helmets for employees who do not have helmets to work at height 2. To reduce cases of work accidents falling from tower height, namely by holding WAH (Working at Height) training for 3% of employees or 1 person who does not have a valid WAH certificate 3. To reduce cases of work accidents electrocuted, namely improvements from the management side that are required to conduct training and also provide PPE in the form of appropriate electrical gloves to 2 employees who do not yet have electrical hand gloves and an electrical certificate.