Investigation of Musculoskeletal Hazards in Atypical Work | How to Divide Unit Work

📌 What is a Unit Task? Why It Is Particularly Difficult in Non-Regular Work

The Korea Occupational Safety and Health Agency Technical Support Regulations (KOSHA GUIDE EG-1-2025) is Unit work It is described as “each of the detailed tasks when the content of a specific task or process can be divided into two or more detailed tasks.” In tasks where the same motion is repeated at a constant period (cycle time), such as an assembly line, the unit tasks are immediately revealed by observing just one cycle.

The situation is different for non-standard work.

• There is no cycle. The school meal preparation process itself changes to the sequence of morning preparation → cooking → serving → washing.
• The composition varies every day. Daily operations for logistics vary depending on incoming volume, while operations for US dollars vary depending on event or construction schedules.
• One person does a mix of different tasks. It is a system where one cleaning worker is responsible for floor cleaning, restroom cleaning, and trash transport.
• It breaks off briefly. The same posture appears several times a day for 10 to 20 minutes.

Therefore, if the job description is recorded as a single line, such as “Maintenance – Cleaning 8 hours,” the burden gets buried in the average; conversely, if unit tasks are viewed individually, each takes less than two hours and is easily excluded from the study. The key to investigating non-standardized work is Recording in small pieces and adding equal burdens together no see.

⚖️ Legal Standards | 'A total of 2 hours per day' is the aggregated time.

Pursuant to Article 657 of the "Rules on Industrial Safety and Health Standards," if a worker performs work that places a burden on the musculoskeletal system, the employer must investigate the workplace conditions, working conditions, and the presence or absence of signs and symptoms of musculoskeletal disorders every three years. Newly established workplaces must conduct an initial investigation within one year of establishment, and an ad hoc investigation must be conducted within one month if there is an occurrence of musculoskeletal disorders, the introduction of new work or equipment, or changes in workload or work processes. Regarding non-routine work, the definition in the notification is particularly important.

For tasks composed of unit tasks in the technical support regulations, the burdensome nature of each unit task is evaluated, and If one worker performs multiple unit tasks, the entire process is considered as a single task. We guide you to evaluate whether the work is burdensome. Ultimately, this means that you must combine “records by unit task” with “daily totals based on the number of people.”

🧭 5 Steps to Breaking Down Unit Tasks

1) Write down your daily tasks in chronological order.

Based on the work schedule and work log, record what is done and in what order from arrival to departure. Since the job assignment known to the manager often differs from the actual order, Confirm directly with the worker performing the relevant work. Please do so. Article 657, Paragraph 3 of the "Rules on Industrial Safety and Health Standards" stipulates that worker representatives or workers involved in the relevant work must participate in the investigation of hazardous factors. We also ask about tasks that vary depending on the day of the week or season (deep cleaning on Mondays, receiving goods before holidays, etc.).

2) Cut at the point where the posture, force, or tool changes.

If any of the five points below change, it is recommended to divide the unit work.

Conversely, cases where only the location changes while using the same posture and tools (e.g., 1st floor restroom → 2nd floor restroom) may be grouped as a single unit of work. However, if you divide it into too small pieces, it will be impossible to maintain records. Only up to the 'unit where the improvement method changes' Sharing is practical.

3) Record the time and frequency for each unit task.

There is no statutory requirement for observation days. However, since observing on just one idle day underestimates the burden, One normal day and one or more days with a heavy workload It is recommended to record this (days with a large number of servings, days with a surge in incoming goods, the day after an event, etc.). A realistic approach is for workers to simply write down the unit task code and start/end times, and for an investigator to directly observe specific time periods to verify accuracy. For lifting tasks, rather than time... Weight and repetitions You must write it down to compare with the official standards.

4) Sum up the same burden types and compare with the notified standards.

Below is a hypothetical day for one sanitation worker Virtual example no see.

If you look at each individual unit task, it takes less than an hour, but if you add up the squatting positions, it exceeds the standard for No. 5. Capturing this difference is the key to investigating irregular work.

5) Organize tasks that can be grouped and transfer them to the survey sheet.

If there are multiple burdensome tasks with the same work type and conditions, only a portion may be surveyed as a sample. The technical support regulations advise that if there are 10 or fewer identical tasks at a single work site, at least the two tasks with the highest work intensity should be included in the sample; if there are more than 10, one additional sample should be added for every five tasks exceeding that number. Regarding which tasks to group as 'identical tasks' Inquiry regarding identical work standards Please also refer to the answer. The summarized unit tasks are recorded in Step 1 of the Working Conditions Investigation Form (Attachment No. 1 of the Notification), and work intensity and frequency are verified through worker interviews in Step 2.

🍳 Examples of Unit Task Division for Cooking, Cleaning, and Logistics

This is an example you can refer to when creating the initial list by job function. The examination-related number is Candidate for review ...and whether it actually applies must be determined through on-site observation and measurement.

⚠️ Common mistakes

• Write only one line with the job title (“Beautification – Cleaning 8 hours”).
• Observe only once on a leisurely day and draw a conclusion.
• Only the time per unit task is considered, and the same types of burden are not aggregated.
• Irregular work is considered 'intermittent work' and excluded. Intermittent work is defined as a total of 60 working days or less per year.
• Interviews with the relevant workers are omitted after listening only to the manager's explanation.
• Outsourced cleaning and food service personnel should be excluded from the scope of the investigation from the outset. It is advisable to determine the implementing entity and the method of cooperation for improvements during the contract stage.

✅ Checklist for Preparing for Hazardous Factor Investigation in Atypical Work

The items below are for internal checks to be verified before investigating non-routine work. In particular Worker participation, records including busy days, aggregate by burden type is a default item. Of the whole If 3 or more are insufficient It is recommended to review the investigation plan again before scheduling the investigation.

🤝 Connecting field workers with EAP

Musculoskeletal pain often occurs alongside sleep deprivation, fatigue, and work stress. Technical support regulations also cite job stress as an example of "other factors" in the working conditions survey. In cooking, cleaning, and logistics roles, burdens such as early morning shifts, excessive workload due to staffing shortages, and customer service are prone to overlapping with pain.

If a worker complains of work stress or insomnia in addition to pain during an interview or symptom survey, separately from medical measures by health managers or medical staff Channels to select EAP counseling You can provide guidance as follows. In this case, symptom survey results and EAP usage information are not combined into a single list, and referrals for counseling are based on the individual's consent. For outsourced personnel, please first check with their affiliated company to see if EAP is available. EAP does not replace diagnosis, treatment, or improvement of the work environment.

❓ FAQ

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📚 Source and Verification Criteria

• National Law Information Center · Article 656 (Definitions) of the Rules on Occupational Safety and Health Standards
• National Law Information Center · Article 657 of the Rules on Occupational Safety and Health Standards (Investigation of Hazardous Factors)
• National Law Information Center · Article 658 of the Rules on Occupational Safety and Health Standards (Methods for Investigating Hazardous Factors, etc.)
• National Law Information Center · Notification on the Scope of Musculoskeletal Burden Work and Methods for Investigating Hazardous Factors (Ministry of Employment and Labor Notification No. 2020-12, Effective Jan. 16, 2020)
• Korea Occupational Safety and Health Agency · KOSHA GUIDE EG-1-2025 Technical Support Regulations on the Prevention of Musculoskeletal Disorders (March 2025)
• Korea Occupational Safety and Health Agency Industrial Safety Portal · Musculoskeletal Disorders and Hazardous Factor Survey

This article serves as a general practical guide for preparing musculoskeletal hazard investigations for atypical work. The job-specific and calculation examples are hypothetical for illustrative purposes; actual determination of whether a task constitutes a burden must be made through on-site observation, measurement, and worker interviews. Information regarding unit work division, sample selection, and subcontracting is based on the Korea Occupational Safety and Health Agency (KOSHA) Technical Support Regulations (Recommended Standards). For matters requiring workplace-specific judgment, please verify with the competent Regional Employment and Labor Office or KOSHA. Date of verification of laws and official data: October 8, 2026.