Determining Eligibility for Special Health Examinations for Irregular Night Work | How to Calculate Working Hours

📌 Two Criteria for Eligibility | 'Frequency Criteria' and 'Time Criteria'

Item 4 of Annex 22 of the Enforcement Rules of the Industrial Safety and Health Act designates night work as a hazardous factor subject to special health examinations. There are two criteria, and Even if only one applies, the target no see.

It is easy to understand that Category A is the criterion for “how many times overnight work was done,” and Category B is the criterion for “how long one worked during nighttime hours.” Therefore, a person who frequently works short night shifts may be eligible under Category B even if they do not meet Category A. You are eligible if you meet the criteria, regardless of the number of regular employees, industry, or whether you are a regular or part-time worker.

⏱️ 5 Common Confusing Points When Counting Working Hours

1) Its purpose is different from 'night work' under the Labor Standards Act.

Night work (10:00 PM to 6:00 AM) under Article 56 of the Labor Standards Act is a standard for paying additional wages. Although it overlaps with the time period in Subparagraph (b), special health examinations are The actual time worked regardless of whether wages were paid Please check the 'night shift allowance hours' from the payroll system. If you use them as is, managers who do not receive allowances or those on a comprehensive wage system may be excluded, so please compare them with attendance and entry/exit records.

2) Waiting, preparation, and handover times are also included in working hours.

In the guidelines for special health examinations for night work, the Ministry of Employment and Labor [stated] time spent preparing for work upon arrival, waiting time, shift change time, etc. Includes all actual working hours We have announced that this will be applied. It is safer to count the time spent waiting on-site for equipment inspection as work time.

3) Establish standards for handling break times in advance and use them consistently.

Whether to deduct free break time during work from Category B hours may result in differing judgments, as recording methods vary by workplace. To prevent the person in charge from calculating it differently on a case-by-case basis Establish workplace standards, verify them with a specialized health examination institution, and keep a record. If it is ambiguous, it is better to tally it without excluding it to reduce the risk of omitting targets.

4) For Item A, 'includes the entire period from 00:00 to 05:00 + 8 consecutive hours' must be met together.

5) Work that spans across the day is recorded based on the 'start date'.

If you divide a shift that starts at 10 PM and ends the next morning into two days, the number of items is likely to be inaccurate. 1 task = Start date, Row 1 Record it as such, and establish a rule that if the end time is earlier than the start time, it is counted as the end of the next day. Work that crosses the monthly boundary can be handled in the same way.

🗓️ Irregular and project-based night work is assessed in this order.

1. Selecting targets for tabulation We are hiring candidates whose attendance, entry/exit, and work logs show at least one instance of work between 22:00 and 06:00. For subcontractors and dispatched personnel, we verify their affiliated company and the implementing entity separately.
2. Calculation per task — For each work assignment, calculate whether Item A applies (1/0) and the time of Item B (overlapping time between 22:00 and 06:00).
3. Sum of the last 6 months — You are eligible if you complete Item A 24 times or more, or Item B 360 hours or more. The preceding 6 months are recalculated based on the same day of each month (e.g., the last day).
4. First special health examination conducted — The Ministry of Employment and Labor explains that in cases where night work is irregular and it is difficult to determine eligibility in advance, if the criteria are met based on records from the past six months First special health examination after placement We will conduct [this] and inform you that pre-placement health examinations will not be conducted at this time.
5. Subsequent period judgment — The same explanation is instructed to be conducted annually if Category A has 48 or more instances or Category B has 720 or more hours within one year of the first diagnosis. If night work has decreased after the project ended, please recalculate before the next cycle.
6. Leaving a record — When sending the list of subjects to specialized health examination institutions, organizing the calculation period, frequency, and time together makes it easier to respond to inquiries regarding omissions or over-selection.

🧮 6-Month Assessment Based on an Example

The following is a hypothetical example to help understand the criteria. Actual judgment must be based on the workplace's work records.

Like the logistics short-term example Even if a single task is short, if the frequency is high, it is subject to Category B. This can happen. Conversely, for project overtime, even if you work late into the night, hours before 10 PM are not included in Category B, so it often falls short of the standards.

🔐 Things to keep in mind when writing attendance records

• Only workday, time, and work type are recorded in the summary sheet, and information such as health status and medical history is not included.
• The scope of access to the aggregated results is limited to health management personnel and those responsible for requesting special health examinations.
• When implementing follow-up measures, such as restricting night work, based on the results of a special health examination for night work, the relevant employee must be notified in advance (Article 20 of the Standards for Conducting Employee Health Examinations). Please be careful not to share the results themselves directly with the department head.
• Attendance records are not mixed with personnel evaluation or performance analysis data.

✅ Night Work Personnel Management Checklist

The checklist below is for internal inspection purposes to verify whether irregular night shift workers have been omitted from special health examinations. In particular, Aggregation scope, includes waiting and preparation time, re-aggregated every 6 months, retention of calculation basis is a basic verification item. Among all items If 3 or more are insufficient It is recommended to re-examine the aggregation standards, personnel in charge, and special health examination request procedures, rather than simply supplementing them.

🤝 Connecting Night/Shift Workers with EAP

The special health examination for night work is a system designed to identify health issues related to night work, such as sleep disorders, cardiovascular diseases, and digestive diseases. However, examinations alone are insufficient to address the difficulties accumulated in daily life, such as fatigue caused by disrupted sleep rhythms, conflicts arising from mismatched schedules with family, and anxiety about night work.

EAP can be utilized as a counseling channel to complement these aspects. Since night shift workers find it difficult to schedule counseling during daytime hours, Consultation hours and availability of non-face-to-face consultation It is recommended to check this and provide guidance along with the work schedule. EAP does not replace follow-up measures based on medical diagnoses or health check results, and if there is an immediate safety risk, you must first check emergency routes such as 119 or 112.

Even if EAP is provided based on the screening results Counseling referral is based on the individual's consent. Do this, and be careful not to combine screening results and EAP usage information into a single list.

❓ FAQ

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📚 Source and Verification Criteria

• National Law Information Center · Annex 22, Item 4 of the Enforcement Rules of the Occupational Safety and Health Act (Night Work)
• National Law Information Center · Article 201 of the Enforcement Rule of the Occupational Safety and Health Act (Tasks Subject to Special Health Examinations)
• National Law Information Center · Article 202 (Timing and Frequency of Special Health Examinations, etc.) and Annex 23 of the Enforcement Rules of the Occupational Safety and Health Act
• National Law Information Center · Article 204 of the Enforcement Rules of the Occupational Safety and Health Act (Timing of Pre-placement Health Examination)
• National Law Information Center · Standards for Conducting Worker Health Examinations (Ministry of Employment and Labor Notice No. 2025-131, Effective January 1, 2026)
• Ministry of Employment and Labor · Explanation (Q&A) and Guidelines on Major Amendments to Special Health Examinations for Night Work
• Ministry of Employment and Labor Seoul Northern Regional Office · Explanation of Key Amendments to Special Health Examinations for Night Work (Guidance on Administrative Interpretation Including Standby, Preparation, and Shift Time)
• National Law Information Center · Article 56 of the Labor Standards Act (Overtime, Night, and Holiday Work)

This article serves as a general practical guide for determining eligibility for special health examinations for night work. For matters requiring workplace-specific judgment, such as the handling of rest periods and the authority responsible for conducting examinations for dispatched or subcontracted personnel, please verify with the special health examination agency or the competent regional employment and labor office. The method for determining irregular work schedules is based on explanatory materials from the Ministry of Employment and Labor, and guidelines are subject to change. Date of verification of laws and official data: October 7, 2026.