To calculate the total safe manhours for a construction project, you’ll need to sum up the hours worked by all employees without any Lost Time Injuries (LTI). Here’s a step-by-step guide:
1. Gather Total Manhours Worked
- Calculate the total hours worked by all employees on the project. This includes regular hours, overtime, and any other recorded work hours.
- Example: If 50 workers worked 8 hours a day for 20 days, the total manhours would be: 50 workers×8 hours/day×20 days=8,000 manhours50
2. Subtract Hours Lost Due to LTIs
- If any injuries caused a worker to miss work, subtract the hours they would have worked during their recovery period.
- Example: If one worker had an LTI and missed 80 hours, you would subtract those 80 hours from the total manhours.
3. Calculate Total Safe Manhours
- The result after subtracting LTI hours is your total safe manhours.
- Using the above example: 8,000 total manhours−80 lost hours=7,920 safe manhours
Formula for Total Safe Manhours:
Total Safe Manhours=Total Manhours Worked−Hours Lost Due to LTIs
If there are no LTIs, the total safe manhours equal the total manhours worked. This metric helps track the duration of safe operations and is often used as a benchmark for project safety performance.
“Amjad Ali is an HSE Manager with over a decade of experience in manufacturing, construction, and oil and gas. Based in Riyadh, he specializes in safety compliance and risk management, holding NEBOSH, OSHA, and ISO 45001:2018 certifications, along with an NVQ Level 7 diploma in HSE.”