Home HSE Articles What Is LTI (Lost time injury); LTIFR & LTISR

What Is LTI (Lost time injury); LTIFR & LTISR

LTI (Lost Time Injury)

As an HSE professional, there are things you must know. You may not have been involved in the administrative duty with regards to HSE documentation, so you may not have had the privilege to know and understand some things.

Now is your opportunity to know this.

We have been hearing of lost time injury (LTI), but there are other subset of lost time injury that we may not know or pay less attention to; that is the LTIFR (LTI Frequency Rate) and LTISR (LTI severity rate).

What is Lost time injury (LTI) :

LTI is said to occur when a worker’s injury prevents him/her from returning to work within 24hours after an accident. The assessment of the LTI has been used as an indicator for the Health and Safety performance, and the subset of the lost time injury which are the LTIFR and LTISR helps in proper assessment of the Health and Safety performance; it is a reactive monitoring strategy (Lagging indicator).

READ: What Is An Occupational Injury



LTIFR is expressed thus: No. of LTI ÷ Manhour (Within the period in assessment) × 1000000


LTISR is expressed thus: No. of days lost ÷Manhour (Within the period in assessment) × 1000000


Both the lost time injury frequency rate and the lost time injury severity rate have its significance.

The Lost time injury frequency rate states the number of lost time injury per 1000000 man-hour, while Lost time injury severity rate explains the severity rate of every lost time injury per 1000000 man-hour.


The lower the value deduced from the above calculation, the better.


Lost time injury frequency rate calculation and standard

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