Quality Control in Occupational Safety & Health > Chapter- 3 > Topic-Measurement and Evaluation of Safety Performance > Subtopic- Indian Standard IS-3786 and its Salient features

Significance of IS-3786 and Important Definitions and Formulas in the standard

IS-3786 is Indian standard "METHOD FOR COMPUTATION OF FREQUENCY AND SEVERITY RATES FOR INDUSTRIAL INJURIES AND CLASSIFICATION OF INDUSTRIAL ACCIDENTS."  

Objectives of the IS-3786 Standard: 

a) To help in evaluating the relative need for taking accident prevention measures in different departments of an establishment.
b) To help in making an appraisa1 of the progress of an accident. Prevention campaign and making people safety-conscious;
c) To provide encouragement when methods used for the prevention of accidents are successful. 
d) To enable comparisons to be made. 

Scope:

This standard prescribes basic methods for recording and classifying industrial accidents. It also includes details of work injury and gives the methods for computation of frequency, severity and incidence rate of work injuries in industrial premises. This would enable adoption of a uniform system of recording events associated with injuries and the determination of corrective action.

1) Accident: 

An unintended occurrence arising out of and in the course of employment of a person resulting in injury. 

Other Definitions: 
An undesired event giving rise to death ,ill-health, injury, damage, or other loss (OHSAS 18001-1999) 

(The revised standard of OHSAS18001-2007 uses the term incident which includes the term accident)

An unplanned, not necessarily injurious or damaging event that interrupts the completion of an activity. 

Accident includes any undesired circumstances which gives rise to - 

• ill health or injury 
• Damage to the property or plants or products 
• Damage to the environment 
• Production losses 
• Increased Liability 

2) Death :

Fatality resulting from an accident. 

3) Injury: 

An injury is an external damage to the human body, disturbance or dysfunction resulted from an accident.

4) Incident: 

It is an undesired circumstance or near miss which has potential to cause a harm.

5) Reportable Accident : 

Where in any factory an accident occurs , which causes any bodily injury by reason of which the person injured is prevented from working for a period of 48 Hrs. or more , immediately following the accident or which is of such nature as may be prescribed in this detail the manager of the factory shall send notice thereof to such authorities and in such from and within such time as may be prescribed. 

6) Non Reportable Accident:  

An injury causing disablement  extending beyond the day or shift on which accident occurred but not exceeding more than 48 Hrs. 

7) Near Miss Accident : 

Any unplanned sudden event that could have caused injury to man , material , or environment or could have involved a loss of containment possibly giving rise to adverse effect not resulted in such accident.  

8) Non-disabling Injury: 

An injury which requires medical treatment only, without causing any disablement whether of temporary or permanent nature. 

9) Disabling Injury (Lost Time Injury) : 

An injury causing disablement extending beyond the day of shift on which the accident occurred. 

10)  Temporary Partial  Disablement : 

Which reduces the earning capacity of an employed person in any employment in which he was engaged at the time of the accident resulting in the disablement. 

11) Permanent Partial Disablement:  

Which reduces his earning capacity in every employment which he was capable of undertaking at the time. 

12) Total Disablement:  

Disablement, whether of a temporary or permanent nature, which incapacitates a workman for all work which he was capable of performing at the time of the accident resulting in such disablement, provided that permanent total disablement shall be deemed to result from every type of injury specified in the appendix of scheduled charges for disabilities. A where the aggregate percentage of the loss of earning capacity, as specified in that part against those injuries, amounts to one hundred percent. 

13) Man-Hours Worked:

The total number of employee-hours worked by all employees working in the industrial premises. It includes managerial, supervisory, professional, technical, clerical and other workers including contractors’ labor. It includes overtime also. 

14) Scheduled Charge:

Charges in days of earning capacity lost due to permanent disability or death 

( Refer Appendix A of IS-3786).

15) Frequency Rate (FR) : 

It is defined as the number of injuries per million manhours worked. 

Formula for Frequency Rate (FR) 

FL   =    No. of lost time injury x 10⁶

                   Manhours worked

F_R   =    No. of lost time injury x 10⁶

                   Manhours worked

NOTE 1 - If the injury does not cause loss of time in the period in which it occurs

but in a subsequent period, the injury should be included in the frequency rate of the period in which the loss of time begins. 

NOTE 2 - If an injury causes intermittent loss of time, it should only be included

in the frequency rate once, that is, when the first loss of time occurs. 

NOTE 3 - Since frequency rate & is based on the lost time injuries reportable to

the statutory authorities, it may be used for official purposes only. In all other cases,

frequency rate FA should be used for comparison purposes. 

16) Weighted Frequency Rate (WFR): 

Weighted  FR is calculated counting each fatal injury as a 10 instead if one. 

It is used only for Safety Contest Purpose 

Formula for Weighted Frequency Rate(WFR):

WFR   =    (No. of fatal accidents x 10) x 10⁶

                        Total man – hours worked

+    (No. of permanent total dis – abilities x 10) x 10⁶

                               Total man – hours worked

 +    (No. of Nonfatal  Accidents) x 10⁶

                        Total man – hours worked

17) Severity Rate (SR): 

Severity rate is defined as man-days lost due to LTI per million man hours worked. 

Formula For Severity Rate (SR): 

SL        =    Man-days lost due to lost time injury x 10⁶

                                   Manhours worked.

SR       =    Man-days lost due to reportable lost time injury x 10⁶

                                   Manhours worked.

Note 1- Since severity rate S_R is based on the lost time injuries reportable to the statutory authorities, it should be used for official purposes only. In all other cases severity rate S_L should be used for comparison purposes.

Note 2- Here man-days lost due to temporary total disability and man-days lost according to schedule of charges for death and permanent disabilities are as given in Appendix A (15:3786-1983). In case of multiple injury, the sum of schedule charges shall not be taken to exceed 6000 man-days. In Appendix A, equivalent man-days for death and other total disablement are 6000, and they are gradually decreased with decrease in percentage of loss of earning capacity against named partial disablement.

18) Incidence Rates (IR):

It is defined as number of loss time injuries per thousand employees. 

 

I_L - Loss-time Injury Incidence Rate

I_{R- Reportable Loss time Injury Incidence Rate} 

I_L         =    No. of lost –time accidents or injuries x 1000

                        Average No. of persons employed

I_R         =    No. of reportable lost time accidents or injuries x 1000

                              Average No. of persons employed

NOTE - Since reportable lost-time injury incidence rate is based on the lost time injuries reportable to the statutory authorities, it should be used for official purposes only. In all other cases lost-time inquiry incidence rate should be used.

19) Frequency Severity Index: 

It is an index combining FR & SR 

Formula for Frequency Severity Index-

20) Classifications of Accidents- 

The principal factors related to Causation of accidents are given below with corresponding definitions. 

1) Classification according to Agency- 

The object or substance which is most closely associated with the accident causing the Injury & with respect to which adoption of safety measure could have prevented the accident. 

2) Classification according unsafe mechanical or physical condition-

Unsafe mechanical or physical conditions related to the agency. 

3) Classification According to the Unsafe Act- 

Deviation from the. accepted & told down safe procedure.

4) Classification According to Unsafe Personal factor-  

Anatomical, physiological or the psychological characteristics which permitted or occasioned the selected unsafe act. 

5) Classification according to the Type of Accident- 

The manner In which the object or substance causing the Injury comes into contact with the Injured person or vice versa. 

6) Classification according to Nature of Injury- 

Injury in terms of its principal physical characteristics.

7) Classification according to Location of Injury- 

Part of the Injured person's body affected directly by the Injury. 

Reference- 

• IS-3786 Standard 
• WWW.Google.com
• Fundamentals of Industrial Safety and Health By - K.U.Mistry 
• Mr. Pravin Pathak Industrial Safety Channel