Document YGxKz34ZKBbMZROpV0Q3LbrYD

6--Accident Records and Injury Rates /A1 r 1 t* / /1 1 1\\ V A '\ , v' r i< 15 UPPER UMIT /h\ \t '\ 'j \\ \ AVERAGE LOWER UMIT Fic 6-7 --Upper and lower control limits of this con trol chait were based on 60 months* experience, and show points at which the number of iniunes can sta tistically be shown to have a "contributing cause" rath er than be "by chance " Thus action can be taken where it will be most ef fective J F M A M J J ASOND MONTHS vealed that an unguarded machine was the cause of the increase in injuries for the month of February It can be assumed that the in stallation of a mechanical guard corrected this cause and brought the work-injury experience for March back "in control " The control chart can be a useful tool when it is used properly As with any tool, it will depend on the skill of the user to yield good results Follow these rules when constructing a control chart 1 Always use several years' experience when calculating the average number of injuries per month to assure that a stable average will be developed Sixty months' experi ence is preferable, except as noted m (3), (4), and (5) following 2. Count all injuries when constructing a control chart The use of disabling injuries alone may not provide enough data A control chart cannot be constructed if the average number of injuries per month is less than four because the lower limit will be negative Since a plant cannot experi ence a negative number of injuries per month, a chart based on an average of less than four would not yield meaningful re sults 3 Calculate a new average each year--add 146 ing the latest year's injuries and subtracting the oldest year's injuries--to reflect any change m the monthly average number of injuries 4 Construct more than one chart if there are seasonal changes in employment For ex ample, if an operation employs one hun dred people for the first 6 months of each year and four hundred people for the last 6 months, a separate chart must be con structed for each 6-month penod 5 Construct a new control chart if external factors, such as a change in the level of employment, a change in the work environ ment, or a change in work hazards, bnng about a permanent change m woik-mjury experience When calculating a new aver age in such a situation, do not use experi ence prior to the change Occupational Safety and Health Act (OSHAct) Recordkeeping The following material has been abstracted from an Occupational Safety and Health Ad ministration pamphlet It provides the basic definitions and recordkeeping requirements of the OSHAct, as they existed at the time this volume was prepared The requirements and