Accident frequency rates calculating

One approach is to compare the risks, calculated from a hazard analysis, with risks that are generally considered acceptable such as, the average risks in the particular industry, and the kind of risks that people accept voluntarily. One measure of the risk to life is the Fatal Accident Frequency Rate (FAFR), defined as the number of deaths per 108 working hours. This is equivalent to the number of deaths in a group of 1000 men over their working lives. The FAFR can be calculated from statistical data for various industries and activities some of the published values are shown in Tables 9.8 and 9.9. Table 9.8 shows the relative position of the chemical industry compared with other industries Table 9.9 gives values for some of the risks that people accept voluntarily. 

To calculate accident frequency rates for injuries, near-miss accidents, and property damage accidents, you need to know... 

The second view is macroscopic. In case more than one event is evaluated, an aggregation of the single events is possible in order to assess the overall effects. If the sample under investigation happens to contain accident and non-accident events, an accident rate or prevention rate can be calculated as ratio of frequency of accidents (or one minus accidents) with a measure by frequency of accidents without the measure. Summary statistics can also be computed in non-accident events by statistically evaluating the indicators defined on the physical level. In comparison to a baseline without measure the change due to a specific safety measure can be evaluated at the desired level of detail. Within the accident group, rates for specific injury severities as well as a fatality rate can be estimated. 

It is important to note that the Frequency Rate of 40 does not indicate how serious these LTIs were. It indicates that the injured worker was aw from work for at least one shift following the accident. Where a worker is killed at work, one (1) is added to the LTIs for the purpose of calculating a Freqnency Rate. 

A particular problem with all of these comparisons is that there is no consistency about what constitutes an accident and it should be remembered that this was one of the problems with any comparison of incidence and frequency rates. One way of improving comparisons is to calculate a rate which takes into accoxmt the severity of the accidents, i.e. the number of days lost per accident, to give the mean duration rate ... 

Frequency rate = number of accidents x 200,000 divided by the total employee hours worked. North Americans use 200,000 hours as a base, the Europeans tend to use 100,000 hours, and still others use 1,000,000 hours in their rate calculations. The reason 200,000 hours is used in North America is because it roughly equals the number of hours worked by 100 employees during a normal work year. Using 200,000 as a base makes it easy to estimate the site s frequency rate by simply knowing the number of employees at work. For example, if your site has 200 employees and you had six recordable injuries, you have a frequency rate of about 3 if you had 400 employees with six recordable injuries, you have an accident rate of about 1.5. Commonly used frequency and severity rates are ... 

Frequency rates tell how many accidents took place per 200,000 hours worked. They do not tell how serious the accidents were. For example, one lost-time accident may involve a day off and another may require 10 days away from work. For this reason, another accident rate was created, called an accident severity rate. To calculate an accident severity rate you need to know the number of work days lost and the number of employee hours worked. The formula for calculating a severity rate is ... 

This is a very basic method for calculating upper and lower control limits. Other methods can also be used to calculate these hmits. To ensure that the statistical control charts are as reliable as practical, keep several guidelines in mind. First, use accident rates that have as many sets of data as possible. For example, an aU injury/iUness frequency rate works better than a lost time frequency rate. Second, try to use at least twenty sets of data in calculating the base rate or average. In our example we only used five data points for practical purposes. However, they represented 60 individual monthly frequency rates. 

Calculations of the total recordable injury frequency rates for the new and the reference platforms showed a small decrease for the new platform. It was concluded that the acceptance criterion was met. The analysis, however, revealed a number of activities where an increase in the injury frequency of more than 20 per cent was expected. The ALARP principle called for actions to reduce the risk of accidents in these activities in particular. They included ... 

The magnitude of the risk to people is normally taken as the Fatal Accident Rate (FAR). This is calculated by multiplying the size of the hazard (measured in fatalities per hazardous event) by the frequency of the hazardous event (measured in events per year). The FAR has units of fatalities per year. 

An important component in a transportation QRA is a frequency analysis. This includes estimating the frequency of accidents, the chance of release (if there is an accident), the range of possible release sizes, and the probability of various outcomes if a hazardous material is released during transit. The general principles that should be considered when calculating the accident rate may include the following ... 

The chance of an incident is generally a function of the distance traveled. Thus, the frequency of an accident is often expressed as an accident rate per mile. Contributions from non-accident-initiated events are typically expressed on a frequency-per-hour or per-year basis. Thus, the duration of the hazardous materials movement is a key parameter. Figure 5.3 illustrates the basic calculation sequence for one trip or movement. If multiple trips are made, the total risk is equal to the number of trips times the risk per trip. The basic calculation sequence will have minor variations for each mode of transport and can be broken down into greater detail as needed. Increased detail might include different accident rates and lengths for each segment of a route or might explicitly address the accident rates and release probabilities for different accident causes. Inputs to the analysis that may be altered or may influence the calculation include ... 

The standard way of reporting the results from QRAs/PRAs is to present calculated frequencies (expected values) and probabilities, for example expressed by PEL (Potential Loss of Life) values, FAR (Fatal Accident Rates) values, IR (Individual Risk) values and F-N-curves (Frequency-Nmnber of fatalities). These risk indices form a risk picture, which constitutes the basis for the risk evaluation, to determine the... 

Nearly all attempts to examine human factors found larger behaviour influences. Most of the accidents resulted from the violation of traffic laws. In one study carried out in Indiana State in USA presented in (Oppe, 1993), the frequencies of cause factors were calculated. The results have shown that in 70.7% of accidents the causes were human, 12,4% environmental and 4.5% vehicles. Furthermore, the measure of Traffic Risk is widely accepted in international comparisons and it deals with the fatalities rates per vehicles, per vehicles-km or per person-km. 

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