Accidents frequency

A job that has repeatedly produced accidents is a candidate for an immediate JSA/JHA. The greater the number of accidents associated with the job, the greater its priority should be. These jobs should be analyzed as soon as possible. 

---

The frequency analysis step involves estimating the likelihood of occurrence of each of the undesired situations defined in the hazard identification step. Sometimes you can do this through direct comparison with experience or extrapolation from historical accident data. While this method may be of great assistance in determining accident frequencies, most accidents analyzed by QRA are so rare that the frequencies must be synthesized using frequency estimation methods and models. 

Accident frequency. The higher the frequency rate of incidents, the greater the reason for implementing a JHA. 

If Step 7 minimizes consequences, and Step 9 minimizes accident frequency, it would seem perforce the risk would be minimized and such is generally the case. However, there is a synergism when frequency and consequences are combined into risk. While the risk of a low-frequency high-consequence accident may be the same as a the risk of a high-frequency low-consequence accident,... 

The model contains a surface energy method for parameterizing winds and turbulence near the ground. Its chemical database library has physical properties (seven types, three temperature dependent) for 190 chemical compounds obtained from the DIPPR" database. Physical property data for any of the over 900 chemicals in DIPPR can be incorporated into the model, as needed. The model computes hazard zones and related health consequences. An option is provided to account for the accident frequency and chemical release probability from transportation of hazardous material containers. When coupled with preprocessed historical meteorology and population den.sitie.s, it provides quantitative risk estimates. The model is not capable of simulating dense-gas behavior. 

The variation in risk between the designs analyzed is influenced more by differences in the consequences of the accidents than by differences in the accident frequencies. 

Briefly discuss the two primary sources for estimates of accident frequencies. Solution 16.4... 

Accident frequencies were evaluated separately for the two types of activity mainline transit and rail yard classification. When an accident occurs and the tank car is damaged, the severity of public exposure depends on several factors, including tlie likelihood of a breach in tlie tank car, the severity level of tlie release (i.e., tlie rale or volume of spillage), the likelihood of an explosion, tlie magnitude of tlie explosion, and die dispersion pattern of the unignited vapors. Recall tliat Part II of tliis book deals witli explosions and tlieir effects Part III treats tliis subject of dispersion. Table 21.3.1 smnmarizes tlie transportation risk data for tlie mainline and rail yard segments of tlie tank car journey. 

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. 

Table 1-8 Risk of Death from Various Activities in the United Kingdom, Showing Fatal Accident Frequency Rates ...

Lost time accident frequency (number, per million hours worked)... 

The lost time accident frequency rate rose from 2.59 incidents per 200 000 working hours in 1996 to 2.72 in 1997, then fell to 1.75 in 1998. 

Lost time accidents in 1998 there were two lost time accidents, giving rise to a labour accident frequency rate of 0.23 accidents per million hours worked, and a labour accident severity rate of 0.012 work days lost per thousand hours worked. Figures are given each year since 1990. While there is no obvious trend in frequency rates, the severity rate increased to a peak of 0.15 in 1996, and has fallen sharply since then. 

Lost time accidents the only accident frequency rate reported is that for notifiable accidents. This rate fell from 10 accidents per thousand employees in 1994 to 3.3 accidents per thousand employees in 1997. 

Have alternative modes by number of trips, number of miles per trip, and accident frequency per mile been evaluated ... 

R D and experimental investigations on substantiation and development of safety measures, assessment of their reliability, estimation of accident frequency and risk ... 

In order to determine how reliable the nuclear criticality safety measures are for installations, plants, institutions, and the nuclear complex in general, the NSD, IPPE, developed a special database, that uses a technique for determining indices of any danger of failure and corresponding software to determine the frequency of nuclear accidents. The technique has been verified by means of the database on nuclear accidents that have happened in the past at nuclear industrial enterprises. The results of nuclear accident frequency estimation were presented in a paper submitted to the international conference on nuclear criticality safety in Albuquerque [9]. The technique is universal and can be used to estimate the frequency of any accident (e.g., nuclear, radioactive, technological). In order to get the results. 

Accidents that will probably not occur during the life cycle of the facility. This class includes the design basis accidents. Frequency between 1 in 10,000 y and once in 1,000,000 y ... 

In 1982, under contract to The Business Round Table, Stanford University s Department of Civil Engineering issued Improving Construction Safety Performance, Technical Report 269. This study was made to provide guidance in reducing accident frequency and severity in the con-stmction industry, as well as reducing the attendant costs. At the Business Round Table, the report is identified as Improving Constmction Safety Performance, Report A-3. ... 

Deming believed that statistical methods should be used as a guide to understanding accidents and to their reduction. The following is quoted from Out of the Crisis on reducing accident frequency ... 

---