The Safety Triangle

Accident investigation indicates that there are often many individual causes to an accident, and that a series of incidents occur simultaneously to cause the accident. The following figure is called the safety triangle", and shows the approximate ratios of occurrence of accidents with different severities. This is based on industrial statistics. 

The safety triangle shows that there are many orders of magnitude more unsafe acts than LTIs and fatalities. A combination of unsafe acts often results in a fatality. Addressing safety in industry should begin with the base of the triangle trying to eliminate the unsafe acts. This is simple to do, in theory, since most of the unsafe acts arise from carelessness or failure to follow procedures. In practice, reducing the number of unsafe acts requires personal commitment and safety awareness. 

Procedures are written to ensure that activities are performed in a systematic way. Accident investigation shows that the majority of accidents occur because procedures are not followed, and this contributes mostly to the base of the safety triangle introduced at the end of Section 4.1. 

Most people involved with workplace safety are aware of the iceberg theory, the safety triangle, or its correct terminology, the accident ratio. For every recorded injury or loss sitting above the surface, there are many unrecorded near miss incidents submerged below the surface. This was first proposed by H. W. Heinrich in 1931 when he published his 1 29 300 ratios. 

The implication of the safety triangle is that many unsafe acts and conditions occur before an injury results. The frequency of these events reflects the probability at each level of the triangle. The probability of getting injured is often simply too small to sustain a consistent level of safe work practices. Each time employees shortcut a safety procedure and do not get hurt, they lose a bit of the fear that typically motivates safety. 

FIG. 23-2 The fire triangle showing the requirement for combustion of gases and vapors. [D. A. Crowl, Understanding Explosions, Center for Chemical Process Safety (CCPS) of the American Institute of Chemical Engineers (AIChE) copyright 2003 AIChE and reproduced with permission. ]... 

The agreement between the Committee on Safety of Medicines and the ABPI on the use of the black triangle is that ... 

For analytical properties to be consistent with the quality expected from an analytical process and the results derived from it, they should be considered in a hierarchical way [4,50]. Thus, there are three primary types of analytical properties, namely (a) capital properties (accuracy and representativeness), which are directly related to quality of the results (b) basic properties (sensitivity, selectivity and precision), which support accuracy and are related to the analytical process and (c) accessory properties (expeditiousness, cost-effectiveness and personnel safety/comfort), which are also related to the properties are related to one another in an additive or contradictory way. The best way of envisaging the ensuing relationships is by means of two analytical tetrahedra sharing a common apex (see Fig. 1.16.A). The apices of the tetrahedron on the left hold the basic analytical properties that define the accuracy triangle, whereas those of the tetrahedron on the right accommodate the accessory analytical properties, which delimit the analytical... 

Newly licensed POMs would not be considered for reclassification until the safety profile had been established. Drugs under intensive safety surveillance are indicated by a black triangle in the British National Formulary, which generally continues for approximately two years, dependent on whether any issues related to safety are discovered. 

Comparison of the Safety Margin and the Triangle Method for Linear Isotherms 815... 

The two main methods used to select the experimental conditions under which there is complete separation in linear SMB are the sa/ety margin approach [27,46] and the triangle method [16,28,43], It is easy to show that both approaches are equivalent in the linear case [47]. Equations. 17.50a to 17.50c result from the Safety Margin approach. Rewriting them and using the classical relationship Q =... 

FIGURE 47.2 A trajectory plot showing the direction of change of a safety biomarker for individual subjects. Open circles represent the basehne safety biomarker values, filled triangles are the safety biomarker values at end of treatment, and the dotted fines show the trends from baseline values of the safety biomarker. 

I Coimtries have national reporting systems. In the UK the Committee for the Safety of Medicines/Medicine and Healthcare products Regulatory Agency (http //www.mca.gov.uk/) encourage notification of possible adverse reactions for new products (indicated by black triangles ) using a yellow cards reporting system. 

The safety culture action principle, behavior based attitudes theory and accident triangle principles work together to promote the change of zero accidents concept to zero accidents objective from three indispensable aspects of idea , action and methods , as is shown in Figure 4. Three principles commonly guide zero accidents concept, which is one of the key elements of safety culture, to strengthen enterprise safety management, prevent accidents and lessen accident rate, as follows ... 

The action principle of safety culture, principle of attitude and behavior and accident triangle principle can explain the action principle zero accident . Improving the safety management system, correcting people s unsafe behavior, controlling near misses and other small incidents are the effective way to achieve zero accidents objective for enterprise. 

To this day, safety practitioners use Heinrich s 300 29 1 ratios, known as the Heinrich triangle, as soundly based premises. But, a review of the Heinrich texts and the lack of documentation require that serious questions be asked as to their validity. In each of the editions following the first edition, the premise to which the ratios apply changed, with no explanation. 

Gole, W. M., Bukowski, J. V. and Brombacher, A. C., "How Common Cause Ruins the Safety Rating of a Pault Tolerant PES," Proceedings of the ISA Spring Symposium - Cleveland. NC Research Triangle Park, ISA, 1996. 

Brombacher, A. C., Van der Wal, J., Rouvroye, J. L. and Spiker, R., "RIFIT A Technique to Analyze the Safety of Programmable Safety Systems," Proceedings ofTECH97, NC Research Triangle Park, ISA, 1997. 

The fire triangle illustrates the elements required for combustion. Only in the proper combination of fuel, oxygen, and heat (the three legs of the triangle), will combustion take place. A Safety Can is designed to eliminate one or two of the legs required for combustion of its contents. 

The principle of fire safety is the simple depiction of the fire triangle. The fire triangle is composed of heat, oxygen, and fuel. To prevent ignition or control a fire after... 

The statistical pattern seen in the BUS data and in many individual companies calls into question one of the core assumptions of modern safety science. For the past 80 years the safety community has assumed that the Heinrich Safety Triangle (HST), first introduced in 1931, is an accurate depiction of the relationship among types of injuries, and how to prevent SIFs. 

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