Eight Steps for Bow Tie Analysis in Occupational Risk Assessment

Risk is a popular word and regularly used in the safety management. One cannot predict the risk in their day to day life. In an apartment with all modern facilities an old couple were living. It was an evening around 7 pm and there was a drizzle. Normally the occupants used to dry their clothes in the open terrace. The old lady reached the terrace through the lift provided in the apartment. She collected the clothes and reached the lift point. There was a sudden power failure and it was pitch darkness. She decided to reach the flat through the steps. By holding the cloth in one hand and started moving down. Due to drizzle the steps were getting wet and in slippery condition. She stepped down with utmost care in 15minutes. Another gentleman was nearby and helped the lady to reach her flat safely Bow Tie Analysis is a risk evaluation process. This analysis is used in high risk scenario. It gives all possible accident that could exist by identifying proper control measures

The Bow Tie gives positive sides of the Fault Tree Analysis and the Event Tree Analysis and provides new insights to the safety professionals . This analysis can be used effectively to assure that hazards are managed to an acceptable level

8 Steps and Bow Tie analysis

Prepare the list of threats and potential causes likely to happen during the event combined with hazards. The list may contain more than 2 threats

Some time the threat may be from one particular point and lead to consequence effect of the first failure point

The threats may range from things that almost certain to happen. It is better to include in the list and need not be ranked at this point of time

Study the possibility and the threats, consequences and action to be taken carefully and rank the preference and importance A threat may lead to consequential effect, hence plan to counter measure and remedial steps to overcome the incident to minimise the damage

Rank the potential causes likely to take place by colouring the Green as LOW, yellow as MEDIUM and red as HIGH

As a preference remedial measures have to be taken against the high rank potential causes and brought into control. As a secondary one the medium level can be taken for proper follow up.

The low level threat can be observed and suitable steps can be taken when necessary arises.

This remedial steps and controls are having good practice for the safety and critical activities that need to be happened and support them

Assume that you use the bow tie to do a safety risk management, you have to think about defining the level of the performance, availability of facilities and any deficiency in the equipment etc

By observing the steps, it is easy to follow risk analysis process in a systematic way. The health and safety are very important and easy for anyone to get involved and understand easily. Once this analysis is understood it is very easy to implement which will benefit the individual and the organisation. The damage to machinery and men can be minimised to great extent

By A.K. Srikantan and V. Narasimhan, principal safety consultants, Enyes Associates