Classifications – Occurence and Consequences are two distinct variables

In Chapter 3 (and in Chapter 9) the models introduced make a distinction between Occurrence (time zone 2 in the Time Sequence Model) and Consequence.  The process by means of which damage occurs is not specifically related to the damage itself.

This short article illustrates the lack of inherent connection between energy sources (and their associated Occurrences) and the damage they are able to create with some combinations I have seen in my career.

If we don’t recognise this fact we met be led into assuming that certain relationships are determined simply because of their common nature.  For example, it is a fallacy to assume that muscle energy always creates strain injury.



Thigh muscles – a small boy had his finger jammed in the grooves of an escalator and, being unable to free it as the end of the travel was reached, stood up in panic.

Amputated joint of the finger

Gravity – a man fell from the top of the load on a truck.  The ring on his finger got caught on the side of the truck.

Amputated finger

Gravity – a woman sat down on a theatre seat, having first lowered the seat.  Her hand was still curled under the seat as her body weight descended on it and a finger got compressed between the seat the bracket against which it came to rest.

Amputated part of finger

Gravity – in one client a large number of lower limb strain injuries arose from stepping on uneven ground.

Strain injury to lower leg, ankle and foot

Gravity – a person slid down a rope from some height, as they were unable to hold themselves on the rope.  To avoid accelerating to a serious speed they gripped the rope tightly as they slid, in an attempt to keep their speed constant.

 Friction burns to the hand

Electricity – an electrician working on a 450V AC substation unintentionally created an arc in front of him when his spanner slipped from his hand.

Radiation damage to the eyes, hot vapour damage to the lungs.

Mechanical power – a fitter used a powered wrench in an attempt to loosen a large nut.  The wrench ‘kicked back’ and it was very hard to restrain the movement of it.

Strain injury

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