Tactics, command, leadership

The time constants of measures

Different types of measures take different lengths of time to ex-

ecute and they can have varying validity in both time and space.

Measures are also often restricted with regard to how long they

can be applied before the resource they are based upon or include

is exhausted. Here we can think in terms of different time con-

stants for different types of measures, i.e. that the measures have

a certain time span within which they can be expected to have

effect. If foam is spread over an area of leaked petrol, there is

an expectation for how long it will remain effective, i.e. before it

becomes necessary to apply more foam. The foam is slowly bro-

ken down and the protection against ignition that is expected of

it decreases with time. The time constant indicates the degree of

inertia the measure has, i.e. the time span between decision and

implementation and the period of time that the measure influ-

ences the course of events. If, for example, a water cannon is put

to work against a burning stack of recycle paper, an effect is ex-

pected within a certain amount of time. Otherwise the measure

is taken as unsuccessful and other measures should perhaps be

considered. So, it takes time for a measure to be implemented

and to take effect. In some cases this time can be considerable,

depending on, for example, preparation or that it has to be trans-

ported over a long distance. It is important for the outcome of

Traffic accident Chemical accident Fire

Freeing using electrical/hydraulic/power

tools

Removing the risk of fire at the incident

site using foam

Stabilising vehicles

Alleviate risk at incident site by

disconnecting batteries

Releasing trapped casualties

Cleaning up the road (glass/other small

articles)

Stopping leakage

Setting up retention barriers

Boom placement

Absorption

Transfer pumping

Evacuation

Packing

Evaluation of protective distances

Measures against static electricity

Door forcing

Water supply

Extinguishing from aerial appliances

Informing the public/media

Pressure ventilation

Property transfer inventory

Water cooling of neighbouring

objects

Shooting/puncturing gas bottles

Shutting of gas/electricity supply

Examples of measures
applied in emergency
response operations in
connection with traffic
accidents, chemical
accidents and building
fires respectively.