arpadveress 
Preventive measures to reduce the explosion risk from flammable materials are based on three principles, which are normally applied in the following order:
1) substitution
2) control
3) mitigation
Substitution involves, for example, replacing a flammable material by one which is either not flammable or less flammable.
Control involves, for example:
a) reducing the quantity of flammables;
b) avoiding or minimising releases;
c) controlling the release;
d) preventing the formation of an explosive atmosphere;
e) collecting and containing releases; and
f) avoiding ignition sources.
NOTE 1 With the exception of item f), all of the above are part of the process of hazardous area classification.
Mitigation involves, for example:
1) reducing the number of people exposed;
2) providing measures to avoid the propagation of an explosion;
3) providing explosion pressure relief;
4) providing explosion pressure suppression; and
5) providing suitable personal protective equipment.
NOTE 2 The above items are part of consequence management when considering risk.
Keep up good work.
Arpad
exprofessional.com
