Safety and safety planning - Tunnel Engineering: Basics and Additional Services for Design and Construction - page 311

Protection measures. Appropriate artificial and/or natural ventilation of a magazine can
lower the concentration of nitroglycerine vapour to the point where there is no health risk
to the employees.
The primary objective must be to ensure that no dangerous mechanical or thermal actions
can affect the explosives in the site magazine. The secondary objective should be to reduce
the consequences for persons and the effects on the surroundings in the case of a catastro-
phe with unintended detonation.
The first principle should therefore be to place the site magazine in such a location that
mechanical actions like rockfall, rock pieces thrown by blasting etc., do not pose any dan-
ger and the second principle should be that in case of a catastrophe involving unintended
detonation, the effects on the surroundings of air blast, vibration, thrown debris and poi-
sonous fumes should be kept to an acceptable minimum.
In every case, the explosives magazine must be placed at an appropriate distance from
transport routes, working and accommodation areas and other facilities. The door to the
magazine must be lockable and should point in the direction that would lead to the least
danger and the least destruction in case of a detonation.
In addition, magazines are built to provide sufficient resistance to unauthorised entry
and to resist mechanical (thrown rocks, rockfall) and thermal actions (fire). This can be
achieved by positioning the magazine in rock or stable ground with the use of appropri-
ately resistant construction materials. A suitable lightning conductor system should be
provided and the electric lighting installation should be explosion-safe.
From the organisational point of view, there are no fireplaces or ovens etc. in the magazine
and no other materials are stored together with the explosives. In order to avoid any risk of
mechanical actions, handling of explosives (opening the cases, packages and packaging,
issue of explosives etc.) is undertaken outside the actual magazine. Fire, open flame and
smoking are forbidden in and around the magazine.
Brisant explosives and detonating cords are kept separate from primary explosive deto-
nators and from each other, so that - in case of a catastrophe - detonation of detonators
cannot detonate the stored explosives or detonating cords.
In addition, explosives are not stored in their entire quantity, but rather separated into
smaller quantities and stored so far apart from each other that - in case of a catastrophe -
detonations cannot carry over.
Explosives magazine above ground. In order to store the large quantities of explosives
required, magazines are placed in natural rock or stable ground, or covered with appropri-
ately thick earth fill. An earth barricade is constructed in front of the entry, and detonators
are kept under lock and key in their own chamber (Fig. 8-3).
Figure 8-3 Explosives
magazine on the surface.