PAINTS AND VARNISHES - COATING
POWDERS - PART J4: CALCULATION OF
LOWER EXPLOSION LIMIT
(ISO 8130-4:1992 (2007), COR. 1:1993, IDT)
This part of ISO 8130 specifies a method for the calculation of the lower explosion limit of a coating
powder, i.e. the minimum concentration of the coating powder in air which will form an explosive mixture. It is based on the knowledge of the gross
calorific value of the product, as determined by the
method described in ISO 1928, or on the gross
calorific values of the constituents of the product.
Reliable methods for the measurement of this
quantity require the use of special apparatus which
may not be readily available, A method for determining the explosion indices of combustible dusts in
air is given in ISO 6184-1. This method is, however,
very intricate, requires considerable expertise and
is expensive. The calculation method leads to lower
explosion limits which have been proved in practice
to be satisfactory when applied to coating application plants.
NOTES
i With powders that are not flammable, such as those
of the poly(vinyl chloride) type, the method may nevertheless give a value for the lower explosion limit in air.
Thus, any underestimation of an explosion risk is effectively avoided.
2 The calculation used In this International Standard is
based on the following assumptions:
a) that material exists in the form of a molecular dispersion;
b) that there is complete combustion of the material to
the highest oxidation level;
c) that there is an adiabatic type of reaction;
d) that the flame temperature for the composition with
which the minimum concentration for explosion in air
is attained is 1 000 °C