3.1 An engineering assessment can be used to extrapolate
the fire test results of a door having a larger geometry than the
tested door.
3.2 Such an assessment should be used for verification
only if the dimensions of the actual door are greater than the maximum
permitted by the furnace (considering a furnace with an aperture of
2,440 mm width x 2,500 mm height) and the door involved has already
been tested, with such dimensions, with satisfactory results in accordance
with section 1 above, and the actual door does not exceed 50% in surface
area.
3.3 The methodology used to extrapolate the fire
tests results should consider the following three steps:
-
.1 standard fire test of the “specimen”
to obtain reference temperature and structural displacements. Such
a “specimen” may be either:
-
.1.1 a door already certified through the fire
test which is identical in design to the door to be analysed (fire
test to include additional instrumentation as per paragraph 3.4.2,
or equivalent arrangement); or
-
.1.2 a specially-built specimen where the finite
element method is to be performed to extrapolate the results of a
specimen of an actual door having a size exceeding the maximum size
allowed by the furnace of the testing laboratory; the specimen should
be a mock-up of the actual door, but having a size that fits in the
furnace;
-
.2 finite element analysis in paragraph 3.6, of
the “specimen” to calibrate the thermal and mechanical
boundary conditions of the FEM model, which are adjusted until the
numerical and experimental temperature and displacement distribution
compare satisfactorily; and
-
.3 finite element analysis in paragraph 3.5, of
the actual door carried out using the model calibrated as per paragraph
3.7, assuming that the differences in the geometry and dimensions
between the actual door and the specimen door do not significantly
influence the results.