Using FRAME for special building types.
Atrium compartments.
Using FRAME for risk evaluation for atriums and compartments with more than one floor requires some explanation to obtain a correct
result. One must always take care to use the most relevant value for the formulas.
Basically, additional floor area for mezzanines and partial levels will be considered in the level factor e, as a percentage of the ground
floor area, but other factors are also modified in an atrium.
Fire load factor q.
The immobile fire load Qi has to include all combustible construction elements: if the mezzanines are built on a wooden structure, this
has to be included in Qi.
For the mobile fire load Qm , one must check if the goods on the mezzanine are protected from fire spread from the level below, e.g. by
a concrete floor.
Basically the fire load on every level can be seen as separate, and the highest value will be used in the formula. But when the fire load is
located on a grating floor, in which case fire spread is likely , it is better to add the fire load of the floors to calculate Qm, but in that case
the area of the grating floor does not count anymore for the level factor e.
Area factor g
To evaluate the compartmentation, the basis is that a complete level of a building is compartment. When in a building, e.g. an
appartment building, sub compartmentation exists between the individual flats, on the same floor and using the same access and
evacuation paths, it is necessary to consider the whole floor as a single compartment, otherwise unrealistic low values will be found for
factors g and t. The sub compartmentation is taken into account in the factors F and U
However, in the case that a floor is subdivided in two or more compartments, so that evacuation is possible to an adjacent compartment
as "safe area" , each part of the floor can considered as a separate compartment.
Level factor e.
To obtain the correct value for the level factor e, it is necessary to consider the largest floor as
"access floor" When e.g. a compartment is composed of a small ground floor and a passage to
a larger floor above, the "access level" for the risk evaluation will be the larger upper floor.
The area of the mezzanine is added as a decimal part of the floor area and added to the floor
number E, which is increased. The rule is: before the decimal point : the floor number , and
after the decimal point : the percentage additional floor area of the mezzanines, if necessary
more than 100 % .
In the special case where the access is located at ground level (number 0) with a connection to
a basement below (90 %)and a mezzanine above (90%) the final level number will be ground
floor number 0 (access) + 0.9 (basement) + 0.9 (mezzanine) = 1.8 (which gives e = 1.34)
Ventilation factor v.
The ventilation factor of a single level compartment is calculated with the average height between floor and ceiling, as typical for the
available space where smoke can accumulate. However, in an atrium or duplex type compartment, the ceiling height is the distance
between the ceiling and the highest floor which has to be evacuated by an path inside the compartment.
Only when there is a direct exit for the mezzanines , the whole height of the atrium can be seen as the ceiling height. Remember that
the software accepts only 15 m as maximum for the ceiling height. Higher values have to be topped off at 15 m.
Access factor z.
The same reasoning is valid for the access factor: It is
the highest mezzanine which the fire brigade has to
access from inside the compartment that has to be used
as "floor level " for the atrium. On the example at the
left the highest balcony is not considered, as access
from outside the compartment is possible. On the right,
the highest balcony is the floor level for the atrium. In
this way, the factors e, z, and v will take into account
the higher risk in the situation at the right.
Using FRAME for narrow buildings
The FRAME v.2 program did not make any distinction between a long and narrow building that can only be reached by its narrow side(s)
as building 1 and one that can be reached by its long side (building 2.).
The following approach was recommended to handle this problem:When defining the area factor g, it is recommended to consider the
access possibilities of the building and to reverse the values of the theoretical length and the equivalent width for narrow buildings. The
values of the factor g and z will then reflect more faithfully the difference of risk in both situations. This precision has been added in the
FRAME 2008 version.
Special case : lofts and duplexes.
A special case which requires some care in the risk evaluation are the upper levels of buildings with loft and a duplex floor which lays
behind the facade.
For the compartmentation the basis is always the whole floor level which is to been seen
as a single compartment, and sub compartmentation is treated as a protection ( in factors
F and U) the duplex floor will be the decimal part of the floor number (as explained
previously).
In the sketch, the fire brigade can reach the buildings from several sides, but in the left
building the upper level (floor 4.5) can only be reached by one way, as the fire brigades'
aerial ladder cannot reach it. In the formula for factor z, Z=1 will be selected, which
reflects the higher risk.
In a number of cases, factor z will not change, which means that the risk increase by the
hampered access is negligible.
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