INFO for sub factors of Potential Risks
Fire load factor q  
Immobile fire load density Qi  
The 'immobile' fire load Qi comes from all combustible elements used for the construction such as the structure: beams, columns, girders, walls and partitions, windows, carpeting and decoration materials. In practice, building types can be classified in five groups with broadly the same fire loads. The following table gives the most relevant values.  
A. Totally Incombustible ( e.g. concrete / steel only) 0
B. Incombustible construction, with max. 10% allowance for combustible construction elements as windows, roof covering, etc. 100
C1. Wooden structure finished with incombustible materials. 300
C2. Masonry construction with wooden floors and girders 300
D. Incombustible structure, combustible finishing. 1000
E. Totally combustible construction 1500
Unchanged 100
Mobile (moveable) fire load density Qm   Range[1]
In theory one must calculate with the total heat release of all materials of the content divided by the total floor area. In practice, the next table gives reasonable estimates.  
User defined 0
a. Low fire hazard (LH or light hazard) occupancies 200
a1. Offices 400 80 - 550
a2. Dwellings 500 330 - 780
a3. Schools 200 215 - 340
a4. Hospitals 250 100 - 330
a5. Hotels 250 310 - 330
b. Ordinary fire hazard with low fire load (OH1 / NFPA: OH Gp1) 600
c. Ordinary fire hazard with medium fire load (OH2 / NFPA OH Gp2) 1500
d. Ordinary fire hazard with high fire load (OH3 / NFPA OH Gp2+) 2000
e. Ordinary fire hazard with very high fire load (OH4) 2500
f. High hazard class HH1 2500
g. High hazard class HH2 (NFPA EH Gp1) 3000
h. High hazard class HH3 (NFPA EH Gp2) 3750
i. Rack storage[2] 6750
j. Large drop sprinklers protected storage 7500
ESFR protected storage 7 m high 12000
ESFR protected storage 5.5 bar 15000
Unchanged 500
Fire spread factor i  
Average dimension of content : m  
Fire spreads essentially on the surface of burning objects. The more surface available, the easier a fire will spread, as can be seen on small twigs in a campfire. The average dimension of the content reflects the ratio between the total volume (in m) of the content and the total surface (in m).  
To calculate m, estimate n typical sizes (length, width, height or thickness) of typical objects. The calculated average dimension of the content is the n-th root of the product of these sizes. The average dimension of the content m can vary between 0.001 m (40 thou) to 2 m (80 inch).  
Enter a maximum of 10 typical dimensions (in meter) here: P-Ref P-V1 P-V2
dimension 1 0,300 0,300 0,300
dimension 2 0,600 3,000 0,001
dimension 3      
dimension 4      
dimension 5      
dimension 6      
dimension 7      
dimension 8      
dimension 9      
dimension 10      
Total number of dimensions entered 2,000 2,000 2,000
Calculated average dimension 0,42 0,95 0,02
DEFINED by the USER (link to Info P) 0,300 0,310 0,320
Unchanged 0,30 0,30
Temperature rise T  
Define the temperature necessary to start ignition or damage of the content. The following scale gives an indication of the relevant values in C Equivalent values in F are in brackets.  
WEIGHED AVERAGE of the following classes (link to Info P)[3] 252 100% 302 100% 292 100%
a. Inflammable liquids ( FP <21 C or 70 F) 20 10% 20 10% 20 10%
b. Plastics, electronics, human beings ( 100 C - 212 F)[4] 100 0% 100 0% 100 0%
c. Textile, wood, paper, food (200 C - 400 F) 200 0% 200 0% 200 0%
d. Average content of residential buildings ( 250 C - 482 F) 250 60% 250 40% 250 60%
e. Machinery, household appliances ( 300 C - 572 F) 300 20% 300 20% 300 0%
f. Metal objects (400 C - 752 F) 400 10% 400 10% 400 10%
g. Non combustible (construction) materials ( 500 C - 932 F) 500 0% 500 20% 500 20%
Unchanged   P- REF 500 P - V1 500 P - V2
Reaction to fire class M   TOTAL:   TOTAL:   TOTAL:
WEIGHED AVERAGE of the following classes (link to Info P)[5] 2,5 100% 3 100% 2,7 100%
A1 per EN13501-1 or Incombustible 0 0% 0 30% 0 30%
A2 per EN13501-1 or Nearly incombustible 0,5 0% 0,5 0% 0,5 0%
B per EN13501- 1 or EN12845 Cat. I : Difficult to ignite (self extinguishing) 1 0% 1 10% 1 20%
C per EN13501-1 : Slow burning materials 2 50% 2 0% 2 0%
D per EN13501 or EN12845 Cat. II: Combustible surfaces 3 50% 3 0% 3 0%
E per EN13501-1 or EN12845 Cat. III Flammable surfaces 4 0% 4 10% 4 0%
F. EN12845 Cat. IV : Highly flammable surfaces 5 0% 5 50% 5 50%
Unchanged   P- REF 2,5 P - V1 2,5 P - V2
Area factor g P - REF P - V1 P - V2
Step 1: Define the longest distance between the centres of two sides of the compartments' perimeter. This is the theoretical length l.
Step 2: Define the total surface area of the compartment : Atot
Step 3: Divide this area by the theoretical length to obtain the equivalent width b.[6]
Step 4: Check if the building is accessible at its long side (left view): If NOT (right view): use the " Narrow building" approach.
Building access for the fire brigade
Building accessible at its long side long
Building only accessible at its narrow side narrow
Unchanged long
Level factor e
Level number E, galleries, mezzanines, etc.
Number all the levels in the following way: E =0 for the main access level. All upper levels are then E = 1,2,3, etc. All underground levels are then E= -1, -2, -3, etc.
For galleries between levels, add the additional floor space as the decimal part of the level number. When a first floor has a gallery of 40 % additional floor space, enter the level number as 1.4.
P - REF P - V1 P - V2
Venting factor v
The venting factor v is calculated with the values of Qm, k and h.
The mobile fire load is the most relevant measure for the potential heat release inside the building.
  P -REF P - V1 P - V2
STEP 1: Define the height h, between the floor and the ceiling of the storey. For a sloping roof or ceiling, it is the average height that is used. The maximum value for h = 15 m. For higher ceilings, FRAME uses 15 m
STEP 2: Measure the total area of single glazed windows, glass and plastic skylights in the ceiling (roof) and upper third of the walls opening to the outside. Enter this area in m[7]
STEP 3 : Measure the aerodynamic area of natural smoke vents in m
STEP 4: Define the capacity for the mechanical exhaust systems for smoke extraction in Nm/hour[8]
OR define the ratio smoke exhaust openings / floor area
Access factor z
The access factor z indicates how difficult it is for outside help to get into the fire area and is calculated with b, H+ or H- and Z.
To define Z, the number of access directions, draw an imaginary map of the building with the north at the main entrance of the building, and check the south, east and west for free access for the fire brigade. The number of accessible directions is Z (1 to 4).
P - REF P - V1 P - V2

Average and variation of fire load densities found in literature
For storage hazards the fire load density is calculated with the total spray density needed for sprinklers. The fire load equals 300 MJ/m per 1 l/min/m sprinkler design density (or 0.1 gpm/sq.ft = 1250 MJ/m. For in-rack protection add 3750 MJ/m for each row of in rack sprinklers to the fire load density derived from the roof sprinklers density.
Any intermediate value is also acceptable. E.g. in a warehouse were packed and unpacked metal spare parts are stored, T= 250 C can be used. Be sure that the total of all classes is 100 %
Human beings only need to be considered as " content" when they will remain for an extended time in the compartment during the fire growing phase.
A weighted average is also acceptable. E.g. where unpacked and expanded plastic protected metal spare parts are stored, a combination of A1 and F can be used. Be sure that the total is 100 %
In this way a rectangle of the same size of the compartment is defined.
It is assumed that about one third of single glazed windows, glass and plastic skylights in the ceiling (roof) and upper third of the walls will be broken by the effects of the fire and be available for smoke venting. DO NOT reckon with double-glazing, as it is not easily broken.
10.000 Nm of mechanical ventilation equals 1 m of venting area. Or: 500 cu.ft/min capacity equals 1 sq.ft of venting area.