1. General review of the foyer. Preliminary assessment of the number, combustibility, smokiness and toxicity of the burning materials.
Before starting the description of presumed dynamics of the fire, I would like, first, to evaluate the size, shape, and other details of some parts of the House of Unions. Also, I want to elaborate on the preliminary assessment of the quantity and quality of combustible substances and materials involved in the process of burning in the lobby and stairwell.
So, the front door:

We can see three such massive double oak doors, spaced at equal distances. Their size is 1700 * 3500 mm.
Behind the doors is a spacious lobby, that is divided by stairs (drop 800 mm) into two parts. The size of this room is 19000 * 11000 * 4000 mm. Steps divide it into two parts along the entire length, the width of the nearest to the front door part is 7000 mm, and the further — 4000 mm:

In front of the central door and almost to the side doors we note the remains of a large barricade:

Pay attention, that that the composition of the barricade, judging by the remains, in addition to the massive wooden pallets, also included chairs from the assembly hall, office chairs and other items of upholstered furniture, that are extremely flammable and its design includes foam, polyurethane, polypropylene, polyvinyl chloride, phenolic and other materials. During the combustion of these substances in addition to carbon monoxide (CO) into the air also emit toxic and deadly components: acrolein, methyl isocyanate, benzo [a] pyrene, cyanide, toxic organichlorines (phosgene, etc.) and others.(see :http://numikosov.livejournal.com/785.html. )We can see the remains of the large burnt fridge and industrial refrigeration chest just in front of the central and right doors.

When freon is heated over 250 ° C a very toxic products, such as phosgene СОСl2 are produced, under the influence of temperatures above 400 ° C freon can decompose with the formation of highly toxic products: tetrafluoroethylene (4th class of danger), hydrogen chloride (2 hazard class) hydrogen fluoride (1st class of danger). Also at a distance of 3500 mm from the central door, we notice remains of Chinese gasoline power generator with capacity of 4.5 kW and a tank for 18 liters. The tank was frustrated with mounts.

We can see the remains of oak linings on the batteries, as well as massive oak constructions behind the central door.

Look at the ceiling and walls, the plaster has completely crumbled from them. Judging by the condition of the walls, as well as a number of other features, it can be concluded that the temperature in the layer near the ceiling in this part of the building was more than 700 degrees. One can see that the plaster on the all ceiling beams, as well as baguettes and other moldings on the ceiling are held on the so-called «shingles», which began to char under this layer of plaster, emitting poisonous carbon monoxide and combustible wood gases.

Move on to a smaller part of the lobby a few steps up. This part moves with a slight narrowing into the left and right corridors. Right corridor was separated with two plastic doors arranged one behind the other at a distance of 4.5 meters, that are currently burnt. The closest to the lobby door has burned completely:

Next door has burned halfway. Thus, burning one by one, these two doors provide a lower temperature and later smokiness in the right side of the corridor on the first floor.

Metal partition in the left side appeared after the fire:

Doors and other wooden constructions were completely charred. Plaster has halfway crumbled from the columns. On the ceiling, we see a pocket formed in a circle by bearing beams. The temperature in this part of the lobby near the ceiling was also about 650 degrees. We note that the power and low current wiring in the building is made of PVC cables (if charring releases phosgene). As we can see, it is completely charred.

Then, we observe the next and the last area before the stairs, with the doors of the elevator on both sides. It has the following sizes: 8000 * 1600 * 4200 mm.

Also we pay attention at the significant narrowing of the doorways on this area (up to 4000 mm), and then on the stairs (up to 3000 mm), compared to the width of the foyer (19000 mm), as well as of the elevator platform and the stairwell (8000 mm ). This narrowing physically separates the lobby and the stairwell, dividing them sort of into two interconnected large vessel. This detail is very important. And later, when considering the dynamics of the fire, and our attempts to establish the reasons for its swiftness, we will come back to this part.

On this elevator platform are situated two elevators and doors. All elevator and wooden doors are completely charred and burnt. Elevator doors were, also, burnt down to the metal. Aluminum corner framing elevator doorway partially melted on the fracture, showing that the peak temperature was over 660 degrees at the height of 2100 mm from the floor.

Pay attention to the ceiling of the elevator platform. Girders form on it quite deep pocket. The temperature of the gases near the ceiling in this pocket was more than 750 degrees Celsius.

2. Research of the walls and ceiling for flammability.
Next, I would like to elaborate on the research of finishing materials of the ceiling and walls of the lobby and the stairwell up to the 4th floor. These surfaces have been actively involved in the combustion process (up to 3 floors) and boiling point (up to the 4th floor). After all the measurements and calculations we find that the area of the walls and ceiling of the lobby and the elevator platform on 1st floor — 350 m2, light of stairs from the 1st to the 2nd floor, including the elevator area of the 2nd floor -215 m2, staircase 2-195 m2 and staircase 3-195 m2. Total — more than 955 square meters of the surface of walls and ceilings that were actively involved in the process of combustion and sublimation (evaporation).For finishing the walls in the researching room of HTU was used oil (presumably on the composite linseed oil) gypsum-based filler putty. Thickness of the layer fillings in some places reaches 12 mm. Also, this putty was packed on heavily grounded by linseed oil previous layer.

On the walls and ceiling, I counted at least 4 layers of paint. Presumably PB and CN paints.

During the calculating the average consumption of building materials for building standards, we get additional 510 kg particularly combustible, flammable and evaporating substances under the influence of temperature, evenly distributed over the entire area of the ceiling and walls of the foyer (150 kg) and the stairwell up to the 4th floor (including dry residue).
Approximate specific heat of burning of these paints and linseed oil-40 MJ / kg, which gives the total amount of heat generated by complete combustion of these finishing materials is 20.4 kJ, 14.4 kJ of which falls only on the stairwell up to the 4th floor. Also one can approximately estimate the amount of CO or CO2 gas in liters, exuded with the complete combustion of these substances. And, by the estimated length of the hydrocarbon data -S24 and molar mass of 300 g/mol, we obtain 914 cubes of these gases in the proportion which strictly depends on the velocity of the combustion process, and access to oxygen. We may also calculate the approximate amount of light hydrocarbons evaporated from a given surface to achieve self-ignition temperature of these materials (380 degrees Celsius). And conditional molar weight of 50 g/mol, the data amount of combustible and toxic substances could be a few hundred cubic meters. These calculations seem to be too approximate and their importance will be recognized by us later, when we move to a description of the fire dynamics and see what is the amount of heat and gases from these surfaces in the stairwell up to the 4th floor was allocated quickly. Must also be considered great value involved in the stairwell in the process of burning time unit of surface area to volume ratio of the stairwell up to the 4th floor.
3. Formation of the temperature and smokiness map of the central wing of House of Trade Unions.
1. Foyer, corridors, rooms.
Separately want to dwell on the detailed description of the surfaces involved and not involved in the process of burning. This assessment is also important for us because it gives the possibility of a more or less accurate map of peak temperature of individual rooms of the building at the time of the fire. As to the lobby and corridors of the House of Trade Unions, here I have used the technique of making the temperature maps of the melting temperatures of various plastics, metals, wood charring, blistering and charring paint, etc. Taking into account these factors, it is determined that the temperature in the lobby was more than 600 degrees Celsius (ceiling layer more than 700 degrees Celsius). On the left side of the corridor of the first floor -250-70 degrees at 2000 mm from the floor, depending on the distance from the lobby.

Separately evaluated the height over the floor and number of soot on the walls and to form the map of smokiness in the building. The left side of the corridor of the first floor had a low degree of smokiness with a pocket of smoke up to 2000 mm from the floor. As for the right side of the corridor of the first floor, due to two metal-plastic doors temperature did not rise above 70 degrees Celsius. Smokiness of the average power (pulling the smoke of burning plastic doors).
The left and right sides of the corridor of the second floor -270-70 degrees at a height of 2000 mm from the floor, depending on the distance from the staircase. Significant smokiness pocket up to 1200 mm from the floor.

В левой и правой частях коридора третьего этажа -180-50 гр.ц на высоте 2000 мм от пола в зависимости удаления от лестничной площадки.Среднее задымление с карманом задымления до 1700 мм от пола.

The corridors of the 4-th and 5-th floors become one-sided (green assembly hall on the left) and due to this and to the additional locus of a flame at the area 3 + most smoky and temperature on the 4th floor, 200-70 degrees at a height of 2000 mm from the floor, depending on the distance from the staircase. The smokiness of these is also significant with pockets of smoke at a height of 1500 mm from the floor.
2. Aerodynamic causes of smokiness and heat distribution along the corridors and rooms.
As you can see, the effects of temperature and smoke in the corridors of all state levels, showed that the degree of influence depends on several factors.
1. Distances from the fire and the central stairwell.( convection column)
2. Aerodynamic thrust in this corridor, which, in its turn, depends on several factors: the number of floors of the corridor, the number of broken windows and embossed doors.
As to the distribution of the smoke and heat from the foyer through the corridors of floors, it was carried out through a vertical smoke duct (convection column) located in the nearest to the lift platforms corners of the staircase. This channel has existed as result of vertical thrust, strengthening and loosening proportional to the difference in temperature between the lobby and the 5th floor. Such a model of convection is fully consistent with the temperature map of the premises. It is, also, indicated by the traces of soot remaining in the field of the channel after the fire on the stone railing of the second flight of stairs:

As well as burnt-out sections of railing of the third and fourth flights of stairs. Railing from the second floor to the platform 2 +:

Estimating the influence of temperature and smoke on the condition of the rooms also showed that the degree of influence depends on two main factors:
1. Aerodynamic connection of this room with the rest of the wing of the building. This relationship magnified when window or door of the room were opened or damaged.
2. Indicators of temperature and smoke in the corridor.
This is also confirmed by the fact that the rooms that have weak wind communication with the central wing of the building: having windows on two sides (green and red assembly halls) or with closed doors and windows — have not undergone any kind of influence from fire at all.

3. Temperature map of the stairwell.
a) Assessment of the condition of oak handrails.
Separately was evaluated the condition of oak handrails at the staircases and flight of stairs. From tabular data we write out primary temperature of oak charring — 275 degrees Celsius, the average temperature of self-ignition of oak wood — 550 degrees Celsius, and its rate of charring at 300 degrees Celsius — 0.45 mm / min.
Railing from the second floor to the area 2 +:

As you can see from the condition of this railing, the temperature at this a flight of stairs (2-3 floor) at a height of 1100 mm was about 400 degrees Celsius. Also very significant is that the burnt area of the wood, the same as I suspected convection channel in which there is a distribution of hot fire and unburned residues from the foyer to the stairwell and, depending on the rod (broken windows, etc.) through the corridors of floors. It is also a very important point and we will come back to it in the description of the dynamics of the fire. We can also note that the same parts of burnt railing are matched to the places of combustion residues furniture or other combustibles on the steps under the railing, such as in front of platform 2 +:

Except peaks in the described areas, the temperature in the stairwell decreased linearly from the 2nd to 3+ floor. The condition of railing on the 3rd floor corresponds to the temperature of about 280 degrees Celsius:

Further, the on area 3 + we again observe a significant section of burnt railing:

that corresponds to the second lower hearth at floor 3+

arisen much later as the result of the spread of flames on flight of stairs ceiling from the platform 2 +:

On this area, locally, the temperature rises again to 400 degrees Celsius.
Also here can be seen apparent inconsistency of the remaining traces of the flames, ash remaining and combustion products of fire. We state that this hearth made a lot of fumes. This suggests that there was burning combustible material in the container. After a brief search, the remains of the container (one of many, that were withdrawn by the investigation team after arriving at the place of the fire) are found in the far right corner of the area:

Above the area 3+ and to the 5th floor, the temperature decreases linearly from 400 to 150 degrees Celsius.
b) Assessment of the surface of the walls and ceiling.
Major surfaces on which the process of combustion and evaporation of gases in the stairwell was, are walls and a ceiling. It is very important to investigate the change of data surfaces to which they were subjected to under the influence of temperature. To describe these changes I suggest to write out the following boundary conditions of these surfaces, and the approximate temperature that correspond to these changes:
1. Putty and plaster crumbled to bricks (more than 650 degrees Celsius):

2. All layers of paint are completely burnt and charred. There are traces of burnt linseed oil on the putty, the putty has cracked in some places, but remained on the wall (about 450 degrees Celsius):

3. All layers of paint were burnt, but not charred. On the surface of putty are the residues of not fully combusted linseed oil (about 380 degrees Celsius):

4. Linseed oil under the paint and the paint itself were boiling and actively evaporating, releasing into the air flammable and toxic gases (250-370 degrees Celsius):

5. Painted surface remained without apparent structural changes (less than 250 degrees Celsius). On this photo is visible vertical boundary between two structural states of the wall covering. Above the border-lines with our item 4, below-5 :

Now, clearly know the types of changes the surface of the walls of flights of stairs and temperature regime that is consistent with these changes, we can describe more detailed temperature map of the stairwell from the 1st to the 5th floor. Moreover, this method allows us to capture the change in the temperature of the surface not only horizontally, but also vertically (from the floor to the ceiling), which greatly complement dynamic model of what had happened later on fire. To illustrate the clarity and convenience of this method for determining the temperature and the processes scene occurring in the stairwell generally I cite a series of photographs of the walls in spans with the description.
Right staircase 1 + 2-nd floor. Temperature of about 650 degrees Celsius. An open flame on the entire height of the flight of stairs:

Left staircase 1 + 2-nd floor. Temperature of about 450 degrees Celsius. An open flame on the entire height of the flight of stairs:

Such a significant difference in the condition of the coverage and thus the influence of temperature on these symmetric walls (there are also a number of important factors and evidence), gives us a reason to suppose the burning of additional amount materials directly before the right elevator on the second floor of the elevator platform.
The first-floor elevator platform. Here the condition of finishing materials corresponds to the temperatures of about 550 degrees to the right and 500 degrees to the left. An open flame on the entire height of the lift platform:

Part of the wall and ceiling of the same elevator platform:

The paint on the stone railing of the stairwell and were burning, adding smoke and heat in the general mouth:

On the right and left stairways from the 2nd to the 3rd floor there is a clear horizontal division of the structural conditions of wall covering, which corresponds to the boundary of an open flame:

This boundary from an open flame from the 2nd to the 3rd floor decreases linearly from the floor to the ceiling and disappears short feet to the 3rd floor:

Thus on this piece gradual linear horizontal reduction of the temperature with 650 to 350 degrees Celsius and sharper spasmodic from a ceiling to a floor in the same temperature borders was observed. On a lift platform of the 3rd floor the open flame was observed only on a ceiling. Temperature is about 350 degrees Celsius.
On the stairs to a platform 3+, structural changes of materials correspond to influence of temperatures not above 280 degrees Celsius.
And on a platform 3+ we again observe sharp change in the structure of a covering of a surface of walls which corresponds to influence of an open flame from defined by us earlier the second center of ignition on a platform 3+. To the 4th floor (without reaching meter to the lift platform)-400-450 degrees Celsius, an open flame in the top part of a wall and on a ceiling:

Starting from the lift platform of the 4th floor, we observe vertical and horizontal borders of a structural condition of a covering of walls which correspond to border of boiling and sublimation of this covering. It corresponds to influence of temperatures within 200-350 degrees Celsius. After a platform 4+ this border is displaced almost under a ceiling, and then vanishes at all, that corresponds to influence of temperatures less 200 degrees Celsius:

As I’ve already told at the beginning of the article, the main final task of this research, is the creation of differential model of the fire. This model will allow us to find the answer to a number of questions concerning the fire in the House of Trade Unions. It will allow us to understand a cause of death of people.
As you can see, now we have obtained a large amount of input data. The maximum temperature in different parts of the building, the lower limit and the intensity of smokiness, distribution and circulation of hot air and the products of combustion, the possible qualitative composition of the products of combustion, the area involved in the process of burning of the surface, the direction and speed of the combustion wave, etc.
Also, to describe the dynamics of the model, we need to restore and sync it with the video time set by the following successive stages of the fire:
1. the beginning and progression of fire in the lobby,
2. blast of the 18-liter tank of gasoline generator,
3. heating of ceiling layer of foyer above 500 degrees Celsius. Formation of the channel of vertical thrust (convection column) in the nearest to the lobby part of the stairwell. Gradual filling of the ceiling pockets and corridors with a hot air, products of combustion and evaporation,
4. abrupt change in the thermodynamic balance of the building with a change in the direction of gas flows (early release of smoke from the rear windows of the stairwell),
5. prompt (flash) involvement of the combustible gases which have collected in the ceiling pockets and the covering of walls of a stairwell heated to boiling in the process of burning (tongues of flame and a jumping of people from back windows of the stairwell),
6. two explosions, presumably of fuels and lubricants on the right side of a lift platform of the second floor after which the flame gets off, and then inflame with a new force,
7. gradual ignition of the linseed oil and paint on walls and ceiling of a stairwell up to the 3rd floor,
8. involvement in process of burning of the remains of furniture and, presumably, fuels and lubricants on a platform 3+. Flare-up of the fire against the background of burnout in the lower part of the stairwell and continuation of burning of the foyer.
After creating the differential model of the fire and imposing it on the building plan we will combine it with the map of the bodies’ location and the conclusions of the FME for each of the victims. Only then will we be able to give reliable answers to all of our questions. There is still a lot of work, but we will try to complete it as quickly as possible.

Yours faithfully, Vladislav Balinsky