JP5429768B2 - Fireproof design method for buildings and fireproof buildings - Google Patents

Description

  The present invention relates to a fire-resistant design method for buildings using fire prevention equipment using glass and a building constructed by the design method.

  For example, the procedure of the fire resistance performance verification method of the Ministry of Construction Notification No. 1433 established by the Building Standards Law Enforcement Ordinance first sets up a fire room (single room or multiple rooms assuming simultaneous combustion) and indoors Calculate the duration of the fire that occurs. After that, for the main structural parts facing the fire room, the limit time that can maintain the fire resistance (non-damage, heat insulation, flame resistance) required for each main structure, that is, the possessed fire resistance time for each member Calculate. If the fireproof time of the main structural part is equal to or longer than the fire duration time, it is determined that the performance is satisfied, and these verifications are performed for all the main structural parts constituting the building.

An effective aperture in the calculation of the effective aperture factor is required to satisfy the following conditions a) and b).
a) It is damaged in the event of a fire or is reliably opened.
b) A ventilation path with outside air is secured.
Under the condition a), an opening provided with fire prevention equipment, that is, fire prevention equipment using glass such as netted glass or heat-resistant tempered glass is not included in the effective opening factor.
Explanation and calculation example of 2001 fire resistance performance verification method, Ministry of Land, Infrastructure, Transport and Tourism

  As described above, according to the above fire resistance performance verification method (hereinafter referred to as “notification verification method”), fire prevention equipment using glass is handled as not falling off at the time of evaluation. Reduces the amount of inflow air from the outside air, slows down combustion and heats up. For this reason, the fire duration time is long for evaluation, and high fire resistance is required for the members in the evaluation target room, so that the cost for the fire resistance treatment is high.

  The present invention was made in order to solve the above problems, focusing on the fact that fire protection equipment using glass such as netted glass and heat-resistant tempered glass is dropped in an actual fire. The objective is to obtain the required fire resistance performance while reducing the cost for the purpose.

When the opening part of the outer wall of a specific fire chamber has a fire prevention equipment using glass, the invention according to claim 1 until the fire prevention equipment using the glass falls off from the occurrence of a fire for the fire room. After calculating the duration of indoor fire after dropping the fire protection equipment using the glass, the time until the fire protection equipment using the glass dropped from the occurrence of the fire and the glass was used. Combined with the duration of the indoor fire after dropping off the fire prevention equipment, to calculate the total indoor fire duration of the specific fire room, while calculating the possessed fire resistance time of the member facing the specific fire room, The room conditions such as members, fireproof coating thickness, outer wall opening area, interior materials, etc. were changed and adapted so that the total indoor fire duration was less than the calculated fireproof time calculated above.
The invention according to claim 2 is a fireproof design method for a building in which all members of a building and fireproof coating thickness are adapted so that the indoor fire duration time is equal to or less than the calculated fireproof time for all fire rooms of the building. When the opening of the outer wall of the fire room has fire prevention equipment using glass, the fire temperature rise coefficient is calculated for the fire room, and the time from the occurrence of the fire until the fire prevention equipment using the glass falls off And recalculate the opening area of the outer wall from which the fire prevention equipment using the glass has fallen, and add it to the effective opening factor to calculate the calorific value per unit time of the residual combustible material when the fire prevention equipment using the glass drops. And after calculating the duration of indoor fire after dropping the fire protection equipment using glass, the time from the occurrence of the fire until the fire protection equipment using glass drops and the duration of the indoor fire after the fire protection equipment using glass is dropped And To calculate the total indoor fire duration of a specific fire room, while calculating the fire resistance time of a member facing a specific fire room, so that the total indoor fire duration is less than the calculated fire resistance time Various conditions of the room such as members, fireproof coating thickness, outer wall opening area, interior material, etc. were changed and adapted.
According to a third aspect of the present invention, a chamber having an opening provided with a fire prevention facility using glass on the outer wall is based on the fireproof design method according to any one of the first to second aspects. It is a built building.

According to the invention of claim 1, the time until the fire prevention equipment using the glass drops after the occurrence of a fire and the duration of the indoor fire after the fire prevention equipment using the glass is dropped are combined to determine the specific Calculating the total indoor fire duration of the fire room of the other, calculating the possessed fire resistance time of the member facing the specific fire chamber, so that the total indoor fire duration time is equal to or less than the calculated retained fire time, Since the thickness of the fireproof coating is adapted, it is possible to calculate the fire duration that suits the actual situation, and the duration of the indoor fire can be made shorter than the conventional one.
As a result, it is only necessary to calculate the holding fire resistance time of the member facing the specific fire room and adapt the member and the fire protection coating thickness so that the total indoor fire duration time is equal to or less than the calculated holding fire resistance time. It is possible to maintain appropriate fire resistance even if the thickness of the fireproof coating and the size and strength of the structural member are lowered.
According to the invention according to claim 2, since it is a fireproof design method compliant with the notification verification method, the indoor fire duration time can be calculated reasonably and in a short period of time, compared with the invention according to claim 1. It becomes possible to keep fire resistance more easily.
Moreover, according to the invention which concerns on Claim 3, since it is not necessary to raise the dimension of the structural member of a building, the intensity | strength, and the thickness of a fireproof coating more than necessary, reduction of construction cost and expansion of an effective area are attained. Become.

  In the invention according to claim 1, as a method for predicting the fire duration before and after dropping of the fire protection equipment using glass, for example, a one-layer zone model, a radiant heat transfer / convection heat transfer calculation between a fire source and glass It is possible to use a prediction method such as glass temperature prediction based on the above. It is effective because there is a good basis.

First of all, the fire properties before the glass fire prevention equipment falls off are predicted based on various conditions such as the floor area of the fire room, the ceiling height, the interior material, the amount of combustible material according to the application, and the opening, and fire prevention using glass. Calculate the time for the equipment to drop out.
Next, after the fire prevention equipment using glass is dropped, the fire is expected with the area where the fire prevention equipment using glass is expected to drop due to a fire (however, the opening ratio is assumed to be r as described later). Recalculate properties and calculate fire duration.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a calculation flow chart when the notification verification method is used, and FIG. 2 is an example of fire prevention equipment using glass in this embodiment. FIG. 3 is a diagram showing the fire chamber temperature and the time when the meshed glass is dropped, and FIG. 4 is a diagram showing when the meshed glass is dropped. FIG. FIG. 5 is a schematic plan view of a room of an apartment house in which the present invention is implemented. FIG. 5 is a diagram showing that the fire duration time is different based on the difference between when and when it is dropped.

Hereinafter, an embodiment will be described based on the calculation flow diagram of FIG. 1 when the notification verification method is used.
The meanings of the symbols used in FIG.
Q _r Calorific value of combustible material in the room [MJ]
q _l Calorific value per 1m ² floor area of combustible materials stored in the room [MJ / m ² ]
A _r Floor area in the room [m ² ]
q _f The surface area of the interior building materials facing the walls, floors, and ceilings of the room concerned is 1 m ² , and the heat generation per 1 mm thickness [MJ / m ² / mm]
A _f Surface area [m ² ] of each part for each type of building material for the interior of the room
d _f Thickness of building material for interior of the room [mm]
f _a Thermal penetration coefficient [-]
q _la Calorific value per 1m ² floor area of combustible material stored in the adjacent room [MJ / m ² ]
A _ra Floor area of adjacent room in the room [m ² ]
q _fa The surface area of interior building materials in the room adjacent to the room is 1m ² , and the heat generation per 1mm thickness [MJ / m ² / mm]
A _fa Surface area [m ² ] of each part for each type of interior building material in the adjacent room
d _fa Thickness of building material for interior of adjacent room [mm]
α Fire temperature rise coefficient [℃ / min ^1/6 ]
α _aft Fire temperature rise coefficient after falling into glass (° C / min ^1/6 )
q _b Calorific value per second of flammable material in the room [MW]
q _{b_aft Calorific} value per second [MW] of combustibles in the room after dropping _{into the} net
χ Combustion type governing factor [m ^1/2 ]
χ _aft Combustion type governing factor after falling into glass (m ^1/2 )
A _fuel surface area [m ² ]
A _c Surface area [m ² ] for each wall, floor, and ceiling of the room
I _h Thermal inertia for each wall, floor, and ceiling of the room [kWs ^1/2 / m ² / K]
f _op effective aperture factor [m ^5/2 ]
f _{op_aft} Effective aperture factor [m ^5/2 ] after dropping glass
t _f Fire duration in the room [minutes]
t _{f_fallout} Fire duration [in minutes] in the room after falling into the glass
t _fallout netting glass falling time [minutes]
A _op Area of each opening [m ² ]
A _{op_aft} Area of each opening after dropping _{into the} net [m ² ]
H _op Vertical distance from top to bottom of each opening [m]
H _{op_aft} Vertical distance [m] from the top to the bottom of each opening after dropping into the _screen .
r Opening ratio in the height direction of each opening after netting glass is dropped [-]
Q _{r_aft Calorific} value [MJ] of combustible materials in the room after dropping into the glass
H _r Average height from floor to ceiling of the room [m]
W _op glass width [m]
t _fr Indoor fire holding time [min]
T _{f_crit} Fire room temperature when netted glass is dropped [℃]

In this embodiment, the present invention is applied to the dwelling unit of the apartment house shown in FIG.
This room has a floor area of 84.3 m ² and a room height of 2.71 m. In the room condition setting procedure shown in FIG. 1, the values necessary for setting the room conditions including these values are determined by the input means of the computer. And stored in the RAM (procedure 1). The type of opening such as float glass or netted glass is entered in step 1.

Next, in procedure 2, the total calorific value of the combustible material in the room is calculated according to the following equation 1.
It should be noted that all the expressions described later are stored in the RAM, and the calculation procedure is programmed.

As a result of the calculation, the total calorific value is 99203 MJ. After calculating the total calorific value, the combustion type control factor χ and the relevant factor are calculated from the floor area of the room, ceiling height, opening height, opening width, combustibles, interior materials, etc. The calorific value q _b per second of the combustible material in the room is calculated by 1 of the following formula 2 and 1 of the formula 3.
A _op and H _op are calculated considering only the opening of the float glass before the netted glass falls off.

Further, the fire temperature increase coefficient α and the effective opening factor f _op before dropping the netted glass are calculated by 1 of the following formula 4 and 1 of the formula 5.

As a result of the calculation, the combustion type controlling factor is χ = max [0.0181, 0.0046], and the calorific value per second of the combustible in the room is calculated as q _b = 1.6 × 0.0181 × 428.6 = 12.4.
Similarly for f _op, only the float glass opening is considered before the netted glass falls off.
When ΣA _c I _h = 426, α is 460, and the fire room temperature T _f is as shown in FIGS.

In step 5, the CPU of the computer determines from the data stored in the RAM in step 1 whether or not the type of the opening is made of netted glass.
As a result, when it is determined that no network entry glass is used jumps to step 13 to calculate a fire duration t _f.
At this time the CPU, for chamber no net entrance glass is used, since the network input glasses never as opening area is increased to fall off, so the t _f follows simply using one of formula 6 To.
t _f = Q _r / 60q _b 1 in Equation 6
Procedures 14 and 15 will be described later.

When the CPU determines that the meshed glass is used in the procedure 5, the process proceeds to the next procedure 6 and subsequent steps in order to predict when the meshed glass is dropped.
As is well known, the fire room temperature T _f is represented by a time function having a temperature increase coefficient α as a coefficient, and is determined by the magnitude of α. The formula is as follows.
T _f = αt ^1/6 +20 Equation 6

The present inventors experimentally and analytically determined the fire room temperature T _{f_crit} when the fire prevention equipment using glass such as netted glass dropped for each value of the fire temperature rise coefficient α. It was found that the temperature of the fire room when the fire prevention equipment dropped out depends on the temperature rise coefficient α.
The present invention was created on the basis of this finding, and for each value of α, the relationship between the fire-protection equipment drop-off time using glass and the temperature in the furnace was experimentally determined, and these values are stored in a database.
In the procedure 6, the relationship between the fire temperature rise coefficient α and the furnace temperature T _{f_crit} of the refractory furnace where the net-filled glass falls off is used.
That is, since the value of the fire temperature increase coefficient α is obtained by 1 in the above equation 4, the fire room temperature when the netted glass is dropped is obtained by searching the database, and the time to reach this temperature. Can be obtained by the above-mentioned formula 6.
As a result of the experiment, as shown in FIG. 3, when α is 460, it has been investigated that the fire room temperature T _{f_crit at which} the 6.8 mm-thick meshed glass falls off is 843 ° C.

[Calculation of netted glass dropout time]
Therefore, the netting glass dropping time t _{fallout at} which the fire room temperature reaches 843 ° C. is expressed by the following equation 7

(823/460) ⁶ = 32.7 (minutes).

[Area of opening after netting glass is dropped]
In step 8, since the opening area increases when the meshed glass falls off, the opening area and the vertical distance from the upper end to the lower end of the opening are calculated again according to the following equation 8.
A _{op_aft} = W _op × H _{op_aft} where H _{op_aft} = H _op × r Equation 8
In calculating the vertical distance _{Hop_aft} from the upper end to the lower end of the opening after the netted glass is dropped, the coefficient r is multiplied.
Since the ratio of the opening area after dropping to the total area of the mesh-filled glass has been confirmed by experiments, the coefficient r is set to 0.5 in the present embodiment for safety.
In the case of float glass, r = 1 is set because the glass drops over the entire opening.
Therefore, the opening after dropping the net-filled glass is
Openings 1 to 5 H _{op_aft} = 1.0 A _{op_aft} = 1.4 × 1.0
Aperture 6 H _{op_aft} = 1.0 A _{op_aft} = 0.74 × 1.0
Aperture 7, 8, 10 H _{op_aft} = 1.8 × 0.5 = 0.9 A _{op_aft} = 1.8 × 0.9
Opening 9 H _{op_aft} = 1.8 × 0.5 = 0.9 A _{op_aft} = 2.8 × 0.9
It becomes.

[The amount of heat that burns after the netted glass falls off]
The calorific value Q _{r_aft} of the combustible material remaining after the netted glass is dropped can be calculated by the following formula 9.

When subtracting the amount of heat burned before the net-filled glass falls off from the total calorific value of housing units 99203MJ,
Q _{r_aft} = 99203−q _b × t _fallout × 60 = 74909
It becomes.

[ _{Recalculation} of χ _aft , q _{b_aft} , t _{f_fallout} after netting glass is dropped]
After the net-filled glass is dropped, the opening area increases, so the combustion properties change.
For this reason, proceeding to the procedure 10, the combustion type factor χ _aft after the net-filled glass is dropped and the calorific value q _{b_aft} per second due to the combustion of the combustible material are _expressed by the following Equation _2-2 and Equation _3-2 . Recalculate.

As a result of recalculation,

Because 13.7 / 428.6 = 0.0320,
χ _aft is max [0.0320, 0.0046], and q _{b_aft} is calculated as 1.6 × 0.0320 × 428.6 = 21.9 MW.
Next, proceeding to step 11, α _aft and f _{op_aft} are recalculated by 2 of the following equation 5 and 2 of equation 4,

As a result, f _{op_aft} = max [13.7, 1.9830]

Becomes 557.
[Calculation of fire duration after dropping out]
Further, the duration time t _{f_fallout} of the indoor fire after the netted glass is dropped is calculated based on Equation 10.

Since q _{b_aft} after dropping the netted glass is 21.9 _MW from the above formula _3-2 of the notification verification method,
t _{f_fallout} = 74909 / 21.9 / 60 = 56.9 minutes.

In step 12, the fire duration t _f [min] taking into account the loss of netted glass is calculated based on Equation 6-2 below.

t _f = t _fallout + t _{f_fallout} = 89.6 (minutes)
On the other hand, the fire duration that does not take into account the loss of netted glass,
t _f = 99203 / 12.386 / 60 = 133.5 (minutes).

With reference to FIG. 4, the indoor fire duration time of a present Example is demonstrated.
In the fireproof design of buildings using netted glass, if the netted glass does not fall off in the event of a fire, the fire temperature rise coefficient α is a smaller value than the actual fire,
The temperature rise becomes gradual as shown by the lower right curve of the lower fine line in FIG. 4, and the fire duration exceeds 130 minutes as shown by the vertical line of the right thin broken line.
On the other hand, if the netted glass is dropped in the event of a fire, the fire temperature rise coefficient α _aft after dropping will be a larger value than if it was not dropped, and the temperature rise curve is as shown in FIG. It becomes abrupt as shown by the upper thick line.
As a result, the fire duration is greatly reduced by 90 minutes, as indicated by the bold broken line on the left.

[Calculation of equivalent fire duration]
By the way, in order to apply the member approved by the Minister as the fireproof structure presented in the fireproof performance verification method, the formula for correcting the fireproof time confirmed in the fireproof test by the standard heating curve to the room fire is converted as follows: become.
t _{f_ef} = t _f × (α / 460) ^3/2
t _{f_ef} : Fire duration by the standard heating curve (equivalent fire duration) [min]
When the above formula is transformed into a formula that takes into account the dropping of the meshed glass, the following formula is obtained.
t _{f_ef} = t _fallout × (α / 460) ^3/2 + t _{f_fallout} × (α _aft / 460) ^3/2
As a result of performing the above conversion in the procedure 14, t _{f_ef} = 108.5 minutes when dropping the netted glass is considered, and t _{f_ef} = 133.5 minutes when not considering.
In the case where the dropout of the meshed glass is not taken into consideration, a member having a fire resistance performance of 2 hours cannot be used.

Next, in the procedure 15, even when considering the omission of the meshed glass, if t _f exceeds t _fr , it is necessary to adopt a member to which a design change or fire resistance is added.
For this reason, go back to step 1, change the design of the floor area, ceiling height, opening, etc. of the fire room, adopt a member with changed fire resistance, and the amount of combustible material according to the interior material and application Recalculate each procedure again, etc., and repeat until the fire resistance time of each member in the room exceeds the fire duration.
Here, Table 1 shows the fireproof structure corresponding to the equivalent fire duration time.

In this embodiment, as shown in FIG. 4, after the netted glass is dropped, the opening area is increased, the fire temperature increase coefficient α is increased from 460 to 557, and the fire chamber temperature increase rate is increased. Fire duration is shortened.
As mentioned above, although the Example of the mesh-filled glass was described, it is possible to show the same effect also about heat-resistant tempered glass.
Therefore, it is possible to calculate the fire duration time in accordance with the actual situation by taking into account the opening formation due to the dropout of the fire prevention equipment using the glass containing the glass or the heat-resistant tempered glass at the time of fire. Therefore, it becomes possible to shorten the fireproof time of the target room, and it is possible to reduce the fireproof coating and reduce the cost of the floor slab.
Specifically, in the example in the dwelling unit of the apartment house shown in FIG. 5, according to the notification verification method, the fire duration time is calculated to be 133.5 minutes, and it must be fireproof for 3 hours. In the embodiment, it is shortened to 108.5 minutes, and it may be fireproof for 2 hours.

FIG. 1 is a calculation flow chart when the notification verification method is used. FIG. 2 is a diagram showing the temperature of the fire room when the netted glass is not dropped in this example. FIG. 3 is a diagram showing the fire chamber temperature and the fire duration time of the room where α is 460, and the time when the meshed glass falls off is shown by a circle. FIG. 4 is a diagram showing that the fire duration time is different based on the difference between when the netted glass is dropped and when it is not taken into consideration. FIG. 5 is a plan view of a room of an apartment house embodying the present invention.

Claims (3)

When the opening of the outer wall of a specific fire room has fire prevention equipment using glass, calculate the time from the occurrence of the fire until the fire prevention equipment using glass falls off for the fire room, and then After calculating the duration of the indoor fire after the glass fire prevention equipment is dropped, the time from the occurrence of the fire until the fire prevention equipment using the glass drops and the indoor fire after the fire prevention equipment using the glass is dropped. The total indoor fire duration time of the specific fire room is calculated by adding the duration time, while the fire resistance time of the member facing the specific fire room is calculated, and the total indoor fire duration time is calculated. A fire-resistant design method for a building, characterized by changing and adapting the conditions of the room such as the member, fire-resistant coating thickness, outer wall opening area, interior material, etc. so as to be less than the retained fire-resistant time. Set various conditions such as floor area, ceiling height, interior material, amount of combustible material according to application, opening area of outer wall of specific fire room, calculate total calorific value of combustible material of the specific fire room, Calculate the calorific value per unit time of the combustible material and the duration of the indoor fire, calculate the retained fire resistance time of the member facing the specific fire room, and calculate the retained fire resistance of the indoor fire duration time For all the fire chambers of the building, changing and adapting the room conditions such as members, fireproof coating thickness, outer wall opening area, interior materials etc. In the fire-resistant design method of a building that changes and adapts the conditions of the room such as the member, the fire-resistant coating thickness, the opening area of the outer wall, and the interior material so that the indoor fire duration is equal to or less than the calculated retained fire-resistant time, The opening on the outer wall of a specific fire room is glassy The fire temperature rise coefficient is calculated for the fire room, and the time from the occurrence of the fire until the fire protection equipment using the glass falls off is used. Recalculate the opening area of the outer wall from which the fire prevention equipment had fallen off, and included it in the effective opening factor, and the amount of heat generated per unit time of the remaining combustible material when the fire prevention equipment using the glass was dropped and the fire prevention using the glass After calculating the duration of the indoor fire after the equipment is dropped, add the time from the occurrence of the fire until the fire protection equipment using the glass drops and the duration of the indoor fire after the fire protection equipment using the glass is dropped And calculating the total indoor fire duration of the specific fire room, while calculating the possessed fire resistance time of the member facing the specific fire chamber, the total indoor fire duration time is less than the calculated retained fire time And Yo member, refractory design method of a building, characterized in that the refractory coating thickness, open area of the outer wall, is adapted to change the conditions of the chamber, such as interior materials. The building which the room which has the opening part provided with the fire prevention equipment which used the glass for the outer wall was fire-proofed based on the said fire-proof design method described in any one of Claim 1 thru | or 2.