KR102059475B1 - Method of assessing smoke risk on fire - Google Patents

Abstract

The present invention relates to a method for assessing the risk of smoke when fire occurs. The method for assessing the risk of smoke when fire occurs comprises a step of determining the risk of smoke generated from combustible materials burned when fire occurs by at least one evaluation index selected from a smoke performance index (SPI), a smoke growth index (SGI), and smoke intensity (SI).

Description

Method of assessing smoke risk on fire}

The present invention relates to a method of evaluating the risk of smoke in a fire, and more particularly, to the smoke risk caused by the combustion gas generation of flammable materials in a fire, the smoke performance index (SPI), the smoke growth index (SGI) and the smoke intensity (SI). It relates to a method of evaluating by one or more evaluation indicators selected from.

Conventional building materials and durable materials have a great damage to human accidents due to the generation of toxic gases harmful to the human body in the event of fire and damage to smoke. Although various flame retardants have been used due to these problems, when the lead and flame retardants are applied to building materials and durable materials, there is a problem that the applied component material is desorbed, so that the durability is poor, and thermal stability effects are not expected.

With the recent increase in buildings using wood and the use of polymer materials in high-tech industries such as automobiles, ships, and electrical appliances, the development of flame-retardant materials considering safety in the event of a fire has become an important issue. The need for non-halogenation is continuously increasing in consideration of the anti-flame and anti-flame properties, and there is an urgent need to develop an eco-friendly and versatile thermal stabilizer that can replace it.

As an organic material, wood is very sensitive to fire and therefore has a high risk in terms of fire safety. Improved flame retardancy is becoming increasingly important to comply with the safety requirements of wood products, and the treatment of wood with chemicals is rapidly increasing to improve the physical, mechanical, biological and fire properties of wood.

Flame retardant treatment of wood has been studied to use a phosphorus compound, a nitrogen compound, a boron compound, a silicon compound, etc. alone or in combination (Non-Patent Documents 1 to 4), the recent interest in flame retardant is simply flame retardant In addition to the effects, attention has been focused on satisfying all of the low harmfulness, low smoke, low corrosion and heat resistance.

However, it is known that some of the effective flame retardants are toxic, and the halogen-based compound is defined as an environmental regulatory substance, thereby expanding the scope of prohibition of use. Most of the non-thermal risk of chemicals in fires is due to smoke, toxicity, corrosion and odors. Fire damage to non-thermal risk factors has been reported to be due to inhalation of oxygen and smoke and toxic gases rather than about 75 to 80% of the victims directly exposed to the flame (Non-Patent Document 5).

On the other hand, conventional smoke measurement and expression methods include smoke production rate (SPR) (Non Patent Literature 6), total smoke rate (TSR) (Non Patent Literature 6), and non-damping area (smoke extinction area). , SEA (Non-Patent Document 6), smoke factor (smoke facor, SF) (Non-Patent Document 7), and the like have been used as a measure of smoke generation.

However, such a conventional smoke generation measure and expression is a limited method, considering only one factor related to the amount of generation over time, and considering the correlation with other factors such as the ignition time and the maximum smoke occurrence time, which are a measure of the risk in a fire. As it only evaluates the fractional aspects of smoke such as considering only the value within 5 minutes, it is still insufficient to implement the risk and quantitative evaluation of smoke generation, which can increase the reliability of smoke risk assessment. There was no problem.

In addition, the patent document discloses a fire risk evaluation system, a fire risk evaluation method (Patent Document 1), a fire prevention method of a wooden building (Patent Document 2), etc., which simulates individual evacuation behavior and casualties in a construction structure fire. The technical configuration is different from the present invention regarding the method for evaluating the risk of smoke in a fire.

Republic of Korea Patent Publication No. 10-2011-0133254 Republic of Korea Patent Publication No. 10-1142849

 Constr. Build. Mater. 170, 193-199 (2018)  Constr. Build. Mater. 24, 2633-2637 (2010)  Constr. Build. Mater. 72, 1-6, (2014)  Fire Saf. J. 44, 497-503 (2009)  R. H. White and M. A. Dietenberger, Wood handbook: Wood as an engineering material, Ch. 17: Fire safety, Forest Product Laboratory U.S.D.A., Forest Service Madison, Wisconsin, USA (1999)  ISO 5660-1, Reaction-to-fire tests-heat release, smoke production and mass loss rate-Part 1: heat release rate (cone calorimeter method) and smoke production rate (dynamic measurement), Genever, Switzerland (2015)  A. W. Coaker, M. M. Hirschler, S. Shakir, C. L. Shoemaker, Flammability testing of new vinyl compounds with low flammability and low smoke release in cables, US Army Communications-Electronics Command, Cherry Hill, USA 643-654 (2006)

In order to solve the problems of the prior art as described above, the present inventors can effectively evaluate the fire risk of flammables, while solving the disadvantages of the conventional smoke risk assessment and researching a method that can compensate for the disadvantages of the expression. The present invention has been completed by knowing that one of the key factors is the quantitative and weighted assessment of the hazards of combustion gases.

Accordingly, it is an object of the present invention to provide logical and reasonable valuation indices and quantitative valuation indicators for enhancing the reliability of smoke risk assessment.

The present invention, in order to achieve the above object, the smoke performance index (SPI) of the following equation (1), the smoke growth index (SGI) of the following equation (2) and the smoke of the following equation (3) It provides a method of evaluating the risk of smoke in a fire, comprising the step of determining the smoke risk in a fire by one or more evaluation indicators selected from the smoke intensity (SI).

[Equation 1]

(In Equation 1, TTI is the ignition time of the test piece treated with a flame retardant material, SPR _peak represents the peak value of the smoke generation rate.)

[Equation 2]

(In Equation 2, SPR _peak represents the peak value of the smoke generation rate, Time to SPR _peak represents the time to reach the SPR _peak .)

[Equation 3]

(In Equation 3, MARHE represents maximum average rate of heat emission, and SEA represents specific extinction area.)

In addition, the present invention, the smoke performance index (SPI) value of the equation 1 increases the smoke safety, and the smaller the smoke performance index (SPI) value is determined that the smoke safety is reduced, the smoke risk assessment in the fire Provide a method.

This correlates with the fire performance index (FPI) of wood and the time of flashover, so as the FPI value increases, the fire stability increases. It is understood that smoke safety also increases.

In addition, the present invention is the smoke growth index (SGI) value of the equation 2 is higher smoke risk, and the smaller the smoke growth index (SGI) value is determined that the smoke risk is lower, the smoke risk evaluation method in the fire To provide.

It is expected that the larger the SGI value, the shorter the time to reach the SPR _peak , and the greater the smoke risk of the material. This is in line with the increased risk of fire.

In addition, the present invention provides a method for evaluating the risk of smoke in a fire, which determines that the higher the smoke intensity (SI) value of Equation 3, the higher the smoke risk, and the lower the smoke intensity (SI) value, the lower the smoke risk. do.

The SI can be used to estimate the potential amount of smoke that can be generated at full scale fire conditions, which are data that can predict the propensity of smoke to occur in a real fire test.

The present invention also provides a method for evaluating the risk of smoke in a fire, wherein the flame retardant includes a boron compound.

The present invention also provides a method for evaluating the risk of smoke in a fire, wherein the boron compound comprises at least one member selected from the group consisting of boric acid and ammonium pentaborate.

The present invention also provides a method for evaluating the risk of smoke in a fire, wherein the test piece is a flammable material.

The present invention also provides a method for evaluating the risk of smoke in a fire, wherein the combustible material comprises cypress wood.

In the present invention, after applying a flammable material such as boric acid and ammonium pentaborate to the cypress wood that is mainly used as interior materials of the building, by using a cone calorimeter (Cone calorimeter) by the combustion characteristics of the external radiation heat source associated with harmful gases and smoke Indexes were measured and new evaluation indicators such as smoke performance index (SPI), smoke growth index (SGI), and smoke intensity (SI) were developed during the initial fire of flame-retardant wood. Predict fire risks.

Therefore, the present invention can be commercialized as a method for evaluating the risk of smoke generation of all combustible materials such as wood, plastic, and fiber during a fire.

Figure 1 shows a cone calorimeter equipment.
Figure 2 shows the oxygen consumption curve of the cypress sample treated with 15% by weight solution of the boron compound.
Figure 3 shows the smoke generation rate curve of the cypress sample treated with 15% by weight solution of the boron compound.

Hereinafter, the present invention will be described in detail through examples. However, these examples are only for illustrating the present invention in detail, and the scope of the present invention is not limited by these examples.

Example 1 Preparation of Wood Test Piece

The wood is a cypress, which was naturally dried for two years after purchasing commercial building materials for the market. As a chemical additive, boric acid (purity 99.5%) was purchased from Kanto Chemical, and ammonium pentaborate (99% purity) was used from Sigma Aldrich. All reagents were purchased with a special reagent and used without purification.

Boric acid and ammonium pentate were dissolved in distilled water, respectively, to make 15 wt% aqueous solution (BA15, APB15). Each 15 wt% solution was mixed in a ratio of 1: 1 to prepare a mixed solution (BA15 / APB15).

After brushing one side of the test piece with an aqueous solution, and then naturally dried at room temperature for 6 hours, and then again carried out twice in the same manner to prepare a wooden test piece.

At this time, all the solution was used after melting by heating, the specimen was used to compare the same method after drying the same wood and then brushed with distilled water.

Example 2 Cone Calorimeter Test

Combustion characteristics tests were performed under a heat flux of 50 kW / m ² using a dual cone calorimeter (Fire Testing Technology) by the method of ISO 5660-1.

The thickness of the used test piece was 10 mm and the size was 100 mm x 100 mm. The test conditions were maintained at 23 ± 2 ° C and 50 ± 5% relative humidity until the constant volume was reached. Wrapped.

Prior to the test, the calorific value of the cone heater was calibrated so that the oxygen concentration within the set point was within ± 2% and the oxygen analyzer was 20.95 ± 0.01%, and the discharge flow rate was set to 0.024 ± 0.002 m ³ / s.

The test piece was controlled by using a low density glass fiber as a heat insulator and insulated with a low density high density ceramic plate material to reduce heat loss to the specimen holder. The specimen holder was placed in the horizontal direction.

The air flow rate into the analyzer was kept constant at 3.5 L / min, and the specimens were exposed to air to allow for sufficient combustion.

The bulk density of the specimen was calculated by measuring volume and weight before testing. The combustion test was terminated after 30 minutes and gave an additional 2 minutes of data collection time. Three experimental values were averaged and used as data.

After combustion, the indexes related to smoke and harmful gas, which are necessary factors for fire analysis, were obtained. 1 shows a photograph of the cone calorimeter equipment.

Most combustible materials release heat by the oxygen consumed during combustion _. Figure 2 shows the oxygen consumption rate (O ₂ consumption rate) over time.

As shown in Table 3 and Figure 2, the second maximum oxygen consumption rate of the test piece treated with the boron compound was 0.1016 ~ 0.1227 g / s, 6.8 ~ 22.8% less than the blank test piece. This means that the oxygen acts on the boron compound to reduce the mass, which means less oxygen consumption when the combustion is unfavorable.

Boric acid and ammonium pentaborate leave free boron oxide (B ₂ O ₃ ) after dehydration during pyrolysis. It is understood that this glass phase blocks the diffusion of oxygen and heat and reduces the oxygen consumption rate because it blocks the diffusion of combustible decomposition products from or to the flame shear.

Example 3 Moisture Content Measurement

The moisture content is measured by drying a certain amount of sample in a dryer at 105 ℃ for a long time until the weight of the sample no longer changes in weight at intervals of 4 hours, and the moisture content measurement results calculated using Equation 4 below Table 1 Shown in

In Equation 4, Wm is the weight of the test piece to determine the moisture content, Wd means the absolute dry weight after drying.

The moisture content of naturally dried cypress was 7.3% by weight. In addition, the initial weight of the cypress test piece treated with a chemical additive is 39.61 g, 39.05 for the solution (BA15 / APB15), 3 mixed with BA15, 1 , APB15, 2 , 15% by weight solution, as shown in Table 1 above. g, 40.15 g.

Example 4 Smoke Generation (1): Smoke Performance Index (SPI)

The smoke production rate (SPR) of specimens treated with boron compounds or untreated specimens increases with combustion time.

As shown in FIG. 3, the first peak reached sharply initially. Smoke during this period consists of gas, water vapor and volatile wood extracts from aerosols and degraded hemicellulose.

The second peak was reached by the reburning of char during the flame period. In the second SPR, the additive-treated wood specimens were 19.9 to 27.7% less than the test specimens. This is expected to generate a second peak due to combustion suppression.

Between the two peaks, the rate of smoke generation and the concentration of smoke decrease, which is believed to be due to the carbonization of wood. Hagen et al. (Fire Saf. J. 44, 1053-1069 (2009)) report that smoke generation and smoke concentration increase with increasing mass loss rate if the heating temperature rises during burning of wood. Therefore, it can be understood that the rate of mass reduction during the carbonization process is lowered, thereby reducing smoke generation and smoke concentration.

As shown in Table 2 below, the specimens ignited after 6 seconds at a heat flux of 50 kW / m ² . The ignition time (TTI) of the test piece treated with boron compound was delayed by 2 to 7 seconds than the test specimen, and the ignition time of BA15 / APB15 was 13 seconds, which was 116.7% longer than the test specimen.

The data used, the maximum of the initial peak of the TTI and heat release rate, characterize the fire hazard of the material. It is also expected that the risk of smoke will be the same. Therefore, in this embodiment, the smoke performance index (SPI) was developed to predict the smoke safety of the boron compound. SPI is defined as the TTI divided by the SPR _peak .

This correlates with the fire performance index (FPI) of wood and the time of flashover, so as the FPI value increases, the fire stability increases. It is understood that smoke safety also increases.

The equation for obtaining a smoke performance index (SPI) is shown in Equation 1 below.

[Equation 1]

(In Equation 1, TTI is the ignition time of the test piece treated with a combustible material, SPR _peak represents the peak value of the smoke generation rate.)

In this example, the SPI of the test specimen was the lowest SPI value as shown in Table 3 below, while the SPI of the boron compound was increased by 1.37 to 2.68 times than the test specimen. It is understood that the smoke risk of wood treated with boron compounds may be lowered.

Example 5 Smoke Generation (2): Smoke Growth Index (SGI)

A smoke growth index (SGI) was developed to predict smoke risks. SGI is defined by dividing the SPR _peak value by the time to reach the SPR _peak , that is, Equation 2 below.

[Equation 2]

(In Equation 2, SPR _peak represents the peak value of the smoke generation rate, Time to SPR _peak represents the time to reach the SPR _peak .)

The larger the SGI value, the shorter the time to reach the SPR _peak and the greater the smoke risk of the material. This is in line with the increased risk of fire.

At a heat flux of 50 kW / m ² , the treatment of the boron compound was 29.4-52.9% less than the test specimens, as shown in FIG. 3 and Table 4 below. It is understood that the smoke risk of wood treated with boron compounds may be lowered.

Therefore, it was found that the greater the SGI value of the cypress wood, the higher the fire risk and the lower the fire stability.

The SPI and SGI are values obtained by using the measured data, and can be viewed as a comprehensive evaluation for determining the smoke safety of materials in a cone calorimeter experiment.

Example 6 Smoke Generation (3): Smoke Strength (SI)

The specific extinction area (SEA) is the smoke production index (SPR) divided by the mass reduction rate (MLR), which has been studied in smoke-related indexes.

As shown in Table 2, when treated with a boron compound was reduced 6.0 ~ 47.7% than the blank test piece. This is considered to have a low fuming action. However, since smoke generation depends on the rise of the flame temperature during the combustion process, the total calorific value of the rise in temperature should be considered as a complementary method.

Therefore, smoke intensity (SI) is proposed as an index for predicting the risk of smoke / fire.

The SI can be used to estimate the potential amount of smoke that can be generated at full scale fire conditions. SI is a factor calculated by multiplying the maximum average heat rate (MARHE) and specific extinction are (SEA) obtained during the initial emission characteristics test of ISO 5660-1. Data that can predict the propensity of smoke to occur in the test.

The equation for obtaining SI is as shown in Equation 3 below.

[Equation 3]

(In Equation 3, MARHE represents maximum average rate of heat emission, and SEA represents specific extinction area.)

Average rate of heat emission (ARHE) is defined as total heat release rate divided by time, and the maximum value MARHE is considered to be a good measure of the tendency of fire to occur in real situations.

The SI obtained by multiplying the MARHE and the SEA shown in Table 5 shows the highest test specimen of 14.239 MW / kg, which is expected to have the highest smoke risk in the real fire test. It is anticipated that the risk of smoke and fire will be lowered by ~ 3.92 times.

As shown in Table 2, the second maximum oxygen consumption rate of the test piece treated with the boron compound was 0.1016 to 0.1227 g / s, 6.8 ~ 22.8% less than the blank test piece. This means that the oxygen acts on the boron compound to reduce the mass, which means less oxygen consumption when the combustion is unfavorable.

The maximum oxygen deficiency concentration of the test piece treated with the boron compound additive was 20.371 ~ 20.394%, which was relatively high. This is no particular differentiation compared to untreated specimens, which is much higher than 15%, which can be fatal to humans, resulting in very low risk.

Although described with reference to the preferred embodiment of the present invention as described above, those skilled in the art without departing from the spirit and scope of the present invention described in the claims below It will be understood that various modifications and variations can be made to the invention.

Claims (8)

A method of evaluating the risk of smoke in a fire performed by a computer system,
Determination of the risk of smoke in a fire by one or more evaluation indicators selected from the smoke performance index (SPI), the smoke growth index (SGI), and the smoke intensity (SI), Evaluating the risk of smoke in a fire.
[Equation 1]

(In Equation 1, TTI is the ignition time of the test piece treated with a flame retardant material, SPR _peak represents the peak value of the smoke generation rate.)
[Equation 2]

(In Equation 2, SPR _peak represents the peak value of the smoke generation rate, Time to SPR _peak represents the time to reach the SPR _peak .)
[Equation 3]

(In Equation 3, MARHE represents the maximum average thermal emissivity and SEA represents the specific attenuation area.) The fire of claim 1, wherein the smoke safety index increases as the SPI value of Equation 1 increases, and the smoke safety decreases as the SPI value decreases. How to assess city smoke risks. The method of claim 1, wherein the larger the smoke growth index (SGI) value of Equation 2, the higher the risk of smoke, and the smaller the smoke growth index (SGI) value, the lower the smoke risk. How to assess the risk of smoke. The risk of smoke in a fire according to claim 1, wherein the greater the smoke intensity (SI) in Equation 3, the higher the smoke risk, and the smaller the smoke intensity (SI) value, the lower the smoke risk. Method of evaluation. The method of claim 1, wherein the flame retardant comprises a boron compound. The method of claim 5, wherein the boron compound comprises at least one member selected from the group consisting of boric acid and ammonium pentaborate. The method according to claim 1, wherein the test piece is a combustible material. 8. A method according to claim 7, wherein the combustible material comprises cypress wood.

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