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GB/T 31593.5-2015: Fire safety engineering -- Part 5: Requirements governing algebraic equations for fire plumes
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Fire safety engineering -- Part 5: Requirements governing algebraic equations for fire plumes
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Basic data | Standard ID | GB/T 31593.5-2015 (GB/T31593.5-2015) | | Description (Translated English) | Fire safety engineering -- Part 5: Requirements governing algebraic equations for fire plumes | | Sector / Industry | National Standard (Recommended) | | Classification of Chinese Standard | C80 | | Classification of International Standard | 13.220.01 | | Word Count Estimation | 19,122 | | Date of Issue | 2015-06-02 | | Date of Implementation | 2015-08-01 | | Quoted Standard | GB/T 5907.1; GB/T 5907.2; GB/T 5907.3; GB/T 5907.4; GB/T 5907.5; GB/T 31593.1 | | Adopted Standard | ISO 16734-2006, MOD | | Regulation (derived from) | National Standard Announcement 2015 No.19 | | Issuing agency(ies) | General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China, Standardization Administration of the People's Republic of China | | Summary | This Standard specifies the fire plume characteristic value calculation method requires the application of the formula, provides the application with the fire plume formulas related to the following general requirements: Description a) physical phenomena; b) calculations; limitations c) Calculation Formula; Input Parameter d) calculation formula; e) the scope of the calculation formula. This Standard applies to fire performance computing construction engineering design and evaluation of the fire plume. | GB/T 31593.5-2015: Fire safety engineering -- Part 5: Requirements governing algebraic equations for fire plumes
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Fire safety engineering Part 5. Requirements governing algebraic equations for fire plumes
ICS 13.220.01
C80
National Standards of People's Republic of China
Fire Safety Engineering
Part 5. Calculate the requirements of the fire plume
(ISO 16734.2006, MOD)
Issued on. 2015-06-02
2015-08-01 implementation
Administration of Quality Supervision, Inspection and Quarantine of People's Republic of China
Standardization Administration of China released
Foreword
GB/T 31593 "Fire Safety Engineering" is divided into nine sections.
--- Part 1. Calculation of the assessment, verification and validation;
--- Part 2. Type the required data and information;
--- Part 3. Fire Risk Assessment Guidelines;
--- Part 4. Setting fire scene and setting selection fire;
--- Part 5. Calculation of fire plume requirements;
--- Part 6. Calculation of the smoke layer requirements;
--- Part 7. Calculation ceiling jet requirements;
--- Part 8. Calculation of the opening airflow requirements;
--- Part 9. Evacuation Evaluation Guide.
This section GB/T Part of 531,593.
This section drafted in accordance with GB/T 1.1-2009 given rules.
This section uses redrafted Law Amendment uses ISO 16734.2006 "Fire Safety Engineering formulas fire plume control requirements."
This part of ISO 16734.2006, compared with more adjustment in the structure, listed in Appendix A of this part of the ISO 16734.2006
The reg number control list.
This part of ISO 16734.2006 is a technical difference between the normative references have been adjusted technical differences, in order to adapt
Our technical conditions, adjust the focus reflected in Chapter 2, "Normative references", the specific adjustments are as follows.
--- With GB/T 5907 (all parts) in place of the ISO 13943 (see Chapter 3);
--- With a modified adoption of international standards of GB/T 31593.1 replaces ISO /T R13387-3 (see 5.1,7.3).
This section also made the following editorial changes.
--- Deleted international standards foreword, preface redrafted;
--- Modify the introduction of international standards, as a part of this introduction;
--- The International Standard Information Appendix A of this Part choreography informative Appendix B, the international standards in the appendix of terms and definitions
This section is adjusted to the body of Chapter 3, delete the definition of common terminology section, adjust the formatting symbols;
--- International standard "this International Standard" be replaced by "GB/T 31593 this part" or "this part";
--- Certain punctuation modified to comply with international standards of the Chinese habit of punctuation.
This section presents the People's Republic of China Ministry of Public Security.
This part of the National Standardization Technical Committee on Fire Building Fire Safety Engineering at the Technical Committee (SAC/TC113/SC13)
Centralized.
This section is drafted. Tianjin Fire Research Institute of Ministry of Public Security, Ministry of Public Security of Sichuan Fire Research Institute, University of Science and Technology of China, China Construction Division
Graduate School.
The main drafters of this section. Han Weiping, Zheng Wei, Guo Song, Yao easing, Bishao Ying, Chi will be strong, strong Kan, Liu Zhijian, Zhang Yuxian, Lu Shou Hong,
Wu Chung day, Charles Zhang, Deng Songhua.
Introduction
The formula discussed in this section apply to setting fire scenario quantitative analysis, professionals without the need for complicated numerical calculation, it
Based on these equations can quickly determine whether the need to adjust the preliminary design of fire safety and how to adjust to meet the anticipated performance metrics to
begging. These formulas have been applied in the following areas.
--- Determination of fire plume convection, including convection and radiation;
--- Prediction ceiling jets in order to adjust the response time of the detector;
--- Calculate vent exhaust capacity;
--- Analysis of fire hazards and other flue gas transmission and flashover separated space.
For the fire plume, the formula can be used to estimate the size of the flame, to calculate the safety distance between the fire source and the target to be protected. fire
Plume formula can also be used to estimate the flame propagation rate storing combustible materials within the construction works, including horizontal and vertical transmission.
Appendix B of this part of the quasi-steady and axisymmetric thermal plume formula application examples.
GB/T 31593.1 provides for the use of mathematical formulas to calculate the general requirements fire dynamics, this section is with these general requirements
Body practices. If the consequences of the development of the mathematical model and the resulting fire use, the formula discussed in this section may be used for its
Conclusion verified.
This section for professionals engaged in fire safety engineering design personnel including fire, fire rescue personnel, fire standards
Makers, insurers, fire safety officers, standard user needs to fully understand the calculation method contained in this section are given in the relevant parameters
Meaning and application conditions.
Fire Safety Engineering
Part 5. Calculate the requirements of the fire plume
1 Scope
GB/T 31593 provisions of this part of the application methods of fire plume characteristic value calculation formula requirements and provide a formula and fire plume
Applications related the following general requirements.
a) description of physical phenomena;
b) calculations;
c) The formula limitations;
d) calculation of the input parameters of the formula;
e) the scope of the calculation formula.
This section applies to calculate performance-based construction engineering design and evaluation of the fire plume.
2 Normative references
The following documents for the application of this document is essential. For dated references, only the dated version suitable for use herein
Member. For undated references, the latest edition (including any amendments) applies to this document.
GB/T 5907 (all parts) Fire Vocabulary
GB/T 31593.1 Fire safety engineering - Part 1. assessment of the calculation method, verification and validation (GB/T 31593.1-2015,
ISO 16730.2008, MOD)
3 Terms and Definitions
GB/T 5907 defined by the following terms and definitions apply to this document.
3.1
Axisymmetric axisymmetric
< Fire plume> average and average kinetic movement characteristic parameters (such as the average temperature) along a vertical center line of symmetry.
3.2
Fire plume fireplume
Turbulent flow upwardly by the buoyancy generated by combustion is formed, typically includes a lower combustion zone.
3.3
Flame flame
Fire plume emitting area streams.
3.4
Jet flame jetflame
Momentum domination without buoyancy force dominated by the flames.
3.5
Quasi-steady-state quasi-steadystate
Other changes in the rate of heat release caused by the change in the flow field can be apparent immediately a hypothetical state.
3.6
Virtual point source virtualorigin
Virtual plume of fire ignition sources.
Note. For flammable liquid pool fire, if the diameter is less than or equal to 10m, the position of the virtual point source above the burning fuel surface may, if the diameter of
10m ~ 20m (see B.9), then the location of the virtual point source could fuel burning below the surface.
4 description of physical phenomena
4.1 Fire Fire plume sources of heat is a complex physical phenomena, it may be highly transient state, it may be close to steady state. Fire plume
By the regional area and away from the fire source close to the fire of two parts, the area near the fire there is usually flaming (except for smoldering fires),
Away from the fire source area does not exist flaming, controlled only by the buoyancy of the upward flow of hot gas turbulence. Fire plume form by a variety of ring
Significant impact on environmental factors, such as the ignition source (either burning or smoldering flame) of combustion properties and its distribution, restricted boundary type,
Degree limit or affect the amount of air, windy conditions or fire partition air movement and so on. For liquid hydrocarbons in the open, quiet
Only (no wind) under combustion conditions, due to the impact of these environmental factors is negligible, so the use of mathematical formulas to describe the fire plume ask
Subject to simplified.
Chart 4.2 should be used to describe the type of ignition source, flow boundary conditions (including symmetric boundary) as well as other factors applicable to the scenario analysis.
4.3 should clearly identify the fire plume characteristic parameters and their scope needs to be calculated, including when appropriate deduced from the correlation calculation amount out special
Sign parameters (such as those based energy and mass conservation law derived flue gas concentration and temperature relationship between values) and transmitted to the other
Radiant heat away from the fire plume position related characteristic parameters.
4.4 should clearly identify the specific formulas applicable fire plume area (if there is flame, to what extent affected by the fire source).
4.5 different formula describes the different fire plume characteristics (see 4.3) or for different fire plume area (see 4.4), when there are multiple
The same method can be used to calculate a given amount of value, shall set forth the results regardless of the calculation method chosen.
5 calculations
5.1 General requirements calculations, see GB/T 31593.1.
5.2 calculating step by a series of formulas statements.
5.3 detailed description of each formula should be expressed in terms of independence, its output should contain a formula, and the formula that interpretative
Ming and qualification.
5.4 should be clearly defined formula each variable, given the applicable SI units; preferred amount is calculated relationship.
5.5 shall, as appropriate, by reference recognized manuals, scientific literature or scientific evidence given by the formula derived by other methods.
5.6 Application of calculation formula should be given examples demonstrate how to use the input parameters and the specific calculation process in line with Chapter 4 requirements.
6 Limitations of formula
6.1 should be given direct application of formulas calculate the output parameters of the quantitative restrictions, and in accordance with Chapter 4 describes the scene requirements.
6.2 should use the formula given in the more general calculation method precautions, including other relationships inspection and calculation methods used in
Style consistency and calculation scheme employed. For example, in the area of \u200b\u200bthe fire plume and ceiling jet is connected to the regional model calculation, so
Results with fire plume formula may be obtained with the use of ceiling jet calculation formula was different, resulting in an error.
7 calculation formula input parameters
7.1 should clearly identify the formula input parameters, such as heat release rate or geometry.
Building works fire under various ambient air and fuel conditions.
D = -1.02 15.6N
1/5 (B.1)
N =
cpTa
gρ2a ΔHc/s () 3
êê
úú
Q̇2
D5
(B.2)
Q̇ = ṁfχaΔHc (B.3)
B.3.1.2 under normal atmospheric conditions, i.e., g = 9.81m · s-2, cp = 1.00kJ (kg · K) -1, ρa = 1.2kg · m-3, Ta = 293K to
And ΔHc
s = 3000kJ
· Kg-1 (refers to the average number of common fuels, see Ref. [38] The table 3-4.19, 3-4.20 and table
3-4.21 table following this Appendix relates to the value of empathy), the average flame height L by the formula (B.4) is given (see reference [9]).
L = -1.02D 0.235̇Q2/5 (B.4)
B.3.2 height above the base of the fire source virtual point source
B.3.2.1 virtual point source height dimensionless relationship zV/D, represented by formula (B.5) ~ formula (B.8) is given (see reference [10]) for more
Construction works within the species under fire air environment and fuel conditions.
zV
D = -1.02 15.6XY
() Q̇
(B.5)
X =
cpTa
gρ2a ΔHc/s () 3
êê
úú
(B.6)
Y = 0.158 cpρa () 4
/ 5T3/5a g2/5 [] -1/2α2/5
T1/20L
ΔT3/50L
(B.7)
T0L = ΔT0L Ta (B.8)
B.3.2.2 under normal atmospheric conditions, i.e., g = 9.81m · s-2, cp = 1.00kJ (kg · K) -1, ρa = 1.2kg · m-3, Ta = 293K,
α = 0.7, ΔT0L = 500K and
ΔHc
s = 3000kJ
· Kg-1, the relationship between the virtual point source height zV and Q̇, D by the formula (B.9) is given, the public
Changes in the type of fuel type is not sensitive (see reference [10]).
zV = -1.02D 0.083̇Q2
/ 5 (B.9)
B.3.2.3 under normal atmospheric conditions, i.e., g = 9.81m · s-2, cp = 1.00kJ (kg · K) -1, ρa = 1.2kg · m-3, Ta = 293K,
ΔT0L = 500K and
ΔHc
s = 3000kJ
· Kg-1, and the virtual point source height zV Q̇c, L relationship given by equation (B.10) and formula (B.11),
The formula to change the type of fuel is not sensitive (see reference [10]).
zV = L-0.175̇Q2
c (B.10)
Q̇c = α̇Q (B.11)
The average temperature rise of the central axis of the flame B.3.3 above average height and position
The central axis of the average temperature rise ΔT0 dimensionless relationship B.3.3.1 flame above average height and position, by the formula (B.12) is given (cf.
See reference [42]).
ΔT0 = 9.1
Ta
gc2pρ2a
Q̇2/3c (z-zV) -5/3 (B.12)
B.3.3.2 under normal atmospheric conditions, i.e., g = 9.81m · s-2, cp = 1.00kJ (kg · K) -1, ρa = 1.2kg · m-3, and Ta =
The central axis of the average temperature rise ΔT0 293K, the average height of the flame and the position indicated by the above formula (B.13) is given (see reference [37]).
ΔT0 = 25.0̇Q2/3c (z-zV) -5/3 (B.13)
The average flame velocity B.3.4 above average height and location along the central axis of the gas
B.3.4.1 The average height of the flame and the average velocity of the gas at the above locations along the central axis of the non-dimensional relationship u0 is given by the formula (B.14)
(See reference [42]).
u0 = 3.4
cpρaTa
Q̇1/3c z-zV () -1/3 (B.14)
B.3.4.2 under normal atmospheric conditions, i.e., g = 9.81m · s-2, cp = 1.00kJ (kg · K) -1, ρa = 1.2kg · m-3, and Ta =
293K, the average height of the flame and the average velocity of the gas at the above locations along the central axis u0 by the formula (B.15) is given (see References
[37]).
u0 = 1.03̇Q1/3c (z-zV) -1/3 (B.15)
Fire flame plume characteristic radius B.3.5 above average height and position
Fire plume characteristic radius (average temperature here is equal to half of the average temperature rise of the central axis) bΔT dimensionless relationship, represented by the formula (B.16)
Given (see reference [42]).
bΔT = 0.12
T0
Ta
(Z-zV) (B.16)
Note. The gas flow rate is equal to the radius of the center axis of the fire plume half the gas flow rate at the position, the central axis than the average temperature is equal to the average temperature rise halfway fire
BΔT plume radius about 10% larger.
Fire flame plume mass flow rate B.3.6 above average height and position
B.3.6.1 flame above average height and position (z≥L) fire plume mass flow rate ṁent dimensionless relationship, given by equation (B.17)
(See reference [18]).
ṁent = 0.196
gρ2a
cpTa
Q̇1/3c z-zV () 5/3 1
2.9̇Q2/3c
g1/2cpρaTa () 2
/ 3 (z-zV) 5/3
êê
úú (B.17)
B.3.6.2 under normal atmospheric conditions, i.e., g = 9.81m · s-2, cp = 1.00kJ (kg · K) -1, ρa = 1.2kg · m-3, and Ta =
293K, fire plume mass flow rate of the flame above average height and position (z≥L) of ṁent by the formula (B.18) is given (see References
[37]).
ṁent = 0.071̇Q1/3c (z-zV) 5/3 [1 0.027̇Q2/3c (z-zV) -5/3] (B.18)
B.3.6.3 Take z = L, by the formula (B.5) ~ formula (B.8) calculated zV into equation (B.17), the average height of the fire plume of flame stream
Mass flow rate ṁent, L dimensionless relationship, by equation (B.19) is given (see reference [37]).
ṁent, L = 0.878
T0L
Ta
5/6 Ta
ΔT0L
÷ 0.647
êê
úú
Q̇c
cpTa
(B.19)
B.3.6.4 under normal atmospheric conditions, i.e. cp = 1.00kJ (kg · K) -1, Ta = 293K and ΔT0L = 500K, according to the equation (B.19),
Fire plume mass flow rate at the average height of the flame ṁent, L by equation (B.20) is given (see reference [37]).
ṁent, L = 0.0059̇Qc (B.20)
Fire plume space B.3.7 Flame average height and average temperature rise above location
Fire flame plume space at and above the average height position dimensionless relationship ΔTave average temperature rise by the formula (B.21) is given (see
Reference [37]).
ΔTave =
Q̇c
ṁentcp
(B.21)
--- Subjected to mechanical ventilation or action from the indoor natural ventilation openings.
B.5.5 Output Data
When the output parameter data appear in any of the following conditions, the formula does not apply.
--- Average temperature rise ΔT0 calculated ambient temperature is much less than before the fire broke out with increasing altitude due to temperature rise (see
B.7), as the temperature rise due to the temperature gradient between the top and bottom of the interior space of the principal;
The average temperature rise is greater than the calculated ΔT0 --- ΔT0L.
B.6 formula input parameters
B.6.1 fire heat release rate
Parameter Q̇ units of kW, which is the actual value of the heat release rate of fire under certain environmental conditions. The argument by using calorimeter
Measuring the collected product gas oxygen, carbon dioxide and carbon monoxide generation rate measurements, or other means to give. This parameter
Usually obtained from setting fire scene. Fire heat release rate and fire calorimetry other relevant information can be found
Tewarson research (see reference [38]) and research Babrauskas (see Ref. [39]).
B.6.2 convective heat release rate of the number of copies
On the exposed surface of a solid or in a pool of oil burning liquid fuel, the dimensionless parameter α (convective heat release rate of the number of copies) of
Usually in the range from 0.6 to 0.7; but for oxidizing liquid fuel or gas fuel of low molecular weight, this parameter may be a value of 0.8 or more
Big. For 3D fire, this parameter in the early stages of fire growth is far less than the aforementioned range of values, and then with the fire growth to a higher stage,
This parameter is also increased to between 0.6 to 0.7. This parameter is usually obtained from setting fire scene, other relevant information can be found Tewarson
Research (see reference [38]).
Diameter B.6.3 fire source
The unit of the parameter D m, the diameter of the circular fire source. This parameter is usually obtained from setting fire scene. For rectangular fire,
Take the same area having a diameter of As (units m2) round source of fire as its equivalent diameter D, by formula (B.22) is calculated.
D =
4As
(B.22)
B.6.4 fire plume height
Fire plume height parameter z in units of m, usually obtained from setting fire scene.
Heat of combustion units B.6.5 air quality
This parameter is expressed as ΔHc
The unit is kJ · kg-1, the specific polymer materials and other materials
ΔHc
Value from the research Tewarson
Study outcomes (see reference [35]), research Babrauskas (see Ref. [39]) and the Chemical Engineers' Handbook "(see
Reference [40]) are found. If some fuel
ΔHc
Parameter values \u200b\u200bare not available reference data, we need to experiment, using
Calorimeter measurement ΔHc, after s value is determined by elemental analysis, and then calculated.
B.6.6 valid range of input parameters
Heat release rate and ignition parameters Q̇ diameter D should be consistent with the parameters of formula (B.23) inequality conditions given requirements, according to the letter of the inequality
Information can be found in research Mccaffrey (see Ref. [30]).
0.04 <
Q̇
ρacpTa gD5
< 2 × 104 (B.23)
Valid range for the fire plume height parameter z is usually between the flame and the value of average height interior space between the top height, or
Who is among the requirements of B.7 corresponding z value of average height in the flame temperature rise in line with the average value.
Scope B.7 Formulas
Scope of this appendix may be determined using a formula based on the literature given by calculating B.4.
In order to satisfy the above formula to maintain the scope should be limited to the temperature gradient from fire surroundings. Therefore, the source of fire above the base height z
At ambient temperature (Ta) z near the base of the flame and the ambient temperature (Ta) z = 0 inequality conditions should be consistent with the requirements of the formula (B.24) given (see
Reference [37]).
Ta () z- Ta () z = 0 < 7ΔT0 (B.24)
Calculation Example B.8
B.8.1 flame height
Suppose there is a 1.8m diameter circular oil pan on fire, combustible liquid heat release rate in the oil pan to 2500kW · m-2. ring
Ambient conditions substantially normal atmospheric conditions (air pressure of 101.3kPa, air temperature of 293K), the mean flame height L (in units of m)
By equation (B.4) calculated.
L = -1.02 × 1.8 0.235 × 2500 × π × 1.82/4 () 2/5 = 5.97
Location B.8.2 virtual point source
Suppose a fire source said oil pan fire B.8.1. Since the heat release rate is known, the position zV virtual point source (in m) by the formula
(B.9) is calculated.
zV = -1.02 × 1.8 0.083 × 2500 × π × 1.82/4 () 2/5 = 0.921
The results show that the position of the virtual point source located at the base of the flame above the 0.921m height. Combined with the actual cases, that is dotted
Location of the source of the flammable liquid surface is located at a height of more than 0.921m.
The average flame temperature B.8.3 above average height and position
Suppose oil pan fire heat release rate of the convective heat B.8.1 parts α value of 0.7, above the surface of 9m highly flammable liquid
Fire plume average temperature rise at the central axis (relative to the ambient temperature) is calculated by equation (B.13) to obtain.
ΔT0 = 25 × 0.7 × 2500 × π × 1.82/4 () 2/3 × 9-0.921 () -5/3 = 208 (K)
Thus, the highest average gas temperature of about 3m in flames at an average height of more than 208 (293-273) = 228 (℃).
B.9 schematic
Quasi-steady, axisymmetric thermal plume characteristic parameters illustrated in Figure B.1, the fire plume cross-section is shown in Figure B.2.
references
[1] GB/T 6379 (all parts) Accuracy of measurement methods and results
[2] ISO/TR 13387-3.1999 Fire safety engineering - Part 3. Assessment and verification of
mathematical fire models
[3] ISO 13943.2008 Firesafety - Vocabulary
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