Fire Safety Assessment of Building Security Systems
Our design organization has completed fire load calculations and technical fire safety inspection of the facility.
Facility Fire Assessment
Combustible Load
Identification of combustible load, prediction of its behavior during ignition sources, expression of facility explosion hazard in terms of room categories according to fire safety codes.
During the work, technical fire safety inspection of the facility was conducted, studying operational features and collecting information about combustible load. The inspection aimed to determine categories of production, storage premises and outdoor installations by explosion and fire hazard.
As a result of calculations, room and outdoor object categories by explosion and fire hazard were established, necessary for developing facility fire protection. Warehouse and production room category determination calculations were performed based on fire safety codes developed according to Federal Law requirements.
Room classification by explosion and fire hazard is used to establish fire safety requirements aimed at preventing fire possibility and ensuring people and property protection in case of fire.
Calculations
Calculations use officially published reference data on fire hazard properties of substances and materials.
The necessity for category determination is regulated by safety standards and building codes. Categorization applies to premises and installations belonging to functional fire hazard classes F5.1 and F5.2. The methodology for determining categories of premises, buildings and outdoor installations by explosion and fire hazard is provided in fire safety codes. During calculations, the following main provisions were adopted:
By explosion and fire hazard, premises are divided into categories A, B1-B4, C, D. Room categories are determined for the most unfavorable period regarding fire or explosion, based on type, quantity and explosion-fire properties of combustible substances and materials in premises, and technological process features.
Section 1. Methodology for Determining Room Categories by Explosion and Fire Hazard
Room categories by explosion and fire hazard, conditions for assigning production-storage premises to particular categories are accepted according to Table 3. Category determination should be performed by sequential checking of belonging to categories from highest A to lowest D.
Table 3 - Room Categories by Explosion and Fire Hazard
|
Room Category |
Characteristics of Substances and Materials in Premises |
|
|
A - High Explosion Hazard |
Combustible gases, flammable liquids with flash point not exceeding 28°C in such quantity that can form explosive vapor-gas-air mixtures, whose ignition develops calculated overpressure exceeding 5 kPa, and substances/materials capable of exploding and burning when interacting with water, air oxygen or each other |
|
|
B - Explosion Hazard |
Combustible dusts or fibers, flammable liquids with flash point above 28°C, combustible liquids in such quantity that can form explosive dust-air or vapor-air mixtures, whose ignition develops calculated overpressure exceeding 5 kPa |
|
|
B1-B4 - Fire Hazard |
Combustible and slow-burning liquids, solid combustible and slow-burning substances/materials, including dusts and fibers, substances/materials capable only of burning when interacting with water, air oxygen or each other |
|
|
C - Moderate Fire Hazard |
Non-combustible substances/materials in hot, incandescent or molten state, whose processing involves radiant heat, sparks and flame emission, and combustible gases, liquids and solids burned or utilized as fuel |
|
|
Room Category |
Characteristics of Substances and Materials in Premises |
|
|
D - Low Fire Hazard |
Non-combustible substances and materials in cold state |
|
Notes
Methods for determining categories A and B are established according to Appendix A.
Assignment to categories B1, B2, B3 or B4 depends on quantity and arrangement of fire load, room layout characteristics, and fire hazard properties of substances/materials comprising fire load.
Section 2. Methodology for Determining Building Categories by Explosion and Fire Hazard
Building categories are determined based on proportion and total area of premises of particular hazard categories. A building belongs to category A if total area of category A premises exceeds 5% of all premises area or 200 m².
A building doesn't belong to category A if total area of category A premises doesn't exceed 25% of total area but not more than 1000 m² and these premises are equipped with automatic fire extinguishing systems.
A building belongs to category B if: it doesn't belong to category A and total area of categories A and B exceeds 5% of total area or 200 m².
Similar conditions apply for categories C and D with different percentage thresholds and area limits.
Section 3. Methodology for Determining Explosion Hazard Criteria for Premises
Selection and Justification of Calculation Scenario
When calculating explosion hazard criteria, the most unfavorable accident scenario or normal operation period should be selected, where largest quantity of gases, vapors, dusts participate in forming combustible mixtures.
Quantity of substances entering premises that can form combustible mixtures is determined based on:
- design accident of one apparatus
- entire apparatus content enters premises
- simultaneous leakage from pipelines during shutdown time
General ventilation maintaining combustible gas/vapor concentration below explosion-safe limits may be considered if equipped with backup fans and first-category power supply.
Determining Fire Hazard Categories B1-B4
B1 Determination of categories B1-B4 is performed by comparing maximum specific fire load value with values in Table B.1.
Table B.1 - Specific Fire Load and Arrangement Methods for Categories B1-B4
|
Room Category |
Specific Fire Load g, MJ·m⁻² |
Arrangement Method |
|
B1 |
Over 2200 |
Not regulated |
|
B2 |
1401-2200 |
According to B.2 |
|
B3 |
181-1400 |
According to B.2 |
|
B4 |
1-180 |
Each fire load area not exceeding 10 m² |
B.2 For fire load including various combinations of materials, fire load Q, MJ, is determined by formula:
Q = ΣGᵢ × Qᵢ
where Gᵢ - quantity of i-th material, kg;
Qᵢ - lower calorific value of i-th material, MJ·kg⁻¹.
Specific fire load g, MJ·m⁻², is determined from:
g = Q/S
where S - fire load area, m², but not less than 10 m².
Tables B.2 and B.3 provide values for limiting distances and critical radiant flux densities for various materials.
Section 4. Technical Fire Characteristics of Premises Subject to Categorization
Functional Fire Load, Technical Fire Characteristics of Substances and Materials, Calculations
Room and building categories are established depending on type, explosion-fire properties and quantity of combustible substances.
Functional fire load of premises subject to categorization is determined based on most unfavorable conditions regarding substances/materials in apparatus and premises, their quantity, explosion-fire properties and technological processes.
Determination of explosion-fire properties is based on test results or calculations considering state parameters. Information about combustible load is taken from facility documentation based on storage norms and daily requirements for each premises.
According to Fire Safety Technical Regulations, fire hazard zones are classified into:
- P-I - zones in premises with combustible liquids (flash point ≥61°C)
- P-II - zones in premises with combustible dusts or fibers
- P-IIa - zones in premises with solid combustible substances (specific fire load ≥1 MJ/m²)
- P-III - outdoor zones with combustible liquids (flash point ≥61°C) or solid combustible substances
Locker Room Premises
Locker room by functional fire hazard class - storage premises for temporary clothing storage. Area 16 m², height 3.9 m. Minimum distance from fire load surface to ceiling is approximately 1.52 m. Installed cabinets with total mass approximately 100 kg, storing leather clothing (50 kg) and textile clothing (50 kg). Fire load area is 10 m².
Lower calorific values: textiles - 16.75 MJ·kg⁻¹, natural and artificial leather - 17.8 MJ·kg⁻¹, particle board - 13.76 MJ·kg⁻¹. For fire load including various material combinations, fire load Q, MJ, is determined by formula: