STR 2.01.01(2):1999 – Essential Building Requirements: Fire Safety Overview
The Statybos techninių reikalavimų reglamentas STR 2.01.01(2):1999 (Building Technical Regulation) titled Esminiai statinio reikalavimai. Gaisrinė sauga (Essential Building Requirements: Fire Safety) is a regulatory statute issued by the Ministry of Environment of the Republic of Lithuania. This consolidated version, effective from October 5, 2002, established the fundamental fire safety framework for the Lithuanian construction sector. It was developed to harmonize national technical standards with the European Economic Community's Directive 89/106/EEC regarding the acquis for construction products, specifically addressing one of the six essential building requirements mandated by law.
The document governs the regulatory domains of fire prevention, structural stability during fire, and emergency evacuation protocols. It applies to all construction participants, including architects, structural engineers, and state supervision institutions. The regulation provides technical definitions for structural elements and defines the mandatory functional properties of construction products. It covers diverse technical areas such as fire load density, reaction to fire (reakcija į ugnį), and fire resistance periods, while establishing the methods for evaluating compliance through the Standartinė temperatūros ir laiko kreivė (Standard Temperature-Time Curve) based on ISO 834 standards.
The structured sections below outline the core technical mandates for structural integrity, the classification of construction products, and the engineering principles required to ensure occupant safety and rescue effectiveness.
Essential Fire Safety Objectives
According to Section III, buildings must be designed and constructed so that in the event of a fire, specific safety benchmarks are maintained for a period determined by the building's purpose and classification.
- Load-bearing capacity: The structure must maintain its stability and carry loads for a specified duration.
- Spread limitation: The emergence and spread of fire and smoke within the building must be restricted.
- External spread: Fire spread to neighboring structures must be limited by safety distances or physical barriers.
- Occupant safety: Persons within the building must be able to leave safely or be rescued via designated means.
- Rescuer safety: Firefighting and rescue teams must be able to operate safely within or around the structure.
Fire Engineering and Impact Assessment
The regulation introduces fire engineering principles in Chapter IV, requiring an assessment of thermal impacts on construction products through radiation, convection, and conduction.
- Standard fire curve: Thermal impact is modeled using the equation T = 345 log10 (8t+1) + 20, where T is temperature and t is time in minutes.
- Natural fire scenarios: Alternative models account for actual fire loads, ventilation conditions, and the geometry of the space.
- Smoldering curve: A specific thermal model applied when construction materials are expected to have a lower ignition threshold.
- Hydrocarbon curve: A specialized thermal model for high-intensity fire scenarios such as transport tunnels or nuclear facilities.
Classification of Construction Products
Structural elements and materials are classified based on their functional performance during a fire, utilizing standardized European letter codes.
- R (Load-bearing): The ability of a structural element to withstand mechanical loads without collapsing.
- E (Integrity): The ability to prevent the passage of flames and hot gases to the unexposed side.
- I (Insulation): The ability to restrict heat transfer so the unexposed side does not exceed safe temperature limits.
- W (Radiation): A criterion specifically for glazed elements to limit heat radiation levels.
- S (Smoke leakage): The ability of an element to restrict the movement of smoke.
Time intervals for these classifications are expressed in minutes, ranging from 15 to 360 (e.g., REI 60, RE 120, or R 30).
Active and Passive Protection Measures
The regulation distinguishes between different systems designed to detect, contain, and extinguish fires.
- Priešgaisrinė užtvara: Fire barriers consisting of non-combustible walls, partitions, or floors with defined fire resistance ratings.
- Aktyvios priemonės: Active systems including automated fire detection, alarms, sprinklers, and smoke/heat ventilation equipment.
- Evakuacijos kelias: Designated evacuation routes that must remain free of smoke and satisfy specific width and lighting requirements.
- Gaisrinis skyrius: A fire compartment separated from other parts of the building by structures capable of containing fire for a predetermined time.
Frequently Asked Questions
What does the REI classification mean for building elements?
REI indicates the duration in minutes that an element maintains its load-bearing capacity (R), integrity (E), and thermal insulation (I). For example, REI 60 means the element must meet all three criteria for at least 60 minutes.
Which authority issued the STR 2.01.01(2):1999 regulation?
It was issued by the Ministry of Environment of the Republic of Lithuania under Order No. 422.
How is the thermal impact of a standard fire calculated?
It is calculated using the formula T = 345 log10 (8t+1) + 20, which models the temperature increase over time based on the ISO 834 standard.
What are the fire safety requirements for load-bearing structures?
Load-bearing structures must be designed to withstand fire-induced loads for a sufficient duration to prevent total or partial collapse of the building.
What defines a 'Fire Compartment' (Gaisrinis skyrius) under this regulation?
It is an enclosed space within a building separated by fire-resistant structures designed to prevent the fire from spreading to other parts of the building for a set time.
Does this regulation apply to all buildings in Lithuania?
Yes, it is a mandatory technical building regulation for all legal and physical persons involved in construction, design, and building supervision in Lithuania.
What are the categories of technical specifications mentioned in the document?
The document defines Category A (regulations and standards for building design and construction) and Category B (standards and technical approvals for construction products).
Are active fire protection measures mandatory?
The regulation requires active measures such as detection, alarms, and extinguishing systems depending on the building's purpose and specific fire risk assessment.
