Fire safety for buildings: P118-2013

Buildings layout and fire conformation

Prevention of fire spreading at / from neighbouring buildings

FIRE SAFETY

The general concept for determination of fire resistance of structural elements is based on the ascertained hypothesis that the temperatures induced by fire action diminish the resistances and the rigidity of materials, leading to their possible collapse.

Fire resistance depends on: thermal load, time of fire exposure, applied loads, structural system, fire resistance of materials.

The Romanian design norm P118 2013 is based on requirements or specifications

A basic parameter for evaluating the fire hazard of a building is the thermal load, which conditions the duration of resistance under fire and the fire resistance degree. Romanian design codes do not consider the influence of volumetric and dynamic characteristics of a building (the area of fire divisions, the height of levels, etc.) in regard to the evaluation of the fire resistance. The requirements are exclusively based on experimental data; the norm P118 doesnt have any specification about analytical evaluation of fire resistance, hence the inflexible character of the norm.

The main problem of the Romanian norm is this relative inflexibility, which renders it impervious to new discoveries and technologies.

NORMATIV DE SIGURAN LA FOC A CONSTRUCIILOR indicativ P118-99, aproved by Ministery of the Interior and MLPAT, structured in four parts:PART I Common consideration for all buildings (Prevederi comune tuturor construciilor)PART II Civil buildings (Cldiri civile (publice))PART III Buildings for production and / or storage (Construcii de producie i/sau depozitare);PART IV Buildings with mixed destinations (Construcii cu funciuni mixte).The 4 parts are developed in 8 chapters.

PART I Common consideration for all the buildingsIn Chapter 1 General aspects, the norm present:1.1 Aim (Scop). Application domain (Domeniu de aplicare)1.2 Terminology and classifications (Terminologia si clasificri)

P118/2013 - General requirements for buildings:Fire risk and fire resistance: Fire risk (risc de incendiu) - one of the criteria of the fire safety quality requirement for buildings set by Law 10-1995 . The fire risk represents the global probability that a fire may occur, related to the interaction of specific properties of combustible materials and substances and potential sources of fire, in given circumstances, in the same time and space.

factors for determination of fire risk; levels of performance, evaluation methodes, averages and extreme - established technical regulations.

Combustibility of materials and buildings elements: capacity to ignite and burn, contributing to the heat amount and propagation of fire.

Stored materials and substances are classified also in combustibility classes, labeled P1 to P5.

Fire stabilityThe fire stability of buildings or fire compartments represents the capacity of maintaining their load-bearing parameters for a given period of time from the fire start to the moment of partial or total collapse.

According to General Norms for Fire Protection aproved by decree nr. 163 from 28.02.2007, when a fire occurs, the main bearing structure of a building must remain stable as long as needed to provide:Users' safety during a normalized duration of time, which approximates the time required for evacuation and / or firefighter intervention;Avoid collapse, if applicable;The continous functioning of certain, common, building areas, as to provide support and access for firefighters

In case of real fire, the fire behavior of a building or a fire compartment depends on factors like:

nature, composition and dimensions of buildings elements, layout and geometry of buildings, speed (rate) of combustion and duration, technical means for fire prevention and extinction, ventilation and heat dissipation.

To evaluate the fire stability, we have to consider the fire resistance, fire behavior, fire prevention equipments and technical means for fire extinction.

The assessment of the fire stability of buildings and instalations where a fire may occur:- very good;- good / corresponsive;- satifactory;- unsatifactory.

Fire safety scenario: considers the most unfavourable situation

Fire hazard is estimated in accord with thermal load density, qi

- very high risk (risc f.mare) qi = over 1680 MJ/m2- high risk (risc mare) qi = 841 - 1680 MJ/m2- medium risk (risc mijlociu) qi = 421 - 840 MJ/m2- low risk (risc mic) qi = under 420 MJ/m2

In the rooms or spaces equipped with automatic fire extinction devices, very high risk can be considered high, high risk can be considered medium and medium risk can be considered low. For the whole fire compartment or building, the fire hazard will be considered that of the area with the greatest risk, if it contains a minimum of 30% from its volume.At buildings for production and/or storage the fire hazard is defined also by the fire danger category.

Civil buildings are classified in levels of fire resistance: I , II , III, IV , V