In everyday life, the consumer does not need to be interested in the characteristics of the fire resistance of equipment and premises. Most of the citizens live with an attitude towards safe living, therefore the indicators fire resistance and the availability of fire-fighting equipment is of interest exclusively to specialists in this field.
Own the interpretation of basic concepts fire safety worth to all citizens, because it can save health and even life. I propose to consider the common abbreviations of fire safety levels and the classification of the degrees of fire hazard and the factors that determine them.
What does REI mean?
The abbreviation can be found on packages some building materials and in buildings (often on signs near fire-fighting equipment). Interpretations differ somewhat from each other, but we will consider those that are included in Building codes and regulations (SNIP). Latin letters REI interpreted as follows:
"R" indicates loss of bearing capacity, in other words, it is the stability of the building / material during a fire. Loss of bearing capacity simultaneously characterizes the weakening of the level of thermal insulation and structural integrity.
The indicator is checked as follows: an element of a structure or equipment amenable to fire treatment. The expert visually determines the time after which the material reaches its ultimate deformation. The time is indicated in minutes.
The sustainability index is calculated not only in the field of fire safety. This concept is used for corrosion, pressure and other factors that can change the design of an object. It turns out that the bearing capacity indicator indicates the permissible load level.
"E" is characterized as loss of integrity. Experts determine the period of fire exposure, after which through cracks and holes are formed on the material. For example, if the designation "60EI" is indicated on the object, this means that with a 180% fire treatment, the material begins to crack after 60 minutes.
The digital indicator always indicates the time, and the alphabetic indicator indicates the tested criterion and temperature.
"I" - Latin index, characterizing thermal insulation properties constructions. It is also called extreme point ignition. The index characterizes the time interval after which the adjacent objects are heated to the maximum level.
Objects of this kind are not directly subject to fire. This often occurs after the loss of integrity, when fire and objects of combustion penetrate through cracks in the heated equipment.
What is fire resistance and how is it determined?
Fire resistance is general characteristics fire safety of the facility... If we are talking about a structure, this level is determined on the basis of the fire safety indicators of individual elements of the building.
It should be borne in mind that the real level will always be slightly lower than the indicated one, because the room does not consist of only walls. Wallpaper, accessories, household items significantly raise the level of fire risk.
Fire resistance classification
First of all, it is divided into actual and required. The required indicator is displayed in SNiP in the section "Fire safety of buildings and structures". When the structure of the building reaches a certain level, a group of experts checks the actual level, i.e. the actual level.
If it is lower than required, a permit for further construction not issued. Each type of facility has its own permissible level of fire safety.
It is defined in terms of fire resistance. There are 5 of them in total. The first degree is REI 120, and the fourth - REI 45 - these are acceptable levels for inside walls living quarters... The same degrees for car windows will be slightly lower. The chapters on the criteria of the fifth degree are not indicated.
What forms the indicator of fire resistance?
The index is mainly influenced by the elements that make up the equipment or structure. Objects are primarily defined as flammable or non-flammable. The item of equipment is classified in the following way:
- non-flammable - K0;
- low fire hazard - K1;
- moderately fire hazardous - K2;
- fire hazardous - K3.
The normative acts of "Fire safety of buildings and structures" detail the characteristics of the materials.
Buildings are classified in a similar way, their indicators depend on the above levels of fire hazard of the elements. The indexes for structures are as follows:
- С0 - if the level of elements used in the process of construction does not exceed К0;
- C1 - when the main indicators are K0, K1. For external walls, K2 is allowed;
- C2 - the maximum fire hazard indicator - K3 (allowed for external and bearing walls);
- C3 - bearing, external walls, non-attic coatings are not standardized. The limit of the walls of the staircase and the fire barrier - K1, for the landing of the stairs - K3.
One of the elements that can help with fire safety purposes is the installation fire barriers... Fire-prevention sparking gates are used to shut openings, in case of fire, to prevent fire from accessing adjoining premises for a certain period of time.
Manufacturing fire gate from fire resistance EI 30, EI 45, EI 60, EI 90, EI 120, E 180 is made using bent elements sheathed with a special parallelepiped frame made of steel sheet. Then, inner space filled with an isothermal bag, which consists of thermal insulation materials. Also, during production it is possible to install a special wicket in the gate leaves, which merges with their general appearance. A similar design is organized in fire curtains.
The choice is usually made depending on the color, type of opening and level fire resistance of the gate... At present the fire resistance limit metal gate EI 60 is equal to 60 minutes. By the type of opening, the gates are divided into swing and sliding, and are selected depending on the greater ease of use. It should be noted that if you need to install a gate large sizesfor hangars, for example, a prefabricated structure is often used.
To indicate the level of fire resistance, the indicator is used EI, located in the time limit from 30 to 180, after overcoming which the barrier loses its protective, original properties. If the indicator EI 90, so it was noted that the appearance of the first signs of destruction occurred after 90 minutes.
Fire resistance EI 30, EI 60, EI 90, EI 120, E 180
Fire resistance EI call the possibility of fire curtains and gates not to lose their stability even under the influence of a flame for a long time. When temperature indicators cross the minimum acceptable line, any ordinary door will begin to deform, in contrast to fireproof gates. The destruction limit of which is on high levelwithout allowing the flame to spread by feeding on oxygen.
In order to determine fire resistance protective structures are installed on a platform, fenced brickwork, and lend themselves to heat. A fire is simulated during certification tests. Fastening system together with the gate, it is kept under fire at 1193 degrees for 24 hours. The test ends when a partial loss of integrity of the refractory doors and fasteners appears.
Fire resistance, indicators (resistance to fire):
- Loss of integrity;
- Flame formation and combustion back side a gate that has not been exposed to heat for more than 10 seconds;
- Appearances through holes and cracks;
- The blade falls out of the fastening base.
Control over the process and summing up is carried out thanks to thermocouples, the readings of which are calculated at the end of the tests. An important point the definition of fire resistance is the use of smoldering tampons. They are placed near the gate, and when heated to a certain temperature, they begin to smolder. If the signal element starts to smolder or ignites after ten seconds, then the gate has lost its integrity. The defectiveness indicator is measured using probes, which measure holes and slots. Indicator E (30, 60, 90, 120, 180) indicates fire resistance limit, on the loss of structural integrity, this parameter does not apply to thermal insulation capacity. Considering the thermal insulation capacity, one should keep in mind the parameter I (30, 60, 90, 120), which tells the consumer about the loss of thermal insulation, but not integrity.
Fire resistance of building structures
For resorting to the use of the following notation:
- Loss of bearing capacity of structures - R,
- Loss of integrity structural elements - E;
- Loss of heat-insulating properties due to an increase in temperature on a structural surface that is not subjected to heating to the limit values, - I,
- Reaching the limiting value of the heat flux density at a distance from the surface that was not subject to heating - W.
Fire resistance limit of metal structuresthat are additionally unprotected are usually small and are in the following ranges:
- R10-R15 for steel structures,
- R6-R8 for aluminum structures.
Exceptions to these two rows are massive columns with high values limit of fire resistance of metal structures - R45. However, such constructions are used rather infrequently.
In cases where the value of the minimum allowable fire resistance limit of building structures (this does not include structures related to fire barriers) is R15 (or RE15), the use of unprotected steel structures is allowed regardless of their actual fire resistance limits with a few exceptions. The latter include the cases when the corresponding quantity fire resistance limit load-bearing structures , according to the results of the tests carried out, reaches only R8 or less.
Quick loss unprotected metal structures the properties of resistance to open fire is a consequence high values thermal conductivity at small values \u200b\u200bof heat capacity. Increased thermal conductivity inherent metal elements, does not lead to the appearance of a temperature gradient inside the structural section. This is main reason rapid increase metal temperature up to a critical value. When these values \u200b\u200bare reached, a sharp decrease in the strength of the material is observed, the structure comes to a state where it cannot withstand the load imposed on it from the outside.
Fire resistance limit of wooden structures
Compared to metal counterparts, wood structures are flammable. On the fire resistance limits wooden structures several factors affect: the time that elapses from the beginning of the interaction of fire with the material to the fact of direct ignition of the tree, the time taken from the beginning of combustion to reaching the limiting state.
To improve the fire resistance of wood, traditionally resorted to applying several layers of plaster. A two-centimeter layer applied to a column of wood can increase fire resistance of a wooden structure up to R60. High efficiency all kinds of fire protection paintwork, impregnation of wood with fire retardants.
Fire resistance limit of reinforced concrete structures
The fire resistance of reinforced concrete structures is influenced by many factors, including the following: geometry features, load, dimensions of concrete layers, type of reinforcement used in construction, type of concrete and others.
When a fire breaks out fire resistance limit of building structures can be achieved for a number of reasons:
- decline strength characteristics concrete due to an increase in temperature,
- the appearance of cracks, chips in sections,
- loss of insulating properties.
The most sensitive structural elements include bending reinforced concrete structures. This fact can be explained by the fact that the working reinforcement of the stretched zone, which provides the main contribution to the bearing capacity of structures, is protected from fire by a small concrete layer. This is the determining factor affecting the high heating rate of the working valve.
Submitted by: 12inches
Often fire doors and other designs are usually divided into classes according to fire protection parameters. In this case, the marking EI, EI is used
W or EIS... What do these designations show? When are they used?Before buying and installing a fireproof door, glass unit and other floors, it is important to familiarize yourself with existing norms regarding the fire safety requirements in a particular building.
Inconsistency installed door, windows, etc. the class of fire protection required in this room will serve as a reason for refusing to put the building into operation.
So in general view The EI fire safety class indicates the ability of a structure to withstand the onslaught of an open fire in the event of a fire for a specified time.
There are also additional letters added to the EI:
EI
EI
S - and this is a common marking for doors with a ventilation grill.The fire resistance class is assigned based on the tests carried out on the product in a special fire chamber. If the test is successful, then the company receives a corresponding certificate.
Fire resistance limit
EI 60
EI 60 fire resistance limit
In this case, a door, window or ceiling corresponding to this class must hold out for at least 60 minutes (one hour) without loss of structural integrity and prevent the spread of fire, combustion products, as well as high temperatures outside the room limited by the door.
Fire resistance limit
EI 45
EI 45 fire resistance limit
Structures with such a fire resistance limit can be installed in places of increased cross-country ability, on staircases, in office and industrial buildings... In a word, wherever 45 minutes should be enough for the complete and safe evacuation of residents or working personnel.
EI 45 fire resistance limit
applies not only to doors, but also to glazed coatings, including windows and partitions.Fire resistance limit
EI 30
One of the most affordable price options is EI 30 protection class. This means the ability of a structure to withstand the spread of flame for half an hour - that is, at least 30 minutes.
Since the spread of fire is mainly facilitated by the presence of an influx of oxygen, such doors provide airtightness during a fire. Due to this, neither smoke nor high temperatures pass outside.
An additional advantage of doors and double-glazed windows with any degree of resistance EI, including EI 60, can be considered their excellent noise and heat insulation characteristics.
EI 60 doors can be ordered both in "warm" and "cold" versions, that is, intended for installation indoors or in the entrance group.
Fire resistance limit
EI 150
Then, for example,
Usually in this case we are talking about the manufacture of products to order according to the individual requirements of the customer.
The thickness of both the working material and the fire-resistant outer coating often increases.
However, the principle remains the same: EI 150 allows you to keep the spread of open flames and high temperatures for 150 minutes. They resort to such high fire protection in crowded places and in many hazardous industries.
Fire resistance of building structures
To give a rough estimate of the fire resistance limit of specific structures, during their development and design, the following points should be followed:
The fire resistance threshold of laminated enclosures is comparable in terms of thermal insulation ability, and, in most cases, exceeds the set of stability limits for individual layers. This indicates that large quantity layers of the enclosing structure does not reduce the fire resistance. In some cases, additional layers may not play a significant role, for example, facing from sheet metal from the side that is not heated;
Fencing structures with an air gap, on average, are 10% higher in fire resistance than analogues without it. Moreover, its efficiency increases in proportion to the distance from the heating source, regardless of the thickness;
The asymmetrical arrangement of the layers affects the fire resistance depending on the direction of the heat flow. It is recommended to place non-combustible materials with low thermal conductivity in the most fire hazardous place;
The increased humidity of structures slows down heating, increases fire resistance, except for those cases when the material becomes more fragile with increasing humidity (which is especially important for products made of concrete or asbestos cement);
Fire resistance decreases when high loads - the indicator for determining the limit of refractoriness are structures with the maximum stressed section;
The period of exposure to heat also affects the material's ability to withstand high temperatures in a fire;
Structures whose heat resistance cannot be determined usually have a higher heat resistance limit of analogous statically determinate structures. It is also important to take into account the additional forces resulting from thermal deformations;
The fire resistance of a structure does not depend on the flammability of the materials of which it is composed. So, thin-walled metal profiles have a minimum fire resistance limit, while wooden structures have a higher indicator with the same ratio of the heated perimeter of the section to the area and impact force, ultimate strength or yield strength.
Attention! Combustible materials used in the design of a building, instead of hardly combustible or non-combustible, can greatly reduce the fire resistance of the entire structure. This is especially true when the burnout rate exceeds the heating rate.
Methods to improve fire safety
To increase the resistance of structures to high temperatures and bring it to the specified parameters, various types of fire retardant materials are used during construction. They allow you to block the surface of the protected structure from the thermal effect and keep it in working order for a certain period of time.
Fire retardant coatings are used for:
building structures that include columns, frames, trusses, blocks, slabs, and floor slabs;
air ducts and gas ducts with appropriate safety requirements;
cabling, penetrations through fire-resistant fences;
containers with petroleum products, flammable and combustible liquids;
plaster, concrete or brick finishes - relevant for structures designed for additional loads.
For these purposes, use special facing plates, protective screens, surface treatment fire retardants, impregnation of wooden structures with chemicals.
Systems that increase the limits of fire resistance are different types and consist of different materials... The most commonly used: heat-resistant aggregates (vermiculite, expanded clay, basalt, etc.), inorganic binders (gypsum, cement), polymers, which increase the overall resistance and strength of structural elements. The above systems can be used independently or combined.
Upon contact with high temperature, the organic components of the coating of a binder nature swell, simultaneously forming a foamed coke. Thus, the material burns out slowly, while the structure remains functional. long time... Mineral coatings block heat flow due to the release of a large amount of steam, since they contain bound water... Due to this, the temperature rises gradually, and the structure is destroyed less intensively.
All fire safety barriers are regulated by the requirements of GOST R12.3.047-98, as well as SNiP 2.01.02-85 "Fire safety standards" and 21-01-97 "Fire safety of buildings and structures", according to which fire walls are divided into two classes.
Features of the classification
The EI-45 (EIW-45) index is a conventional unit for measuring the fire resistance of a structure, which classifies a partition with this designation to the first class of fire resistance. Each letter of the index, as well as the conditional digit, have a specific meaning:
- E - the partition completely loses its structural integrity in at least 45 minutes;
- I - the structure loses its thermal insulation properties after at least 45 minutes;
- W - the structure's ability to contain heat is lost after at least 45 minutes.
That is, it turns out that GCR or with another filler with the EIW-45 index is capable of holding back a fire for 45 minutes or more. EIW-45 is the lower limit of class 1 fire resistance and is the most common standard that has become widespread, except for fire hazardous facilities, for which the requirements for fire resistance of the partition are much higher.
Let's take as an example - PP partitions EI-45 from gypsum plasterboard
Due to many factors, it was the GKL fireproof partitions that received most widespread... This is due to the relative ease of installation, as well as the final cost of the finished barrier. It is made on the basis of a steel frame filled with refractory material and the classic closure of all this with sheets of drywall. In the future, such a partition is equipped with entrance group and windows, if necessary, and is also decorated in accordance with the design of the surrounding interior.
Structurally, the EI-45 GKL firewall looks quite simple and takes up very little space. With a total barrier thickness of 100 mm, 1 class of fire resistance can be easily ensured if used thermal insulation material of mineral wool not thinner than 50 mm. It is really easy to install such partitions both in the process of general construction and with an already functioning building, in which the redevelopment of the area is planned.
Places of application
The places of application of fireproof partitions with the index EI-45 (EIW-45) are as follows. They are recommended for use in buildings with large crowds on the floors. 45 minutes of fire resistance of the barrier provides enough time for a calm and unhurried evacuation, as well as for a group of firefighters and an ambulance to arrive at the fire site. In general, the range of objects for the installation of fire barriers looks like this:
- healthcare facilities: hospitals, clinics, health resorts, sanatoriums, etc.;
- educational facilities: preschool educational institutions, schools, universities;
- trade: shopping and entertainment centers;
- business: offices and business centers;
- services: cafes, restaurants, etc .;
- entertainment: nightclubs, cinemas, etc .;
Also partitions of this class can be found in production and warehouses... However, this is relevant for ordinary conditions, but at fire and explosion hazardous facilities, it is customary to use partitions with indexes EI-90 and higher.
Certification and testing
The certification of firewalls is mandatory in accordance with Federal law dated July 22, 2008 N 123-FZ "Technical regulations on fire safety requirements." The certificate is issued only after testing, regulated by: GOST 30247.0-94, 30247.1-94, 30403-2012, R 53308-2009.