Fire classification of construction products and building elements - Part 2: Classification using data from fire resistance tests, excluding ventilation services
Summary
TAV. 00Defines the procedure for classifying the fire resistance of construction products and building elements from fire-resistance test data. It uses the performance criteria R (load-bearing capacity), E (integrity) and I (insulation) and their combinations (R, RE, REI, EI), with performance expressed as a time in minutes. It is the resistance-side counterpart of UNI EN 13501-1, which instead classifies the reaction to fire of products.
Scope of application
TAV. 01Applies to construction products and building elements with a load-bearing and/or separating function (for example walls, floors, beams, columns, doors and closing elements) whose fire-resistance performance must be classified on the basis of test data. Ventilation services are excluded and are covered by other parts of the same series. It provides the classification language referenced by national fire-safety rules (for example the Italian Fire Prevention Code) to set compartmentation and structural-integrity requirements.
How this standard works
TAV. CThe standard turns the results of fire-resistance tests into a compact symbol. Each performance to be certified corresponds to a letter - R for load-bearing capacity, E for integrity against flames and hot gases, I for thermal insulation - and the letters combine (R, RE, REI, EI and others) according to the functions the element must guarantee. The symbol is followed by a number stating for how many minutes that performance is maintained. We describe this logic here - without reproducing the time tables or the test criteria, which remain protected content of the standard.
If reaction to fire describes how much a material feeds a fire, fire resistance answers a different question: for how long a building element keeps performing its function while the fire is under way. UNI EN 13501-2 brings order to that answer, turning test data into a readable, comparable classification.
The three performances: R, E, I
At the core of the standard are three criteria, each with its own letter. They are certified singly or together, depending on what the element must guarantee.
| Symbol | What it guarantees | Logic |
|---|---|---|
| R | Load-bearing capacity | the element keeps carrying its loads without collapsing |
| E | Integrity | prevents the passage of flames and hot gases to the unexposed side |
| I | Insulation | limits the temperature rise on the unexposed face |
How the letters combine
The letters are placed together according to the element's function: a beam or column, which only has to bear loads, is classified with R alone; a wall that separates two compartments without a structural role may be EI; a load-bearing, separating wall is REI. A number always follows the letters: it states the minutes for which those performances are guaranteed, chosen from a set of standardised values (for example 30, 60, 90, 120 minutes).
Where the classification comes from
- 01Test or extended applicationThe element undergoes the relevant fire-resistance tests, or its performance is inferred through extended-application rules that transfer results to similar configurations.
- 02Comparison with the criteriaThe measured behaviours (load-bearing capacity, integrity, insulation) are compared with the performance criteria corresponding to R, E and I.
- 03Assignment of the classThe relevant letters are assigned, together with the time in minutes up to which each requirement is satisfied.
Beyond R, E, I
For particular elements and performances the standard provides further symbols that accompany the class - among others W (radiation), M (resistance to mechanical action), C (self-closing device) and S (smoke leakage). They remain a complement: the backbone of the language is the R, E, I criteria and the time in minutes.
Key points
TAV. K- Three performance criteria: R (load-bearing capacity), E (integrity), I (insulation)
- They combine (R, RE, REI, EI) according to the element's function
- Performance is expressed as a time in minutes for which the requirement is maintained
- Classifies on the basis of fire-resistance test data (ventilation services excluded)
- It is the language by which fire-safety rules set requirements (e.g. compartmentation)
Frequently asked questions
TAV. QWhat is the difference between reaction and resistance to fire?
Reaction to fire (UNI EN 13501-1) measures how much a material contributes to a fire and is a property of the product. Fire resistance (this standard) measures for how long an element keeps its function - load-bearing, integrity, insulation - during a fire, and is expressed with the R, E, I criteria.
What does the symbol REI 120 mean?
It indicates an element that for 120 minutes keeps load-bearing capacity (R), integrity against flames and hot gases (E) and thermal insulation (I) together. Changing the letters changes the set of guaranteed performances: for example EI without R, or R alone for purely load-bearing elements.
Who decides which class (e.g. REI 60) is required?
Not this standard: the required class is set by fire-safety rules (for example the Italian Fire Prevention Code) according to the fire load, the compartmentation and the use of the building. UNI EN 13501-2 only provides the classification language; it does not impose the values.
Why do some classes omit the I (e.g. RE or E)?
Because not every element has to provide thermal insulation. A structure that only has to bear loads is classified R; an element that only has to stop the passage of flames and smoke without limiting the temperature on the unexposed side is E or RE. Only the performances relevant to the element's function are declared.
Glossary
TAV. G- Resistenza al fuoco
- The ability of a building element to retain, for a defined time, its load-bearing capacity and/or its separating function during a fire.
- R (capacità portante)
- The criterion expressing the element's ability to keep carrying loads during the fire.
- E (tenuta)
- The criterion expressing the element's ability to prevent the passage of flames and hot gases to the unexposed side.
- I (isolamento)
- The criterion expressing the element's ability to limit heat transmission, containing the temperature rise on the unexposed face.
- Compartimentazione
- The division of a building into portions bounded by fire-resistant elements, to confine a fire and its effects within a limited area for a given time.