ÖNORM EN 1996-1-2|Fire design

The general objectives of fire protection are to limit risks with respect to the individual and society, neighbouring property, and where required, environment or directly exposed property, in the case of fire.

Construction Products Directive 89/106/EEC gives the following essential requirement for the limitation of fire risks:

„The construction works must be designed and built in such a way that in the event of an outbreak of fire:

  • the load-bearing capacity of the construction can be assumed for a specific period of time,
  • the generation and spread of fire and smoke within the works are limited,
  • the spread of the fire to neighbouring construction works is limited;,
  • occupants can leave the works or be rescued by other means and
  • the safety of rescue teams is taken into consideration.”

According to the Interpretative Document No 2 "Safety in Case of Fire" the essential requirement may be observed by following various possibilities for fire safety strategies like conventional fire scenarios (nominal fires) or 'natural' (parametric) fire scenarios, including passive and/or active fire protection measures.

EN 1996-1-2 deals with specific aspects of passive fire protection in terms of designing structures and parts thereof for adequate load bearing resistance that could be needed for safe evacuation of occupants and fire rescue operations and for limiting fire spread as relevant.

Required functions and levels of performance are generally specified by the national authorities - mostly in terms of a standard fire resistance rating. Where fire safety engineering for assessing passive and active measures is acceptable, requirements by authorities will be less prescriptive and may allow for alternative strategies.

This Part 1-2, together with EN 1991-1-2, Actions on structures exposed to fire, supplements EN 1996-1-1, so that the design of masonry structures can comply with normal and fire requirements.

Supplementary requirements concerning, for example

  • the possible installation and maintenance of sprinkler systems
  • conditions on occupancy of building or fire compartment and
  • the use of approved insulation and coating materials, including their maintenance

are not given in this document, as they are subject to specification by the competent authority.

A full analytical procedure for structural fire design would take into account the behaviour of the structural system at elevated temperatures, the potential heat exposure and the beneficial effects of active fire protection systems, together with the uncertainties associated with these three features and the importance of the structure (consequences of failure).

At the present time it is possible to perform a calculation procedure for determining adequate performance which incorporates some, if not all, of these parameters and to demonstrate that the structure, or its components, will give adequate performance in a real building fire. However the principal current procedure in European countries is one based on results from standard fire resistance tests.

The grading system in regulations, which call for specific periods of fire resistance, takes into account (though not explicitly), the features and uncertainties described above.

Due to the limitations of the test method, further tests or analyses may be used. Nevertheless, the results of standard fire tests form the bulk of input for calculation procedures for structural fire design. This standard therefore deals principally with the design for the standard fire resistance.

For design according to this part, EN 1991-1-2 is required for the determination of temperature fields in structural elements, or when using general calculation models for the analysis of the structural response. Where simple calculation models are not available, the Eurocode fire parts give design solutions in terms of tabular data (based on tests or general calculation models), which may be used within the specified limits of validity.

This Part 1-2 of EN 1996 deals with the design of masonry structures for the accidental situation of fire exposure, and is intended to be used in conjunction with EN 1996-1-1, EN 1996-2, EN 1996-3 and EN 1991-1-2. This part 1-2 only identifies differences from, or supplements to, normal temperature design. This Part 1-2 deals only with passive methods of fire protection. Active methods are not covered.

This Part applies to masonry structures which, for reasons of general fire safety, are required to fulfil certain functions when exposed to fire, in terms of:

  • avoiding premature collapse of the structure (load bearing function) and
  • limiting fire spread (flames, hot gases, excessive heat) beyond designated areas (separating function).

This Part 1-2 deals with the following:

  • non-loadbearing internal walls,
  • non-loadbearing external walls,
  • loadbearing internal walls with separating or non-separating functions and
  • loadbearing external walls with separating or non-separating functions.

Current Document

ÖNORM EN 1996-1-2
EUROCODE 6: Design of masonry structures - Part 1-2: General rules - Structural fire design

Current status:

ÖNORM

Publication:

2006-01-01

Document superseded:

PRESTANDARD ÖNORM ENV 1996-1-2

Further Information & Order:

ÖNORM EN 1996-1-2

National Annex (German only)

ÖNORM B 1996-1-2
Eurocode 6: Design of masonry structures - Part 1-2: General rules - Structural fire design - National specifications concerning ÖNORM EN 1996-1-2

Current status:

ÖNORM

Publication:

2006-07-01

National Specifications:

Overview

Further Information & Order:

ÖNORM B 1996-1-2