Structurial fire behaviour engineering


Structurial fire behaviour engineering

Efectis is able to perform all Fire Safety Engineering (FSE) applied to structural fire behaviour for assessing building collapse modes, taking into account their building functions (storage, industrial, residential) or their different types of structure (steel, concrete, timber, aluminium or any composite ones).

Generally speaking, the Fire Safety Engineering is a performance-based approach checking following requirements:

Analyses are based on fire development and fire spread modelling in order to predict the structural fire behaviour of the buildings.

Efectis use specific modelling tools such as: fire development tools (simplified model, zone model, CFD model like FDS) and Finite Element Model for heat transfer and/or for mechanical calculations (SAFIR, ANSYS, LENAS, DIANA).

Risk assessment

Building and equipment collapse mode (Diagnosis, design, model and review)

Building vulnerability and reinforcement against toxicity, thermal and explosion effects

In critical hazards such as boil-over, BLEVE, flash-fire, pool fire, jet-fire and explosions in an industrial site, a petrochemical site or a power plant, toxicity, thermal and explosion domino effects inside and outside the site can have disastrous consequences to the surroundings.

Efectis can assess the vulnerability of your facilities, and define the best solutions to reinforce your installations, to manage the risks for people. We offer an overall structured approach to the problem:

  • Step 1 – Characterization of effects:
    • Identification and characterization of the phenomena (type, intensity, duration)
  • Step 2 – Characterization of the structure (buildings and facilities):
    • Ad-hoc survey
  • Step 3 – Vulnerability diagnosis for the parts of a building (roof, facades, etc.) and types of effects
    • Explosion effects: Dynamic mechanical calculations
    • Thermal effects: Heat transfer and fluid dynamics calculations
    • Toxic effects: Permeability measurements and calculations
  • Step 4 – Definition and optimization of reinforcement work:
    • Technical and economic feasibility

Building and equipment seismic analysis (diagnosis, design, model and review)

Earthquakes are one of the most lethal natural risks and those which cause most damage. According to the French environmental code, there are two types of structures, “normal risk” and “special risk” structures, referring to a specific earthquake-resistant regulation.

For these installations, earthquake risk prevention must be subject to a case-by-case study.

In this context, CTICM and Efectis France have joined forces to offer their expertise. A wide range of services is thus proposed:

  • Inventory of applicable regulatory requirements
  • Risk analysis of a classified installation
  • Diagnosis of seismic vulnerability (on-site) of industrial equipment and buildings
  • Seismic behavior engineering simulations and definition of protective measures
  • Technico-economic analysis of the ways of improvement
  • Technical assistance in constituting administrative files

Fire risk analysis of power plants and nuclear installations (NNP, R&D center, Laboratory…)

For more than 15 years, Efectis has performed fire risk studies for nuclear operators.
A fire risk study of an installation consists in considering that a fire can occur in any premises of the installation and includes:

  • A qualitative study of fire risks
  • A quantitative study of fire development

Efectis performs fire stability studies for nuclear operators. In most cases, the initial requirements for structural stability are based on the standard ISO-fire curve over two hours. However, when the initial requirements against the standard fire curve cannot be satisfied, the performance is then assessed on the current fire risk. Assessment is also requested when ISO-fire rating is satisfied if the real thermal actions may be more severe than the standard fire curve in terms of intensity or duration.


Conception, design & modeling (Prescriptive design and performance-based design)

The fire safety of a building is determined by four aspects namely, the measures taken in the architectural and the installation provisions, by the function the building serves, and by the way the evacuation of building users is handled. When one aspect has a poor score it will have consequences for the overall fire safety.

Assessment of performance-based design

In the national regulations, for each fire safety aspect, requirements are established for both existing and new structures. Distinction is made between:

  • Functional requirements, by which the objective of the regulation is determined,
  • Performance requirements, by which definition is given to the functional requirement; if you meet these performance requirements then you will satisfy the functional requirements.Efectis can help during the design, implementation, and in the service phase of the structure. Listed below are some possible services that Efectis can perform.

It is also possible to meet the functional requirements with another set of safety measures and to obtain a sufficiently fireproof building. The equivalence of these measures should be proven in that case. This risk-based assessment is referred to as “Proof of equivalent fire safety.”

Efectis can help during the design, implementation, and in the service phase of the structure. Listed below are some possible services that Efectis can perform.

Design (new buildings):

  • Assessing compliance with the chosen fire safety measures and meeting the performance requirements of national regulations (= performance assessment).
  • Determining the fire and smoke resistance, not only in height but also in terms of direction and the criteria that apply. Assessing whether, in a specific construction, the required fire/smoke resistance can be met.
  • Assessing whether the desired materials can meet the required fire classification.

Service phase (existing buildings):

  • Global site inspection in order to:
    • Obtain insight into the fire safety as a whole
    • Obtain insight into the escape safety for users
    • Obtain insight into the quality of fire and smoke separations
  • Detailed site inspection with the additional purpose (compared to global inspection):
    • Establishing the necessary temporary measures
    • Determining the required long-term measures
  • Specific inspections:
    • Performing insurance reviews
    • Providing legal advice

Smoke and heat exhaust systems analysis, design and review

Fire Safety Engineering is recognized as a real alternative to the usual descriptive approach, and currently used all over the world in elaborating an overall fire safety strategy in a building.

The engineering approach gives greater flexibility to architects and contractors in designing complex or innovative buildings, and provides an appropriate tool in the refurbishment of buildings to make them comply with regulations, such as historic buildings.

Efectis can perform the following engineering smoke control studies that can be useful in cases of non-compliance with regulations such as:

  • Smoke extraction less than required,
  • Smokescreen size smaller than required,
  • Ceiling higher than required,
  • Limited fresh air intake,
  • Several superimposed open levels,
  • Assessment of active smoke control systems (jet-fan, smoke curtain, air curtain, etc.) Efectis utilizes and follows a performance-based approach in close relationship with rescue services in order to define and validate the reference fire scenarios.

Fire Protection Design

To combat the risk of fire one must understand the extent and nature of the fire hazards present and then design systems to address these risks. The fire scientists and fire protection engineers at Efectis are fire behavior and systems design experts.

Prescriptive Design: The majority of projects are governed by regulatory requirements that mandate the use of active fire detection and suppression systems. Efectis specializes in conventional and unconventional fire protection system design including many international and recognizes standards and codes.

The nature and level of detail of detail provided by Efectis will vary depending upon the needs of the project. Efectis can produce everything from performance specification documents to full shop level submittals. In all cases Efectis led designs clearly identify the scope of the project in detail which ensures more competitive bids and fewer potential change orders.

Performance Based Design: Some facilities like public transit systems, sports arenas, large atriums, and industrial sites often require special analysis to identify and mitigate risks. The fire scientists and fire protection engineers at Efectis draw upon decades of fire modeling and fire testing experience to quantify the risks and use that expertise to develop customized solutions. Some of the performance based design services that Efectis provides includes, but is not limited to:

  • Fire & smoke behavior modeling
  • Calculated fire resistance modeling
  • Fire loss estimation
  • Smoke management system design
  • Stairwell pressurization
  • Atrium exhaust
  • Timed egress analysis

Egress analysis: design, model and review

The increasing complexity of buildings combined with a demand for higher safety levels, in relation to size and configuration, requires particular attention for egress conditions. Several methods may be used to analyze the escape possibilities of a building such as simple calculation and modeling to solve more complex scenarios. The main parameter in egress analysis is time. On one hand the required safe egress time (RSET) which depends on discovery time for the calamity, reaction time, number of people, walking speed, choice of exit, size and number of doors, staircases and buffer rooms, height of the building, emergency response team etc. On the other hand the available safe egress time (ASET) which depends (in case of fire) on fire load density, flammability of materials, compartmentation, height of the fire compartment, openings in de compartment, emergency response team, fire suppression systems, fire brigade etc.

The main purpose of egress analysis is to provide accurate evaluation, to propose solutions for optimization of a (safe) building design, and to find the critical locations in an existing building.


Fire behavior of materials and structures

Building regulations define the ways and methods for the assessment of fire resistance of buildings, structures and materials (fire test standards, Eurocodes …), and usually propose an alternative to the prescriptive approach that is Fire Safety Engineering (FSE). This alternative is based on performance-based approach/design and consists of assessing fire resistance of structures under real/natural fires (as opposed to standard fire curves).

Efectis has the skills and the advanced modeling tools and the experimental facilities for the assessment of the fire performance of construction products and structures.

Efectis has performed such fire resistance studies of structures for more than 40 years, utilizing:

  • Standard ISO fire curve (prescriptive approach),
  • Real/natural fire curve with a FSE approach. These studies can be performed to all kind of buildings (public buildings, high rise buildings, nuclear facilities, tunnels, etc.) and all kind of structures (steel, concrete, wood, and mixed).

Different steps of calculations use specific modeling tools such as: fire development tools (simplified model, zone model, CFD model like FDS), Finite Element Model code for heat transfer (DIANA, SAFIR, ANSYS) and Finite Element Model code for fire mechanical calculations (SAFIR, ANSYS, LENAS).


Study on fire resistance of steel structure of a tower


Inspection, testing, commissioning and certification

Efectis can provide a wide range of Technical Assistance Services, such as:

  • Code Compliance Verification: Being able to demonstrate that an existing building is code compliant is critical in many healthcare, educational and industrial occupancies.
  • Plan/design review services for fire alarm and fire suppression systems
  • Fire testing and research
  • Third party review
  • Smoke Control Systems
  • Forensic Fire investigation

Fire behaviour

Most often starting fires will not result in a fully developed fire. Within natural fire development three phases are recognized.

The development phase leading into a phase of a fully developed fire though a flash-over. When all fuel for the fire is depleted the fire will go into a decay phase.

Various aspects influence the development of a fire in a building, some of these are:

  • Types of material and means of construction;
  • Geometry of a room;
  • Installations that influence the movement of heat and smoke;
  • Available oxygen;
  • Suppression systems;
  • Interior setup and placement throughout the room.

With our knowledge of fire behavior, material behavior and ventilation we can help to model possible fire development according to the standard t2-development curve. Because this curve is limited in its field of application Efectis can help to develop suitable fire scenarios for:

  • 3-dimentional fire development (spread of fire in height as with storage warehouses);
  • Fire development in more than one place (arson or falling burning materials);
  • When low oxygen levels occur in a room and there are possibilities of backdraft.

Smoke control

Efectis can perform smoke spread modeling to assess the conditions for evacuating people according to tenability criteria (toxicity, opacity, temperature and heat radiation of smoke). This analysis directs the choice of the most appropriate smoke exhaust systems to implement, or justifies the effectiveness of smoke exhaust systems, despite their non-conformity to the usual descriptive approach.

Engineering smoke control studies can be useful in cases of non-compliance with regulations such as:

  • Smoke extracts smaller than required
  • Smokescreen size smaller than required
  • Ceiling higher than required
  • Limited fresh air intake
  • Several superimposed open levels
  • Assessment of active smoke control systems (jet-fan, smoke curtain, air curtain, etc.)

 Risk analysis

Operators of hazardous sites may wish to or must perform, in accordance with local regulations, a hazard study to assess the impact of the facilities on the environment and the surroundings and to guarantee that risks are under control. As part of regulatory process, the authorities having jurisdiction over the site may require a third-party analysis of the hazard studies, in order to obtain an independent expert analysis.

Efectis has been carrying out third-party analysis of hazardous sites for more than 15 years.

Our service focuses in particular on the critical analysis of:

  • The risk analysis method used
  • Preventive measures and protection used to prevent accidents and limit their consequences
  • The accidental scenarios chosen
  • Calculation methods and tools used to assess consequences on the environment (toxicity, thermal and explosion effects)
  • Domino effects on facilities (explosion and thermal effects)

Effectiveness of active and passive fire protection systems (sprinklers – fire doors – smoke extraction – partitioning elements – etc.)


Fire protection building design

Standard rules in regulations often don’t meet the requirements of the market. Efectis can help developers, builder and owners to meet a fire safety level equivalent to the level provided by standard solutions.

The assessment may consist of modelling, calculating and testing of construction behavior, to determine fire development, smoke spread and evacuation possibilities.

The equivalent safety approach especially applies to:

  • complex and large buildings such as high-rise buildings, stadiums;
  • underground infrastructures like tunnels, parking garages;
  • and industrial structures as refineries.

Efectis does all sorts of equivalent safety assessments for all types of structures. Many are assessments of proposed solutions. Others are investigations into the feasibility of products and systems to provide equivalent solutions, which may be combined with optimizing the products and systems themselves.

Code consultancy

Building code evaluation, compliance review, conflict resolution

Failure to identify and demonstrate building code compliance creates risks that can hamper a project’s progress and/or subjects a facility to undue operational and legal risks.

Efectis code experts work as a part of your team to help incorporate the design details needed to comply with the codes and standards, no matter how unique the project. Whether you need to comply with a version of the ICC Code family, NFPA’s Life Safety Code (NFPA 101) and/or other locally adopted codes, standards or specifications, Efectis engineers have the experience to assist you.

  • Facility Design: Efectis has developed three products that allow everyone to focus on what really matters—the functional and operational needs of the owner.
    • Code Compliance Narratives summarize all of the major Building and Fire Safety requirements applicable to the project and how compliance will be achieved. Two revisions of the document are typical; The draft document serves as compliance verification and decision making tool for the design team. The final document is intended to be submitted to the reviewers as part of the design document package to make the plan review process substantially easier.
    • Code Compliance Plans are a sub-set of the design documents. These drawings illustrate the critical Building and Fire Safety design features including: construction type, height and area, rated construction, occupant load calculations, egress routes and capacity, travel distances, and other related features. (ADA and plumbing fixture capacity can also be included as an option).
    • Code Summary Matrix is a management tool created for use by project managers to identify each critical code compliance item, assign responsibility by disciplines or individually, track its status, and create an index to the drawings/documents that demonstrate compliance.
  • Variance/Equivalency Development and Negotiation: Need to incorporate new technology or unique design features not otherwise covered by the codes? Efectis’ code experts have the experience to help your project team develop a design approach that achieves the code’s intent and in doing so develops the documentation and presentation needed to submit the concepts for approval.
Code en standards

Efectis has extensive codes and standards experience that includes:


  • International Code Council (ICC)
    • International Building Code
    • International Fire Code
    • International Existing Building Code
  • NFPA
  • NFPA 5000 Building Construction and Safety Code


  • NFPA 1 Fire Code
  • NFPA 3 Recommended Practice for Commissioning of Fire Protection and Life Safety Systems
  • NFPA 4 Standard for Integrated Fire Protection and Life Safety System Testing
  • NFPA 13 Standard for the Installation of Sprinkler Systems
  • NFPA 30 Flammable and Combustible Liquids Code
  • NFPA 30B Code for the Manufacture and Storage of Aerosol Products
  • NFPA 45 Standard for Fire Protection of Laboratories Using Chemicals
  • NFPA 72 National Fire Alarm and Signaling Code
  • NFPA 101 Life Safety Code
  • NFPA 130 Standard for Fixed Guideway Transit and Passenger Rail Systems
  • NFPA 409 Standard on Aircraft Hangars
  • NFPA 750 Standard on Water Mist Fire Protection Systems
  • NFPA 2001 Standard on Clean Agent Fire Extinguishing Systems

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