Assumptions & Limitations

Assumptions

EFFECT™ is based on the following assumptions:

The scope of EFFECT™ is for high rise buildings comprising residential or business occupancies or a mix of both. Where the building is a mix of residential and business, it should be treated as a residential building due to the greater life safety risk associated with sleeping occupants.

High rise is defined as a building over 18m in height, measured from fire department access level to the topmost occupied floor.

It is assumed that there will be ignition risks throughout the high rise building interior, possibly within the facade system cavities and on the exterior of the building (parked vehicles, cabling, electrics, lights, PV panels, balconies, BBQs, adjacent buildings etc.). The likelihood of a fire is reviewed in the context of fire load within the vicinity of the exterior façade systems, within the façade system itself and from a fire breaking out from the interior of the building.

EFFECT™ is intended to have global applicability with minor geographical variations. It is not a code compliance check although it is based on the first principles of fire safety to, as far as practicable, meet the intent of life safety codes.

EFFECT™ is distributed by NFPA as a risk assessment tool for use by an Authority Having Jurisdiction (AHJ). While other parties (owners, facilities managers, fire safety engineers, fire risk assessors) may also use the tool it is developed with the NFPA specified end users in mind.

Limitations

The scope of the EFFECT™ is for high rise buildings comprising residential or business occupancies or a mix of both. It is limited to three occupancy types:

  • Sleeping risk and all out evacuation strategy (which may occur in phases);
  • Sleeping risk and stay put (defend in place) evacuation strategy; and
  • No sleeping risk, i.e. Office premises and all out evacuation strategy (which may occur in phases).

EFFECT™ is not applicable to timber frame buildings. The structural frame should be steel or concrete. Timber frame buildings should be assessed by a qualified team of façade and fire engineers.

The risk rankings produced by EFFECT™ are intended to err on the side of caution.

EFFECT™ cannot address all possible combinations of façade system and building characteristics. In some instances the assessment will highlight the need for a more detailed risk assessment by a qualified engineering team of façade and fire engineers. This could be because of the complexity of the building, complexity of the façade patterns across the building and difficulties in identifying the façade systems/materials/components.  

EFFECT™ addresses life safety only. The building owner or their insurer may have wider reaching objectives around business continuity or property protection.

Issues such as business continuity, property protection, loss of belongings and loss of a place to stay are secondary and while important are not addressed by EFFECT™.

The life safety of fire fighters is not explicitly addressed although mitigation measures for the life safety of the occupants can also be expected to reduce the risk to fire fighters. It is assumed that the Commanding Officer would risk assess the building’s access and egress routes as well as the structural stability of the building before entering the structure for prolonged periods of time.

EFFECT™ is for use in assessing existing buildings with a possible combustible façade system. It is not a design tool and should not be used for design of new buildings.

There is limited statistical data on fires involving the exterior façade system. Test data is largely proprietary and therefore generally not available to inform this study with the exception of test data explicitly cited by this work.

The adopted risk ranking approach used in EFFECT™ is based on the available literature and the engineering judgment of the global Arup and Jensen Hughes teams and the NFPA advisory panel.

The tool assesses buildings in their completed state; i.e. it does not assess “temporary risks” that arise from construction work or partially occupied buildings; there are clear guidelines and tools available to assess those.

EFFECT™ references ASTM, NFPA, EN and the equivalent ISO reaction to fire tests only. Other National fire test standards are not considered.

This is because:

  • The abovementioned test standards are the most prevalent internationally and most suppliers test to these standards.
  • Addressing all National test standards was not possible within the scope of this project. This is because they are not directly comparable to each other.
  • If a façade material is found to have as-built information that references other reaction to fire test properties then the advice of a fire engineer should be sought.

Similarly, large scale exterior wall fire test standards recognized by the FRA tool are NFPA 285 and BS 8414 parts 1 and 2 with performance criteria from BR 135.

EFFECT™ does not address membranes within the façade system and does not take any benefit from perimeter fire stopping, cavity barriers or thermal barriers. Ignoring the benefits of perimeter fire stopping and cavity barriers is conservative.