Antecedentes de variables utilizadas en otros indicadores

6.7.1. Fire Service Staff Opinions of the FBIM

It is clear after speaking with the various brigades and many individuals within those

brigades that there is a wide and varying opinion about the FBIM and not all of it is positive. It is clear that the opinions expressed to the author have been made depending on the individual‘s level of exposure to the FBIM and understanding of the model and the context to which it is being applied.

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There are a number of variables that can explain why such a wide range of opinions exist within the brigades., including:

the respective state and fire services legislation and understanding of how the FBIM fits in with this legislation;

the individual fire service‘s involvement in the building design process and the effect that this has upon the use of the FBIM in the design process;

the individual‘s exposure to the FBIM including training and length of involvement with the FBIM;

the individual‘s understanding of performance-based engineering and its effect upon the built environment;

the enforcement powers of the individual fire services and use of these to lever the FBIM as a design tool as and when required.

As the author‘s time with the brigades was mostly spent with staff members familiar with the FBIM, it could easily be argued that with regards to trying to gain a balanced view of the fire brigades opinion of the FBIM, the results would be biased. This is certainly true. However, mixed opinions were found amongst those persons talked to. Such opinions ranged from the belief that the model represented realistic fire brigade times as accurately as could be expected, to the other end of the scale where individuals believed that the times predicted by the model were typically excessive and not realistic. Some people considered that this type of model was unnecessary, while others considered it essential to the life safety of fire fighters.

There are a number of reasons why the author feels that concerns regarding the model exist, and why those individuals expressed such beliefs. An understanding of the design environment and the background to the FBIM is crucial to understanding why there is a need for the FBIM and why the model is structured in the way it is. The individuals who expressed concerns over the need for the FBIM and those that expressed concerns over the times predicted by the model did not appear to be greatly involved in the design or fire-safety field, i.e. they had little real experience in building design and the implications of performance- based design on fire-fighting operations or had not used the FBIM first hand in a challenging design environment.

An example of this is the belief that the FBIM does not reflect reality and that it predicts unrealistic and excessive intervention times. This opinion stems from operational experience and a belief that that the fire services should not promote and associate

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themselves with times that appear excessive and could be detrimental to the public's perception of their ability. However, as with any building design egress analysis, it is not appropriate to always consider best-case scenarios and times which are only attainable during normal conditions.

An example of how the FBIM should be applied, and in which the times can appear excessive, is considering the response times from fire stations given the proximity of the building to the fire station. If, for example, the building being analysed is only 100 m from the nearest fire station, it might not be appropriate to only assume a vehicle response

distance of 100 m. Some scenarios might need to consider that the station is not manned at the time of an incident and that the appliance is not available as a result of it being

committed to another incident, for example. A second fire station or even a third might need to be used for the FBIM analysis, increasing times from what a designer or even a fire service person might have expected. However, issues such as this need to be taken into account to ensure that a credible worst-case scenario is being considered.

6.7.2. Consultants’ Views of Fire Brigade Intervention and the FBIM

As was to be expected, the opinions expressed by the consultants were variable. Disagreements arose over what actually constituted fire brigade intervention and to what degree fire service involvement was required within the building design process. A

proportion of the consultants visited had fire service operational experience and their views were slightly more biased towards the needs of the fire services within designs. However, the common theme expressed by all those consultants was that they considered the fire services to be important stakeholders and as such needed to be incorporated in the design process.

Another significant difference that became apparent from the time spent with the consultants in Australia in comparison with the design fraternity in New Zealand is that the Australian fire engineers appear to reinforce fire-service requirements and see these as positive design factors. An example would be hose run distances from hydrant outlets and the

acknowledgement from consultants that distances prescribed by building codes are ‗maximums‘ as they reflect the upper limit of capabilities during intervention and not the minimum. Typically, extending hose run distances is not acceptable and so it is not possible to extend means-of-escape travel distances significantly, even if analysis can show this is acceptable.

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During the time with the Australian fire services the author was given the opportunity to sit in on FEB meetings. The previous view was reinforced within these meetings as the

consultants appeared to respect and understand the needs of the fire services. The FBIM was not specifically discussed within any of the meetings attended. However, the tone of the meetings and designs put forward were such that it was clear the consultants were spending considerable effort designing fire service facilities into the buildings rather than spending that effort trying to design them out.

All the consultants talked to had undertaken FBIM analysis for building projects they had worked on. However, the common view expressed between them was the desire not to have to undertake such analysis. This view was partly formed as a result of the added costs associated with undertaking the additional analysis but could also be put down to the

opinions that they did not want to propose alterations that would ultimately affect fire service intervention.

6.7.3. Concerns Relating to the Assumptions Made Within the FBIM

A number of concerns have been raised by both fire brigades and designers over the values and assumptions that are made within an FBIM analysis should these assumptions change over time. For example, if travel times from a fire station are used within the model,

concerns have been expressed as to the implications of moving the station location in the future. Similar issues are also relevant to other assumptions within the model that relate to the capabilities of the fire services with respect to resources and equipment and the

implications of these changing over time. However, the assumptions on which the FBIM are based should not be that sensitive to changes that could be reasonably expected, including inputs such as fire station location. It should also be recognised that with any performance- based design, assumptions regarding the basis of the design have to be made. Therefore, defining fire-service operations does not mean that these are locked in for the remaining life of that building. If any significant changes do occur that alter the design base assumptions significantly, then as with other aspects of the design, these should be rechecked and the design changed accordingly.

Similarities with other building design aspects can be made, for example with water supplies. When a building is constructed the design of systems (including sprinkler systems) are typically based on the flows and pressures of the water infrastructure available at the time of construction. These may change over time as can be seen with water supplies and water

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companies which are reducing water supply pressures as much as possible for various reasons. This has an effect on sprinkler systems that may induce required changes and alterations to the systems to take such changes into account. To reduce the impact that such issues could create, appropriate safety factors need to be applied to an FBIM

assessment. The involvement of appropriate fire service personnel should also help reduce such issues.

6.7.4. Use of the FBIM to Remove Fire-Fighting Facilities

Because the FBIM quantifies fire service activities, it could be possible using the FBIM to demonstrate that the fire services have sufficient time available to undertake required

operations without using specific equipment. Such examples could include manipulating the model in an attempt to show that the fire service may have the time available to extend hoses through and up buildings without the need to use internal hydrant risers, for example. It should be stressed that this is not the intention of the FBIM and that no fire services were found to accept such an analysis in Australia. Many fire-fighting facilities including hydrant facilities are provided due to inherent limitations in the capabilities of fire service equipment and physical ability of fire fighters. A time-based analysis in this circumstance may not always be appropriate.

For example, fire hoses have the capability to be extended almost indefinitely to any length. However, practicable limitations exist given the safe working pressures of the hoses and pressure losses and also the limitations in the ability of fire fighters to manoeuvre hoses due to their increasing weight with increasing length. Such factors are not included within the FBIM as consultation with the local fire services should ensure that their standard

operational procedures are followed which would incorporate any equipment limitations.

The FBIM should be seen solely as a tool for assessing fire-fighter safety given the proposed building design. If fire-fighter safety cannot be proven, the building design should be

adapted accordingly. The FBIM should not, therefore, be used to remove or reduce the level of safety to fire fighters.

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6.7.5. Buildings Reliant on Fire Service Response

The safety of occupants within buildings should never be predicated on the attendance of fire brigades and based on assumptions that persons will be rescued. This is identified within many performance-based codes throughout the world as identified in chapter 5. However, situations will always occur which require fire brigades to undertake rescue operations, and specific building types, such as hospitals and tall buildings, will always to some degree rely on fire brigade intervention in the event of a fire. However, a building design should

ultimately be ‗self sufficient‘ and not rely on fire brigade intervention. In the future, it is likely that the funding and strategic direction of fire services will change as a result of ever-

increasing financial pressures and increasing efforts in other non-traditional emergency service responses, including environmental protection and vehicle incidents. This further enforces the intent of the FBIM in that it should be a tool used to assess the life safety of fire fighters and to facilitate their role rather than a means of designing these features out of the buildings. This argument may be perceived to be contradictory by some, but is an important aspect of the intended use of the model as it relies on fire services‘ standard operational procedures as a critical part of the analysis.

An example of this is the consideration of the fire service as an ‗active suppression‘ system similar to that of a sprinkler system. For example, many building codes allow the reduction of fire ratings if sprinklers are provided. However, they do not remove the need for such ratings and typically only allow them to be halved, even though it could be shown that no ratings are required should the sprinkler system work. The redundancy provided in this requirement takes into account the fact that such systems are not 100% reliable and

dismisses the actions of the fire services, even though it could be shown by the FBIM that a fire service could potentially suppress the fire, reducing the need for higher fire ratings. In this example, the FBIM could be used to argue that the fire service should be able to extinguish the fire in a given time given the resources available and thus determine any fire ratings on this basis. However, such a design approach would significantly deviate from any currently accepted design approaches and insufficient data is currently available that could clearly demonstrate that such an approach would be acceptable.

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