“Are South African Buildings as Safe as New Zealand Buildings?” A person going into or using a building anywhere in the world has certain expectations as to the perceived and acceptable level of risk to life safety. There are also societal expectations and acceptability levels which are perhaps not explicitly stated. Building legislation in both New Zealand and South Africa appear to have similar goals, yet when applying the relative prescriptive document to a similar building in each country the perception is that one country has a higher level of safety over the other. Having worked for a number of years under both sets of building design regimes, the author was of the opinion that aspects of one prescriptive document has more stringent requirements than the other and that buildings in the one country thus had a higher apparent level of life safety than the other. The question was asked: How much difference is there in (fire) life safety for an occupant of a building in New Zealand compared to a building in South Africa? Is a similar building designed to a higher standard in one country as opposed to the other? To test the author‟s hypothesis in a measured way a scoring system was required to quantify the relative level of safety. The comparison is carried out using the Fire Safety Index scoring system developed by McGhie. A spreadsheet analysis is carried out for similar building types (Building Use, Height, Fire Load and Number of Occupants) complying with each country‟s relevant acceptable solution or deemed-to-satisfy document using McGhie‟s weighted risk ranking model. Buildings are assessed across four Building Use Parameters (Purpose Group, Escape Height, Occupant Numbers and Fire Hazard Category). As the buildings assessed are very similar, the Building Use Scores are virtually identical; with some variations, for example, when occupant numbers are capped because of limitations on fire cell floor areas. The Fire Safety Features Score for each building is then assessed for the minimum requirements of the prescriptive documents across eight main category headings (Fire Barriers, Fire Alarm, Smoke Control, Building Fire Control, Emergency Power Supply, Communication System, Fire Service and Means of Escape) and a number of sub-categories. Once the attribute score is assigned and the ii weighting applied the total score is summed and a numerical rating score is achieved for each building out of a possible maximum score of 5. As approximately 63% of commercial buildings (in NZ) are single storey and a further 28% are two-storey‟s high, the discussion of the differences in score between the two sets of buildings will primarily focus on one and two storey buildings, and the scoring is weighted to account for the relative building stock, with averaging used for the various occupant loads. The results show that for equivalent Working Purpose groups (WL), Mercantile Occupancies (CM) and Residential Occupancies (SR) the South African buildings are safer than the New Zealand buildings. Occupancies which are Crowd Activities (CL) and Sleeping Accommodation (SA) are safer in New Zealand than in South Africa. The Working Moderate fire load (WM) occupancy is rated equal for both countries.

In fire, any information about the actual condition within the building could be essential for quick and safe response of both fire–fighters and occupants. In most cases, however, the emergency responders will rarely be aware of the actual conditions within a building and they will have to make critical decisions based on limited information. Recent buildings are equipped with numbers of sensors which may potentially contain useful information about the fire; however, most buildings do not have capability of exploiting these sensors to provide any useful information beyond the initial stage of warning about the possible existence of a fire. A sensor–linked modelling tool for live prediction of uncontrolled compartment fires, K– CRISP, has therefore been developed. The modelling strategy is an extension of the Monte– Carlo fire model, CRISP, linking simulations to sensor inputs which controls evolution of the parametric space in which new scenarios are generated, thereby representing real–time “learning” about the fire. CRISP itself is based on a zone model representation of the fire, with linked capabilities for egress modelling and failure prediction for structural members, thus providing a major advantage over more detailed approaches in terms of flexibility and practicality, though with the conventional limitations of zone models. Large numbers of scenarios are required, but computational demands are mitigated to some extent by various procedures to limit the parameters which need to be varied. HPC (high performance computing) resources are exploited in “urgent computing” mode. K–CRISP was demonstrated in conjunction with measurements obtained from two sets of full–scale fire experiments. In one case, model execution was performed live. The thesis further investigates the predictive capability of the model by running it in pseudo real–time. The approach adopted for steering is shown to be effective in directing the evolution of the fire parameters, thereby driving the fire predictions towards the measurements. Moreover, the availability of probabilistic information in the output assists in providing potential end users with an indication of the likelihood of various hazard scenarios. The best forecasts are those for the immediate future, or for relatively simple fires, with progressively less confidence at longer lead times and in more complex scenarios. Given the uncertainties in real fire development the benefits of more detailed model representations may be marginal and the system developed thus far is considered to be an appropriate engineering approach to the problem, providing information of potential benefit in emergency response. Thus, the sensor–linked model proved to be capable of forecasting the fire development super–real– time and it was also able to predict critical events such as flashover and structural collapse. Finally, the prediction results are assessed and the limitations of the model were further discussed. This enabled careful assessment of how the model should be applied, what sensors are required, and how reliable the model can be, etc.

"This research effort addresses key challenges associated with the technical review and acceptance of performance-based design approaches to fire safety engineering through development of a decision support framework and associated tool. Such design approaches seek to confirm that the overall fire safety system, which includes the building and its protective features, meets a set of fire safety objectives established by relevant stakeholders, and this confirmation is achieved through fire safety analysis, or the application of analytical and computational tools and methods. While the current approach to performance-based fire safety analysis relies on guidelines and standards, these rather generic, process-oriented documents do not provide fire protection engineers (FPEs) sufficient guidance to address critical elements of the analysis process in a systematic, consistent and technically adequate manner. Should a fire safety analysis contain technical deficiencies, then it becomes less clear that the design solution being proposed truly achieves the desired fire safety objectives. Moreover, project stakeholders, including the authority having jurisdiction (AHJ), may lack the necessary qualifications, expertise, or design intimacy to, suitably and reliably, identify and challenge deficient analyses. As a result, the current approach to fire safety analysis and its quality assurance has led to large variations in analysis quality and consequently levels of delivered performance. With no existing equivalent, a decision support framework is proposed that will assist the AHJ and FPEs in determining whether a fire safety analysis is of sufficient technical adequacy to support decision-making, regulatory or otherwise. Additionally, a decision support tool is developed to provide measures of confidence regarding an analysis’s conclusions and assist in identifying those aspects of the analysis most requiring corrective action. Lastly, while developed to address performance-based design approaches to fire safety engineering, the framework may easily be adapted to similar approaches in other fields of engineering, or more generally, applications that make use of process-oriented, analysis-driven design."

The ability to predict the temperatures in protected steel structures is of vital importance for the progress of fire safety engineering. Existing methods are limited in several respects, typically being computationally restricted and limited to examination of the performance of specific components. This thesis investigates a generalised CFDbased methodology for thermal analysis of structural members in fire, developed to overcome these limitations. A novel methodology has been developed, known as GeniSTELA (Generalised Solid ThErmal Analysis), which computes a “steel temperature field” parameter in each computational cell. The approach is based on a simplified 1D model for heat transfer, together with appropriate corrections for 2D and 3D effects, to provide a quasi- 3D solution with a reasonable computational cost. GeniSTELA has been implemented as a submodel within the SOFIE RANS CFD code. The basic operation of the model has been verified and results compared to the empirical methods in EC3, indicating a satisfactory performance. The role of the surface temperature prediction has been examined and demonstrated to be important for certain cases, justifying its inclusion in the generalised method. Validation of the model is undertaken with respect to standard testing in fire resistance furnaces, examining the fire ratings of different practical protection systems, and the BRE large compartment fire tests, which looked at protected steel indicatives in full-scale post-flashover fires; in both cases, a satisfactory agreement is achieved. Model sensitivities are reported which reveal the expected strong dependencies on certain properties of thermal protection materials.

I Sverige styrs det förebyggande brandskyddsarbetet sedan 2010 av en nollvision som lyder: ”Ingen ska omkomma eller skadas allvarligt till följd av brand”. Utvecklingen av antalet dödsbränder har stadigt minskat under lång tid och ligger nu på runt 100 dödsfall i brand varje år. För åldersgruppen 65+ har utvecklingen dock stagnerat och på senare tid sker inte längre någon minskning av antalet dödsfall i brand i denna grupp. Dessa står för drygt hälften av alla omkomna i brand årligen och med tanke på den kommande ökade andelen äldre i samhället finns det nu oro för hur detta kommer att påverka utvecklingen av äldre som omkommer i brand. Det brinner inte oftast hos äldre, men när det brinner omkommer de. Äldre bor främst i egna bostäder och på senare tid har bostäder som marknadsförs åt äldre (t.ex. senior-/trygghetsbostäder, 65+, 70+, etc.) upptagit en växande andel av dessa. Detta i takt med ett ökat bostadsbehov bland äldre och en kvarboendeprincip där individer så långt som möjligt ska beredas möjlighet att bo kvar i sina egna bostäder när de blir äldre. Problemet är att dessa bostäder trots att de marknadsförs som tryggare bara uppfyller det i social bemärkelse. Brandskyddsmässigt har de inte högre brandskydd än vanliga bostäder eftersom de tilldelats samma verksamhetsklass (Vk 3A). I denna studie har det nuvarande byggnadstekniska brandskyddet studerats i ett urval av projekt som marknadsförts åt äldre. Studien visar att projekten i urvalet alla möter Vk 3A och endast några få har högre ambitioner brandskyddsmässigt. I två av dessa fall handlar ambitionerna om förstärkt varseblivningssystem och i ytterligare två om installation av spisvakt i samtliga bostäder. Dessutom framkom det att fler än hälften av projekten dimensionerats med utgångspunkt i att räddningstjänsten ska bistå utrymning. Något som är bekymmersamt med tanke på att mer än hälften av landets räddningstjänster i en nylig studie uppgav att de har problem med att upprätthålla en kontinuerlig beredskap. Dessutom har studien sökt sakkunniga för att i en enkät redogöra för äldres förmåga att utrymma själva i bostadstypen och det individanpassade brandskyddsarbetet i kommunen. En enkät skickades även till räddningstjänster för att ta reda på deras perspektiv och deras erfarenheter av problemet. Sammantaget identifierar både tidigare studier, och respondenter till denna studie, verksamhetsklassificeringen som ett stort problem i bostadstypen. De vidhåller att individanpassat brandskyddsarbete aldrig kan ersätta individens förmåga att utrymma. Därtill arbetar bara hälften av landets kommuner med individanpassat brandskydd i någon form. Konsekvensen av detta är att brandskyddet äldre får är beroende på var i landet de bor och följaktligen blir inte brandskyddet jämlikt. Detta är inte ett problem utan lösning, snarare tvärt om. Det är ett problem som kräver en mängd lösningar på nationell och lokal nivå. En del av problemen kan lösas med relativt enkla medel genom ökat stöd från myndigheter till kommuner som kämpar med att få igång individanpassat brandskyddsarbete. Andra problem – som verksamhetsklassificeringen – kräver en översyn av utformningen av den existerande brandskyddslagstiftningen. Det är förståeligt att myndigheter, med tanke på den kommande demografiska utvecklingen, vill driva på byggnation av bostäder. Men det borde inte behöva vara på bekostnad av de boendes säkerhet och trygghet. / Since 2010 preventive fire-safety measures in Sweden are all based on a common zero vision that reads: “No one should die or be seriously injured because of fire”. For the past half-century there has been a steady decline in fire-related deaths and in recent years that number has been around 100 each year. However, for one group of individuals that decline has ceased. For individuals older than 65 the death toll has been a steady average of 50 fire-related deaths per year for some time. These represent half of all fire-related deaths each year and the predicted population-increase in this age-group has started to cause some concern about how this will affect the death-toll. Individuals older than 65 primarily live in their own homes. In recent years homes specifically marketed to the elderly (in terms of safety and comfort) have taken up a larger portion of those. This increase in homes marketed to the elderly has followed a greater need for homes for the elderly as well as a Swedish principle of “home-living”. The idea is that individuals should be afforded every possibility to remain in their own homes as they age. The problem with these marketed homes is that the safety and comfort they promise is so in no other way than socially. Current fire-safety regulation sets no higher standard for these homes than for regular homes.  This study has examined what level of fire-safety a chosen group of build-projects for marketed homes has. The study shows that all the studied projects meet current regulations, only a few indicate higher safety-ambitions. In two of these those, the higher ambitions were enhanced warning-systems and in another two stove guards were installed in all apartments. What was more the study found that more than half of the projects were designed to require assistance from fire-rescue services in order to evacuate the building. This is particularly alarming since more than half of the fire-rescue services in Sweden reported not being able to maintain continuous service in a recent study.  Additionally, this study has surveyed municipal-experts for information on what ability elderly in these marketed homes have to evacuate on their own and on how they work with individually adapted fire-safety in the municipality. Fire-safety services were also surveyed for their knowledge and experience with the issue. In conclusion, both previous studies and the respondents to this study identify the fire-safety regulations applied to these marketed homes as an issue of significance. They all conclude that individually adapted fire-safety cannot possibly replace the individual’s capability to evacuate. Furthermore, only half of Swedish municipalities have adapted the process of individually adapted fire-safety in some way or shape. The main consequence of this is that the level of fire-safety elderly are prepared varies across the country and consequently fails to be equal. The issue at hand requires a multitude of solutions on a local and national scale. Some issues are relatively easily solved by government agencies providing more support to struggling, smaller municipalities. Other issues – like the lacking regulations for the marketed homes – require a review of current fire-safety regulations. It is understandable for agencies to want to meet a housing deficit, especially considering the looming demographic changes. But it should not come at the cost of elderly individuals’ safety and comfort.

The model building and fire codes in Canada permit prescriptive-based design and performance-based design approaches. Within this regulatory framework, prescriptive-based designs are attributed objective and functional statements to qualify the level of fire protection and life safety required. Performance-based designs, or alternative solutions to prescriptive-based designs, must be demonstrated to achieve at least an equivalent level of performance as the prescriptive requirement based on evaluation of each associated objective and functional statement. Due to the qualitative performance descriptions available, the current system for developing and reviewing alternative solutions is vulnerable to the acceptance of over-designed or under-designed life safety and fire protection measures in buildings. The objective of this thesis is to establish a method to compare the performance of alternative solutions with prescriptive design requirements on a quantitative basis. This thesis generates eight objectives for a fire risk analysis tool to address the challenges identified in the building regulatory industry. Based on review of existing techniques, a new fire risk analysis framework is developed. The Quantitative Design Decision (QDD) method, integrates risk analysis with quantitative decision assessment techniques to facilitate application-specific quantification of performance objectives and to aid evaluation of performance-based designs. The method utilizes an iterative three-stage structure. To demonstrate the application of the QDD method, a case-study simulation has been conducted. The case-study provides an evaluation of alternative designs to the prescriptive requirements for explosion-relief ventilation in rooms housing flammable vapour producing operations. The case study supports the conclusion that QDD achieves the eight objectives set out in this thesis. For validation, the QDD method must be applied to a wider variety of practical design challenges and it is recommended that the results be considered in conjunction with live fire test data to verify key aspects of the performance decisions generated. Future work should include evaluation of Delphi technique application in the Design Decision Stage of the QDD method. It is proposed that the method developed can be extended for use as a general performance-based design tool.

Tyrimo objektas - ūkininkų konsultavimo priešgaisrinės saugos klausimais organizavimas. Tyrimo dalykas – ūkio priešgaisrinė sauga. Darbo tikslas - nustatyti ūkininkų konsultavimo priešgaisrinės saugos klausimais organizavimo ypatumus ir parengti konsultavimo organizavimo gerinimo planą. Uždaviniai : 1. Surinkti, susisteminti ir išanalizuoti literatūrą apie konsultavimo priešgaisrinės saugos klausimais organizavimą. 2. Ištirti ūkininkų konsultavimo priešgaisrinės saugos klausimais organizavimą Lietuvoje 3. Nustatyti ūkininkų konsultavimo priešgaisrinės saugos klausimais organizavimo būklę, principus ir metodus. 4. Parengti ūkininkų konsultavimo priešgaisrinės saugos klausimais organizavimo gerinimo priemonių planą. Tyrimo metodai : loginis, indukcijos, dedukcijos, analizės, sintezės, palyginimo, grafinio vaizdavimo, focus grupių interviu. / Research object - advising farmers on the fire safety aspects of organization. Research subject - agricultural fire safety. Research aim - Farmers set fire safety advice on the organization of special features and advisory organization to develop a plan to improve. Objectives: 1. Collect, codify, and analyze the literature on fire safety advice on the organization. 2. Investigate the farmers' advice on fire safety in the organization of Lithuania. 3. Set of advising farmers on the fire safety aspects of the organization of the state, the principles and methods. 4. Develop farmers' advisory organization on matters of fire safety improvement plan Research methods: logic, induction, deduction, analysis, synthesis, comparison, and graphic imaging, focus group interviews.

In recent years several high-profile building fires have highlighted shortcomings in the way we design for the complex interaction of structures and fire. These weaknesses appear to arise from a combination of gaps in knowledge of some of the more intricate aspects of compartment fire dynamics and from limitations in the engineering applications developed to date from hitherto established fundamentals. In particular the One Meridian Plaza Fire (1991), the Madrid Windsor Tower Fire (2005) and the Lakanal House Fire (2009) have emphasised the need for further study in the field of post-flashover compartment fires and the often consequent external fires that emerge from the compartment openings. External fire plumes impinge upon the structural façade, causing added structural stress, and often result in external fire spread and secondary ignition in upper level compartments. Hence a better understanding of the effect had by the internal compartment fire on the development of external flaming and the insult of the plume to its surroundings is beneficial for Structural Engineers, Fire Protection Engineers and Emergency Response Personnel alike. This research explores existing correlations, identifies their limitations and proposes a simplified methodology that links key parameters found to govern the internal post-flashover compartment fire to the heat flux potentially imposed on the exterior façade. Existing correlations addressing the effect of compartment fires on the insult to the external structure have largely been compiled by Law and are summarised in the form of a design manual for bare external structural steel [1]. Formulated in the 1970s, these correlations are based on the combined findings of several different experimental tests devised to investigate component phenomena of compartment fires and external flaming, forming an analytical model which is mostly empirical in nature. The methodology is convoluted and has several inherent assumptions which give rise to various limits of applicability however it is currently still used in structural-fire design, but best known as Annex B of both Eurocodes 1 and 3 [2,3]. As part of the present research, full-scale fire tests are conducted in situ, in a highly instrumented high-rise building, to provide high-resolution measurements of several internal compartment fire characteristics during a post-flashover fire in a modern, realistically-furnished compartment. External high resolution instrumentation in the main test also provides detailed measurements of the external flaming and distribution of heat flux incident on the façade. The tests provide realistic benchmark scenario data for comparing physical measurements against the analytical Law Model, the difference in which allows for an evaluation of the assumptions used in the model, which are often defined as ‘conservative’ in nature from the perspective of structural design. A detailed sensitivity study of the main input parameters in the Law Model allows for the identification of parameters of pivotal influence on the resultant heat flux incident on the plane of the external façade. Analysis of the Law Model and its underlying experimental basis also enables the identification of several limits of applicability of the model. Combined, these assessments show the analytical model can be stripped of unnecessary complexity and a Simplified Model is proposed with clear bounds of applicability. The proposed model describes the distribution of heat flux to the façade above a compartment opening and features only parameters of key importance, where low-dependency parameters are grouped into associated error bars. This results in a model that can be applied in the design of several building components that fall in the plane of the façade, such as structural elements, façade cladding and window arrangements. Its ease of implementation renders the model more widely accessible to different factions of the Fire Engineering Community. Furthermore, analysis of the Law Model identifies further parameters of potential importance that have, as of yet, not been addressed. A preliminary investigation conducted using Computational Fluid Dynamics (CFD) tools shows that variation in some parameters – that are not individually accounted for in the Law Model – may influence the compartment fire conditions, the consequent external flaming and the resultant external heat exposure. Therefore, it is recommended that further comprehensive experimental research be conducted into the potential influence of the identified parameters.

Over the last 20 to 30 years, the field of structural fire design has shifted from relying on single element fire resistance testing to the consideration of the effects of full-frame behaviour. The change has been driven by the desire to build more advanced structures and reduce costs. It has been facilitated in part due to structural testing, and in part due to development of complex modelling techniques. This thesis considers the modelling of concrete structures, and presents new techniques and methodologies for analysing the performance of structures in fire. The first part of this work traces modelling techniques from fundamental constitutive behaviour through to sectional capacity calculation. Load induced thermal strain and constitutive modelling approaches are investigated and their impact on structural behaviour is considered. A new, general, technique for conducting sectional analysis on concrete elements is also created. The method relies on analysis of the sectional tangent stiffness to efficiently calculate the biaxial bending capacity of a concrete section subject to any heating regime. This approach is more accurate and conservative than current methods and has the potential to be used as a design tool. This work develops a series of new approaches for the design of large structures subject to fire. A rational and quantifiable methodology is developed for assessing the performance of a structure when subject to fire; this new approach addresses the mismatch in complexity between current vi modelling techniques and measures of structural performance. It allows a more precise approach to be taken to the definition of failure; and can be easily used to compare the structure’s response to different design fires. Finally, a new technique for the definition of design fires founded on fundamental fire dynamics is presented. The approach challenges the assumptions typically made when applying temperature-time curves and is based around the observed phenomenon of travelling fires. A concrete framed structure is subject to a number of travelling fires and the response is assessed using both conventional techniques and the new, in depth analysis.

This research project aims to investigate the level of risk/safety inherent in intermediate floors of buildings designed to the Compliance Document for the New Zealand Building Code, Fire Safety Clauses C1, C2, C3, C4 (C/AS1), and develop guidance for Fire Engineers on designing fire safety for firecells containing intermediate floors. The project also aims to develop a new set of prescriptive fire safety requirements for intermediate floors and proposes an outline of a verification method for designing fire safety for intermediate floors. This study includes a literature review of the fire safety requirements for intermediate floors (mezzanines) of prescriptive requirements in New Zealand and other countries such as USA, Canada, UK and Australia. The results of this literature review found that the intermediate floor size is limited and varies with country. An intermediate floor that has an area exceeding the limit set out by the prescriptive requirements is considered as a storey in all the countries prescriptive requirements reviewed including the New Zealand prescriptive requirements prior to 1991. Since 1991, in New Zealand Acceptable Solutions, the intermediate floor that has an area exceeding the limit will not be treated as a storey, however, a smoke control system is required. The level of risk was quantified using a factor of safety (FoS) - the ratio of Available Safe Egress Time (ASET) to Required Safe Egress Time (RSET). Two fire models; BRANZFIRE and FDS were used to calculate ASET and SIMULEX, an evacuation program, was used to calculate movement times of the occupants of the studied buildings. Unlike the traditional method in which RSET and FoS are assessed using single value, in this project the distribution of RSET and FoS were assessed using the @RISK software package. The analysis showed that the level of risk to the occupants of the firecells containing intermediate floors is always higher than that of the equivalent firecells without intermediate floors with the same occupant load and the differences in FoS range from 10% to 60%. The analysis also highlighted that the level of risk to the occupants of firecells having intermediate floors increases as the intermediate floor size increases, however, there are no clear cut-off points at which a higher level of fire safety precaution should be provided. The cut-off points in C/AS1 of 20% for a closed intermediate floor and 40% for an open intermediate floor, are not justified by this analysis. Occupant load has significant impact on the level of safety of the occupants of the firecells containing intermediate floors. The higher the occupant load the lower the level of safety is. The definitions for open and closed intermediate floors are proposed to which open and closed intermediate floors are clearly distinguished. The term “limited area intermediate floor” in the current C/AS1 is proposed be removed and all related clauses are proposed to be amended or deleted accordingly. A proposed new set of prescriptive fire safety requirements for intermediate floors has been developed based on the occupant load of intermediate floors and not the intermediate floor size in the form of a table similar to the current Table 4.1 of C/AS1. The occupant load and fire safety precautions (FSPs) of the intermediate floors are determined based on the occupant load and their required FSPs of the equivalent firecells without intermediate floors that have the same factor of safety with the firecells containing intermediate floors. With the proposed FSPs, a firecell with lower occupant load would require lesser fire safety requirements than a firecell with higher occupant load regardless of intermediate floor size. Moreover, with the proposed FSPs for intermediate floors, the level of safety of the occupants of the firecells having intermediate floors would be very similar to the level of safety of the equivalent firecells without intermediate floors. In addition to the proposed tables of FSPs, some clauses regarding the changes in the fire safety requirement and definitions for intermediate floors are proposed. Guidance for designers in designing fire safety for firecells containing intermediate floors in which the methods of modelling using BRANZFIRE and Fire Dynamics Simulator (FDS) are presented in detail, has been developed. The analysis has pointed out that the location of the exits is critical in designing fire safety for firecells containing intermediate floors and majority of exits from the lower floor should not be located under intermediate floors. Although one of the main objectives of this research project was to propose an outline of a verification method for designing fire safety for intermediate floors, the analysis showed that it is very difficult to develop a rational verification method for designing fire safety for firecells containing intermediate floors. Using the proposed FSPs for intermediate floors which are based on the occupant load of the intermediate floors in designing fire safety for firecells containing intermediate floors is recommended by this study. These recommendations do not preclude the use of specific fire engineering design for designing fire safety for firecells having intermediate floors.