Means of Escape in Residential Buildings - Term Paper Example

Means of escape in residential buildings Abstract This paper looks at the basic standards that are implemented in the provision of routes of escape in residential buildings and the design of the escape routes in the residential buildings. In the paper the standard by laws used in building of residential houses will be applied in their relation to residential buildings. There is much concern to the issue of fire safety due to the chances of occurrence of fires in buildings. The case of the Charm house will be taken as a case study. The manner of improvement of the house will be checked and a performance based modeling will be done using ASET-RSET. Attributes of fire safety will be identified and risk components in the building will also be assessed with a particular concern to risks to life and the process of evacuation in such a case (Ramachandran, 1999). Introduction There has been a growing concern on the level fire management concerning fire safety in the buildings. Due to the broad nature of the fire safety subject as at the moment, there are no firm standards that can be said to be followed in the design of residential buildings. The adequacy of the escape routes that are used in the fire instances cannot be measured through any empirical means yet. The present methods which are being used provide escape through a set of procedures in form of rules and regulations. The rules have been constantly changing over time are deemed to provide the escape routes in a satisfactory manner (Gwynne, et al. 1999). In the fire safety definitions, there is a variety of factors that seem to answer the question that are taken into consideration. According to Rasbash, et. al. (2004), fire safety is defined as goals and also as aims prevention, control and protection of the occupants of a building from fire. Fire safety is the application of a certain set of principles, policies, tools, information, standards and practices so as to analyze, evaluate and control fire safety. The building and the design of the fire escape routes should be in such a way that they have enough fire doors in order to avoid trapping the occupants in the building once the buildings catch fire. One of the major problems that are experienced when evacuating people from a building is smoke penetrating to the escape routes in instances of breakages and spaces in the fire doors. At the same time, problems are encountered when there is heavy traffic in the evacuation process. When there are enough aspects of fire safety such as active “fire separation systems”, detection systems, and such should be maintained at a high standard due to the vulnerability of the buildings to fire outbreaks. In the uplifting of the fire safety standards of charm house, it is necessary to put the basic fire safety regulations for standard residential buildings into consideration (Shields & Silcock, 1987). Fire safety: Background Fire safety in a building is a very pertinent issue which should meet adequate addressing from the management and any other person in the design and construction of a building, in particular a residential building. This is a matter that should be put into consideration prior to occurrence of a fire hazard. In the design and reconstruction of the charm house, it is important to look at the design and construction of the escape routes and also the safe assembly. In the first place, there should be a reconsideration of the use of iron grills at the main entrance as a means of harnessing security as this greatly increases the potential of a fire outbreak to a great extent. Safety in a building, like in any other place will be increased with a considerable reduction in the risk that is posed. This building cannot have absolute safety but the risk of fire can be reduced by reducing the risk associated with the structure, occupants and the contents which will be used in the design of this building. This is so due to the nature in which the occupants of a building affect the rate by which a certain fire affects a place if the evacuation procedures are theoretically put followed. Evacuation and escape A residential house has some basic concepts which provide the escape routes during the construction process. They compose of a primary escape route and a secondary escape route. In a residential area such as the Charm house which has more than two rooms, every bedroom as well as every sitting room deserves to have at least one primary escape route and one secondary escape route. The primary means of escaping from a building on fire are realized through escape doors, stairways and or a ramp which can provide a means through which one can get unobstructed movement to the outside of the building at the streets or the ground. Secondary escape routes may comprise of: - 1) Doors, stairways, passages or halls that can provide unrestricted travel from the building to the outside at the streets or the ground and which is free from the primary means of escape from the building. 2) A passage which is through adjacent non lockable spaces that is independent of the primary means of escape and also remote from those means. 3) An exterior window or a door that can be opened from inside the building without the application of any tools and subsequently provides an opening which is clear and of at least 20 inches wide, 24 inches high and with an area of 5.7 feet (squared). The bottom of this opening shall be at most 1.12 meters from the ground. These means of escape shall meet the following condition: - The window to be within 6,1 meters of grade The window to be directly accessible to the rescue apparatus of the fire department as per the jurisdiction of the authority, The door or the window opens to a balcony at the exterior Performance based assessment The response in design of this house can be compared to the evacuation dynamics of a standard house. In design of the fire escape routes, some factors need to be considered in the building such as the behavior of the occupants, the architecture of the house and the fire products. Considering the human behavior, two models can be applied in evacuation design processes which are the lattice gas and the social force model. In designing the fire protection system to be optimal and also rational, it is pertinent that we calculate the “required safe egress time-RSET” in the proper manner. In this case, one has to consider the process of fire development and evacuation which are synchronous and also happen at the same time. For human safety, the most important phases of fire development are the fire breaking out period and the fire increasing period. The process of evacuation will then involve perception of the fire, preparation, evacuation and reaching of safe place. In evacuation, the most significant moments are “fire detection time” and “fire endangering human safety”. So as to have guaranteed human safety in this building, RSET must be smaller than the ASET (“Available Safe Egress Time”). In the above explanations, RSET represents the time span between the moments the fire breaks out to the moment that all people are safely evacuated. It includes the following aspects: - Detecting time and alarm time: talarm Pre-movement : tpre movement time: tmove recognition time: treg response time: tresp RSET = talarm + tmove + tpre = talarm+( treg + tresp) + tmove The alarm time estimate is through the simulation of the smoke spread and detection system characteristics. Pre-movement time is gotten from the statistics and the movement time comes from empirical formula or from the evacuation model (Lewin, 1992). The FDS and the CFAST models can be used to tell the source of a certain fire through some computations. CFAST - “Consolidated Fire and Smoke Model”, makes a prediction in accordance to the fire source and FDS- “Fluid Dynamic Simulator”, is driven on fluid flows. These models are tailored to show the manner in which smoke and heat transports from the fire and can thus be applied in this case to make calculations which are necessary for the design of the escape routes in the charm house (Derek & Chakib, 1999). In order to come up with workable ASET, a simulation of a window break is necessary in the FDS model. In order to come up with such a simulation in charm house, vents are set in the living room of the house. The maximum height of this window from the floor is 2m. if we adopt a polyurethane with a power of like 2.25MW/m2. In FDS, the fire does not include the walls as they burn so fast (Helbing, et al 2000). On calculating the fire result from the start of the fire, the fire rises to 1.6m after 6minutes. Considering that a temperature of over 800C can injure a person, and then the temperature will be higher than 800C at 1.6m in 220s. Carbon monoxide will reach 880ppm in 280s. Considering this calculations, the ASET will be 220s through the simulation of the FDS. This value can be used to determine the viability of the escape routes in the design process. Conclusions This paper has looked at the designing the escape routes through basic standards with an example of the charm house. Fire modeling techniques have also been looked into with an insight into the FDS and CFAST techniques and the manner in which RSET can be calculated. These values can assist in the design of the fire escape and the evacuation routes. References Canadian Wood Council (CWC), (2000), Fire safety in Residential Buildings,Building performance bulletin, series 2. Pg. 3. Derek, J. & Chakib (1999), “Fire Safety Management at Passenger Terminals”, Disaster Prevention and Management Journal, Vol. 8, No. 5, pp 362 – 369, MCB University Press. Gwynne, et al. (1999). “A review of the Fire & Materials. 23: 383-388.Howarth D.j.,Chakib Helbing D., Farkas I. and Vicsek T. (2000). “Simulating dynamical features of escape panic”, Nature. 407: 487-490. Kara-Zaiti, (1999), “Fire Safety Management at Passenger Terminals”, Disaster Prevention and Management, Vol. 8, pp 362 – 369 Lewin K., (1992). “Field Theory in Social Science”, Harper, New York. Ramachandran,G., (1999), “Fire Safety Management and Risk Assessment”, Facilities Journal, Vol. 17 No. 9/10, pp363 – 377. Shields, T. & Silcock, G. (1987), “Buildings and Fire, Longman Scientific & Technical”, New York. pg. 355. Yatim, Y.M., (2001), Fire safety in Buildings – Causes and Risks, Paper presented in National Construction Industry Symposium 2001, Sofitel and Palm Resolt, Johor. Malaysia. Read More