Very tall buildings have distinctive fire security design points that aren’t skilled in different types of structures. For instance, as a result of the peak of the construction is beyond the attain of ladders, tall buildings are geared up with more fireplace safety options as it isn’t attainable for the hearth department to initiate exterior rescues from ladders and suppress fires with exterior hose streams.
In regards to fireplace safety, the efficiency history of very tall buildings whereas very successful, has not been without catastrophic incidents. Many of these incidents have resulted in 1) quite a few deaths and injuries, 2) excessive property loss and 3) disruptions in enterprise continuity. For example, the One Meridian Plaza high-rise hearth in Philadelphia that occurred in 1991 resulted within the loss of three firefighters and building never being re-opened. In 1988, the hearth in the Interstate Bank Building in Los Angeles experienced one fatality and resulted within the constructing being out of use for six months.
Based on analysis and classes learned, the mannequin constructing codes have made important progress in addressing fire issues of safety in very tall buildings. At the same time, the complexity and distinctive challenges of today’s very tall buildings have created an surroundings the place comprehensive performance-based options have turn into a necessity.
To assist the design group with developing performance-based fireplace security options for very tall buildings, in 2013, the Society of Fire Protection Engineers (SFPE) partnered with the International Code Council (ICC) to develop the Engineering Guide: Fire Safety in Very Tall Buildings.1 This publication is written as a guide to be used in conjunction with native codes and requirements and serves as an added device to these concerned within the hearth protection design of distinctive tall buildings. The guide focuses on design points that have an effect on the fireplace safety efficiency of tall buildings and the way engineers can incorporate performance-based hearth safety by way of hazard and danger analysis methodologies into the design of tall buildings. This article will talk about some of the unique hearth safety design strategies/methodologies employed in the design of tall buildings which may be referenced in the ICC/SFPE Guide.
Emergency Egress
Developing an efficient evacuation technique for a tall constructing is difficult because the time to complete a full building evacuation increases with building peak. At the identical time, above sure heights, the normal methodology of requiring all occupants to simultaneous evacuate will not be sensible as occupants become more weak to further risks when evacuating by way of stairways. That is why tall buildings typically make use of non-traditional or various evacuation strategies.
When designing an egress plan for a tall constructing, the primary objective should be to provide an applicable means to permit occupants to maneuver to a place of safety. To accomplish this aim, there are several evacuation methodologies that are available to the design team. These evacuation strategies can embody however are not limited to 1) defend-in-place, 2) transferring individuals to areas of refuge and 3) phased/progressive evacuation. It is also possible that a mixture of those methods may be this finest answer. When deciding on an applicable strategy, the design staff should contemplate the required degree of security for the constructing occupants and the building efficiency aims which may be identified by the building’s stakeholders.
Using protected elevators has become one other evacuation technique that is turning into extra prevalent within the design of tall buildings. In addition to helping the fireplace division with operations and rescues, protected elevators are actually getting used for building evacuation, particularly for occupants with disabilities. When considering elevators in an evacuation strategy, there are a variety of design considerations to contemplate: 1) security and reliability of the elevators, 2) coordination of elevator controls and building safety techniques, 3) training of constructing occupants and first responders and 4) communication to constructing occupants through the emergency.
Tall buildings typically employ non-traditional or various evacuation strategies.
Fire Resistance
The penalties of partial or world collapse of tall buildings due to a extreme fire pose a big threat to a lot of folks, the hearth service and surrounding buildings. At the same time, tall buildings typically have distinctive design options whose function within the structure and hearth response aren’t simply understood utilizing conventional fireplace protection methods. These distinctive elements might warrant a have to adopt an advanced structural fire engineering analysis to reveal that the building’s efficiency objectives are met.
Performance-based design of structural hearth resistance entails three steps: (1) willpower of the thermal boundary situations to a construction ensuing from a fire; (2) calculation of the thermal response of the construction to the hearth exposure, and (3) determination of the structural response of the construction. Guidance on performing this sort of evaluation could be discovered within the SFPE Engineering Standard on Calculating Fire Exposures to Structures2, and SFPE Engineering Standard on Calculation Methods to Predict the Thermal Performance of Structural and Fire Resistive Assemblies.three
Water-Based Fire Suppression Systems
In tall buildings, the water supply required for fireplace protection systems can be greater than the aptitude of the public water supply. As such, fire protection system water supplies for sprinkler systems and standpipes require the utilization of pumps and/or gravity water tanks to boost the water strain. ร้านซ่อมเครื่องวัดความดันโลหิต of this water supply is a key consideration. As such, redundant hearth pumps, gravity-based storage provides, or both could also be wanted to boost system reliability.
Another problem to contemplate when designing water-based hearth suppression systems is strain management as it’s attainable for system parts to be exposed to pressures that exceed its most working stress. Consequently, it may be essential to design vertical stress zones to manage pressures in the zone. Additionally, pressure regulating valves are sometimes wanted. When put in, care have to be taken to ensure that these stress regulating valves are installed correctly and adequately maintained.
Fire Alarm and Communication Systems
Providing constructing occupants with accurate data during emergencies increases their capacity to make applicable decisions about their very own safety. Fire alarm and communication methods are an necessary source of this information. Very tall buildings make use of voice communication techniques which may be integrated into the fire alarm system. When designing voice communication systems you will need to make sure that the system provides dependable and credible data.
Fire alarm system survivability is another import issue to think about in hearth alarm system design. For tall buildings, consideration ought to be given in order that an attack by a fireplace in an evacuation zone does not impair the voice messaging exterior the zone. Some of the design issues to attain survivability may embrace: 1) safety of control gear from fire, 2) protection of circuits. 3) configuration of circuits and 4) shielding of panels.
Tall buildings typically make use of smoke control techniques that both vent, exhaust or restrict the unfold of smoke.
Smoke Control
Controlling the spread of smoke is extra complicated in tall buildings. For instance, tall buildings expertise a phenomenon referred to as stack effect. Stack effect happens when a tall building experiences a strain distinction all through its top on account of temperature differentials between the skin air temperature and the within constructing temperature. This causes air to maneuver vertically, depending on the skin air temperature – either upward or downward in a building. It can even trigger smoke from a constructing hearth to spread all through the constructing if not controlled. That is why tall buildings typically employ smoke administration techniques that both vent, exhaust or limit the unfold of smoke.
Other considerations in tall buildings included the air motion created by the piston effect of elevators and the effects of wind. Air movement caused by elevator automobiles ascending and descending in a shaft and the effects of wind can end result in smoke motion in tall buildings. These impacts become extra pronounced as the height of the building increase.
Because very tall buildings complicate smoke unfold, effective smoke control is more difficult to attain. The possible options are quite a few and embrace a mixture of active and passive options similar to however not restricted to: 1) smoke barrier partitions and floors, 2) stairway pressurization techniques, 3) pressurized zoned smoke control offered by the air-handling gear, and 4) smoke dampers. The answer implemented into the design wants to deal with the building itself, its makes use of, relevant occupant characteristics and reliability.
First Service Issues
It goes without saying that tall buildings present unique challenges to the fire service. During the planning and design phases, it is necessary for the design group to work with the hearth service to debate the type of assets which are needed for an incident and the actions that will be wanted to mitigate an incident. This includes creating construction and post-construction preplans. These preplans ought to embrace and never be restricted to creating provisions for 1) fireplace service entry including transport to the best stage of the constructing, 2) establishing a water provide, 3) standpipe systems (temporary and permanent), 4) communication systems, and 5) understanding the operations of the hearth protection methods in the constructing.
One of the challenges the fire service faces throughout incidents in tall buildings is the power of firefighters to maneuver gear to the incident location. Designers ought to keep in mind how the fire service can transport its equipment from the response level to the best level in a protected method.
Additionally, care needs to be taken when designing the fire command middle as it’s going to present the fireplace service command workers with important information about the incident. The hearth command heart must be accessible and should include 1) controls for constructing methods, 2) contact info for constructing management, 3) current buildings plans, 4) emergency response and egress plans and 5) preplans.
1 International Code Council/SFPE. (2013). Engineering Guide: Fire Safety for Very Tall Buildings. Country Club Hills, IL.
2 SFPE. (2011). SFPE Standard S.01 2011, Engineering Standards on Calculating Fire Exposures to Structures. Gaithersburg, Maryland.
three SFPE. 2015). SFPE Standard S.02 2015, SFPE Engineering Standard on Calculation Methods to Predict the Thermal Performance of Structural and Fire Resistive Assemblies. Gaithersburg, Maryland.
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