Very tall buildings have unique hearth safety design issues that are not skilled in other types of constructions. For example, because the peak of the construction is beyond the reach of ladders, tall buildings are geared up with extra hearth security features as it isn’t possible for the fireplace department to initiate exterior rescues from ladders and suppress fires with exterior hose streams.
In regards to fireside security, the efficiency history of very tall buildings while very successful, has not been without catastrophic incidents. Many of those incidents have resulted in 1) numerous deaths and accidents, 2) extreme property loss and 3) disruptions in business continuity. For example, the One Meridian Plaza high-rise hearth in Philadelphia that occurred in 1991 resulted in the lack of three firefighters and building by no means 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 lessons discovered, the mannequin building codes have made important progress in addressing hearth safety issues in very tall buildings. At the identical time, the complexity and unique challenges of today’s very tall buildings have created an setting where complete performance-based solutions have turn into a necessity.
To assist the design community with developing performance-based fireplace security solutions 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 at the aspect of native codes and requirements and serves as an added device to those involved within the fireplace safety design of unique tall buildings. The information focuses on design issues that affect the hearth safety performance of tall buildings and the way engineers can incorporate performance-based hearth safety through hazard and threat evaluation methodologies into the design of tall buildings. This article will discuss a few of the unique hearth safety design strategies/methodologies employed within the design of tall buildings which are referenced in the ICC/SFPE Guide.
Emergency Egress
Developing an efficient evacuation strategy for a tall building is challenging because the time to finish a full building evacuation increases with constructing peak. At the same time, above certain heights, the standard technique of requiring all occupants to simultaneous evacuate will not be practical as occupants become extra vulnerable to extra dangers when evacuating by way of stairways. That is why tall buildings often make use of non-traditional or alternative evacuation methods.
When designing an egress plan for a tall building, the primary goal should be to offer an applicable means to allow occupants to maneuver to a place of security. To accomplish this objective, there are a number of evacuation methodologies which would possibly be out there to the design group. These evacuation methods can embrace however usually are not limited to 1) defend-in-place, 2) shifting folks to areas of refuge and 3) phased/progressive evacuation. It is also possible that a mixture of those methods could be this greatest answer. When deciding on an appropriate technique, the design group ought to think about the required degree of safety for the constructing occupants and the building performance aims that are identified by the building’s stakeholders.
Using protected elevators has turn into one other evacuation strategy that’s becoming more prevalent within the design of tall buildings. In addition to aiding the fireplace department with operations and rescues, protected elevators at the second are being used for building evacuation, notably for occupants with disabilities. When contemplating elevators in an evacuation strategy, there are a variety of design issues to contemplate: 1) security and reliability of the elevators, 2) coordination of elevator controls and building security systems, 3) schooling of constructing occupants and first responders and 4) communication to building occupants during the emergency.
Tall buildings typically employ non-traditional or various evacuation strategies.
Fire Resistance
The penalties of partial or global collapse of tall buildings because of a extreme fireplace pose a big danger to a massive number of people, the fire service and surrounding buildings. At the same time, tall buildings usually have unique design features whose role within the construction and hearth response usually are not easily understood using traditional fire protection methods. These distinctive components may warrant a need to adopt a complicated structural fire engineering evaluation to show that the building’s efficiency aims are met.
Performance-based design of structural hearth resistance entails three steps: (1) determination of the thermal boundary circumstances to a construction resulting from a hearth; (2) calculation of the thermal response of the construction to the hearth publicity, and (3) willpower of the structural response of the construction. Guidance on performing this kind of analysis may be discovered in 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.3
Water-Based Fire Suppression Systems
In tall buildings, the water supply required for fireplace safety methods may be larger than the capability of the public water supply. As such, fireplace safety system water provides for sprinkler systems and standpipes require using pumps and/or gravity water tanks to boost the water stress. Reliability of this water provide is a key consideration. As such, redundant hearth pumps, gravity-based storage supplies, or each could also be wanted to boost system reliability.
Another concern to think about when designing water-based fire suppression techniques is pressure control as it’s attainable for system parts to be uncovered to pressures that exceed its most working stress. Consequently, it may be essential to design vertical pressure zones to control pressures in the zone. Additionally, strain regulating valves are sometimes needed. When installed, care must be taken to ensure that these strain regulating valves are put in correctly and adequately maintained.
Fire Alarm and Communication Systems
Providing constructing occupants with correct data during emergencies increases their capability to make acceptable selections about their own safety. Fire alarm and communication methods are an essential source of this information. Very tall buildings employ voice communication techniques which are integrated into the hearth alarm system. When designing voice communication methods you will need to be positive that the system provides dependable and credible information.
Fire alarm system survivability is another import factor to assume about in fire alarm system design. For tall buildings, consideration must be given so 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 achieve survivability might embody: 1) safety of management equipment from hearth, 2) protection of circuits. 3) configuration of circuits and 4) shielding of panels.
Tall buildings typically make use of smoke control methods that both vent, exhaust or restrict the unfold of smoke.
Smoke Control
Controlling the spread of smoke is more sophisticated in tall buildings. For example, tall buildings experience a phenomenon known as stack effect. Stack impact occurs when a tall constructing experiences a pressure distinction all through its peak because of temperature differentials between the surface air temperature and the inside building temperature. This causes air to move vertically, depending on the outside air temperature – both upward or downward in a building. It can even cause smoke from a building fireplace to spread all through the constructing if not controlled. That is why tall buildings typically employ smoke administration systems that either vent, exhaust or restrict the spread of smoke.
Other considerations in tall buildings included the air motion created by the piston effect of elevators and the results of wind. Air movement caused by elevator vehicles 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 management is more difficult to realize. The attainable options are numerous and embody a combination of energetic and passive features similar to but not restricted to: 1) smoke barrier walls and flooring, 2) stairway pressurization systems, 3) pressurized zoned smoke control offered by the air-handling tools, and 4) smoke dampers. The answer carried out into the design wants to handle the building itself, its uses, related 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 staff to work with the fireplace service to discuss the kind of sources that are wanted for an incident and the actions that shall be wanted to mitigate an incident. This consists of developing development and post-construction preplans. These preplans ought to embrace and not be restricted to creating provisions for 1) hearth service entry including transport to the very best level of the building, 2) establishing a water provide, 3) standpipe techniques (temporary and permanent), 4) communication methods, and 5) understanding the operations of the fireplace safety techniques within the constructing.
One of the challenges the fire service faces throughout incidents in tall buildings is the ability of firefighters to move tools to the incident location. Designers ought to bear in mind how the hearth service can transport its tools from the response level to the very best degree in a safe method.
Additionally, care needs to be taken when designing the fire command middle as it’s going to present the fire service command workers with important details about the incident. The hearth command center must be accessible and may embody 1) controls for building systems, 2) contact information for constructing management, 3) present 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. ร้านซ่อมเครื่องวัดความดันomron , 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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