Fire Safety for Very Tall Buildings

Very tall buildings have unique fireplace security design points that aren’t experienced in other kinds of buildings. For instance, as a end result of the height of the construction is beyond the attain of ladders, tall buildings are geared up with more hearth security options as it’s not potential for the fireplace division to initiate exterior rescues from ladders and suppress fires with exterior hose streams.
In regards to fire safety, the performance history of very tall buildings while very successful, has not been without catastrophic incidents. Many of these incidents have resulted in 1) numerous deaths and injuries, 2) extreme property loss and 3) disruptions in business continuity. For example, the One Meridian Plaza high-rise fire in Philadelphia that occurred in 1991 resulted within the lack of three firefighters and constructing never being re-opened. In 1988, the fireplace within the Interstate Bank Building in Los Angeles experienced one fatality and resulted in the constructing being out of use for six months.
Based on research and lessons learned, the mannequin building codes have made important progress in addressing fire questions of safety in very tall buildings. At the identical time, the complexity and unique challenges of today’s very tall buildings have created an environment the place complete performance-based options have turn into a necessity.
To assist the design group with creating performance-based fire 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 facet of native codes and requirements and serves as an added tool to those involved within the fire protection design of unique tall buildings. The information focuses on design points that have an result on the hearth safety efficiency of tall buildings and how engineers can incorporate performance-based fire safety by way of hazard and danger evaluation methodologies into the design of tall buildings. This article will discuss some of the unique hearth safety design strategies/methodologies employed in 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 as the time to complete a full building evacuation increases with building peak. At the same time, above sure heights, the normal method of requiring all occupants to simultaneous evacuate may not be sensible as occupants turn out to be more weak to extra risks when evacuating by way of stairways. That is why tall buildings often employ non-traditional or different evacuation methods.
When designing an egress plan for a tall building, the first goal must be to supply an applicable means to allow occupants to move to a place of safety. To accomplish this aim, there are a number of evacuation methodologies that are out there to the design staff. These evacuation strategies can embody however usually are not restricted to 1) defend-in-place, 2) transferring folks to areas of refuge and 3) phased/progressive evacuation. It can also be possible that a combination of those strategies can be this best resolution. When deciding on an applicable technique, the design group should think about the required level of security for the building occupants and the constructing efficiency aims that are recognized by the building’s stakeholders.
Using protected elevators has become another evacuation technique that is turning into extra prevalent within the design of tall buildings. In addition to assisting the hearth department with operations and rescues, protected elevators are now getting used for building evacuation, notably for occupants with disabilities. When contemplating elevators in an evacuation strategy, there are a number of design considerations to contemplate: 1) safety and reliability of the elevators, 2) coordination of elevator controls and constructing safety techniques, 3) education of building occupants and first responders and 4) communication to building occupants through the emergency.
Tall buildings typically make use of non-traditional or alternative evacuation strategies.
Fire Resistance
The penalties of partial or international collapse of tall buildings as a end result of a severe hearth pose a major risk to numerous individuals, the hearth service and surrounding buildings. At the identical time, tall buildings usually have unique design features whose role in the structure and fire response usually are not simply understood using traditional hearth protection strategies. These unique factors could warrant a have to undertake a sophisticated structural fire engineering analysis to reveal that the building’s performance aims are met.
Performance-based design of structural fire resistance entails three steps: (1) dedication of the thermal boundary situations to a structure resulting from a hearth; (2) calculation of the thermal response of the construction to the fire exposure, and (3) dedication of the structural response of the structure. Guidance on performing this kind of evaluation could 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 hearth protection techniques can be greater than the aptitude of the basic public water provide. As such, fireplace protection system water supplies for sprinkler systems and standpipes require using pumps and/or gravity water tanks to boost the water pressure. Reliability of this water provide is a key consideration. As such, redundant fire pumps, gravity-based storage supplies, or both may be needed to reinforce system reliability.
Another concern to consider when designing water-based hearth suppression methods is strain management as it’s attainable for system parts to be exposed to pressures that exceed its most working strain. Consequently, it might be necessary to design vertical strain zones to regulate pressures in the zone. Additionally, stress regulating valves are sometimes needed. When put in, care should be taken to ensure that these stress regulating valves are put in correctly and adequately maintained.
Fire Alarm and Communication Systems
Providing building occupants with accurate information throughout emergencies increases their capability to make acceptable selections about their very own security. Fire alarm and communication methods are an important supply of this data. Very tall buildings employ voice communication methods which are integrated into the fireplace alarm system. When designing voice communication systems it is essential to ensure that the system supplies reliable and credible info.
Fire alarm system survivability is one other import issue to contemplate in hearth alarm system design. For tall buildings, consideration ought to be given in order that an attack by a hearth in an evacuation zone doesn’t impair the voice messaging outside the zone. Some of the design concerns to attain survivability could embrace: 1) safety of control gear from fire, 2) safety of circuits. 3) configuration of circuits and 4) shielding of panels.
Tall buildings typically make use of smoke control systems that both vent, exhaust or limit the spread of smoke.
Smoke Control
Controlling the unfold of smoke is more difficult in tall buildings. For example, tall buildings experience a phenomenon called stack effect. Stack effect happens when a tall constructing experiences a pressure difference all through its peak because of temperature differentials between the skin air temperature and the within constructing temperature. This causes air to move vertically, depending on the surface air temperature – both upward or downward in a building. It also can cause smoke from a building hearth to unfold all through the building if not controlled. That is why tall buildings usually make use of smoke management systems that either vent, exhaust or restrict 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 motion attributable to elevator vehicles ascending and descending in a shaft and the results of wind can result in smoke motion in tall buildings. These impacts turn out to be extra pronounced as the height of the constructing enhance.
Because very tall buildings complicate smoke unfold, effective smoke management is tougher to achieve. The potential solutions are numerous and embrace a mixture of energetic and passive features similar to but not limited to: 1) smoke barrier walls and flooring, 2) stairway pressurization methods, 3) pressurized zoned smoke management provided by the air-handling equipment, and 4) smoke dampers. The resolution carried out into the design needs to deal with the building itself, its makes use of, related occupant traits and reliability.
First Service Issues
It goes with out saying that tall buildings current unique challenges to the fire service. During the planning and design phases, it is important for the design staff to work with the hearth service to debate the sort of sources that are needed for an incident and the actions that shall be wanted to mitigate an incident. This consists of growing building and post-construction preplans. Triple should embrace and never be limited to making provisions for 1) fireplace service entry including transport to the best degree of the building, 2) establishing a water supply, 3) standpipe techniques (temporary and permanent), 4) communication methods, and 5) understanding the operations of the fireplace safety techniques within the building.
One of the challenges the hearth service faces during incidents in tall buildings is the flexibility of firefighters to move gear to the incident location. Designers should take into account how the fire service can transport its equipment from the response stage to the best degree in a protected method.
Additionally, care must be taken when designing the fire command center as it’ll provide the hearth service command employees with important details about the incident. The fireplace command center must be accessible and should include 1) controls for constructing methods, 2) contact information for building 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.
3 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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