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Very tall buildings have unique fireplace security design points that aren’t experienced in other types of structures. For instance, because the height of the structure is past the attain of ladders, tall buildings are outfitted with extra hearth safety options as it’s not potential for the fire division to provoke exterior rescues from ladders and suppress fires with outside hose streams.
In regards to fire security, the efficiency history of very tall buildings whereas very successful, has not been without catastrophic incidents. Many of those 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 building never being re-opened. In 1988, the hearth within the Interstate Bank Building in Los Angeles skilled one fatality and resulted in the building being out of use for six months.
Based on research and classes learned, the model building codes have made important progress in addressing fire safety issues in very tall buildings. At the identical time, the complexity and distinctive 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 developing performance-based hearth 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 along side local codes and standards and serves as an added software to those involved within the fire safety design of unique tall buildings. The information focuses on design issues that have an result on the fire safety performance of tall buildings and how engineers can incorporate performance-based fireplace protection via hazard and danger evaluation methodologies into the design of tall buildings. This article will focus on a few of the unique fire security design strategies/methodologies employed within the design of tall buildings that are referenced in the ICC/SFPE Guide.
Emergency Egress
Developing an effective evacuation strategy for a tall building is difficult as the time to complete a full constructing evacuation increases with constructing height. At เพรสเชอร์เกจไฮดรอลิค , above certain heights, the standard method of requiring all occupants to simultaneous evacuate will not be sensible as occupants become more weak to extra risks when evacuating via stairways. That is why tall buildings often employ non-traditional or different evacuation strategies.
When designing an egress plan for a tall building, the first aim must be to supply an acceptable means to permit occupants to maneuver to a place of security. To accomplish this aim, there are several evacuation methodologies which are out there to the design team. These evacuation methods can include but usually are not limited to 1) defend-in-place, 2) shifting people to areas of refuge and 3) phased/progressive evacuation. It can also be possible that a mixture of those methods may be this finest solution. When deciding on an applicable technique, the design team ought to consider the required stage of safety for the constructing occupants and the building performance objectives which would possibly be identified by the building’s stakeholders.
Using protected elevators has turn into one other evacuation strategy that is becoming more prevalent within the design of tall buildings. In addition to aiding the fire division with operations and rescues, protected elevators at the moment are getting used for building evacuation, particularly for occupants with disabilities. When contemplating elevators in an evacuation strategy, there are a variety of design concerns to consider: 1) security and reliability of the elevators, 2) coordination of elevator controls and constructing safety methods, 3) education of constructing occupants and first responders and 4) communication to constructing occupants in the course of the emergency.
Tall buildings typically employ non-traditional or different evacuation strategies.
Fire Resistance
The consequences of partial or world collapse of tall buildings because of a severe hearth pose a big danger to a large number of folks, the fire service and surrounding buildings. At the identical time, tall buildings often have distinctive design features whose role within the structure and fireplace response are not easily understood utilizing traditional fire protection strategies. These unique components might warrant a have to adopt a complicated structural fireplace engineering evaluation to show that the building’s performance objectives are met.
Performance-based design of structural fireplace resistance entails three steps: (1) willpower of the thermal boundary conditions to a structure resulting from a hearth; (2) calculation of the thermal response of the structure to the hearth publicity, and (3) determination of the structural response of the structure. Guidance on performing this kind of evaluation may be found 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.three
Water-Based Fire Suppression Systems
In tall buildings, the water provide required for hearth protection systems can be larger than the capability of the general public water supply. As such, fire safety system water supplies for sprinkler systems and standpipes require the use of pumps and/or gravity water tanks to boost the water stress. Reliability of this water provide is a key consideration. As such, redundant fire pumps, gravity-based storage supplies, or each could also be wanted to reinforce system reliability.
Another concern to contemplate when designing water-based hearth suppression techniques is strain control as it is attainable for system elements to be uncovered to pressures that exceed its maximum working pressure. Consequently, it may be necessary to design vertical stress zones to regulate pressures within the zone. Additionally, stress regulating valves are often 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 constructing occupants with correct data during emergencies increases their capability to make acceptable choices about their very own safety. Fire alarm and communication systems are an necessary source of this info. Very tall buildings make use of voice communication methods that are integrated into the fire alarm system. When designing voice communication techniques you will want to be sure that the system provides reliable and credible info.
Fire alarm system survivability is one other import factor to consider in fireplace alarm system design. For tall buildings, consideration ought to be given in order that an attack by a fire in an evacuation zone doesn’t impair the voice messaging exterior the zone. Some of the design issues to attain survivability could embrace: 1) protection of control equipment from fire, 2) protection of circuits. 3) configuration of circuits and 4) shielding of panels.
Tall buildings typically employ smoke management systems that either vent, exhaust or limit the unfold of smoke.
Smoke Control
Controlling the unfold of smoke is more complicated in tall buildings. For instance, tall buildings expertise a phenomenon referred to as stack effect. Stack impact occurs when a tall building experiences a pressure distinction all through its peak on account of temperature differentials between the surface air temperature and the inside building temperature. This causes air to maneuver vertically, depending on the surface air temperature – either upward or downward in a building. It also can trigger smoke from a constructing hearth to unfold throughout the building if not managed. That is why tall buildings usually employ smoke administration systems that both vent, exhaust or restrict the unfold of smoke.
Other issues in tall buildings included the air motion created by the piston impact of elevators and the effects of wind. Air movement brought on by elevator automobiles ascending and descending in a shaft and the effects of wind can lead to smoke movement in tall buildings. These impacts turn into more pronounced as the peak of the constructing increase.
Because very tall buildings complicate smoke spread, efficient smoke management is tougher to achieve. The potential solutions are quite a few and include a combination of active and passive features such as however not limited to: 1) smoke barrier walls and floors, 2) stairway pressurization techniques, 3) pressurized zoned smoke management supplied by the air-handling gear, and 4) smoke dampers. The solution applied into the design wants to deal with the constructing itself, its uses, related occupant traits and reliability.
First Service Issues
It goes with out saying that tall buildings present unique challenges to the fireplace service. During the planning and design phases, it is important for the design group to work with the fire service to discuss the sort of assets which may be wanted for an incident and the actions that shall be needed to mitigate an incident. This consists of growing building and post-construction preplans. These preplans ought to embrace and never be limited to making provisions for 1) fireplace service access including transport to the very best stage of the building, 2) establishing a water provide, 3) standpipe systems (temporary and permanent), 4) communication techniques, and 5) understanding the operations of the fireplace protection methods within the building.
One of the challenges the hearth service faces throughout incidents in tall buildings is the ability of firefighters to move gear to the incident location. Designers should keep in mind how the fire service can transport its equipment from the response level to the very best degree in a protected method.
Additionally, care needs to be taken when designing the hearth command middle as it’ll present the fireplace service command workers with essential details about the incident. The fire command heart must be accessible and will embody 1) controls for building techniques, 2) contact data for constructing administration, 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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