Optimization of Positive Pressure Ventiliation Tactic for Wind Driven High Rise Fires

2011 ◽  
Author(s):  
Prabodh Panindre ◽  
Sunil Kumar ◽  
Atulya Narendranath ◽  
Vinay Kanive Manjunath ◽  
Venkata Pushkar Chintaluri ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Close Agreement ◽  
Positive Pressure Ventilation ◽  
Combustion Products ◽  
Positive Pressure ◽  
High Rise ◽  
Fire Scenarios ◽  
Dynamic Simulator ◽  
Fire Dynamic Simulator ◽  
Fire Location

Positive Pressure Ventilation (PPV) is a firefighting tactic that can mitigate the spread of fire and the combustion products to improve the safety of firefighters and civilians in wind-driven high-rise fires than without PPV. The performance of a PPV tactic in wind-driven high-rise fires depends on various parameters that include wind speed, control of stairwell doors, number of fans, fan positions and placements, fire location etc. This paper describes the influence of these parameters on the efficacy of PPV operation that was studied by simulating wind-driven high-rise fire scenarios using computational fluid dynamics softwares Fluent 12.0 and NIST’s Fire dynamic simulator (FDS 5.0). The results obtained from Fluent and FDS found to be in close agreement with each other and have been used to optimize the PPV operation for better performance.

Technique to Improve Performance of Positive Pressure Ventilation Tactic in High-Rise Fires

2011 ◽  
Author(s):  
Prabodh Panindre ◽  
Sunil Kumar ◽  
Atulya Narendranath ◽  
Vinay Kanive Manjunath ◽  
John Ceriello
Keyword(s):  
Numerical Simulation ◽  
Positive Pressure Ventilation ◽  
Real Life ◽  
Fire Department ◽  
Combustion Products ◽  
Positive Pressure ◽  
Simulation Methods ◽  
Efficient Manner ◽  
High Rise ◽  
Numerical Simulation Methods

Positive Pressure Ventilation (PPV) is a firefighting tactic that can assist firefighters in venting of smoke and high temperature combustion products in a more efficient manner and make the fire-rescue /suppression operation safer than without PPV. The pressure created by PPV operation must be greater than that of created by spread of fire. In real-life structures such as high-rise buildings, considering the leakages and size of stairwells, it becomes difficult to achieve the desired pressure at upper floors using PPV operation. With the help from FDNY (Fire Department of New York), on-site tests and computer simulation techniques were performed to study the behavior of PPV tactic. A technique was developed that significantly increases the positive pressure level achieved by a typical PPV operation. The efficacy of this technique was tested by conducting on-site experiments and numerical simulation methods using computational fluid dynamics software - Fluent 12.0 and NIST’s Fire dynamic simulator (FDS 5.0). The results of on-site experiments and numerical simulation methods found to be in close agreement with each other and confirmed the efficacy of this technique in improving the performance of typical PPV operation. This paper describes the results obtained from these on-site tests and numerical simulation methods. As FDNY is in the phase of implementing this instrument to ease and improve the PPV deployment operation, numerical simulation methods have been used to optimize this technique and the analysis discussed in this study also simplifies the PPV fan deployment operation for firefighters.

Evaluation of Positive Pressure Ventilation for High-Rise Buildings in Compartment Fire Situation

2012 ◽  
Vol 446-449 ◽  
pp. 2908-2913 ◽  
Author(s):  
Xiao Feng ◽  
Yan Feng Li
Keyword(s):  
Positive Pressure Ventilation ◽  
Optimal Rate ◽  
Positive Pressure ◽  
Airflow Rate ◽  
Compartment Fire ◽  
Fire Dynamics ◽  
High Rise ◽  
Fire Dynamics Simulator ◽  
Fire Condition ◽  
Fire Scenarios

An alternate means for protecting high-rise stairwell enclosures using the positive pressure ventilation is evaluated. An analysis performed by using the Fire Dynamics Simulator (FDS) model shows that the positive pressure ventilation can be an effective method for protecting the stairwell enclosure. Three types of ventilation methods are compared in the same fire condition and the best one is determined based on the decrease of temperature in the stairwell. The optimal rate for ventilating the stair requires optimization of the airflow rate according to postulated fire scenarios for the building and the desired performance with respect to tenability conditions within the stair.

Effects of Exit Vent Location on Fire Room Conditions During PPV

2008 ◽  
Author(s):  
Colin M. Beal ◽  
Ofodike A. Ezekoye
Keyword(s):  
Positive Pressure ◽  
Computational Simulations ◽  
Cold Flow ◽  
Flow Simulations ◽  
Advantages And Disadvantages ◽  
Experimental Compartment ◽  
Dynamic Simulator ◽  
Fire Dynamic Simulator ◽  
Hot Products ◽  
Vent Location

Positive Pressure Ventilation (PPV) is a widely used fire fighting tactic in which a fan is used to push hot products of fire out of a burning structure. There is a recent body of research that has been conducted regarding the advantages and disadvantages of PPV. Studies of PPV most commonly use full scale experimental fires and/or computational simulations to evaluate its effectiveness. This paper presents computational simulations that have been conducted using Fire Dynamic Simulator (FDS) version 5 to evaluate the effects of exit vent location on resulting fire room conditions during the application of PPV to a ventilation constrained fire. The simulations use a simple one room structure with an adjacent hallway. We are simulating this geometry because we are in the process of designing and constructing a similar experimental compartment. Cold flow simulations are first conducted to understand how much the presence of the fire heat release affects the flow patterns. Then, two simulations which employ PPV with different exit vent locations are compared. The differences between the two simulations are detailed and a physical explanation for the differences is presented.

Large Outdoor Fire Model Analysis

2003 ◽  
Author(s):  
Peter Vidmar ◽  
Stojan Petelin
Keyword(s):  
Fluid Dynamic ◽  
Fire Behavior ◽  
Combustion Products ◽  
Validity Of Results ◽  
Quality Of Results ◽  
Fire Model ◽  
Dynamic Simulator ◽  
Fire Dynamic Simulator ◽  
The Mathematical Model

The idea behind the article is how to define fire behavior. The work is based on an analytical study of fire origin, its development and spread. Mathematical fire model called FDS (Fire Dynamic Simulator) in used in a presented work. CFD (Computational Fluid Dynamic) model using LES (Large Eddie Simulation) is used to calculate fire development and spread of combustion products in the environment. The fire source is located in the vicinity of the hazardous plant, power, chemical etc. The article present the brief background of the FDS computer program and the initial and boundary conditions used in the mathematical model. Results discuss output data and check the validity of results. The work also presents some corrections of physical model used, which influence the quality of results.

Simulation of Smoke Movement in a Loop Corridor under Mechanical Exhaust with Compound Model

2013 ◽  
Vol 475-476 ◽  
pp. 1459-1462
Author(s):  
Wei Shi ◽  
Fu Sheng Gao
Keyword(s):  
Field Model ◽  
Unit Area ◽  
Zone Model ◽  
Smoke Control ◽  
Smoke Movement ◽  
High Rise ◽  
Compound Model ◽  
Ceiling Height ◽  
Dynamic Simulator ◽  
Fire Dynamic Simulator

The mechanical smoke exhaust is as acknowledged as an effective smoke control manner by making use of some necessary exhaust facilities, also with more stability than natural exhaust. In this paper, the field model FDS (Fire Dynamic Simulator) with a combination of zone model CFAST (Consolidate Fire and Smoke Transport) were used to simulate the mechanical smoke exhaust in a loop corridor of the fire floor in a high-rise hotel, for the propose of evaluate fire safety of mechanical smoke exhaust. The mainly discussion was about the height of layer interface with the ceiling height changed, also with different smoke exhaust volume. The conclusions were obtained that, when two exhaust vents were set symmetrically in the loop corridor, the volume of smoke exhaust per unit area with 60m3/h according to regulations, always could ensure safety of smoke exhaust. The smoke exhausted worse within the corridor when ceiling height reduced. It was recommended that the ceiling lowest height limit should be provides in correlative regulation.

PPV Effect on Smoke Movement Through a Shaft in High-Rise Fires: Experiments and CFD Simulation

2019 ◽  
Author(s):  
Xiaoman Ye ◽  
Ofodike A. Ezekoye ◽  
Qize He
Keyword(s):  
Positive Pressure Ventilation ◽  
Cfd Simulation ◽  
Positive Pressure ◽  
Gas Temperature ◽  
Air Flow Rate ◽  
Smoke Control ◽  
Smoke Movement ◽  
Cfd Simulations ◽  
High Rise ◽  
Reduced Scale

Abstract While Positive Pressure Ventilation (PPV) has proven to be effective in high-rise fire-fighting, its effect on smoke movement through a stairwell shafts in high-rise fires is still inconclusive. Towards better understanding of the effects of PPV for smoke transport in high-rise type structures, a 1/4 reduced-scale 7-floor building with dimensions of 1.0 m × 0.5 m × 4.2 m consisting of a vertical shaft and several rooms over a number of floors has been designed and tested. Both experiments and CFD simulations for this model were conducted. It was found that there are several potential PPV tactics that could be useful in high-rise smoke control in fires. In the cases examined, PPV was considered to be applied from outside the building through vents in external rooms of the building. When a PPV fan is applied above the floor containing the fire layer, the pressure induced by the PPV flow should be larger than the pressure difference caused by the stack effect induced by the hot fire product gases. Insufficient PPV flow rates is shown to lead to accumulation of smoke and further increase in the gas temperature within the shaft due to the blocking effect. A better option is applying PPV below the fire floor. With the same pressurization air flow rate, applying PPV from below the fire floor is more effective than applying it from the top of building. In this situation, PPV not only prevents accumulation of the smoke in the shaft, but also prevents smoke from entering the shaft. The results of this study can guide the development of firefighter ventilation tactics for smoke control in high-rise fires.

Numerical Analysis on Parameters Adjustment of Smoke Control System in a Complicated Underground Commercial Zone

2013 ◽  
Vol 341-342 ◽  
pp. 743-747
Author(s):  
De Wen Li ◽  
Jing Zhao Zhang
Keyword(s):  
Control System ◽  
Fire Spread ◽  
Smoke Control ◽  
Smoke Movement ◽  
Technical Parameters ◽  
Fire Scenarios ◽  
Dynamic Simulator ◽  
Underground Fire ◽  
Fire Dynamic Simulator ◽  
Smoke Control System

The technical parameters adjustment of smoke control system in a complicated underground commercial zone is studied by numerical simulations. An underground fire model (it encloses a hotel, a supermarket, and a net bar) and five typical fire scenarios are designed. The Fire Dynamic Simulator code is used to investigate the characteristics of fire spread and smoke movement, and obtain the available safety egress times in different fire scenarios. The required safety egress time is calculated based on the data of actual simulation exercises and numerical simulation by Building EXODUS. The simulation results show that, when the smoke exhaust rate is 5.56 cubic meter per second and air low rate reaches 3.89 cubic meter per second simultaneously, the available safety egress time is more than the required safety egress time.

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