Improvement of fire door design using experimental and numerical modelling investigations

PurposeFire door should withstand a high temperature without deforming. In the current paper, the challenges of improving the behaviour of the conventional fire door were described using various internal stiffeners in pair swinging-type fire door.Design/methodology/approachThe temperature distribution on the outside door surface was measured with distributed eight thermocouples. Subsequently the internal side was cooled with pressurized water hose jet stream of 4 bar. The transient simulation for the thermal and structure analysis was conducted using finite element modelling (FEM) with ANSYS 19. The selected cross sections during numerical simulation were double S, double C and hat omega stiffeners applied to 2.2 m and 3 m door length.FindingsDuring the FEM analysis, the maximum deformations were 7.2028, 5.4299, 5.023 cm for double S, double C and hat omega stiffeners for 2.2 m door length and 6.57, 4.26, 2.1094 cm for double S, double C and hat omega stiffeners for 3 m door length. Finally, hat omega gives more than three times reduction in the deformation of door compared to double S stiffeners which provided a reference data to the manufacturers.Research limitations/implicationsThe research limitation included the limited number of fire door tests due to the high cost of single test, and the research implication was to achieve an optimal study in fire door design.Practical implicationsAchieving the optimum design for the internal door stiffeners where the hat omega stiffener gives minimum door deformation compared to the other stiffeners was considered the practical implication. The work included two experimental fire door tests according to the standard fire test (ANSI/UL 10C – Positive Pressure of Fire Tests of Door Assemblies) for a door of 2.2 m length with double S stiffeners and a door of 3 m length with hat omega stiffeners, which achieved minimum deformation.Originality/valueThe behavior and mechanical response of door leaf were improved through using internal hat omega stiffeners under fire testing. This study was achieved using FEM in ANSYS 19 for six cases of different lengths and stiffeners for fire doors. The simulation model showed a very close agreement with the experimental results with an error of 0.651% for double S and 1.888% for hat omega.

Effects of Fire Compartmentation and Smoke Exhaust Measures on Smoke Spread Caused by Cable Fire in Utility Tunnel

Investigating the behavior of fire smoke in utility tunnel as well as smoke prevention and control measures are of vital significance for exhausting smoke from utility tunnel, realizing efficient firefighting and rescue, and guaranteeing the normal operation of cities. Taking utility tunnel as the research background, this paper builds a simulation calculation model for fire smoke prevention and control in the utility tunnel using PyroSim numerical simulation software and explores the rules of smoke spread under conditions such as building ceiling screen, changing fire compartmentation tightness, and adding smoke exhaust facilities. According to study results, before the tunnel was filled with smoke, ceiling screens lowered smoke spread rate, and smoke spread rate was inversely proportional to the ceiling screen height. When the fire door was opened, fire smoke spread to the adjacent fire compartment, and smoke spread rate was directly proportional to the fire door opening angle. Before the tunnel was filled up, mechanical smoke exhaust facilities significantly lowered the smoke spread rate by as much as 50%. When the entire tunnel was full of smoke, mechanical smoke exhaust facilities significantly reduced the smoke concentration in the utility tunnel; smoke layer temperature dropped by as much as 32°C, while visibility improved by as much as 66%. By studying smoke spread in utility tunnel, this paper aims to determine the optimal measures of preventing and controlling smoke spread in utility tunnel. This paper could also offer some reference for practical engineering applications in smoke prevention and control in utility tunnel.

A Study on the Improvement Plan of Performance-based Design of Officetels of Residential Structure

This study aims to identify the effect of the occupant density, application of the evacuation delay time, and the degree of opening of the fire doors in the household, parameters that are used in the performance-based design of the officetels of a residential structure, on the evaluation of evacuation safety and to suggest realistic alternatives. To this end, a preliminary survey was conducted on the number and ratio of residential officetels among the performance-based design targets in Gwangju Metropolitan City, which were implemented up to December 2020. Following this, two representative examples were selected, and for each type, an occupant density of 9.3 m2/person and 18.6 m2/person and an evacuation delay time of W1 and W2 were applied. In addition, for the degree of opening of the fire doors, full opening, 1/4 opening, and leakage gap were applied. With these conditions, the evaluation of evacuation safety was performed for 32 cases. Results of the evaluation showed that evacuation safety was secured in all cases for an occupant density of 18.6 m2/person, an evacuation delay time of W2, and the application of a leakage gap to the opening of the fire door. Therefore, using the above mentioned three parameters for the performance-based design of officetels of residential structures, we have proposed a more realistic design method in this study.

Performance Analysis of Smoke Control Systems for Elevators based on Pressurization Method

The pressurization of emergency or evacuation elevator shafts or duct systems during installation is used for smoke control. In this study, the performance of smoke control systems applied to emergency and evacuation elevators were compared and analyzed using the airflow network analysis program CONTAM 3.2. Under the stack effect condition (temperature difference of 30 ℃), the differential pressure formed in the vestibule was analyzed by adjusting the air volume by changing the value of the loss coefficient factor of the automatic pressure smoke damper. In the case of the duct pressurization method, the air flow in the lower floor was introduced to the elevator shaft owing to the duct pressure and the airflow in the upper floors was from the elevator shaft out to the elevator lobby. In the case of the elevator shaft pressurization method, the pressurized air passing through vestibule from the elevator shaft created a differential pressure at the fire door of vestibule. To maintain the differential pressure in the lower floor, relatively more relief dampers should be installed in the upper floors as compared to those in the duct pressurization method.

Performance Improvement of Smoke-Control System Using CONTAMW

In the event of a fire in a building equipped with air-pressure smoke-control equipment, if the smoke-control system is operated with a closed fire door, then the smoke discharge results in difficulty in opening the door. In this study, an optimal solution was devised to solve the problem of negative pressure generation in building corridors, and the proposed solution was verified using CONTAMW, a numerical analysis program for smoke-retardant facilities. Thus, it was confirmed that negative pressure in a corridor could be resolved by installing flap and automotive pressure dampers between the corridor and annex.

A Study on Major Issues in Litigation on Fire Door Performance

In this study, we attempted to analyze the predominant issues that have emerged from the fire door litigation process that has been conducted until recently, and to suggest alternatives. The results of analyzing the contents and outcomes of fire door litigation were confirmed by the issue of the durability period of the fire doors’ fire protection performance. Further, they were supported by the confirmation of the fire protection performance of fire doors that have already been installed, and the extent of the defect repair when the fire door performance is not confirmed. To solve these issues, performance verification must be executed at the manufacturing, delivery, and construction stages of fire doors. In the use stage, after completion, the user (Resident) should be the subject of performance maintenance. To this end, it is necessary to introduce the duty of maintenance and management of fire doors at the stage of use and the introduction of a professional inspection system that carries out inspections. Additionally, since the soundness of the fire door frame was confirmed through simulation and test results, the fire protection performance of the fire door in use can be confirmed by only separating the door. This can be achieved by excluding the door frame and conducting a test. It is considered that performance can be sufficiently secured despite the performance of the fire door being confirmed to be inferior, even if performance is improved by limiting the repair range to fire door pairs.

Numerical Study on Air Egress Velocity of Ancillary Room Pressurization Systems in Apartment Fires

In this study, numerical simulations were performed on the air egress velocity of pressurization systems in an ancillary room when a fire occurred in an apartment house. The relationship between the air supply flow rate of a damper and air egress velocity at a fire door is predicted to be linear. Additionally, a minimum flow rate of the damper, which meets national fire safety standards for air egress velocity, i.e., 0.7 m/s can be estimated. Air egress velocity at the fire door is analyzed according to the supply air direction and installation height of the damper. When the damper has an upward supply air direction and is installed at a high level, the egress velocity at the top section of the fire door is larger, whereas the soot concentration at the ancillary room is lower than when the supply direction of the damper is downward. Therefore, it is found that increasing the air egress velocity at the top section of the fire door helps to efficiently prevent the inflow of smoke.

Towards the Use of Novel Materials in Shipbuilding: Assessing Thermal Performances of Fire-Doors by Self-Consistent Numerical Modelling

Nowadays, fire-doors optimization is approached by using consolidated design guidelines and traditional materials, such as rock wool. Then, selected solution is directly tested in a mandatory fire-test. Unfortunately, few pieces of information could be retrieved either if the test succeeds or fails, which makes both improvements in the design and use of innovative materials difficult. Thus, in this work, a self-consistent finite element method (FEM) analysis is developed and assessed against experimental fire-test results, highlighting the critical parameters affecting the numerical simulations. Using this tool, a new fiberglass-containing foam, with improved acoustic and mechanical properties, as compared to the rock-wool, is studied as a potential insulating material for on-board fire-doors. The assessment of the performance of the new material demonstrates that, contrary to common believe, the effective thermal insulation capacity is not necessarily the critical factor in determining the fire-resistance of a fire-door. Using the validated FEM analysis, it has been proven that the reduction of the thermal bridges originated at the door edges allows, firstly, for the attainment of a fire-door 37% thinner and 61% lighter with respect to a traditional one, and, secondly, the use of new material as insulator in fire-doors that, even if less thermally capable, could improve other properties of the door, as an example its soundproofing.