1. Fire Study in Multiple Compartments
Fire Dynamics Laboratory
Indian Institute of Technology Kanpur
Compartment Description 
State-of-the-art four room compartments are used to study compartment fires. However, the current work focuses on a two room compartment of a two storey building (see Figure 1 and Figure 3). Figure 1 is an illustration of first compartment made on ground floor while second compartment is above the first one with same dimensions. The ground floor compartment and first floor compartment are sharing a grid of 16 adjustable slabs (4X4) as shown in pictures of setup. The dimensions of the compartment are 410 cm x 410 cm x426 cm (L×B×H). It consists of single inspection door opening on North-wall with the dimensions of size 86 cm × 206 cm (B × H). The inspection door remains closed during tests. The first compartment has multiple windows on the East-wall at the South-East corner of the compartment. Dimension of each window is 84 cm x 51 cm (L x H). The gas burner was placed at centre of the floor, for the first phase of experiments. The ceiling wall of first compartment, consisting adjustable 16 slabs grid in which 4 slabs were kept open during tests. This opening is used to measure the velocity and pressure profiles of hot air rising upward to second compartment. The ceiling of second compartment is connected with exhaust duct.
The compartment represents any confined space that controls the ultimate air supply and thermal environment of the fire. Both thermal and oxygen-limiting feedback processes can affect fire in a compartment. In the course of fire safety design or fire investigation in buildings, all of these effects, along with fire growth characteristics of the fuel, must be understood. Fire in enclosures may be characterized in different phases, the most important phase is fully developed fire which is affected by (a) the size and shape of the enclosure, (b) the amount, distribution and type of fuel in the enclosure, (c) the amount, distribution and form of ventilation in the enclosure and (d) the form and type of construction materials comprising the roof (or ceiling), walls and floor of the enclosure. The size, shape and ventilation of compartment are discussed below in the experimental setup. Liquefied Petroleum Gas (LPG) is used as fuel to produce fire at different flow rates of 10, 20 & 30 LPM. The study of fire in a compartment primarily involves three elements: (a) fluid dynamics, (b) heat transfer and (c) combustion. Currently we are studying the interrelation between all of these.
Experimental Setup
Introduction
Instrumentations
During these tests currently heat flux, temperature, pressure and velocity profile, gas sampling and laser induced incandescence (LII) data is obtained. For measuring heat flux, different type of heat flux meters (from Hukseflux) are used to measure heat flux at different locations in compartment. For measuring temperature at various locations k type thermocouple rods are used with heat resistant extension wires. For measuring the velocity and pressure profiles, Aeroprobe's multi-hole probe is mounted on an automated traverse which is used to measure data at 16 different points on grid. Gas sampling is done using ZRE Gas Analyzer for 5 gases (O2, CO2, CO, CH4 & NO). LII (Laser Induced Incandescence) measurements are done for measuring mass concentration as well primary particle size of particles. The gas analyzer input and the LII input are both being taken from the upper openings. Their input pipes are placed on the centre of corresponding two openings at the top of the room. Data acquisition for temperature and heat flux is done on Data acquisition devices from National Instruments using LabView program. The whole experimental setup is shown through pictures and illustrations in figures 1, 2 and 3.
Results
Following figures show the results for the test conducted at 20 LPM fuel flow rate. Under every test there are few cases, created by combinations of four windows made on east wall of compartment. Data was acquired for 300 seconds for a full phase fire. Few of the measurements taken from different sensors at different location, pressure and velocity profile measured at grid, mass concentration and primary particle size measured by LII are shown below.
In future we have planned to increase the number of burners with high flow rates of fuel, burning in multiple compartments at different locations (centre and corners). This will give us more information about thermal aspects due to effects of large fire pools in multiple compartments.
Future Steps
Experimental Setup Pictures
Figure 6. Measurements from (LII) Laser Induced Incandescence
Figure 1. Schematic Diagram of Compartment
Figure 2. Block Diagram of Data Acquisition
Figure 4. Measurements from Heat flux sensors and thermocouples
Static Pressure (Ps) in Pascal
Velocity Magnitude (Vmag) in m/sec
Total Pressure (Pt) in Pascal
Velocity in downward direction (u) in m/sec
Figure 5. Pressure and Velocity Profile measured at grid