Reference no: EM132851367

FV1001 Introduction to Combustion and Fire 

International Fire Safety Engineering/ Fire Safety and Emergency Management

SECTION 1:

1. You must answer both parts a) and b) a) Consider a structure fire. Find the conductive heat flow rate through a brick wall 0.6 m wide (x), 2.8 m high and 3 m long when the temperature in the room is 800oC (T2) and the ambient temperature on the other side is 30oC (T1). Find the value of k from the table. b) Find the thermal penetration time for a 1% and 50% increase in temperature rise through a concrete wall 0.4 m wide (x). Find the values of a from the table.

2. You must answer both parts a) and b) a) Using suitably annotated diagrams, explain the Upper Flammability Limit and Lower Flammability Limit. b) Explain what conditions cause dark and light smoke and how they may affect evacuation time.

SECTION 2:

3. Find the heat flux due to radiation from a wood flame 1.6m tall (a), 1.2m wide (b) and 1.2 m thick(l) at a distance 1.4 m away (c), when the absorption coefficient → is 0.6, the temperature is 723 K (T2) and s = 5.67x10-8.

Find the value of F12 from the table 4. Using suitably labelled diagrams, describe the process of smouldering combustion. Include the properties a material must have in order to undergo smouldering combustion.

SECTION 3: 5. Balance the following chemical reactions.

a) C8H18 + O2 → CO2 + H2O b) C9H20 + O2 → CO2 + H2O + CO c) C3H7OH + O2 → CO2 + H2O d) C6H12O6 + O2 → CO2 + H2O e) Pb(OH)2 + HCl → H2O + PbCl2 f) AlBr3 + K2SO4 →KBr + Al2(SO4)3 g) FeCl3 + NaOH → Fe(OH)3 + NaCl h) C20H42 + O2 → CO2 + H2O i) C8H18 + O2 → CO2 + H2O + CO j) C18H38 + O2 → CO2 + H2O + CO

6. Using suitably labelled diagrams, describe the stages of fire growth in an enclosure in relation to temperature and pressure.

SECTION 4:

7. Calculate the Heat Release Rate, and Fire Flame Height using the Heskestad method for a 1.2 m diameter pool of Butane when: m" = 0.078 kg/m2-s →Hc = 45700 kJ/kg

8. Describe how complete and incomplete combustion affect the production of smoke.

SECTION 5:

9. Determine the time for 0.015m (l) thick cork board to ignite subject to a flame heat flux (q) of 5W/cm2. The properties for cork board are: Tig 395oC T8 30oC → 220 kg/m3 c 1.9 kJ/kg-K 10. With the use of annotated diagrams, explain fire spread over the surface of a solid. APPENDIX EQUATIONS AND TABLES Material Thermal Conductivity (k) (W/m-K) Thermal Diffusivity (a) (m2/s) Copper 387 1.14x10-4 Steel 45.8 1.26x10-5 Brick 0.69 5.2x10-7 Concrete 0.8-1.4 5.7x10-7 Figure 1: Configuration Factor F12