READING PASSAGE 40

You are advised to spend about 20 minutes on Questions 1-13 which refer o Reading Passage 40 below

FIRE TESTS

Most fires start in a building’s contents, not its structure Understanding how fire grows indoors – in enclosed spaces – is the fire step in limiting its potential for death and destruction Fire tests have been around for years, and most building codes make reference to them Some, however, are obsolete, in the sense that they can’t accommodate a growing number of new materials in new configurations Nor can they rank items in order of flammability What is needed are graded tests that attach numbers to the degree of flammability These numbers could then be plugged into suitable computer models The computer could work out the total flammability of an item, depending on what it’s made of, how it’s put together, and where it’s placed.

Computer models are becoming important in fire research Scientists are hoping that one day, with enough data and sufficiently powerful computers, they will be able to calculate, without actually setting fire to anything, the way a fire will spread in any given building.

A fire indoors is a very different animal from one outdoors When you put a match to your incinerator, the flames build up steadily Most of the heat is lost to the atmosphere, so you have no trouble staying close by inside a room, it obeys different and more complex physics, and the danger quietly multiplies First, instead of a match, imagine a cigarette dropped into the back of a lounge chair Cigarettes, you should know, are among the major causes of fires in houses A carelessly Discarded cigarette can stay alight in a oncealed crevice for as long as 45 minutes then, after smoldering away, the chair’s upholstery suddenly ignites Within perhaps 30 seconds, smoke, combustion gases, and heat egm curling upwards, and before 1 minute las passed, they have started building up in a rapped layer under the ceiling as the chair continues to burn the layer gets hotter and thinker, and after 2 minutes it starts radiating heat back down to the chair and other furniture in the room After 3 minutes or so the trapped heat can become so intense that we see ‘flash-over’ – everything in the room, including combustible gases, has reached ignition point and bursts into flame.

Experiments have shown that some polyurethane armchairs can, 5 minutes after ignition, give out 1-2 megawatts of heat That’s no more than a lively incinerator produces, but when it’s confined in a room it can easily induce flash-over After flash-over anybody still in the room would be dead People rarely appreciate how quickly a small fire indoors can turn into a deadly inferno They waste time going to the laundry to get a bucket of water instead of making sure everybody else is out of the house By the time they get back, the fire will almost certainly be out of control Billowing clouds of smoke and toxic gases quickly spill through doorways and along halls, enveloping and incapacitating sleeping occupants in the rest of the house.

You can appreciate that modeling the entire course of an indoor fire on a computer is a daunting task The program needs to consider the flaming combustion zone, the rising thermal plume above it, the hot gas layer beneath the ceiling, and ventilation Turbulence of air is cry difficult to model because large eddies can grow from features as small as 01 mm cross.

 Nevertheless, fire researchers overseas have simplified models to study aspects of fire behavior in homes, hospitals, aircraft, tunnels, stadiums, shopping malls and airports, For example, the Fire Research Station in Britain has spent 7 years developing ‘Jasmine’, which can show how air circulates into a burning building and how the smoke layer deepens with time.

In the United States, the National Bureau of Standards has developed ASET, which calculates ‘available safe egress lime’. This fire-growth model requires figures for rates of mass loss, smoke release, production of toxic gases, and heat build-up. Most existing tests, as we have noted, fail to provide the necessary data. They will need to be modified, or a whole new generation of tests devised.

Questions 1-4

Decide whether the following statements are true or false according to the reading passage and write T for true or F for false in the spaces numbered 1-4 on the answer sheet.

1. Some older fire tests only show how a fire starts in a building’s structure.

2. A computer would be able to grade the flammability of an item.

3. Flash-over can best be prevented with a bucket of water.

4. An adequate computer program for predicting the effects of a fire is not easy to set up.

Question 5-11

Below is a list of the stages in the build-up of an indoor fire caused by a cigarette dropped down the back of an upholstered chair. Decide where each stage fits in the following table according to the time when it occurs and write the appropriate letters A-H in the spaces numbered 5-11 on the answer sheet.

Stage 1	Stage 2	Stage 3	Stage4
Up to 45 mins. Before ignition	Up to 1 min. after ignition	2 mins.	3 mins and after
Example: A	5. -------	8.	10. -------
	6. -------	9.
	7. -------		11.

List of stages

A   The cigarette smolders unseen

B  The heat trapped in the room intensifies

C  Smoke, gases and heat rise towards the ceiling

D  The hot layer beneath the ceiling spreads heat back to the chair and other furniture in the room

E  A layer of heat is formed under the ceiling

F  Smoke and gases spread into other parts of the house, endangering anyone who may be there

G  Everything in the room reaches ignition point and bursts into flame

H  The upholstery catches fire

Questions 12-13

What are two models for observing fire behavior that has developed overseas? 

Write the answers in the spaces numbered 12-13 on the answer sheet.

12._____________

13._____________