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(A) Aim---P3(B) Introduction---P4(C) Theory---P6 (D) Apparatus---P7(E) Chemicals---P8(F) Procedure---P9(G) Photographs of the Experimental Wooden Blocks—P10(H) Results Table---P15(I) Discussion---P16(J) Sources of Errors—P18(K) Improvement---P20(L) Conclusion---P22(M) Reference---P23(N) Member List---P24

Contents

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Aim The purpose of the

experiment is to find out the way to minimize the

damage of fire to the public by synthesizing an effective

fireproof paint.

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Introduction Wood-made products, especially those co

ated with flammable paint catch fire easily. Certain additives can be added to ordinary paint to give fireproof paint so as to resist fire for a longer time.

The method presented here is called 'Protection by thermal decomposition',in which makes use of heat-absorbing ability of the decomposition processes to remove heat released during combustion. Chemicals such as starch, calcium carbonate and sodium hydrogen carbonate were chosen as additives for the following two reasons.

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First, they can undergo thermal decomposition within the temperature range of the Bunsen flame. Second, they give harmless products such as carbon, water vapour and carbon dioxide which can help to remove heat and oxygen from the burning sites. The equations for some of these decomposition reactions are shown below:

(C6H10O5)n 6nC + 5nH2O

Ca(OH)2 CaO + H2O

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TheoryThe main idea to put off fire is cutting

off the fuel, removing the oxidants and removing the high temperature.

During burning , we have to find out which kind of chemicals can give out carbon dioxide

and water vapour so as to remove the contact between the burning item and oxygen as well as

lower the high temperature.

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ApparatusPaper cups,beakers,thermometer,Bunsen

burner,stop watch

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ChemicalsOrdinary paint,

calcium carbonate,sodium hydrogencarbonate,

starch

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Procedure1. Additives of different compositions were

added into individual paper cups in which containing equal portion of diluted paint.

2. After thorough mixing, they were coated on one side of equivalent wooden blocks respectively. The wooden blocks were left overnight for complete drying.

3. The painted sides of the dried blocks were then heated by a full-powered Bunsen burner after inserting a thermometer into the hole of the unpainted sides.

4. The temperature change was recorded every 420 seconds .

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Photographs of the Experimental Wooden Blocks

mixture=5g Calcium Carbonate+5g Sodium Hydrogencarbonate+5g starch

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Sodium hydrogencarbonate

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Ordinary fireproof paint

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Calcium carbonate

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Starch

15Remark: mixture=5g Calcium Carbonate+5g Sodium Hydrogencarbonate+5g starch

Results TableMass of

n

(g)

Mass of paint

(g)

Initial temperature

( )℃

Final temperature

( )℃

Change in temperature

( )℃

Mixture 5 18.1 26 80 54Sodium hydroge

n- carbonat

e

5 18.1 26 84 58

Ordinary fireproof

paint

5 18.1 26 92 66

Calcium carbonat

e

5 18.1 26 98 72

Starch 5 18.1 26 100 74

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Discussion There are two large fireproofing system cate

gories: extinguishing systems using water, foam or gas (CO2 or other gases) and protective systems making use of cooling with water or foam.

Fireproof paint can reduce fire risks, limit the time required for action without flame damage. Adding catalysts to the original paint is an effective and inexpensive way of fire proofing wooden buildings. Since they give harmless products, it is environmentally friendly.

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If a wood item is coated with the paint containing catalyst, the wood will no longer support combustion after it dries. This procedure is satisfactory: not only the raw material is cheap, but also the labor is cheap. From the experimental results, we find out that adding catalysts to original paints are more effective than the fireproof paint which were bought from the market. On the other hand, the use of the combination of different catalysts gives better results than that of a single additive.

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Sources Of Errors1.Ordinary thermometer is not precise eno

ugh 2.The length inserted by the thermometer i

nto each wooden block cannot be exactly the same

3.The thickness of the fireproof paint coated on each wooden block is different

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4.The mass of each block is different

5.The painted surface area of each wooden block is different

6.The human reaction time in controlling the stop watch

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Improvement

1.Replace the thermometer with a more precise one

2.Ensure the length inserted by the thermometer into each wooden block are the same by using an electric driller with right position

3.Ensure the thickness of the fireproof paint coated on each wooden block are the same, for example, coat each block with paint for one layer.

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4.Use the electronic balance to ensure the mass of each block is equal.5.Repeat the experiment more times and take average results to minimize the errors.

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Conclusion Adding catalysts to original paints are more effective than the fireproof paint. Also, the

use of a combination of different catalysts gives better results than the use of a single

additive does

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Reference• http://www.ed.gov.hk/aid/english/tea

ching/sciences/physics/download/ilc.doc

• http://www.siges.com/anti-firesector.html

• http://www.angelfire.com/nc/isoptera/

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6BMak Hei Man (15)Sze Lam Lam (21)Tsang Bo Yee (22)

Tsang Tsz Shan (23)Un Kam Sio (24)

Member List

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