t4-safety in sc labpart2

8/12/2019 T4-Safety in Sc Labpart2

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T4: Safety Procedures In SLSlide 1 of 49

Pajuzi Awang

IPG KDRI

Topic 4Safety Procedures In Science Laboratories

PISMP Semester 6

SCE3112-Management ofthe Science Lab and

Resources


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SAFETY PROCEDURES IN

SCIENCE LAB

FireAnd

Explosion


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Question

a) Fire can classify into 4 general categories.

i. State four (4) categories of fire and explain

briefly the causes

[8 marks]ii. Identify suitable fire extinguishers for each

categories.

[4 marks]


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Question


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Fire And Explosion

Fire and explosion are the most common serious hazards that one faces in a

typical science laboratory. Laboratory makes use of flammable materials including

solids, liquids, and gases. The following are among the more common

sources of fire and explosion hazards encountered in science laboratories:

Ignition of solvent vapours

Ignition by reactive chemicals

Uncontrolled chemical reactions Inadequate storage and disposabletechniques

Heating due to electric faults

Loose clothing and hair ignited by the Bunsen burner

Misuseof gas cylinders

Inadequate maintenance Inadequate temperature control, especially in the areas where solvents

are stored


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Fire Prevention Control

Setiap makmal sepatutnya mengandungi:

Alat pemadam api jenis karbon dioksida,

jenis busa dan jenis serbuk kering (Fire

Extinguisher)

Selimut Api (Fire Blankets)

Baldi berisi pasir (Dry Sand Buckets)


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Fire And Explosion

Fire is a chemical reaction involving rapid

oxidation or burning of a fuel. It needs three

(3) elements to occur i.e. oxygen, heat and

fuel, as shown in Figure 1

Figure 1 : Fire Triangle


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CONTOH-CONTOH ALAT

PENCEGAHAN KEBAKARAN

Cuba kenal pasti fungsi setiap jenis alat di atas


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Classification of Fire


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Classifications of Fire

Kelas Punca Jenis Alat

Pemadam Api

A Bahan pepejal yang boleh membakar

seperti kayu, kertas, kain, getah,

plastik

Serbuk, Busa,

Air.Selimut api,

pasir dan air

B Cecair yang mudah terbakar seperti

minyak, spirit, alkohol dan petrol

Serbuk, Karbon

dioksida,

C Elektrik Serbuk, Karbon

dioksida

D Logam seperti magnesium Serbuk kering yang

direka khas untukapi logam , karbon

dioksida


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Type of Fire Extinguisher

Different types of fire extinguishers are designed to

fight different classes of fire. The threemost common types of fire extinguishers are:

Water (APW)

Carbon Dioxide (CO2) Dry Chemical (ABC, BC, DC)


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Type of Fire Extinguisher1.Water (APW)

Large, silver fire extinguishers that stand about 2 tall and weigh about 25

lbs when full.APW stands for Air-Pressurised Water. Filled with ordinary tap water

and pressurised air, they are essentially large squirt guns.

APWs extinguish fire by taking away the heat element of the Fire Triangle.

APWs are designed for Class A fires only: Wood, paper, cloth, etc.


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Type of Fire Extinguisher2. Carbon Dioxide

CO2cylinders are red. They range in size from 5 lbs to 100 lbs or larger. On larger

sizes, the horn will be at the end of a long, flexible hose.

Carbon dioxide is a non-flammable gas that takes away the oxygen element of the

Fire Triangle. CO2is very cold as it comes out of the extinguisher, so it cools the fuel

as well. A CO2may not be very effective in extinguishing a Class A fire because it

may not be able to displace enough oxygen to successfully put the fire out. Class A

materials may also smoulder and re-ignite.


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Type of Fire Extinguisher3. Dry Chemical (ABC, BC, DC)


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You dont want to mistakenly use a BC extinguisher on a ClassAfire thinking that it is an ABC extinguisher.

Dry chemical extinguishers with powder designed for Class B

and C fires (BC extinguishers) may be located in places suchas commercial kitchens and areas with flammable liquids.

On campus you will find ABCs in public hallways of new

buildings, laboratories, break rooms, offices, chemical storage

areas, mechanical rooms, university vehicles,etc.


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ABC extinguishers are filled with a fine, yellow powder. This powder is

mostly composed of mono-ammonium phosphate. The extinguishers are

pressurised with nitrogen.

Dry chemical extinguishers put out fire by coating the fuel with a thin layer

of dust. This separates the fuel from the oxygen in the air. The powder also

works to interrupt the chemical reaction of fire. These extinguishers arevery effective at putting out fire.

Dry chemical extinguisherscome in a variety of types. You may see them

labelled:

DC(for dry chemical)

ABC(can be used on Class A, B or C fires) BC(designed for use on Class B and C fires)


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How to Use a Fire Extinguisher?

Po rta bl e e xting uis he rs , h owever , are no t d esi gne d t o f igh t a large

or sp re ad ing fire. Even aga inst s ma ll fires, t hey a re use ful on lyun der cer tain con di tio ns.

* The ext inguishe r m ust b e ra te d for the type of fire you a re

figh t ing.

* The ext inguishe r m ust b e la rge enough to p ut ou t the fire. M ost

portab le ex t ingu ishers di sch arge comp le tely in as few as e ight

se con ds.

* The ext inguishe r m ust b e with in e asy rea ch a n d in workin g

ord er, full y ch arg ed .

* The op era to r m ust know how t o use the e xtin g uisher. Read the

ins truc tions when y ou b uy it. There is no tim e to r ead di rec tionsdurin g an e merg ency .

* The op era to r m ust be str ong en ough to lift a nd o p era te the

ex tingu isher.


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Should You Fight The Fire?Before youbegin to fight a smallfire:

* Make sure everyone has left,or is leaving, the building.

* Make sure the fire departmenthas been called.

* Be certain that the fire is contained to a small area, suchas a wastebasket, and that is is not spreading beyond the

immediate area.

* Make sure that the fire isNOT betweenyou and an escapeexit.

* Make sure you have adequate fire fightingequipment.


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If You DO F igh t The Fire, Rem emb er Th e Word P ASS

PULLthe p in: s om e ex tingu ishers re quire rele asin g a lock la tch,

p ress ing a p unc ture lever, or t akin g anoth er first ste p .

AIMlow: po int the e xtin g uisher n ozz le ( or it s horn or h ose) at the

ba se o f t he fire.

SQUEEZEthe h an dle: This re lea s es th e ex tinguish ing agen t.

SWEEP fro m s id e t o sid e: Keep the extin g uisher aim ed at the b ase

of t he fire an d s wee p ba ck an d for th unt il i t app ea rs to be ou t.

Wat ch th e fire a re a. If t he fire br eak s out ag ain, re pea t the p rocess


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Bolehkah anda mengenalpasti arah semburan yang

sepatutnya dilakukan?

Aim at the base of fire


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Alat Pemadam Api

Harus diingati bahawa alat pencegahan

kebakaran yang dibekalkan di sekolah adalah

untuk bantuan kecemasan sahaja bagi mencegah

kebakaran kecil. Misalnya alat pemadam api

mudah alih yang ada di sekolah anda hanyamampu memadam kebakaran yang meliputi

keluasan dua meter persegisahaja!


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Tindakan Jika Berlaku Kebakaran

Jenis Kebakaran Langkah-langkah yang perlu diambil

Kebakaran pakaian Berhenti berlari, rebahkan diri di atas lantai

dan bergolek untuk halang api terus merebak;

balut dengan selimut kalis api atau siram

dengan air. JANGAN gunakan alat pemadam

api ke atas seseorang yang terbakar

Kebakaran kecil bahan-

bahan mudah terbakar

seperti minyak, alkohol,spirit.

Tutup mulut bikar/bekas dengan kain lembab

atau kepingan asbestos.

Kebakaran besar Bunyikan siren kebakaran/ kecemasan

Kosongkan bangunan dan bilik darjah danberkumpul di tempat lapang atau padang

Hubungi pihak bomba

Tutup semua suis utama elektrik dan gas

Periksa senarai murid yang ada


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Exercises : Refer pg 85-86


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Question

b) Fire can classify into 4 general categories.

i. State four (4) categories of fire and explain

briefly the causes

[8 marks]ii. Identify suitable fire extinguishers for each

categories.

[4 marks]

t4-safety in sc labpart2

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