spacer spacer Go to Kaye and Laby Home spacer
spacer
spacer spacer spacer
spacer
spacer
spacer
spacer spacer

You are here:

spacer

Chapter: 3 Chemistry
    Section: 3.11 Miscellaneous data
        SubSection: 3.11.5 Flammability of gases and vapours

spacer
spacer

spacer

« Previous Subsection

Next Chapter »

Unless otherwise stated this page contains Version 1.0 content (Read more about versions)

3.11.5    Flammability of gases and vapours

The main parameters which describe the ability of mixtures of substances in air to propagate a flame and/or explode are flammable limits, flash points and auto-ignition temperatures. None of these parameters are basic physico-chemical properties of a substance or mixture but are defined by standard tests and, for this reason, values are given to the nearest integer. If the test conditions are varied, then the values of the parameters will change. In particular, values will change considerably if the concentration of oxygen in the mixture is changed.

The flammable limits; lower flammable limit and upper flammable limit, are the values, by volume, of the concentrations in air, at normal temperature and pressure, between which a mixture can propagate a flame.

The flash point is the lowest temperature, at one atmosphere pressure, at which a liquid gives off flammable vapour in sufficient quantity to ignite when mixed with air at or near the surface of the liquid on application of a flame or spark. Substances with a flash point <21 °C are termed ‘extremely flammable’. Substances with flash points between 21 °C and 55 °C are termed ‘flammable’ whilst the term ‘combustible’ applies to all other combustible solids and liquids, including those with flash points above 100 °C.

The auto-ignition temperature is the lowest temperature of a glass surface at which droplets of a combustible liquid falling onto the surface will undergo spontaneous combustion. A glass surface is assumed to be chemically inert and in practice, because of catalytic effects, the values for other types of surfaces can be lower.

Aerosols of combustible solids will also propagate a flame in the appropriate concentration range. However, the flammable limits of aerosols are affected by the size of the particles although, in general, the smaller the particle size, the closer the behaviour of the aerosol resembles that of a vapour.

References

For further information see:

Walsh (1989) Chemical Safety Data Sheets, Roy. Soc. Chem., Cambridge.
Fire Hazard Properties of Flammable Liquids, Gases and Volatile Solids (1984). NFPA 325M, National Fire Protection Ass., Quincy, M. A.

Substance

Lower flammable
limit
%v/v

Upper flammable
limit
%v/v

Flash point
°C

Auto ignition
temperature
°C

         

 Acetic acid

5

16

     43

427

 Acetone

3

13

   −19

538

 Acetylene

2

83

305

 Benzene

1

  8

   −11

560

 Butyl acetate

1

  8

      22

421

 Butane

2

  9

365

 Butyl alcohol

1

11

      29

345

 Butyl methyl ketone

1

  8

      25

423

 Carbon disulphide

1

44

    −30

  90

 Cyclohexane

1

  8

    −18

260

 Cyclohexanol

1

  9

      68

300

 Cyclohexanone

1

  9

      44

420

 o-Dichlorobenzene

2

  9

      65

648

 1,1-Dichloroethane

6

11

      14

458

 1,2-Dichloroethane

6

16

      13

413

 Dichloromethane

16  

66

600

 Diethanolamine

2

13

      12

662

 Diethylamine

2

10

    −26

312

 Diethylether

2

48

    −45

160

 Diisobutyl ketone

1

  6

      49

396

 Diisopropyl ether

1

21

   −28

443

 Dimethyl sulphoxide

3

42

      88

215

 1,4-Dioxane

2

22

      12

180

 Epichlorohydrin

4

21

      31

416

 Ethane

3

12

515

 Ethanol

3

19

      12

363

 Ethyl acetate

2

12

   −4

410

 Ethylene glycol

3

22

 111

400

 2-Ethoxyethanol

3

18

   43

235

 2-Ethoxyethyl acetate

2

  8

   56

379

 Ethylene

3

34

305

 Furan

2

14

 −36

 Furfural

2

19

   60

316

 Glycerol

3

19

 199

370

 Heptane

1

  7

  −4

204

 Hexane

1

  8

 −22

223

 Hydrogen

4

76

 Isobutyl alcohol

2

11

   28

426

 Isophorone

1

  4

   84

460

 Isopropyl alcohol

2

12

   12

399

 Methanol

6

37

   11

385

 Methyl acetate

3

16

−10

455

 Methyl ethyl ketone

2

11

  −6

516

 Nitrobenzene

2

  9

   88

482

 Octane

1

  7

   13

206

 Pentane

1

  8

 −40

285

 Propane

3

12

515

 Propyl acetate

2

  8

   13

450

 Propylene

2

11

−108

460

 Pyridine

2

12

    20

482

 Styrene

1

  6

    31

490

 Tetrahydrofuran

2

12

 −14

321

 Toluene

1

  7

     4

530

 1,1,1-Trichloroethane

8

11

   −1

537

 Trichloroethylene

13   

90

   32

420

 o-Xylene

1

  6

   17

464

 m-Xylene

1

  7

   25

528

 p-Xylene

1

  7

   25

529

         

J.G. Firth

spacer


spacer
spacer
spacer spacer spacer

Home | About | Table of Contents | Advanced Search | Copyright | Feedback | Privacy | ^ Top of Page ^

spacer

This site is hosted and maintained by the National Physical Laboratory © 2017.

spacer