Page 13 - Electrical Installation in Hazardous Area

x Contents

11 Apparatus using protection concept pressurization 'p' 275

11.1 Standards for pressurization 'p' 275
11.2 Methods of pressurization 278
11.2.1 Static pressurization 279
11.2.2 Pressurization with leakage compensation 280
11.2.3 Pressurization with continuous dilution 283
11.3 Purge and dilution gases 284
11.4 Flammable materials imported into enclosures
and their containment 284
11.4.1 Flammable materials imported into enclosures 284
11.4.2 Containment of flammable materials within
enclosures 285
11.5 Enclosures, ducting and internal components 287
11.5.1 Enclosures 287
11.5.2 Ducting 290
11.5.3 Internal electrical components, etc 292
11.6 Safety provisions and devices 293

12 Apparatus using protection concept increased safety 'e' 296
12.1 The situation in regard to standardization 297
12.2 Basic construction requirements 297
12.2.1 Construction of enclosures 297
12.2.2 Terminals and connection facilities 298
12.2.3 Separation of conducting parts 300
12.2.4 Insulation 305
12.2.5 Windings 309
12.3 Additional requirements for specific types of
apparatus 311
12.3.1 Terminal enclosures 311
12.3.2 Mains powered luminaires 313
12.3.3 Caplamps 317
12.3.4 Measuring instruments and transformers 317
12.3.5 Secondary batteries 319
12.3.6 Heating devices 322
12.3.7 Rotating machines 324
12.3.8 Other types of apparatus 329

13 Apparatus and systems using protection concept intrinsic
safety 'i' 331
13.1 The situation in respect of standardization 332
13.2 Basic application of the concept 333
13.2.1 Intrinsically safe apparatus 333
13.2.2 Associated apparatus 334