Avoiding Static Ignition Hazards in Chemical Operations A CCPS Concept Book

by Britton, Laurence G.

• ISBN13: 9780816908004
• ISBN10: 0816908001
• eBook ISBN(s): 9780470935392
• Edition: 1st
• Format: Hardcover
• Copyright: 1999-09-15
• Publisher: Wiley-AIChE
• More Book Details
• Purchase Benefits

Summary

Written by Laurence Britton, who has over 20 years' experience in the fields of static ignition and process fire and explosion hazards research, this resource addresses an area not extensively covered in process safety standards or literature: understanding and reducing potential hazards associated with static electricity. The book covers the nature of static electricity, characteristics and effective energies of different static resources, techniques for evaluating static electricity hazards, general bonding, grounding, and other techniques used to control static or prevent ignition, gases and liquids, powders and hybrid mixtures.

Author Biography

Laurence G. Britton is the author of Avoiding Static Ignition Hazards in Chemical Operations: A CCPS Concept Book, published by Wiley.

Table of Contents

Preface
Acknowledgments
Introduction
Purpose	1	(3)
Exclusions	4	(1)
Units	5	(1)
Organization of the Book	5	(2)
Fundamentals of Static Electricity
What Is Static Electricity?	7	(4)
Charge Separation	8	(1)
Magnitude of Current and Potential	8	(1)
Concentration of Charged Species	9	(1)
Importance of Trace Contaminants	9	(1)
Hazard Evaluation	10	(1)
Statistics	10	(1)
Charge Generation	11	(2)
Induction Charging	12	(1)
Ionic Charging	13	(1)
Charge Dissipation	13	(3)
Variability of Conductivity	15	(1)
Charge Accumulation	16	(1)
Ignition	17	(3)
Effective Energy	17	(3)
Static Discharges	20	(24)
Corona Discharge	21	(2)
Brush Discharge	23	(9)
Bulking Brush Discharge	32	(3)
Spark Discharge	35	(3)
Propagating Brush Discharge (PBD)	38	(5)
Surface Streamer	43	(1)
Personnel Spark and Shock Hazards	44	(3)
Body Capacitance and Resistance	44	(1)
Voltage (V) and Energy (W) Attained	45	(1)
Human Shock Response	46	(1)
Evaluating the Hazard of Static Electricity
General	47	(1)
Hazard Identification Methods	47	(1)
Decision Trees	48	(1)
Charge Accumulation	48	(1)
Conductive Objects	48	(1)
Nonconductive Objects	49	(1)
Energy Estimates	49	(1)
Charge Sharing	50	(1)
Instrumentation	50	(16)
Charge	50	(4)
Electric Field	54	(3)
Potential	57	(3)
Ignition Energy	60	(3)
Conductivity of Liquids	63	(1)
Resistivity of Solids	64	(1)
Resistance	65	(1)
Direct Observation of Discharges	66	(1)
Radio Frequency Detection of Discharges	66	(1)
Measuring the Effective Energy of Nonspark Discharges	66	(5)
Gas Composition	67	(4)
Controlling electrostatic Hazards
Bonding and Grounding	71	(4)
Definitions	71	(1)
Purpose of Bonding and Grounding	71	(1)
Resistance to Ground	72	(1)
Bonding and Grounding Systems	73	(1)
Ground Rods	73	(1)
Grounding and Cathodic Protection	74	(1)
Control of Charge Relaxation	75	(3)
Increase of Conductivity	75	(1)
Charge Neutralizers	76	(2)
Control of Personnel Charging	78	(3)
Personnel Grounding	78	(2)
Clothing	80	(1)
Gloves	80	(1)
Control of Flammable Atmospheres	81	(2)
Liquid Nitrogen/Liquid Air Hazards	81	(2)
Flammable Liquids, Vapors, and Gases
Ignition Hazards of Liquid Vapor and Mist	83	(13)
Flammable Liquid	83	(3)
Flammable Limits	86	(1)
Liquid Mist	87	(2)
Minimum Ignition Energy (MIE)	89	(6)
Explosion Prevention Systems	95	(1)
Generation and Relaxation (Loss) and Charge in Liquid Systems	96	(10)
Charge Generation	96	(1)
Charge Density	97	(1)
Factors Influencing Charge Generation	97	(1)
Charge Relaxation	98	(3)
Classification of liquids based on Conductivity	101	(3)
Antistatic Additives	104	(2)
Bonding and Grounding	106	(1)
Flow in Pipe, Hose, and Tubing	106	(14)
Metallic Piping Systems	106	(5)
Nonconductive Pipe and Linings	111	(3)
Flexible Hoses	114	(2)
Dip Pipes	116	(1)
Filters and Relaxation Tanks	116	(2)
Suspended Material	118	(1)
Valves and Other Line Restrictions	119	(1)
Filling Criteria for Tank Operations	120	(22)
Storage Tanks	122	(6)
Road Tankers	128	(4)
Rail Cars	132	(1)
Liquid Phase Mixers, Blenders, and Reactors	132	(3)
Liquid-Solid Mixers, Blenders and Reactors	135	(2)
Vaccum Trucks	137	(2)
Plastic Tanks	139	(3)
Sampling, Gauging, and Analysis	142	(2)
Sample Container Cord	142	(1)
Sampling	142	(1)
Gauging	143	(1)
Portable Flammable Gas Analyzers	144	(1)
Tank Cleaning	144	(5)
Water Washing	144	(2)
Solvent Washing	146	(1)
Steam Cleaning	147	(1)
Acid Washing	148	(1)
Grit Blasting	149	(1)
Portable Tanks	149	(1)
Metal Portable Tanks	149	(1)
Plastic Portable Tanks	150	(1)
Portable Containers Less Than 60 Gallons Capacity	150	(7)
All-Steel Drums	151	(2)
Plastic Lined Drums	153	(1)
Plastic Drums	154	(1)
Hand-Held Containers	154	(3)
Wet-Dry Vacuum Cleaners	157	(1)
Miscellaneous Flammable Atmospheres	157	(8)
Clean Rooms	157	(1)
Water and Steam Curtains	158	(1)
Static Electrification in Gas Flow	158	(1)
Ignition of Vented Gas	159	(1)
Hazards of Plastic Sheet and Wrap	160	(1)
Oxidant Enriched Atmospheres	161	(1)
Elevated Temperature and Pressure	162	(1)
Automative and Marine	163	(1)
Aerosol Spray Cans	164	(1)
Cathody Ray Tube Video Display Screens	165	(2)
Cleaning	165	(1)
Screens in Hazardous Locations	165	(1)
Static Dissipating Screen Overlays	166	(1)
Powders and Solids
Flammability of Dust Suspensions	167	(10)
Flammable Limits	169	(1)
Minimum Ignition Energy (MIE) of Dust Suspensions	170	(2)
Hybrid Mixtures	172	(3)
Unstable or Energetic Powders	175	(1)
Effect of Temperature on Ignition Energy	176	(1)
Effect of Moisture on Ignition Energy	177	(1)
Charging Mechanisms	177	(6)
Charge Density	179	(1)
Classification of Powders Based on Conductivity	180	(3)
Pneumatic Conveying	183	(6)
Charging in Pipeline Flow	183	(4)
Special Grounding Cases	187	(2)
Types of Static Discharge in Power Systems	189	(6)
Sparks	190	(3)
Bulking Brush Discharges	193	(1)
Propagating Brush Discharge	194	(1)
General Operations	195	(4)
Vaccum Trucks	197	(1)
Bag Houses	198	(1)
Manual Transfers from Portable Containers	199	(1)
Flexible Intermediate Bulk Containers (FIBCs)	199	(6)
Power Transfers in Air Atmospheres	200	(2)
Power Transfers from FIBC to Flammable Liquids	202	(1)
Conductive and Antistatic FIBCs	202	(2)
Vacuum FIBC Transfers	204	(1)
Appendix A. EXPLANATORY MATERIAL
A-2-6.5 Propagating Brush Discharge	205	(1)
A-4-1.3. Resistance to Ground	206	(3)
A-5-1.4.4. MIE of Liquid Mists	209	(2)
A-5-2.4.1 Hyperbolic Relaxation	211	(2)
A-5.3.5. Filtration	213	(1)
A-5-4. Filling Criteria for Tank Operations	214	(2)
A-5-4.2-1. Effect of Road Tires	216	(1)
A-5-6.1. Potentials during Water Washing of Tanks	217	(2)
A-6-1.2. Effect of Particle Size on Dust MIE	219	(1)
A-6-1.3.1 Ignition Energy of Hybrid Mixtures	219	(1)
A-6.1.5. Effect of Temperature of Powder MIE	220	(3)
Appendix B. DATA TABLES
Flammability Data for Gases and Vapors	223	(4)
Typical Conductivities, Dielectric Constants and Relaxation (or Dissipation) Times of Liquids	227	(7)
Typical Resistivities, Dielectric Constants, and Breakdown Strengths of Solid Dielectrics	234	(3)
Appendix C. FORMULAS AND MATHEMATICAL RELATIONSHIPS (SI UNITS)
C-1. Principal Relationships	237	(1)
C-2. Analysis: Grounded Sphere above Charged Nonconductive Disc	238	(11)
References	249	(12)
Glossary	261	(12)
Index	273