ABSTRACT
Explosion Hazards 1664 NEC De«nition of Hazardous Locations 1665 IEC De«nition of Hazardous Locations 1666 ATEX De«nition of Hazardous Locations
and Equipment Group 1666 Protection Methods 1666
Explosion Proof (“Flameproof” in Britain) 1666
Purging, Pressurization, or Ventilation 1667 Intrinsic Safety 1668 Other Methods 1671 Advantages and Disadvantages of
Protection Methods 1673 Abbreviations 1674 Units 1674 Organizations 1674 Bibliography 1675
8.3 EXCESS FLOW AND REGULAR CHECK VALVES 1677
Introduction 1677 Valve Designs 1677
Operation 1678 Applications 1678 Rupture Disk Leakage 1679 Gas Station Application 1679 Sizing of Excess Flow Valves 1679 Installation of Excess Flow Valves 1679 Testing 1680 Regular Check Valves 1680
Abbreviations 1684 Bibliography 1684
8.4 EXPLOSION PROOFING OF INSTRUMENTATION 1685
Introduction to Explosion Proo«ng of Instrumentation 1685
Codes, Regulations, Approvals, Certi«cation, and the Authority Having Jurisdiction 1685
Purpose, Scope, and Caveats for Explosion Proo«ng of Instruments 1686
Guidance to the Instrumentation Engineer and Designer for Using Chapter 8.4 1686
Example of Hazardous Area Classi«cation within Process Equipment 1687
International Standards and Codes 1687 Hazardous Areas and the Conditions for Fire
and Explosions 1688 Overview of Hazardous Area Classi«cation
Drawings and Data Sheets 1689
Hazardous Area Classi«cation for Flammable Gases, Vapors, and Mists 1690
Hazardous Area Classi«cation as per NFPA Codes and Standards 1695
Hazardous Area Classi«cation for Combustible Dusts, Flyings, and Fibers 1695
Miscellaneous Hazardous Area Classi«cation Considerations 1696
Overview of Explosion-Proof techniques 1696 Overview of the Installation of an Instrument
in a Hazardous Area 1698 IEC Flameproof and NFPA Explosion-Proof
Design (Explosion Containment) 1699 Ex e Avoidance/Prevention Explosion-
Proo«ng Technique 1701 Ex n as Avoidance/Prevention, Exclusion,
and Containment Explosion-Proo«ng Technique 1702
Ex ia/ib/ic Energy Limitation 1702 Dust Ignition Proof and Other Protection
Methods in Combustible Dust Environments 1707
Interaction of Explosion Proo«ng and Instrument Function 1708
Conclusion and Supplementary Notes 1708 De«nitions 1709 Abbreviations 1710 Organizations 1710 Standards 1711 Bibliography 1711
8.5 EXPLOSION SUPPRESSION AND DELUGE SYSTEMS 1712
Introduction 1712 Explosion Suppression 1713
Explosions 1713 How Suppression Works 1714 Suppressant Chemicals 1715 Suppression Hardware 1715 Control Units 1716 Actuated Devices 1716 Applications 1718
Deluge Systems 1718 Detectors 1719 Control Units 1719 Actuated Devices 1719 Applications 1720
Conclusions 1720 De«nitions 1720 Abbreviations 1720 Bibliography 1720
8.6 FLAME ARRESTOR, CONSERVATION AND EMERGENCY VENTS 1722
Introduction 1723 Vent Sizing and Types 1723 Types of Vents 1725 Conservation Vents 1725
When to Use 1725 Emergency Vents 1728 Desiccating Vents 1728 Flame Arrestors 1728 Conclusions 1730 Speci«cation Form 1730 Organizations 1732 Standards 1732 Bibliography 1732
8.7 FLAME, FIRE, AND SMOKE DETECTORS 1733
Introduction 1734 Smoke Detector Types 1734
Ionization Chamber 1734 Photoelectric 1734 Thermal 1734 Heat Detection Cables 1734 Intelligent 1735
Flame Detector Types 1735 Radiation Type 1735 Ultraviolet 1736 Infrared 1737 UV/IR Combination 1737 Dual and Multispectrum IR 1737
Fire Detector Types 1737 Burner Management Sensors 1737
Heat Sensors 1738 Flame Conductivity Detectors 1738 Flame Recti«cation 1739 Radiation Types 1739 Installation 1741
Conclusions 1742 De«nition 1742 Abbreviations 1742 Bibliography 1742
8.8 NUCLEAR ACCIDENTS 1743
Introduction 1743 History 1743 The Process 1745
Boiling Water Reactor (BWR) 1745 Pressurized Water Reactor (PWR) 1746
Accidents 1748 3-Mile Island 1748 Chernobyl 1750 Fukushima 1753
Spent Fuel Storage 1761 Automation Would Have Prevented All
Three 1762 De«nitions 1763 Abbreviations 1764 Organizations 1764 Bibliography 1764
8.9 NUCLEAR RADIATION DETECTORS 1765
Introduction 1766 Effects of Radiation 1766 De«nitions of Units 1766
Conversion between Units 1767
Exposure Consequences 1768 Exposure Limits 1769
Detection History 1769 Radiation Detector Designs 1770
Gas Filled 1770 Ionization Chambers 1771 Proportional Counters 1771 Geiger-Müller Counters 1772 Quenching in GM Tubes 1773 Scintillation Counters 1773
Neutron Detectors 1774 Fission Chambers 1775
Solid-State Detectors 1775 Calibration and Testing 1775 Selection 1776 Shielding 1776 De«nitions 1777 Abbreviations 1777 Organizations 1778 Bibliography 1778
8.10 OIL INDUSTRY ACCIDENTS 1779
Introduction 1779 Fossil Fuels 1779
Oil 1779 Natural Gas 1781
The Drilling Process 1782 The Methane “Kick” 1782
Offshore Production 1783 Drilling 1784 Cementing 1785 Safety Automation 1786
Production 1787 Killing the Well 1787
Measurements 1787 Flow Measurement 1788 Coriolis Flowmeter 1788 Density Measurement 1789 Velocity Measurement 1789 Well Logging Instruments 1790
Blowout Preventer 1791 The BP Accident 1792
Failed Negative Pressure Test 1793 Other Failure Causes 1793 Keeping the Pipe Straight 1794 BP Installation and Operation 1795 Accident Causes 1795 Operating Practices 1795 Emergency Controls 1796 Envelope Control 1797 Platform Controls 1797
Lessons to Learn 1798 Safety Regulations 1798
Conclusions 1800 De«nitions 1800 Abbreviations 1801 Organizations 1801 Bibliography 1801
8.11 RELIEF VALVES: DETERMINATION OF REQUIRED CAPACITY 1802
Introduction 1802 Applicable Codes and Standards 1802
ASME Codes 1802 API Standards and Recommended
Practices 1805 ISO Standards 1805 NFPA Codes 1805 OSHA Codes 1805
Causes of Overpressure 1805 Fire Protection 1806
Gas-Filled Tanks 1806 Low Liquid Inventory Tanks 1808 Heat Absorption across Wetted Surfaces 1808 Environmental Factors 1812 Calculating the Relieving Capacity 1812 Protecting Liquid-Full Tanks 1813
Non«re Protection Overpressure 1813 Thermal Expansion 1813 Blocked Outlet Conditions 1814
Process Equipment Considerations 1814 Low-Pressure Storage Tanks 1814 Heat Exchangers 1815 Pumps and Compressors 1815
Distillation Towers 1816 Pipe Headers 1816 Liquid Pipelines 1817 Gas Pipelines 1817 Chemical Reactors 1817 Nuclear Reactors 1817 Discharging the PRVs 1818 Discharging to Closed Locations 1818
Substituting for Pressure Relief Devices 1818 Excerpts from API 521 Annex E:
High-Integrity Protective Systems (HIPS) 1818
Conclusions 1818 Speci«cation Form 1819 De«nitions 1821 Abbreviations 1822 Organizations 1822 Bibliography 1822
8.12 RELIEF VALVES: SIZING, SPECIFICATION, AND INSTALLATION 1825
Introduction 1826 Nature of PRVs 1827 Purpose of PRVs 1827 System Integrity and Noise 1827 Reliability, Testing, and Redundancy 1827 Safety Checklist 1828
Sizing of PRVs 1828 Backpressure 1828 Sizing for Vapor and Gas Relief 1830 Sizing for Steam Relief 1834 Sizing for Liquid Relief 1834 Sizing for Flashing Liquid Relief 1836 Special Cases 1836
Speci«cation and Selection 1837 Conventional PRVs 1838 Balanced PRVs 1839 Pilot-Operated PRVs 1841 Speci«cation and Selection Checklist 1843 Pipeline Surge Relief 1844 Power-Operated PRVs 1845 Code Safety Valves 1846 Tandem Safety Relief Valves 1846 Differential PRVs 1846
PRV Operation and Performance 1847 Blowdown 1847 PRV Chatter 1847 PRV Tightness and Leakage 1848
PRV Installation 1851 PRV Location 1851 PRV Mounting 1851
PRV Inlet Piping 1851 PRV Outlet Piping 1851 PRV Block Valves 1852 Multiple PRVs 1852 Spare PRVs 1852
Test, Inspection, and Audit 1853 PRV Testing 1853 PRV Inspection 1853 PRV Audit 1853
Speci«cation Forms 1854 Abbreviations 1856 Organizations 1856 Bibliography 1856
8.13 RUPTURE DISCS 1858
Introduction 1859 Code Requirements 1859 Rupture Discs vs. Relief Valves 1859 When to Use 1859
For Sole Relief 1860 For Supplemental Relief 1860
Rupture Disc Location 1860 Upstream of a Relief Valve 1860 Downstream of a Relief Valve 1861
Types and Features 1861 Forward Acting 1861 Reverse Acting 1862 Non-Fragmenting 1862 Vacuum Supports and Back
Pressure 1862 Special Applications 1863
Cycling Pressure 1863 Two-Way Relief 1863 Self-Cleaning 1863 Corrosive Service 1863 Explosion Relief 1864 Fluid Service 1864
Selection and Speci«cation 1864 Material Selection 1865 Graphite Discs 1866 Burst Pressure and Range 1867 Disc Holders 1867 Accessories 1867
Sizing Methods 1868 Standards 1868
Speci«cation Forms 1869 De«nitions 1872 Abbreviations 1872 Organizations 1872 Bibliography 1872
EVOLVING SAFETY PHILOSOPHY
The majority of today’s alarm systems (while described in this chapter) are outdated. They re²ect the thinking in the twentieth century, when we believed that it was enough if we let the operator know that this level or that temperature is high and he will know what to do about it. Today, a totally new safety philosophy is needed. First, the annunciator or alarm system should not only indicate that a condition is unsafe but also instruct the operator about what needs to be done. In addition, in some cases, the response is more complex than just responding to a single condition, because other unsafe conditions might also exist and must be evaluated simultaneously to determine what actions must be taken.
