Gas Detection Hand Book HSSE WORLD

Gas Detection Handbook is a reference guide for customers considering using fixed or portable gas detectors. It provides both basic and comprehensive
information about gas detection.
Gas detectors and environmental monitoring devices protect people from invisible hazards by swiftly detecting combustible and toxic gases that can cause disasters. Above all, our mission is to create an environment that allows people to work with peace of mind̶something essential for industrial growth and development.

Table of Contents

What is gas?

Air composition

Air consists of approximately 78 % nitrogen, 21 % oxygen, and 1 % other gases (e.g., argon and carbon dioxide). Nitrogen, the largest component of air, forms the basis of proteins made of amino acids and contained in numerous living organisms. Nitrogen is essential for almost all life on the planet. However, nitrogen is not absorbed directly into the body from the air. ( The basics of alarm in the Process Plant )

The nitrogen we breathe in is simply expelled when we breathe out. Essential to life and absorbed directly into our bodies, oxygen accounts for 21 % of air. Carbon dioxide, which is vital for plant photosynthesis, accounts for less than 1 %. Animals absorb oxygen and expel carbon dioxide and plants absorb carbon dioxide and
expel oxygen, maintaining a constant balance of the overall air composition and life processes on the planet.

( Read more:Gas Leak Detection System )

Gas hazards

Broadly speaking, gas hazards fall into the following three categories:

① Combustible gases
Gases that have an explosive range (combustible range) when mixed with air.
The GHS* refers to substances in a gaseous state at standard atmospheric pressure (101.3 kPa) and 20 °C.

GHS: Globally Harmonized System of Classification and Labelling of Chemicals

② Toxic gases
Gases that impair human biological function Toxic gases are regulated based on threshold values set to safeguard against harmful health effects for workers exposed to such substances at the work site eight hours a day, 40 hours a week. ( What is the Meaning of %LEL, %UEL, PID )

② Oxygen deficiency
The human body is able to function normally at atmospheric oxygen concentrations of around 21 %. If oxygen is consumed and its concentrations are reduced (by metal oxidation or by microorganisms) or if oxygen is displaced by other gases (e.g., N2 and Ar), effects on the human body become apparent when concentrations fall below around 18 %. Death becomes a risk between 6 % and 8 %.

Know more about Carbon dioxide

The content of Gas Detection Hand Book:

1- Introduction ……………………………………………………………………………………………………………………………. 4
2- What is gas? …………………………………………………………………………………………………………………………… 5
- 2-1. Air composition ………………………………………………………………………………………………………………….. 5
- 2-2. Gas hazards ……………………………………………………………………………………………………………………….. 6
3- Combustible Gas Hazards ………………………………………………………………………………………………………. 7
- 3-1. Three elements necessary for combustion ………………………………………………………………………… 7
- 3-2. Explosive Limit …………………………………………………………………………………………………………………… 8
- 3-3. Combustible vapor ……………………………………………………………………………………………………………… 8
- 3-4. Physical properties of combustible gases ………………………………………………………………………….. 10
4- Toxic Gas Hazards ………………………………………………………………………………………………………………… 32
- 4-1. Toxic gas hazards ……………………………………………………………………………………………………………… 32
- 4-2. Threshold limit values of toxic gases ………………………………………………………………………………… 33
5- Oxygen Deficiency Hazards …………………………………………………………………………………………………. 39
- 5-1. Oxygen deficiency …………………………………………………………………………………………………………….. 39
6- Typical Areas That Require Gas Detection ………………………………………………………………………….. 41
- 6-1. Gas detector market …………………………………………………………………………………………………………. 41
7- Gas detection technologies ………………………………………………………………………………………………….. 45
- 7-1. RIKEN Gas sensor technologies ………………………………………………………………………………………… 45
- 7-2. Catalytic Combustion Method ……………………………………………………………………………………………. 46
- 7-3. New Ceramic Catalytic Method …………………………………………………………………………………………. 47
- 7-4. Semi-Conductor Method ……………………………………………………………………………………………………. 48
- 7-5. Hot Wire Type Semi-Conductor Method ……………………………………………………………………………. 49
- 7-6. Thermal Conductivity Method …………………………………………………………………………………………… 50
- 7-7. Potentiostatic Electrolysis Method ……………………………………………………………………………………. 51
- 7-8. Membrane-Separated Electrode Method …………………………………………………………………………… 52
- 7-9. Membrane Type Galvanic Cell Method ………………………………………………………………………………. 53
- 7-10. Non-Dispersive Infrared Method……………………………………………………………………………………… 54
- 7-11. Interferometer Method ……………………………………………………………………………………………………. 55
- 7-12. Chemical Tape Method ……………………………………………………………………………………………………. 56
- 7-13. Photo-Ionization Detector ……………………………………………………………………………………………….. 57
- 7-14. Pyrolysis-Particle Detection Method ………………………………………………………………………………… 58
8- Selecting Gas Detectors ……………………………………………………………………………………………………….. 59
- 8-1. Gas detector selection ………………………………………………………………………………………………………. 59
9- Fixed Gas Detectors ………………………………………………………………………………………………………………. 61
- 9-1. Explosion-proof Gas Detector Head ………………………………………………………………………………….. 61
- 9-2. Non-Explosion-proof Gas Detector Head …………………………………………………………………………… 65
- 9-3. Indicator/alarm unit ………………………………………………………………………………………………………….. 67
10- Portable Gas Detectors ………………………………………………………………………………………………………. 69
- 10-1. Multi Gas Detector (Multi-sensor) …………………………………………………………………………………… 69
- 10-2. Single Gas Detector (Single-sensor) ……………………………………………………………………………….. 72
11-Typical Applications for Portable Gas Detectors ……………………………………………………………… 75
- 11-1. Applications in Automotive Market ………………………………………………………………………………….. 75
- 11-2. Applications in Steel Market ……………………………………………………………………………………………. 81
- 11-3. Applications in Fumigation Market ………………………………………………………………………………….. 85
- 11-4. Applications in Pharmaceutical Market ……………………………………………………………………………. 89
- 11-5. Applications in Food Product …………………………………………………………………………………………… 94
- 11-6. Applications at Universities and Research Institutions ………………………………………………….. 102
- 11-7. Applications in Gas Market…………………………………………………………………………………………….. 108
- 11-8. Applications in Electric Power Market ……………………………………………………………………………. 112
- 11-9. Applications in Paper Manufacturing Market …………………………………………………………………. 122
- 11-10. Applications in Oil and Fossil Fuel Market ……………………………………………………………………. 127
12- Standards and Certification ……………………………………………………………………………………………… 134
- 12-1. ATEX …………………………………………………………………………………………………………………………….. 134
- 12-2. IECEx ……………………………………………………………………………………………………………………………. 135
13- Product Ingress Protection Rating ………………………………………………………………………………….. 137
14- Maintenance ……………………………………………………………………………………………………………….