1. Introduction to Functional Safety Standard for Gas Detection
Preeju Anirudhan (Instr. & Elec. Eng.)
Product & Application Manager – Fire & Gas Detection Solutions
Marketing Manager – Chemical, Oil & Gas
Draeger Safety Pacific Pty. Ltd.
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

2. Functional Safety – Fire and Gas Detection Systems
Objectives
Create awareness on
–The functional safety standards 60079-29-3 which applicable for fire & gas
detection to end-users.
–Why gas detection should not be clubbed together with Process Control
Standard IEC 61511 and the various standards applicable.
–Gas dispersion & placement of Gas detectors & role of gas detectors in risk
reduction.
–Technologies used in Flame & gas detection
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

3. 1 Gas Dispersion & Sensor Placement
2 Principle of Operation – F&G System
3 Risk reduction & Role of F&G detectors
4 Functional Safety Standards for F&G and Projects.
5 Decision Making on Type Of F&G System
6 Applications of F&G Detectors
7 Why Using PLC's may generate trouble?
Functional Safety – Fire and Gas Detection Systems
AGENDA
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

4. 1 Gas Dispersion & Sensor Placement
2 Principle of Operation – F&G System
3 Risk reduction & Role of F&G detectors
4 Functional Safety Standards for F&G and Projects.
5 Decision Making on Type Of F&G System
6 Applications of F&G Detectors
7 Why Using PLC's may generate trouble?
Functional Safety – Fire and Gas Detection Systems
AGENDA
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

5. Gas heavier than air:
dense gas
Gas lighter than air:
buoyant gas
Functional Safety – Fire and Gas Detection Systems
Gas dispersion & Gas categories
Hydrogen
Methane
Ammonia
Acetylene
Nitrogen
Oxygen
Carbon dioxide
Propane
Chlorine
Benzene
Phosgene
Gas behaving like liquids liquefied gas
Gas behave unpredictably gas jet elevated release
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

6. Different scenarios which are typical for gas leaks within a building
Functional Safety – Fire and Gas Detection Systems
Gas dispersion in closed Rooms
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

7. Different scenarios which are typical for gas leaks within a building
Functional Safety – Fire and Gas Detection Systems
Gas dispersion in closed Rooms
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

8. Functional Safety – Fire and Gas Detection Systems
Gas Dispersion
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

9. • The correct installation of gas sensors for the gas detection in outdoor areas is
extremely important.
• Determining “what is to be protected” is important, i.e. people, process, asset and
visualising the possible impact in the event of a gas leak/explosion.
• Environmental conditions can have a detrimental impact on the efficiency of the gas
detection systems if care is not taken during the installation process.
• Sensors must be protected from weather conditions, e.g. heavy rains can splash more
than 30Cm off the ground, so it makes sense for sensors to be placed above 30Cm
when detecting heavy gases.
• Gas sensors should also be located downstream of prevailing winds; also consider the
wind effects caused by buildings, tanks and other obstructions. Areas where wind
changes directions during seasons will also need to be considered.
• Access to the detectors must be considered for ease of maintenance and use of remote
sensors, remote calibration adaptors, remote display, remote bump-test adapter must be
considered.
Functional Safety – Fire and Gas Detection Systems
Placement of Gas detectors – Outdoor Environment
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

10. 1 Gas Dispersion & Sensor Placement
2 Principle of Operation – F&G System
3 Risk reduction & Role of F&G detectors
4 Functional Safety Standards for F&G and Projects.
5 Decision Making on Type Of F&G System
6 Applications of F&G Detectors
7 Why Using PLC's may generate trouble?
Functional Safety – Fire and Gas Detection Systems
AGENDA
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

11. 12
Functional Safety – Fire and Gas Detection Systems
Gas & Flame Detection Methods & Principles of Operation
Gas
•Infra red: Point & Open Path
•Catalytic: Point
•Electro-chemical: Point for Toxic gases & Oxygen
•Laser: Open Path for Ammonia, H2S & CO2
•PID: Point for VOC
•MOS: Point for H2S –low humidity applications
•IMS: Point for warfare gases
•Paramagnetic: Oxygen (low/high)
•Acoustic: for high pressure leaks (Ultrasonic)
Flame
•UV
•IR
•Triple IR
•UV-IR
•Visual Flame (CCTV Flame)
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

12. FLAMEPROOF ENCLOSURE
MEASURING
DETECTOR REFERENCE DETECTOR
BEAM SPLITTER
IR-SOURCES SAPPHIRE WINDOW
GAS
HEATED REFLECTOR
C
H
4
IR SOURCE GAS CUVETTE OPTICAL FILTER
Hydrocarbons absorb Infra-red light if present in the measuring area. The difference between the reference &
signal is proportional to the amount of hydrocarbon or other gases present.
Functional Safety – Fire and Gas Detection Systems
Principles of Operation of Infra-Red Point-Gas Detectors
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

13. Functional Safety – Fire and Gas Detection Systems
Principles of Operation of Open Path Detectors (Flammable & Toxic)
Transmitter Receiver
An infrared/Laser beam (2 wavelengths) sent from TX to RX
Reference wavelength
Signal wavelength
Gas will absorb only the signal wavelength
Signal wavelength absorbed C
HH
HH
Reference wavelength unaffected
Receiver outputs a gas reading
Pulsar 1 Pulsar 2Pulsar Duct
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

14. Functional Safety – Fire and Gas Detection Systems
Principles of Operation of Catalytic Sensors
Wheatstone bridge
uBridge
Rth R2
R1Rref
HEAT
Oxidation leads to energy release
The resulting heat is proportional to the
amount of reactions per time
Temperature increase can be
measured as resistance change of an
embedded platinum coil and is
proportional to the flammable gas
concentration.
The resulting heat leads to a
temperature increase ∆T
The resulting heat is proportional to the
amount of flammable gas molecules
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

15. Electrochemical Sensors
Principle
A chemical reaction of the target gas with the electrolyte produces electrons (current) which is proportional
to the gas concentration.
Why?
Electrochemical sensors are very specific in general to the target gases and measure gases or vapours of
very low concentration of gases that are difficult to measure using catalytic or Infra red type gas detectors.
Very low levels alarms to comply with exposures
Functional Safety – Fire and Gas Detection Systems
Principles of Operation of Electro-Chemical sensors
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

16. 1 Gas Dispersion & Sensor Placement
2 Principle of Operation – F&G System
3 Risk reduction & Role of F&G detectors
4 Functional Safety Standards for F&G and Projects.
5 Decision Making on Type Of F&G System
6 Applications of F&G Detectors
7 Why Using PLC's may generate trouble?
Functional Safety – Fire and Gas Detection Systems
AGENDA
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

17. risk
Risk – ignition from non-Ex rated equipmentdangerous
safe
necessary
risk reduction
actual risk
reduction
tolerable risk
Functional Safety – Fire and Gas Detection Systems
Risk reduction & role of Fire & Gas detection.
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

18. risk
Risk – ignition from non-Ex rated equipmentdangerous
safe
Air inlet positioning
Ventilation rate
emergency shut-
down
Gas Detection
residual risk
risk
reduction
necessary
risk reduction
actual risk
reduction
tolerable risk
Functional Safety – Fire and Gas Detection Systems
Risk reduction & role of Fire & Gas detection.
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

19. risk
Risk – ignition from non-Ex rated equipmentdangerous
safe
Air inlet positioning
Ventilation rate
emergency shut-
down
Gas Detection
residual risk
risk
reduction
necessary
risk reduction
actual risk
reduction
tolerable risk
Functional Safety – Fire and Gas Detection Systems
Risk reduction & role of Fire & Gas detection.
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

20. risk
dangerous
safe
Gas Detection
residual risk
Risk – ignition from non-Ex rated equipment
risk
reduction
necessary
risk reductionactual risk
reduction
tolerable risk
Functional Safety – Fire and Gas Detection Systems
Risk reduction & role of Fire & Gas detection.
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

21. 1 Gas Dispersion & Sensor Placement
2 Principle of Operation – F&G System
3 Risk reduction & Role of F&G detectors
4 Functional Safety Standards for F&G and Projects.
5 Decision Making on Type Of F&G System
6 Applications of F&G Detectors
7 Why Using PLC's may generate trouble?
Functional Safety – Fire and Gas Detection Systems
AGENDA
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

22. Functional Safety – Fire and Gas Detection Systems
What IEC 61508 Standards says
The scope of IEC 61508 ( Part-1,Clause 1.1)
…….A major objective of this standard is to facilitate the
development of application sector international
standards by the technical committees responsible for
the application sector. This will allow all the relevant
factors, associated with the application, to be fully taken
into account and thereby meet the specific needs of the
application sector. ……….
Old Edition and NEW Edition
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

23. Functional Safety – Fire and Gas Detection Systems
Functional Safety Standards & where gas detection fits
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

24. Functional Safety – Fire and Gas Detection Systems
Gas Detection Standards - Explained
EN 50402 : 2005 (2013) IEC 60079-29-3
A Product based standard for the
Manufacturers
A life cycle approach for the system
designer, engineering contractor,
installation, start-up, service,
modification and decommissioning
Includes some good guidance of the
special requirements in the world of
Gas Detection
An entire Clause describing the
special requirements of gas detection
Mandates the need for a R&D facility
to operate under a functional safety
management system
Mandates the need for everyone
involved with the life cycle to operate
under a functional safety management
system
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

25. Functional Safety – Fire and Gas Detection Systems
Various Standards for Fire & Gas Detection Systems
EN 60079 – 10 -1:2009 (EN 1127-1 : 2011)EN 60079 – 10 -1:2009 (EN 1127-1 : 2011)
ISO 31000 : 2009ISO 31000 : 2009
BS 6079 -1 : 2010BS 6079 -1 : 2010
EN 60079 – 1 : 2007EN 60079 – 1 : 2007
IEC 60079 – 29 – 1 : 2007
IEC 61508 : 2011IEC 61508 : 2011
EN 60079 – 19 : 2011EN 60079 – 19 : 2011
• Standards for specifying the hazardous locations
• Standards for Risk Analysis
• Standards for Project Management
• Standards for Product design with respect to Ex areas
• Standards for Product performance
• Standards for Product Integrity and associated QA systems
• Standards for repair workshops
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

26. Functional Safety – Fire and Gas Detection Systems
Explosive atmospheres – 60079 Part 29-3:
Guidance on functional safety of fixed gas detection systems –
This International standard gives guidance for the design and implementation
of a fixed gas detection system, including associated and/or peripheral gas
detection equipment, for the detection of flammable gases/vapours and Oxygen
when used in a safety-related application in accordance with IEC 61508 and
IEC 61511. This International standard also applies to the detection of toxic
gases.
Other parts of this international standard and pertinent local, national and
international standards separately specify the performance requirements of a
gas detector and a gas detection control unit (logic solver). These standards
are commonly known as Metrological Standards and are concerned with the
accuracy of the measured value, the overall system performance, but not the
device or system integrity with respect to the safety function. This international
standard applies to the integrity of the safety function.
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

27. Functional Safety – Fire and Gas Detection Systems
Standards currently applied in Projects
Project
Products developed under IEC 61508
Application standards written
within the framework of IEC 61508
Machinery safety delivered under IEC 62061
Process safety delivered under IEC 61511
ANSI/ISA 84.00.01
Fire and Gas Detection Systems
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

28. Functional Safety – Fire and Gas Detection Systems
Standards that shall be followed in Projects
Project
Products developed under IEC 61508
Application standards written
within the framework of IEC 61508
Machinery safety delivered under IEC 62061
Gas Detection delivered under BS EN 50402 / IEC 60079-29-3
ANSI/ISA 84.00.07 Fire & Gas
Process safety delivered under IEC 61511
ANSI/ISA 84.00.01
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

29. Functional Safety – Fire and Gas Detection Systems
Interpretation of Standards
General Understanding Actual Requirement
A Fire & Gas control circuit includes a
detector, a control card and an output
device
A Fire & Gas control loop includes
performance approved detectors,
performance approved control cards
and output devices
The wiring diagram and the Cause & Effects chart are identical
The Ex zoning and the use of Intrinsically Safe isolators does not change
The Control System is programmed
using competent engineers using
Ladder Logic
Programming is not allowed
(Competency would show that programming is
not allowed and performance approved
equipment is a pre-requisite)
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

30. Functional Safety – Fire and Gas Detection Systems
Importance of Performance Approvals
What needs
performance
approval?
Why need
performance
approval?
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

31. 1 Gas Dispersion & Sensor Placement
2 Principle of Operation – F&G System
3 Risk reduction & Role of F&G detectors
4 Functional Safety Standards for F&G and Projects.
5 Decision Making on Type Of F&G System
6 Applications of F&G Detectors
7 Why Using PLC's may generate trouble?
Functional Safety – Fire and Gas Detection Systems
AGENDA
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

32. Functional Safety – Fire and Gas Detection Systems
Decision path - Types of Fire and Gas detection system
Is there a stated
Safety function
&
Safety integrity?
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

33. The definition of a Standard Fire and Gas detection system is
– A system who’s specification does not detail a contribution to ‘risk reduction’
– A system which alarms only, with no supporting operational measures which
are announced as ‘risk reduction’
– A system which is not guarded against modifications
– A system which has no mandatory service and proof test intervals
– A system which is not supported by a fixed spare parts list for inspection,
maintenance and repair
Functional Safety – Fire and Gas Detection Systems
Standard Fire and Gas detection system
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

34. Functional Safety – Fire and Gas Detection Systems
F&G Classification – Protection, Mitigation or Safeguarding system
The definition of a Fire and Gas detection system having a Protection
function
• A Protection system reduces the frequency of the hazard
The definition of a Fire and Gas detection system having a Mitigation
function
• A Mitigation system reduces the consequence of the hazard
The definition of a Fire and Gas Safeguarding system is
• An additional system which operates in parallel to the SIS
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

35. The definition of a Fire and Gas detection system having a ‘function of safety
(safety requirement specification)
– A system who’s specification includes a contribution to ‘risk reduction’
• Safety Integrity level
– A system which alarms only, but is supported by operational measures
which are announced as ‘risk reduction’
• Safety Integrity level and Operational procedures
– A system which is fully supported by a service regime, proof test interval
and supporting documentation for spare parts interchangeability
– A system which is guarded against unauthorised modification
– A system who’s life cycle is supported by a Functional Safety Management
system
Functional Safety – Fire and Gas Detection Systems
Safety Function - Fire and Gas detection system
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

36. • The speed of response of the sensing element (proof test)
• Alarm philosophy
• The trip level for a specific measuring point
• The action required behind the trip point
• The time taken for the action to be complete
• The required integrity of the complete safety function
• The operational procedures
• Environmental conditions
Note : sensor coverage or mitigation effectiveness is not part of the safety function
Functional Safety – Fire and Gas Detection Systems
Criteria of a Safety Function
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

37. 1 Gas Dispersion & Sensor Placement
2 Principle of Operation – F&G System
3 Risk reduction & Role of F&G detectors
4 Functional Safety Standards for F&G and Projects.
5 Decision Making on Type Of F&G System
6 Applications of F&G Detectors
7 Why Using PLC's may generate trouble?
Functional Safety – Fire and Gas Detection Systems
AGENDA
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

38. Functional Safety – Fire and Gas Detection Systems
Applications using gas detectors.
Detection of Hydrocarbons
(oil & gas/Chemical/manufacturing)
Detection in 0 – 100% LEL
Leak Detection
(Analyzer rooms/labs/solvent storage)
Detection in PPM /0 – 10% LEL
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

39. Functional Safety – Fire and Gas Detection Systems
Applications for monitoring Flammable gases at heights
Special attention must be paid when
installing gas detector at heights. E.g.
•At entrance of air intake ducts.
•Inside air intake ducts
•Under ceiling or roof space at heights for
CH4 detection in storage facilities &
turbine rooms.
•Cost of maintenance (scaffolding/ cherry
picker/height safety permits)
Solutions:-
Select performance detectors which has
remote test/maintenance/calibration
features, so basic maintenance can be
performed without direct access to the
sensor.
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

40. Functional Safety – Fire and Gas Detection Systems
Applications for monitoring Flammable gases at Depths (confined Space)
Special attention must be paid when
installing gas detector at depths or
confined spaces. E.g.
•In confined spaces (sumps)
•Drains /Well heads/collection points
•Tank Bund walls subject to flooding.
•Cost of replacement due to water
damage, CSE extra permits)
Solutions:-
Select performance approved detectors
which has remote test/maintenance/
calibration features, so basic
maintenance can be performed without
direct access to the sensor. Ensure the
sensors are suitable for the application
and can withstand flooding/submersion
(IP 67/68)
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

41. Functional Safety – Fire and Gas Detection Systems
Applications – inline monitoring
When designing Sampling systems,
consider the following
•Delay for gas transit
•Ensure proper flow for reliable gas
reading.
•Ex-Approvals all the equipment used in
the system.
•Calibration of gas sensors inline.
•Easy access for maintenance
(cleaning/replacements)
•Process conditions (heat/ humidity/
temperature/ Pressure /corrosion)
•Sample Conditioning as required.
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

42. 1 Gas Dispersion & Sensor Placement
2 Principle of Operation – F&G System
3 Risk reduction & Role of F&G detectors
4 Functional Safety Standards for F&G and Projects.
5 Decision Making on Type Of F&G System
6 Applications of F&G Detectors
7 Why Using PLC's may generate trouble?
Functional Safety – Fire and Gas Detection Systems
AGENDA
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

43. – SAFETY may be compromised because the programming is open
to the programmer. Plant operations may be affected due to false
alarms.
– Analogue input channels need to be configured correctly to
recognise the Special signals of Fire & Gas detection transmitter (0
– 4mA & 20 – 22mA)
– PLC’s are not designed for gas detection applications with respect
to the International Standards for gas detection systems
– PLC’s does not have local displays to indicate gas readings – only
external viewing panels are available which require configuration
– Gas detection system manufacturer has no control on PLC quality,
availability, obsolescence, pricing etc.
– Skilled engineers are not always available and our tech support do
not support PLC based central control systems
Functional Safety – Fire and Gas Detection Systems
Why using a PLC can generate trouble?
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas

44. Functional Safety – Fire and Gas Detection Systems
Thank you
Preeju Anirudhan - Product & Applications Manager – F&G / Marketing Manager – Chem, Oil & Gas
Email: Preeju.Anirudhan@Draeger.com