Summary/Conclusions
Although there are explosion protection systems in place, it is still important to reduce the demand on these
systems. Protection systems such as explosion vents are not intended for frequent use – hence it is critical to
control ignition sources where flammable atmospheres are unavoidable. Over the years and after discussion
with several clients, the team of experts at Chilworth Technology has determined that there are several myths
regarding process safety in general and ignition sources in particular.
Top
Ten Myths
Hazards
Control &Regarding
AssessIgnition Sources
For further information on identification of ignition sources and mitigation of the corresponding hazards, please
contact Swati Umbrajkar, Ph.D., Manager – Chemical Process Evaluation Group at Tel: 609-799-4449, Fax: 609799-5559, Email: safety-usa@chilworthglobal.com, or you may also visit our website at: www.chilworth.com.
Dr. Swati Umbrajkar
Dr. Swati Umbrajkar, Ph.D. is the Manager of the Chemical Process Evaluation Group. Dr. Umbrajkar received
her Doctorate from the New Jersey Institute of Technology. Her research interests include the synthesis of metal/
metal oxide nanocomposites; analysis of highly energetic materials using X-ray diffraction, scanning electron
microscopy (SEM), differential scanning calorimetry (DSC), and a number of post analysis techniques to
characterize the thermodynamic and kinetic parameters of a test system.
Dr. Umbrajkar consults with clients on a variety of process safety issues including but not limited to high-pressure
DSC cell tests, adiabatic calorimetry (ARC and ADC), reaction calorimetry (RC-1), all of which allow for the safe
scale-up of batch and semi-batch processes. She has expertise in determining self-acceleration decomposition
temperature (SADT) and time to maximum rate (TMR), which are critical issues associated with the storage of
bulk materials. As the Manager and Consultant in the Chemical Process Evaluations Laboratory, she is proficient
in the interpretation of data for a wide variety of process safety scenarios. She has authored several articles in the fields of, ‘Synthesis and
Analysis of Highly Energetic Materials’ and ‘Chemical Process Safety’.
She received the Excellence Award from NASA for her services in NASA’s SHARP student program in 2005 and Research Experience
for Undergraduate (REU) students at the New Jersey Center for Engineered Particulates (NJCEP) in 2006. She was awarded the Best
Graduate Student Research Overall presented at the Graduate Student Research Day on November 6, 2006. She is also the recipient of
the ‘best presenter’ award at the AIAA (American Institute of Aeronautics and Astronautics) Young Professionals in Science and Engineering
Conference (Northeast Section) in November 2006. She is a member of the American Institute of Chemical Engineers.
CHILWORTH TECHNOLOGY, INC.
Chilworth Technology, a DEKRA company, helps its clients achieve enabling and sustainable Process Safety Management
programs, Process Safety Proficiency (competency, know-how, and experience), and a culture that encourages excellence
in process safety. Our full range of services includes:
Process Safety Management (PSM) Programs
•
Design and creation of relevant PSM programs
•
Support the implementation, monitoring, and sustainability of PSM programs
•
Audit existing PSM programs, comparing with best practices around the world
•
Correct and improve deficient programs
Process Safety Information (Laboratory Testing)
•
Flammability/combustibility properties of dusts, gases, vapors, mists, and hybrid atmospheres
•
Chemical reaction hazards and chemical process optimization (reaction and adiabatic calorimetry RC1, ARC, VSP, Dewar)
•
Thermal instability (DSC, DTA, and powder specific tests)
•
Energetic materials, explosives, propellants, pyrotechnics to Dot, UN, etc. protocols
•
Regulatory testing: REACH, UN, CLP, ADR, OSHA, DoT
•
Electrostatic testing for powders, liquids, process equipment, liners, shoes, FIBCs
Specialist Consulting (technical/engineering)
•
Dust, gas, and vapor flash fire and explosion hazards
•
Electrostatic hazards, problems, and applications
•
Reactive chemical, self-heating, and thermal instability hazards
•
Hazardous area classification
•
Mechanical equipment ignition risk assessment
•
Transport & classification of dangerous goods
PS - US - WP - 045 -01
Chilworth serves clients throughout the agrochemical, chemical, engineering, food processing, government, insurance/legal, metals, oil/gas, pharmaceutical, plastics, rubber and other industries. Chilworth has offices throughout North America,
Europe, and Asia. For more information about Chilworth, visit www.chilworth.com.
To contact us:
> France:
info-fr@chilworthglobal.com
>Spain : info-es@chilworthglobal.com
> Netherlands: process-safety@dekra.com
>UK
> India:
info-in@chilworthglobal.com
>USA : safety-usa@chilworthglobal.com
>Italy
: info-it@chilworthglobal.com
: info-uk@chilworthglobal.com
TOP TEN MYTHS REGARDING
IGNITION SOURCES
Swati M Umbrajkar, PhD, Manager, Chemical Process Evaluation Group
Fundamentals related to the conditions that lead to an explosion will be discussed. Some of the potential
ignition sources are described. It is impossible to cover everything there is to know about ignition sources
in this article; however the key focus is to discuss the things the plant personnel really need to know.The
process safety specialists at Chilworth continue to find sites where ignition source management is poor.
The various myths associated with these ignition sources are discussed in this article.
Background Information
Fire Triangle: There are three conditions
essential for a fire.
1. fuel;
2. oxidant, typically the oxygen in
air; and
3. a sufficiently energetic ignition
source.
These three elements are commonly
referred to as the fire triangle.
Atmospherics
Lightning strikes
Compression
Ingestion of flammable mixture: Compressor, high speed blower
Reactive and Unstable Material
Pyrophoric material
Incompatible material: material which reacts with material of
construction
Static Electricity
Explosion Pentagon: In case of an
explosion, elements of confinement and
mixing, dispersion (suspension in case
of dust explosions) are also involved.
Ignition Sources
“Ignition sources are the only thing we get for free in the chemical industry” – T. Kletz
Whenever flammable liquids, gases or powders are handled, ignition sources are never far away. The consequences
of ignition can be devastating resulting in loss of life, business and bad publicity to name a few. Some of the potential
ignition sources are as follows: (Loss Prevention in the Process Industries Hazard Identification and Control – Frank
P Lees Volume 2 Second Edition)
Ignition sources
Flames
Examples
Flare: elevated or ground level
Incinerator
Furnace
Laboratory heater: Bunsen burner
Boiler
Personnel heater: solid fuel, electrical heater
Accidental fire
Burning operations, Flare, etc
Hot work
Welding: Arc Welding, oxyacetylene welding
Cutting: oxyacetylene
Grinding
Hot surfaces
General: Vessel and pipework
Machinery: Engines, turbines, exhausts
Laboratory equipment: Hot plate, oven
Hot particles: Soot
Friction and Impact
Impact: Hand tools, power tools, moving vehicle etc.
Rubbing: Belt, conveyor, roller brake, clutch on machinery etc.
Smoking
Means of lighting: matches, lighter.
Item smoked: Cigarette, cigar, pipe
Vehicles
General vehicles: Petrol, diesel or electrically driven
Crane
Forklift truck
Aircraft
Self heating
Dust layer
Oil soaked lagging
Mechanical rupture
Spark associated with rupture giving rise to release
Machinery: Motors, alternators, dynamos, convertors
Fixed equipment: contact devices such as switches, relays, contactors
Insulators: Arcing across spark gaps at high voltage insulators
Cable: broken cable, damaged cable, water ingress
Batteries: connecting up damaged battery
Heating tape
Lighting
Fault current conductor: Poor joint
Portable equipment: meter, radio, TV, camera, hearing aid
Earth movement: Sparking due to earth movement such as
earthquake or subsidence
Despite ATEX and several regulatory requirements, Chilworth continues to find sites where ignition source
management is poor. Examples are many but some include:Inadequate bonding and grounding of equipment and people
No maintenance of grounding systems
Lack of awareness of how to handle highly flammable non-conductive liquids
Use of plastic bags to add powders to solvents
Incorrect selection of big bags for electrostatic control
‘Run to failure’ maintenance of non-electrical equipment in hazardous areas
Poor management of hot work including a lack of understanding of what constitutes hot work
‘Ex’ electrical equipment poorly maintained, wrongly specified or wrongly installed
No data on safe powder drying and storage temperatures
Insufficient understanding of the ignition characteristics of combustible dusts
Some of this is due to lack of awareness, but some is due to the complexity of the problem. Guidance is there but
can be hard to interpret and apply practically.
Myths about Ignition Sources:
It is impossible to cover everything there is to know about ignition sources in this article; however the key focus is to
discuss the things the plant personnel really need to know. Over decades of working in the field of process safety,
the team of experts at Chilworth Technology has determined that there are several myths regarding process safety
in general, and ignition sources in particular.
Myth
Myth No. 1
Myth No. 2
Myth No. 3
Myth No. 4
Myth No. 5
Myth No. 6
Myth No. 7
Myth No. 8
Myth No. 9
Myth No. 10
Description
“I’ve been loading powder to that reactor via an open manway for 30 years and have never
had an explosion so I can’t have an ignition problem”
“I operate the process below the liquid flashpoint so I’m safe”
“We can use literature data for our dust ignition properties”
“We don’t have an ignition problem because we use a hot work permit”
“How can my operators get charged, they don’t rub against anything”
“Everything is grounded so I have no static problem”
“We must bond across all pipework joints”
“We use a grounding clip for that drum so we are safe”
“I don’t have any isolated conductors on my plant” and “It’s metal to metal contact so it
should be grounded – right?”
“We issue static dissipative footwear so we don’t have a problem with sparks from people
or hand held tools” and “I didn’t think people could ignite flammable vapors anyway”
Avoidance of ignition sources is not usually advised as the ‘sole’ basis of safety.
However, where protection systems such as inerting or explosion venting are also
present, minimizing demand on these systems is paramount.