chapter 3 zone concept
TRANSCRIPT
8/10/2019 Chapter 3 Zone Concept
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Session 3 – Zone Concept
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Area Classification to IEC
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Area Classification to IEC
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Area Classification to NEC
• Division 1 ‐ hazard can exist under normal operating conditions or because of leakage
[NEC 500‐5,6,7],
• Division 2 – flammable concentrations are processed but normally confined within
containers or
systems
[NEC
500
‐5,6,7]
• Zone Conce t – Reco nized under NEC 505
Division/Zone 2Division/Zone 2
Division 1/Zone 0
Division Zone 1
Division 1 Zone 0
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Comparison of IEC vs. NA
Gas
Groupings…
Gas rou in s in the North American world do differ sli htl from the IEC world as to as rou in s…
IIC = A, B
IIB = C
IEC
IIB
NFPA
B
Material
Ethylene Oxide
CHANGE
IIA = D IIC
IIA
IIA
C
C
C
Carbon Disulfide
Acetaldehyde
Eth l Merca tan
IIB
IIB
D
D
Isoprene
Cyclopropane
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Comparison of IEC vs. NA
Zone
vs.
Division
Concept
Frequency of CEC / NEC IEC/CENELEC/CEC
Occurrence
Continuous
Division System /NEC Zone System
Zone 0
Intermittent
Periodically
Class I, Division 1Zone 1
Abnormal
ConditionClass 1, Division 2 Zone 2
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Class 1, Division 1 & 2 Wiring Examples
Division 1
• Conduit or Approved MC/MI Cables
• Seals Used in Division 1 on Cables
Division
2
• Tray Cable (Unarmored)
• Standard Location Cable Glands permitted
• Non Explosion‐proof Conduit Bodies
Conduit Seals used:
• Within 18” of arcin s arkin in Division 1
• Boundary of
Hazardous/Non
‐Hazardous
• Conduit 2” or larger Division 1 entering non‐
arcing enclosures
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Gas Grouping per NPFA for US
Installations
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Class 1, Division 1 Wiring Examples
:
• Explosion Proof conduit
Fittings even when not
directly exposed to explosion
potential from
enclosures/lighting…
• Seal fittings or factory
sealing on
all
arcing
devices
equipment
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Class 1, Division 2 Wiring Examples
:
•Non Explosion proof conduit fittings such as LB’s, T’s, etc.
• Seal fittings or factory sealing on
all arcing devices
• Die cast /FRP construction of
some devices
• Not limited
to
conduit
but
is
…
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North American Zone 1 & 2 Installation
Similar to IEC EX
different cable
construction and
different marking
and testing
requirements for
the products. In
some cases,
products have
certification per
Cenelec and
ANSI/NEMA
standards….
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Who is The Authority Having Jurisdiction ?
• Countries Determine Who Is Responsible For Product “Standards”
and “Testing”
–
• US ‐ America National Standards Institute ‐ ANSI
• Canada
‐ Standards
Council
of
Canada
– Internationa y
• Depends On Your Country
– e.g. Standards Australia, BOMBA, South Africa Bureau Of Standards, Türk
Standardlari Enstitüsü,
Saudi
Arabian
Standards
Organization,
Directorate
of Standardization and Metrology, Ministry of Finance and
IndustrySingapore Productivity and Standards Board (PSB), Dirección
General de Normas
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Who is The Authority Having Jurisdiction ?
•
Regulations
May
Vary
By – County
– Province
–
State – y
– Accredited Testing
Agency
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Authority Having Jurisdiction ‐
Europe
Explosion protection is legally regulated worldwide by the governments of the individual states.
Country‐specific differences in the technical requirements and requested approvals for explosion‐
proof devices are a significant hindrance to the trade of globally operating manufacturers, and
necessitate high development and approval overheads. It has been the interest of leading
industrial nations for a long time already to eliminate these hindrances by harmonization of the
relevant technical
standards,
and
to
implement
uniform
safety
standards
at
the
same
time.
Within
the European Community, the harmonization process in the explosion protection sector has been
largely completed in the meantime. At the international level, the IEC is attempting to reach the
" " ‐ .