División Industria
ELECTRICAL ARC FLASH
HAZARD STUDY
APRIL 2008
Industry Division Your success is our aim
ArcFlash
Estudio de Riesgos
VIDEO – LIBERATION OF ENERGY
ArcFlash
Estudio de Riesgos
Electrical Arch
We are exposed?
Applicable Regulations
Risks
Incidents
Arc Flash Study
AGENDA
Topics to Covering:
ArcFlash
Estudio de RiesgosArcFlash
What´s this?
Electrical
Accident
Traffic of current
across the body for
ArcFlash
Direct contact
Indirect contact
It is a short circuit across the air, produced when :
The insulation between two energized drivers collapses
The same between a wire and earth, provoking an explosion for the
liberation of energy
ArcFlash
Estudio de Riesgos
VIDEO II – ARC in 500 kV
ArcFlash
Estudio de Riesgos
Accidents of ArcFlash
Where they can happen ?
Distributions
Panels
MV / LV
Center
Center
Control of
Control of
Engines
Engines
Electrical
Electrical
Engines
Engines
Areas
Areas
with
with
high
high
temperatures
temperatures
Areas with
High
High
Risk of Occurrence
Risk of Occurrence
ArcFlash
Estudio de Riesgos
Our Offer
His Purpose ….
To minimize the ocurrence and consequence of accidents
for ArcFlash
To determine reliable procedures of operation
To define levels of appropiate PPE
To normalize a program of permanent training
The
Purpose of
Purpose
Our Study
Our Study
ArcFlash
Estudio de Riesgos
¿WE ARE EXPOSED?
¿WE ARE
EXPOSED?
ArcFlash
Estudio de Riesgos
¿WE ARE EXPOSED?
Isn’t this a common situation in your plant?
ArcFlash
Estudio de Riesgos
¿WE ARE EXPOSED?
Isn’t this a common situation in your plant?
ArcFlash
Estudio de Riesgos
¿WE ARE EXPOSED?
Isn’t this a common situation in your plant?
Study of RisksArcFlash
Estudio de Riesgos
ARC FLASH REASONS
The contact with parts under voltage for fall of tools
Insulations fault
Overvoltage
Dirt
Corrosion
Condensation
Study of RisksArcFlash
Estudio de Riesgos
NORMS
NORMS
ArcFlash
Estudio de RiesgosARCFLASH
Applicable Regulations
Applicable Regulations
:
Study of RisksArcFlash
Estudio de Riesgos
ARCFLASH
Applicable Regulations
Applicable Regulations
:
NFPA 70E Part II Articles 110 and 130
require a flash hazard analysis be performed
to protect qualified electrical personnel
National Electrical Code NFPA 70 Article
110.16 requires equipment be marked to warn
personnel of arc flash hazards
ArcFlash
Estudio de Riesgos
OSHA 29CFR1910.269(I)(6) discusses
appropriate PPE apparel to protect against
arc flash hazards
The 2004’ s version of IEEE 1584a
provides precise methods for ArcFlash 's
calculation.
Procedures and safeties measurements specified
ARCFLASH
Applicable Regulations
Applicable Regulations :
ArcFlash
Estudio de Riesgos
RISKS
RISKS
ArcFlash
Estudio de Riesgos
Produce thermal energy that is released during a fault
and is a function of:
Available fault current and system voltage
Distance from fault
Clearing time of protective device
May generate higher energy at lower system voltages
(due to longer time arc fault current duration)
Electrical Arc Flash Hazards
ArcFlash
Estudio de Riesgos
TYPES OF RISKS FOR ARC FLASH
There are principally five ways in which an electrical
ArcFlash can to cause damage and even the death:
Thermal Risk
Risk of Pressure
Risk of Hearing
Risk for Missiles
Risk for Inhalation
ArcFlash
Estudio de RiesgosARCO ELECTRICO
Waves of Pressure
Steam of Copper:
Occurred to
Steam It expands
to factor of
67.000 times
Molten Metal
Intense Light
Warm air
Rapid expansion
20.000 °C
Missil
Waves of sound
Study of RisksArcFlash
Estudio de Riesgos
INCIDENTS of ARCFLASH
INCIDENTS
ArcFlash
Estudio de Riesgos
ArcFlash
Estudio de Riesgos
INCIDENT for ARCFLASH
ArcFlash’ s Incident
System of 480Volt
22,600 Amper Symmetrical Current
Panel of Motor’s Control
It comes out of 6 cycles (0.1 sec)
ArcFlash
ArcFlash
Estudio de Riesgos
RESULT OF AN ACCIDENT FOR
ARCFLASH
ArcFlash
Estudio de Riesgos
INCIDENT for ARCFLASH
480 Volt System
22,600 22,600A Symmetrical Current
Panel of Motor’s Control
Limiter equipment with < ½ cycle of operation (.0083 sec).
To notice that the exhaust will have to be kept in the range
of limit of current
INCIDENT for ARCFLASH
ArcFlash
ArcFlash
Estudio de Riesgos
VIDEO
ARC FLASH ’s INCIDENT
ArcFlash
Estudio de Riesgos
VIDEO
ArcFlash
Estudio de RiesgosAGENDA
ARC FLASH
STUDY
Study of RisksArcFlash
Estudio de Riesgos
WHAT IS A STUDY OF RISK FOR ARC FLASH?
Definition:
The NFPA 70E defines a study of
risks for ArcFlash as :
“A study where is investigated the potential exhibition
of a workman to the energy caused by an electrical
arch
¾
To anticipate injuries ,
With the aim of:
¾
To determine sure procedures of operation ,
¾
Levels of appropriate PPE .”
ArcFlash
Estudio de Riesgos
WHAT IS THE MINIMAL DISTANCE OF
PROTECTION ?
Definition:
The NFPA 70E defines a minimal distance of protection as:
“
“
Distance, from the critical point, inside which a
Distance, from the critical point, inside which a
person can suffer burns of second degree due to
person can suffer burns of second degree due to
an accident for Arc Flash
an accident for Arc Flash
.
.
”
”
ArcFlash
Estudio de Riesgos
PPE as cal/cm
2
PPE Selection
Range of Calculated Incident Energy (cal/cm²)
Clothing
Class No. Clothing Description, (No. of Layers)
Total Weight (oz/yd²) 0 – 2 0 Untreated Cotton (1) 4.5 – 7
2 - 5 1 FR Shirt and Pants (1) 4.5 - 8 5 - 8 2A Cotton Underwear plus FR Shirt and Pants (2) 9 - 12 5 - 16 2B FR Underwear plus FR Shirt and Pants (2) 10 - 14 8 - 25 3 Cotton Underwear plus FR Shirt and Pants plus
FR Coverall (3) 16 - 20 25 - 40 4 Cotton Underwear plus FR Shirt and Pants plus
Double Layer Switching Coat (4) 24 - 30 Protective Clothing Guidelines, from “Predicting Incident Energy to Better Manage the Electric Arc Hazard on
600-V Power Distribution Systems,” Table III, IEEE Transactions on Industry Applications, Jan./Feb. 2000 Proposed Protective Clothing Classes FR Clothing System
ArcFlash
Estudio de Riesgos
Flash hazard label
(one per analysis point)
ArcFlash
Estudio de Riesgos
Customer to Provide:
One line diagram of power delivery
system
Current copy of power system short
circuit study and coordination study
Single point of contact to establish each
analysis point with our power systems
engineer
Input on typical working distances
desired for each location or default to
applicable standards
Purchase order authorizing Siemens to
proceed
Electrical Arc Flash Hazard Study
ArcFlash
Estudio de Riesgos
SUMMARY
Siemens Solutions
:
Step #2:
The short circuit study of the energy system.
Step #3:
Analysis of the current state of the protection system
Step #4: Coordination study of the protection system.
Step #1:
Generation/Review of unifilar complete of the plant
Step #5:
Electrical Arc Flash Hazard Study.
Step #6:
Identify equipment locations that exceed available
PPE ratings
Step #7:
Presentation of the Program of Electrical Security
Study of RisksArcFlash
Estudio de Riesgos
Sample of Customer Deliverable :
Electrical Arc Flash Hazard Study
Arc Energy calculations
Example Customer
Summary of Incident Energy Calculations
Incident Energy in cal/cm2 and Working DistanceMarzo 18, 2004 Voltage Normal Operation Normal Operation Working Distance Arc Flash Boundary
Location kV J/cm2 cal/cm2 inches feet
12.47 kV Main Switchgear 12,47 129,2 30,9 36,0 84,5
Unit Sub #1 480 V Main Breaker 0,48 474,4 113,4 24,0 43,9
Unit Sub #1 480 V Bus 0,48 55,3 13,2 24,0 10,2
MCC A 0,48 84,1 20,1 12,0 5,6
MCC B 0,48 64,5 15,4 12,0 4,7
Panel 16 0,48 52,5 12,5 12,0 4,2
ArcFlash
Estudio de Riesgos
Electrical Arc Flash Hazard Study
Study of Risks
Customer Benefits
Reduced risk of employee injury or death due to arc flash
hazards
Possible revisions to customer system protection to limit
equipment damage
Provides critical safety information for subcontractors
entering facility
Possible reduction in workers compensation and
insurance claims
Demonstrates company effort to satisfy OSHA and NFPA
regulations
ArcFlash
Estudio de Riesgos
A BENEFICIAL RELATION
Thank you very much for your attention
.
ArcFlash
Estudio de Riesgos
