making electrical and fire safety management effective · 2019. 8. 26. · 25,000 1 205 122 15% 140...
TRANSCRIPT
MUDIT MAHESHWARI
MAKING ELECTRICAL AND FIRE SAFETY MANAGEMENT
EFFECTIVE
ITC LIMITED
ELECTRICAL SAFETY
Electrical Mishaps & Accidents
Need for safe work environment
ALL INDIA ACCIDENT STATISTICS
Source: https://data.gov.in/
• Design, procurement
and installation as per
standards
• Training & Behavioural
controls
• Robust tracking through
Audits/ Inspections
• Operation & Maintenance
as per standards
SAFETY MANAGEMENT IN ITC LIMITED
SAFETY HAZARDS✓ITC’s Approach
✓Electrical & fire safety starts at the drawing board.
✓Designs of all projects is done as per national and international codes & standards, e.g., BIS, IEC, NFPA, IEEE etc.
✓Power system designs undergo a check at Corporate level - verification vis-à-vis codes, standards, best practices, etc.
✓Existing systems maintained as per BIS and international codes & standards and undergo periodic audit/ verification from Corporate
ELECTRICAL SAFETY
✓ Main hazards - Electrocution & Fire
✓ More importantly – Mitigation and prevention at different stages
✓ Then what should be the approach?
✓Design as per codes & standards
✓Procurement as per codes & standards
✓Installation as per codes & standards
✓Operation & Maintenance as per codes & standards
This is the process followed in ITC
STAGE WISE PREVENTION & MITIGATION
✓Design - example of Earthing & Lightning
✓Procurement – example of Transformer
✓Installation – example of Cable
✓O & M – example of Switchgear panels
Electrical Safety
✓IEC 61140 & IS 3043 provides guidance for protection against electric shock.
✓Under normal conditions – hazardous live parts shall not be accessible.
✓Under fault conditions – accessible conductive parts shall not be hazardous.
Measures adopted to protect against this hazard, include;
✓Automatic disconnection of power supply.
• Let us start with the minimum basic safety requirement for automatic disconnection of power supply system.
• Interventions in earthing system design
DESIGN STAGE - EXAMPLE
EART
HIN
G
As per IS:3043 - 1987 Clause 12.2.2.1
Issc/S = k/√t
S = (Issc *√t)/k
where
S = Cross-sectional Area (sq.mm)
Issc = Value (ac, rms) of fault current (Amp)
t = Operating time of disconnection device (sec)
k =
Available Parameters
t = 1 sec (max)
k = 80 (for Steel with initial temp 40 deg C & final temp 500 deg C)
= 205 (for Copper with initial temp 40 deg C & final temp 395 deg C)
Earthing Strip Area Calculations (GI)
Issc (Amp) t (sec) k (for bare
Steel)
Earthing Strip Area
(sq. mm)
Corrosion Allowance Final Earthing Strip
Area Requirement
(sq.mm)
GI Earthing Strip
Size (sq. mm)
10,000 1 80 125 15% 144 25 x 6
18,000 1 80 225 15% 259 50 x 6
25,000 1 80 313 15% 359 50 x 10
35,000 1 80 438 15% 503 50 x 10
42,000 1 80 525 15% 604 75 x 10
50,000 1 80 625 15% 719 75 x 10
65,000 1 80 813 15% 934 2 x 50 x 10
Earthing Strip Area Calculations (Cu)
Issc (Amp) t (sec) k (for bare
Copper)
Earthing Strip Area
(sq. mm)
Corrosion Allowance Final Earthing Strip
Area Requirement
(sq.mm)
Cu Earthing Strip
Size (sq. mm)
10,000 1 205 49 15% 56 25 x 3
18,000 1 205 88 15% 101 25 x 6
25,000 1 205 122 15% 140 25 x 6
35,000 1 205 171 15% 196 40 x 6
42,000 1 205 205 15% 236 40 x 6
50,000 1 205 244 15% 280 50 x 6
65,000 1 205 317 15% 365 50 x 10
Factor dependent on the material of the protective conductor, the insulation & initial & final
Temepratures
Earthing Strip Sizing Basis
DESIGN STAGE - EARTHING
200 amps circuit breaker
Earth resistance 0.8 Ω Earth resistance 0.8 Ω
Bonding wire 300m, 70sq mm
copper @0.2 Ω /km = 0.06 Ω
Without bonding fault current = 240 / 1.6 = 150 amps (circuit breaker will not trip)
With bonding fault current = 240 / 0.06 = 4000 amps (circuit breaker trips instantly)
DESIGN STAGE – LIGHTNING PROTECTION
Precautions against lightning
LIGHTNING PROTECTION
Source: https://NCRB.gov.in
LIGHTNING PROTECTION✓ Air termination location – Angle method or Rolling sphere method
✓ An equal spacing of downconductor is preferred around the perimeter of the
building/ structure. Typical preferred values of distance between the
downconductors should be as per following table.
LIGHTNING PROTECTION
LIGHTNING PROTECTION
CHECKING DURING PROCUREMENT
Equipment – transformer / motor / switchgear / cable / UPS etc., conforms to relevant standards.
How to verify ?
Check the type test report and verify it as per relevant standard.
Check the routine test report and verify it as per relevant standard.
Let us see the same for a power transformer ..
CHECKING DURING PROCUREMENT
Tests on a power transformer (Refer IS 2026 & IEC 60076)
Type tests Temperature rise test as per IS 2026-2
Lightning Impulse test as per IS 2026-3
Routine tests Winding resistance
Voltage ratio and phase displacement
Short circuit impedance and load loss
No-load loss and current
Dielectric routine tests
Tests on OLTCs.
✓Most common failures for oil filled transformers
✓OLTCs
✓Bushing failure
CHECKING DURING INSTALLATION
CHECKING DURING INSTALLATION
✓Mode of power cable laying
✓MV power cables directly buried
IS 1255 : Installation & maintenance of
power cable
CHECKING DURING O & M✓Relevant codes of practice to be followed. For LV switchgear assemblies:
➢Annual mV drop test across terminations or thermography tests.
Refer IS 16168
CHECKING DURING O & M
FIRE SAFETY
STEPHEN COURT - KOLKATA
Date of tragedy: 23rd March 2010
Fatalities: 43
COACHING CENTRE – SURATCourtesy Inshorts
TROUBLING ISSUES
Preliminary investigations (for various incidents) revealed:
1. Deviations from the approved municipal plan
2. Highly flammable materials stored
3. Exit routes and emergency exit staircases locked
25
WE, MUST KNOW
What are the fire risks/ hazards involved in the process/ operations?
Are the risks acceptable ?
Who could be harmed ?
Can the risks be reduced by altering designs or use of alternate technology/ materials ?
What are the statutory Implications?
Which codes/ standards are applicable ?
What types of fire safety systems are required?
FACTORS INFLUENCING FIRE SAFETY
Factories Act and State factory Rules
National Building Code of India
Oil Industry Safety Directive (OISD)
Petroleum Act and Rules
CEA Regulations 2010 (Measures relating toSafety and Electric Supply)
Insurance
Risk Assessments
FIRE PROTECTION
How to restrict fire?
Incipient
stage
Smouldering
stage
Flaming
stage
Fully developed
stage
Degradation
stage
Time
Tem
p
FIRE PROTECTION
How to restrict fire?
Prevent Ignition:
• Good House Keeping
• Good Storage Practices
• Good Engineering practices
• Good O&M practices
Incipient
stage
Smouldering
stage
Flaming
stage
Fully developed
stage
Degradation
stage
Time
Tem
p
• Adopt standards
• Best training
management
FIRE PROTECTION
How to restrict fire?
Control combustion:
Use of Fire retardant/ non-combustible
material for interiors, Upholstery, office
partitions, false ceiling etc.
Incipient
stage
Smouldering
stage
Flaming
stage
Fully developed
stage
Degradation
stage
Time
Tem
p
FIRE PROTECTION
How to restrict fire?
Suppress fire:
• Portable fire extinguishers
• Automatic sprinklers
• Water mist suppression systems
• Special extinguishing systems
Incipient
stage
Smouldering
stage
Flaming
stage
Fully developed
stage
Degradation
stage
Time
Tem
p
FIRE PROTECTION
How to restrict fire?
Restrict by construction:
• Fire compartmentation
Incipient
stage
Smouldering
stage
Flaming
stage
Fully developed
stage
Degradation
stage
Time
Tem
p
Almost 74% of fire deaths have been due to panic and inhalation of smokeand other toxic fire gases. (Source: NFPA)
Causes of deaths
Inadequate exiting arrangements
Exits kept locked preventing people from escaping
Inhalation of toxic gases such as Carbon monoxide, hydrogen cyanide (burning of plastics),phosgene (vinyl materials), etc.
FIRE PROTECTION
• Typical Building 3-D view
BASEMENTS 1,2
KC
ITC 1
IT1 [ building with fire consideration]
FIRE PROTECTION – EGRESS MODELLING
FIRE PROTECTION
FIRE PROTECTION
Emergency Egress and Relocation Drills Shall be held with sufficient frequency to familiarize occupants with the drill
procedure and to establish conduct of the drill as a matter of routine.
Planning and conduct of drills shall be assigned only to competent persons.
To be held at expected and unexpected times and under varying conditions.
Orderly evacuation should receive priority over the speed of evacuation.
Occupants should be accounted for.
A record shall be kept.
Sources: Oregon Fire Code, NFPA, OSHA.
FIRE PROTECTION - TRAINING
FIRE PROTECTION
✓Standards followed in ITC
✓BIS
✓IEC
✓IEEE
✓BS EN
✓NFPA
ADOPTING STANDARDS & CODES TO ENSURE EFFECTIVE SAFETY MANAGEMENT SYSTEMS
Overview through Design Reviews and Audits
✓ Best in class Hazard Identification and Risk Assessment System
✓ Work permit controls
✓ Training Management
✓ Accident Investigations
✓ Usage of PPEs enforced
BEST PROCESSES TO ENSURE EFFECTIVE SAFETY MANAGEMENT SYSTEMS
Overview through Audits and Inspections
THANK YOU Lets make a difference..