MAKING ELECTRICAL AND FIRE SAFETY MANAGEMENT EFFECTIVE MUDIT MAHESHWARI ITC LIMITED
ELECTRICAL SAFETY Need for safe work environment Electrical Mishaps & Accidents
ALL INDIA ACCIDENT STATISTICS Source: https://data ta.gov.i v.in/
SAFETY MANAGEMENT IN ITC LIMITED • Design, procurement • • • Training & Behavioural Robust tracking through Operation & Maintenance and installation as per controls Audits/ Inspections as per standards standards
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 code des s & s standa andards ds ✓ Procurement as per code des s & s standa andards ds ✓ Installation as per code des s & s standa andards ds ✓ Operation & Maintenance as per code des s & s standa andards ds This s is the proce cess ss followe wed in ITC
STAGE WISE PREVENTION & MITIGATION ✓ Design - example of Earthing & Lightning ✓ Procurement – example of Transformer Electrical Safety ✓ Installation – example of Cable ✓ O & M – example of Switchgear panels
DESIGN STAGE - EXAMPLE ✓ 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
Earthing Strip Sizing Basis 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 = Factor dependent on the material of the protective conductor, the insulation & initial & final Temepratures Available Parameters EARTHING 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 Earthing Strip Area Corrosion Allowance Final Earthing Strip GI Earthing Strip Steel) (sq. mm) Area Requirement Size (sq. mm) (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 a ip ip
DESIGN STAGE - EARTHING 200 amps circuit breaker Bonding wire 300m, 70sq mm copper @0.2 Ω /km = 0.06 Ω Earth resistance 0.8 Ω Earth resistance 0.8 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 downcond conduct ctor 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: 23 rd March 2010 Fatalities: 43
COACHING CENTRE – SURAT Courtesy 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 to Safety and Electric Supply) Insurance Risk Assessments
FIRE PROTECTION How to restrict fire? Fully developed stage Flaming stage Degradation stage Temp Smouldering stage Incipient stage Time
FIRE PROTECTION Prevent Ignition : • How to restrict fire? Good House Keeping • Adopt standards • Good Storage Practices • Best training • Good Engineering practices management • Good O&M practices Fully developed stage Flaming stage Degradation stage Temp Smouldering stage Incipient stage Time
FIRE PROTECTION Control combustion : Use of Fire retardant/ non-combustible How to restrict fire? material for interiors, Upholstery, office partitions, false ceiling etc. Fully developed stage Flaming stage Degradation stage Temp Smouldering stage Incipient stage Time
FIRE PROTECTION Suppress fire : • Portable fire extinguishers How to restrict fire? • Automatic sprinklers • Water mist suppression systems • Special extinguishing systems Fully developed stage Flaming stage Degradation stage Temp Smouldering stage Incipient stage Time
FIRE PROTECTION Restrict by construction : • Fire compartmentation How to restrict fire? Fully developed stage Flaming stage Degradation stage Temp Smouldering stage Incipient stage Time
FIRE PROTECTION Almost 74% of fire deaths have been due to panic and inhalation of smoke and 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 – EGRESS MODELLING • Typical Building 3-D view IT1 [ building with fire consideration] ITC 1 KC BASEMENTS 1,2
FIRE PROTECTION
FIRE PROTECTION
FIRE PROTECTION - TRAINING 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
ADOPTING STANDARDS & CODES TO ENSURE EFFECTIVE SAFETY MANAGEMENT SYSTEMS ✓ Standards followed in ITC ✓ BIS ✓ IEC ✓ IEEE ✓ BS EN ✓ NFPA Overview through Design Reviews and Audits
BEST PROCESSES TO ENSURE EFFECTIVE SAFETY MANAGEMENT SYSTEMS ✓ Best in class Hazard Identification and Risk Assessment System ✓ Work permit controls ✓ Training Management ✓ Accident Investigations ✓ Usage of PPEs enforced Overview through Audits and Inspections
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