PROTECTING AGAINST ARC FLASH HAZARDS - New · PDF fileOhms Law : V=IR Kirchoff’s ......

COMMITMENT & INTEGRITY DRIVE RESULTSCOMMITMENT & INTEGRITY DRIVE RESULTS

PROTECTING AGAINST ARC FLASH HAZARDS

Presented by:Andrew J. Fitzpatrick, P.E.

COMMITMENT & INTEGRITY DRIVE RESULTS

Electricity

Simply stated electricity is the flow of electrons Electricity is governed by laws:

Ohms Law : V=IR Kirchoff’s Law: Total Voltage around a closed loop must be equal

to zero Electricity is predictable Electricity is a potential hazard


What is Electrical Safety?

OSHA 1910 Subpart S Addresses electrical safety requirements for safeguarding of

employees in the workplace NFPA 70E

The standard defining safe work practices to protect personnel from electrical hazards

2015 NFPA Report Last 20 years has seen a dramatic decrease of fatal electrical

injuries, non-fatal is not as consistent, recent trend is decreasing OSHA investigations found majority of injuries due to inappropriate

work on energized equipment


Electrical Safety – Engineers Perspective

Employer is responsible for providing PPE used to comply with OSHA requirements. All electrical systems greater than 50V NFPA 70E defines two methods of selecting PPE

Incident energy analysis (IEEE 1584 equations) Arc Flash PPE Categories

Accurate Data, data collection and understanding of electrical distribution systems paramount to accurate assessments


IEEE 1584 Empirical Method based on testing in certified test laboratories Voltages from 208V – 15kV (Lee Method available above

15kV) 50 or 60Hz systems Bolted Fault Current from 700A – 106,000A Different grounding types, ungrounded Different enclosure types and protective devices Use computer based software:

Easypower SKM ETAP


IEEE 1584 Con’t

Two (2) main components: Ia = arcing current (based on bolted fault current with adjustments) t = time (in seconds) arcing time

A reduction of Ia or t will decrease incident energy levels Arc Current

Modify service transformer characteristics (increased impedance, reduced size)

Add resistance


IEEE 1584 Con’t

Protection Scheme changes to reduce time Current limiting fuses (selected appropriately) Adjustable type circuit breakers (LSIG) Reduced Energy – Maintenance Mode Circuit Breakers Zone Interlocking Relays - Differential protection Relays – Optical Add protection devices to system (i.e. main ahead of main)


High Incident Energy Level Examples “Small” distribution systems (Pump Stations, Wells, etc)

Low utility fault current Protection devices not adjustable (MCCB Thermal-Magnetic,

fuses) Service sizes mismatched with utility transformers Utility Fuses

Large distribution systems (Treatment Plants) High utility fault current Device Coordination Emergency Power Scenarios


Preferred Method of Protection: De-energize

“It is now an industry standard to de-energize live parts, whenever possible, before an employee

works on or near them.”


If you Cannot De-energize…

“Employees are permitted to work on or near exposed live parts only if they are qualified and it can be demonstrated that de-energization introduces additional or increased hazards or is infeasible due to equipment design or operational limitations.”


What are “Exposed Live Parts”?

that could be inadvertently touched or approached


Electrically Safe Work Condition

Infeasible: not capable of being carried out or put in practice

Examples: Interruption of life support

equipment Deactivation of emergency

alarm systems Shutdown of hazardous

location ventilation equipment

▀ Inconvenient: not suited to your comfort, purpose or needs

▀ Examples:▀ Financial▀ In a hurry▀ “I know what I’m doing.”▀ Want to serve client


Hierarchy of Hazard ControlHow do we want to control the hazards?

Engineering Controls

Administrative Controls

PPELeast effective

Most effective

Change of operation; do it a different way; training

Move/add switches, meters, or phase loss monitors

Last resort


Qualified Person One who has skills and knowledge related to the

construction, installation, maintenance and operation of the electrical equipment and installations and has received safety training on the hazards involved.o Ability to distinguish exposed live parts from other parts of

electrical equipmento Ability to determine nominal voltage of exposed live partso Knowledge of clearance distanceso Familiar with proper use of special precautionary techniques,

PPE, and tools

Qualified vs. Unqualified

Can be “qualified” for certain tasks and not for others


What this training qualifies you to do

Work around or near live exposed parts: e.g., Accessing a live panel

Work on live exposed parts: Use a voltage meter (including verification of de-energized state)


Really? I have to be “qualified” to do LOTO?


Electrical Safety Training Includes:

Basics of electricity Basic requirements of NFPA 70E and NEC Recognizing common electrical hazards Distinguishing exposed live parts from other electrical equipment Determining nominal voltage of exposed live parts Clearance distances for working on/near exposed live parts Safe work practices and PPE Ability to determine the extent of the hazard How to release victims from contact with live circuits Methods of first aid Recognizing electrical tasks that you are not permitted to perform


Electrical Safety Program

Key Components: Training Energized Electrical Work Permit PPE Risk Assessment Job Briefing Safe Work Practices Electrical Contractors Evaluation/Performance Review


Energized Electrical Work Permit (EEWP) Required when working within

the restricted approach boundary Exceptions - permits not

required for: Testing, troubleshooting, and

voltage measuring (as long as safe work practices and PPE are used)

Thermography and visual inspections (as long as restricted approach boundary will not be crossed)

Be sure to know the boundaries before you start!


Safety Signs and Tags. Safety signs, safety symbols, or accident prevention tags shall be used where necessary to warn employees about electrical hazards that might endanger them.

Barricades. Barricades shall be used in conjunction with safety signs where it is necessary to prevent or limit employee access to work areas containing energized conductors or circuit parts.

Attendants. If signs and barricades do not provide sufficient warning and protection from electrical hazards, an attendant shall be stationed to warn and protect employees.

Alerting Techniques


Reading a Label

Depending on who did your study and when it was done, the labels may look a little different, but the information should be the same.


If an arc flash analysis hasn’t been done….


EEWP


Personal Protective Equipment (PPE) All of these are PPE: Insulated tools Meters and testing equipment Arc-rated (AR) clothing Rubber insulating equipment (gloves, matting, blankets,

sleeves..) Fall Protection Harnesses Day glow vests


Must comply with IEC 900 and ASTMF 1505-94 standards. Will have the 1000 volt

double triangle symbol on all rated/certified tools. Dielectrically tested with

10,000 volts, and rated for use on energized circuits up to 1000 volts.

Insulated Tools

http://www.aplussafety.net/products/index.cfm?d=3053&c=4194&p=26616&do=detail



http://www.1000vtools.com/catalog/item/2835230/2330814.htm

http://www.1000vtools.com/catalog/item/2866426/2361959.htm

http://epub1.rockwellautomation.com/images/gl2/1270049.jpg


Variety of Arc Flash PPE Shirts – Fire Retardant Pants – Fire Retardant Over clothing wear – Arc-rated

(Coveralls, or overcoat and over pants). Hardhat and face shield. Hoods – Arc-rated Hearing protection Rubber gloves. Leather protectors. Cotton glove liners. Glove bag. Rain gear – Arc-rated Winter wear (coats) – Arc-rated Dielectric boots. Safety shoes rated EH.

(Electrical Hazard- no metal fasteners) Harness – Arc-rated

http://www.nationalsafetyinc.com/product.asp?Product_Id=173110&d_id=17679&l1=&l2=




http://www.aplussafety.net/products/store.cfm?d=3053&c=4548&p=16169&do=detail

http://www.70estore.com/product/

http://www.70estore.com/product/HRC_Level_Kit_short_coat_bib_Ultra_Soft

















Typical PPE Kit

Arc rated long-sleeve shirt & pants, or arc rated coverall.

Class OO, 11” high certified rubber gloves with leather protectors.

Hard hat. Safety glasses or goggles Head covering (hood). Arc rated face shield with arc rated

balaclava. Hearing Protection. Leather safety shoes.

PPE Category 2 arc rated clothing (min rating 8 cal/cm2)


When do you need to wear this?

This category of PPE will NOT protect you against all hazards for all tasks. It is appropriate for: Voltage testing/troubleshooting Removal of covers Verifying de-energizationProviding the equipment matches or exceeds the potential hazard.

PPE Category 2 arc flash apparel


PPE: Hand Protection Rubber gloves need to have

the class and voltage rating visible on the outer cuff.

Wear heavy-duty leather protectors when using rubber gloves, and remember leather gloves are not voltage rated, they are only to protect the rubber.

Glove liners need to be 100% cotton.


PPE: Hand Protection

Store gloves in a canvas glove bag to protect against damage and UV damage and store flat (do not fold).

Inspect gloves before every use for damage, which includes an inflation test.

Gloves need to be dielectrically tested by a certified lab before being put into service and then every 6 months.


Hazard Risk Analysis Evaluate hazards in each

step of the job and consider safety controls Same as JSA – Job Safety

Analysis

Required whenever an electrical hazard exists


Job Briefing Required for all electrical

work Must cover:

Hazards Work procedures Energy source controls PPE

Can be simple and verbal, or more detailed and written


When you hire Electrical Contractors…… Follow Established Contractor

Policy: Contractor Pre-qualification

Contractor Orientation, including notice of hazards

Performance Evaluation

Note: The meeting between owner and the electrical contractor must be documented. If imminent danger exists,

STOP WORK!!!


Evaluation/Performance ReviewThe owner is required to perform field audits to verify you are

following these electrical safety requirements.

So make sure you are following safe work practices and wearing your PPE when you’re supposed to.


Why we need to be careful


You just don’t know what is out there

COMMITMENT & INTEGRITY DRIVE RESULTSCOMMITMENT & INTEGRITY DRIVE RESULTS

QUESTIONS?THANK YOU!

PROTECTING AGAINST ARC FLASH HAZARDS - New · PDF fileOhms Law : V=IR Kirchoff’s ......

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