what a little less sizzle at work

8/8/2019 What a Little Less Sizzle at Work

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What a little less Sizzle at Work

Well than teach your employeesWell than teach your employeeselectrical safety practiceselectrical safety practices

P bar Y Safety Consultants Alberta Canada



ELE

CTRICAL

SAFE

TY HAZARDSArc-Flash and Shock Hazard




Q uestions

Do you have workers install power cables on energized panels? (example:

running new circuit for server rack?)

Do you have work/modifications performed on energized electrical

systems? (example: upgrading power, UPS, generator systems?)

Do you commission live electrical systems (example: UPS, batteries,generators, PDUs)

Do your UPS vendors service equipment while energized?

Do your employees have unrestricted access to areas where energized

electrical equipment is open or being worked on?

Is you data center designed to allow electrical equipment to be de-energized without shutting down the IT loads?

Do you understand the potential risks, hazards and liabilities associated

with these questions?




Observations

Compliance with existing safety laws mayrequire you to change how you manage,operate and design your data center

Data centers require large amounts of power and this increases safety risks Data centers do not like to shut down and

this increases electrical safety risks Many people choose to ignore, deny or

dismiss their responsibilities when itcomes to electrical safety and thisincreases risks and liabilities




Electrical Facts

Electricity will take path of any resistance including you!!

Electric current will always return to the source (utility

transformer or separately derived source)

Electricity flows in complete paths, if you complete the path you

will get shocked!

The earth is a ground fault current path!

The earth can conduct enough electrical current to

electrocute a person The earth shall not be considered as an effective ground-

fault path. (An earth ground could or could not cause

overcurrent devices to open)




Electricity Risk Areas

Electrical Shock Hazards ± Existing standards and practices address many of

these risks

Arc Flash/Burn Hazards ± Existing Standards and practices address some

these risks

Arc Blast Hazards ± Existing standards and practices address very few

of these risks




Risk issues

Both employer and employee risks

Injury or death to personnel

Rehab / disabilities

Lost / damaged equipment

Unplanned outages and repairs

Increased insurance and workercompensation costs

Expensive lawsuits




Shock Hazards

Most personnel are aware that there is a dangerof electrical shock, even electrocution. Its theone electrical hazard around which mostelectrical safety standards have been built.

However, few people really understand just howlittle current is required to cause injury, evendeath. Actually, the current drawn by a 7.5W,

120V lamp, passing across the chest, from hand-to-hand or hand-to-foot, is enough to causedeath by electrocution.




Shock Hazards

The human body will conduct electrical current! A circuitpath can be through both arms, through an arm or leg toground, or through any body surface to ground. There is acertain current level at which an individual cannotvoluntarily release from the circuit. This is the "no let gocurrent" from which burns and death by electrocution canresult.

When the current increases to about 0.015 to 0.020 amperes,it becomes impossible to let go of the circuit. At higher

values of current, e.g. above about 0.100 amperes,ventricular fibrillation and/or heart stoppage will causecertain death.




Arc-Flash Hazards

Arc-Fl ash is an unexpected sudden release of heatand light energy produced by electricity travelingthrough air.

This explosive condition includes a broad spectrum

of electromagnetic energy, plasma, fragments anda spray of molten materials.

Temperatures at the arc terminals can exceed35,000 deg F, (4 times hotter than the surface of the sun)

Air and gases surrounding the arc are instantlyheated and the conductors are vaporized causing apressure wave called an Arc Bl ast .




Arc-Flash Hazards

Burns from direct heat exposure orclothing ignition. At distances of morethan 10 feet, arc flash is capable of causingserious burns requiring skin grafts.

Loss of eyesight from UV light emitted byvaporized metal

Death

Equipment damage/outages

Fire




Burn Hazard

First-degree burns are limited to the top layer of skin: ± Signs and symptoms: These burns produce redness, pain,

and minor swelling. The skin is dry without blisters.

± Heal i ng t i me: Healing time is about 3 to 6 days; the

superficial skin layer over the burn may peel off in 1 or 2days.

Second-degree burns are more serious and involve theskin layers beneath the top layer: ±

Signs and symptoms: These burns produce blisters, severepain, and redness. The blisters sometimes break open andthe area is wet looking with a bright pink to cherry red color.

± Heal i ng t i me: Healing time varies depending on the severityof the burn




Burn Hazard

Third-degree burns are the most serious type of burn and involveall the layers of the skin and underlying tissue: ± Signs and symptoms: The surface appears dry and can look waxy

white, leathery, brown, or charred. There may be little or no pain orthe area may feel numb at first because of nerve damage.

±Heal i ng t i me: Healing time depends on the severity of the burn.Deep second- and third-degree burns (called full-thickness burns)will likely need to be treated with skin grafts, in which healthy skin istaken from another part of the body and surgically placed over theburn wound to help the area heal.

Internal burns muscle, organs, veins, ± Could continue to burn after shock event due to internal heating





Photos



Arc-Flash Metrics

The amount of instantaneous heat energyreleased by an Arc-Flash is called incidentenergy.

Expressed in calories per squarecentimeter (cal/cm²)

Five Hazard Risk categories

(HRC 0 to 4) Calculations are based on working

distance of 18 from arc terminals




Arc-Blast Hazards

High energy arc-flash heats and expands air

Vaporized copper expands 67,000 times its

mass when it changes from solid to vapor Blast pressure can exceed 2000 pounds per

square foot.

Blast speed can exceed 700 MPH

Injuries from falls or collision with equipment.An arc fault of 50 kA can accelerate a nearbyworker at speeds of up to 110 mph.




Arc Blast Hazards

Hearing damage or total hearing loss fromruptured eardrums. The sound of a blastcan exceed 160 dB. (Sounds above 140 dBcause hearing loss even with protectiveequipment.)

Lung collapse or scarring from the shockwave and inhalation of vaporized metal

Memory loss and other neurologicaldamage from concussion

Injuries from flying shrapnel Death Equipment damage




Electrical Safety Compliance

NFPA 70

National Electrical Code

NFPA 70E

Electrical Workplace Safety

NFPA 70BElectrical Equipment

Maintenance

Law, rules,

regulation

OH &SInstallation codes, safe

products, safe installation,

inspections and enforcement

Policies, procedures, training, risk analysis,

qualified workers, PPE

Scheduled maintenance, testing and

replacement per manufacture and

industry best practices

P bar Y Safety

Consultants

AlbertaCanada



Four Protection Boundaries

Flash Protection Boundary (FPB)Safe approach distance from energized parts <1.2 cal/cm²

Three shock approach boundaries1. Limited Approach Boundary

Unqualified persons must be accompanied by aqualified person and use PPE2. Restricted Approach Boundary

Only qualified persons are allowed in this areaand must use PPE

3. Prohibited Approach BoundaryWork in this area considered the same asmaking direct contact with energized parts.Only qualified persons are allowed in thisarea and must use PPE




PPE

Personal Protective Equipment

Provides shock and arc flash burn protection

Suits are rated in cal/cm²

Electrically rated shoes, gloves

Resistant to flame and

self-extinguishing

Thermal insulation from

heat radiation

Over 40 cal = arc flash/blastthat you cannot be protected

from, you could be killed!




Q ualified Individuals

Q ualified workers must be

knowledgeable on the equipment and

the hazards that exist and receivedocumented training.




Employee Training

An essential element in an effective electrical safety program is

training. From both a legal and effective point of view, training

records are important. Training should be based on the program

and procedures in place within an organization. The trainingshould focus first on increasing knowledge and understanding of

electrical hazards and second on how to avoid exposure to

these hazards. As a person completes a specific segment of

training, a record should be established and maintained. An

electrical safety program should accomplish the following

objectives: Make personnel aware of the rules, responsibilities

and procedures for working safely in an electrical environment;




Documentation

Demonstrate the employers intention to fully comply with

federal law;

Document general requirements and guidelines to provide

workplace facilities free from unauthorized exposure toelectrical hazards;

Document general requirements and guidelines to direct the

activities of personnel, who could be either deliberately, or

accidentally, exposed to electrical hazards;

Encourage, and make it easier for each employee to beresponsible for his or her own electrical safety self-discipline.




Summary

Employers/owners have requirements includingproviding appropriate PPE

Employees have requirements

Contractors have requirements

Cannot transfer liabilities and responsibilities

Get trained!

Perform Electrical Hazard Analysis Use appropriate PPE

Keep unqualified persons out of hazard areas


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