r Removal and replacement of livecomponents.

r Replacement of fuses and links.r Live underground cable jointing. r Inadvertent energised equipment

penetrations.

“Risk enhancing situations”, meanwhile,include: r Poor equipment maintenance.r Poor/“old” equipment design and

installation.r Poor equipment commissioning and

initial inspection.r Poor worker competence.r Human error.r Lack of concentration and distraction.

A ‘four-pronged approach’At the guide’s core is a four-stageapproach to minimising and, wherepossible, eradicating, electrical arc flashhazard, based on what DuPont dubs “the4Ps” – “Predict, Prevent, Protect andPublish.” (see Fig. 1)

The dedicated guide “public” website,www.arcguide.dupont.com, explains, andgives information and brief guidance on,subjects including: what constitutes anarc flash, the key contributory factors, andthe circumstances when incidents arelikely to have the most severeconsequences. The site makes clear that,alongside the more obvious consequence– injury (see panel) and death to workers– these consequences can include theneed to pay heavy fines or compensation,and severe damage to equipment.

Detailing the fundamentals of the “4P”preventative approach, the site

emphasises that DuPont believes the bestway to minimise the risk of, or eliminate,arc flash hazard, is via robust riskassessment. Thus, in addition to clearlyand concisely setting out on the publicsite some of the key information on howto address arc flash hazard, the companycan now also offer a “pre-assessmentmodule”, on payment of pre-arrangedfees, to, say, a hospital estates teamwishing to obtain a clearer picture of the existing electrical arc hazard risks on its site, and how to minimise them.This package will include:r A personalised one-day visit by an arc

‘European approach’to arc flash risk

Electrical safety

DuPont claims that electrical arc, and the resulting “arc flash”, are among the deadliest, least understoodhazards of electricity”, and can potentially occur in many industrial and other applications, includinghospital plant rooms. Technical and engineering personnel from DuPont Engineering Technology, DuPontPersonal Protection, and external independent experts, have thus collaborated to develop “a Europeanapproach to electrical arc risk assessment”. The resulting free online resource, the DuPont Arc-Guide,sets out key steps to minimise serious arc flash incident risk, and details a range of optional, paid-fortailored risk assessment services, and an accompanying secure web portal, offering more in-depthguidance on this important, but apparently often overlooked, issue. HEJ editor Jonathan Baillie reports.

37Health Estate Journal

November 2011

According to DuPont – which held a“webinar” recently to highlight thenew guide’s launch – while

European legislation requires businessesand other organisations to perform regularrisk assessments for all work activities andtasks, “electrical arc is often overlookedbecause most people are unsure how toassess and manage the hazard effectively”.The resulting danger is that the potentialrisks of an arc hazard incident which, atthe very least, can cause second degreeburns to those working on electricalequipment, and, at worst, may lead to asizeable explosion and death or seriousinjury (see panel on page 38), are oftenunderestimated, and even ignored, untiltoo late.

It is hoped, therefore, that the new free-to-access online guide, and (for thosethat sign up to pay to use them), anoptional accompanying pre-assessmentservice, plus access to a secure portalproviding further tools and information,will help duty holders and buildingowners including hospital estates andfacilities teams, as well as externalcontractors undertaking electrical workon site, to “understand, evaluate, andreduce, the severities and consequencesof electrical arc hazards”.

Among the many instances whereelectrical arc hazard may be presenthighlighted by the guide are:r Testing.r Visual and infrared inspections. r Manipulation of live conductors. r Switching/racking breakers. r Installation of cables into energised

equipment.

An electrical arc occurring.

flash risk assessment expert, who will review the arc flash hazards associatedwith the site in relation to whichworkers are likely to be affected (e.g. contractors/direct staff, site-based,or field-based, personnel).

r An examination and identification of inwhich types of working environments,and during which tasks, the hazard islikely to be predominant.

r Examination of the complexity of on-siteelectrical distribution networks.

Also included as part of the “module” are:r A presentation to management staff

and other “stakeholders” on arc flashand “the European approach”,including initial feedback on any on-sitefindings.

r Personal feedback and advice duringthe day on questions raised, orobservations made, during the visit.

r A summary report recommending apath forward which will detail “the mostcost-effective solutions and choices inorder to effectively carry out riskassessments for the electrical archazard”.

Ongoing, paid-for supportA further option, for those organisationswishing to obtain ongoing help andsupport in assessing and controlling arcflash hazard risk over a longer period,(including access to calculation softwareand tools that will allow them toaccurately calculate the risks with anypiece of electrical equipment), is a rangeof paid-for contracts. These afford alimited number of user licenses withinthe organisation for, say, one or two years.The licences allow authorised personnelto access a secure portal (which is notavailable to the wider public) thatprovides further, more in-depth, technicaland practical information and tools tosimplify arc flash risk assessment and,where these are deemed necessary,facilitate the task of putting in placepreventative measures. Furtherinformation on the various options is

“At DuPont, we use the ‘4P’ approach torisk assessment:r Predict: Safeguard your workers by

predicting the severity of arc flashhazard so that you can assess andmanage risk more effectively.

r Prevent: Look at ways to prevent arcflash from occurring and endangeringyour workers.

r Protect: When prevention is notenough, protective measures such as PPE may be required.

r Publish: Employ training measures,produce risk assessment forms, andpublish EU-compliant labels to warnworkers of high levels of incidentenergy and risk of arc flash injury.”

A collaborative effortSpeaking during the webinar as the guidewas launched, Mike Frain, managingdirector of Sheffield-based ElectricalSafety UK, a specialist company“concerned with the safety of workers who carry out electrical work”, whichadvises industrial and commercialorganisations and utility service providerson electrical safety, writes procedures and rules, and trains staff andcontractors, and which worked withDuPont to develop the guidance, said:“The team that produced this guide,including a number of representativesfrom academia, collaborated for over two years to put it together.

“It not only clearly explains what arcflash hazards are, and the potentialconsequences of an incident, but alsolooks at key elements such as theincident energy level, which, inconjunction with factors including how far a worker is from the centre of the arcflash, the amount of current that flows

Electrical safety

38Health Estate JournalNovember 2011

available via the DuPont Arc-GuideSupport Desk, details of which are on the public website.

The recent webinar focussed on boththe public site, and the secure paid-forportal, and explained the different levelsof guidance available through them.

DuPont says in its pre-amble on thepublic site: “Risk assessment is definedby the European Agency for Safety andHealth at Work as the process ofevaluating risks to workers’ safety andhealth from workplace hazards. It is asystematic examination of all aspects of work that considers:r What could cause injury or harm.r Whether the hazards could be

eliminated and, if not,r What preventive or protective measures

are, or should be, in place to control the risks.”

Referring to the preventative approach it advocates, DuPont goes on to say:

Common injuries from arc flashOf the types of injury that can resultfrom arc flash, DuPont says: “Arc flashinjury can include external burns to theskin, internal burns from inhaling hotgases and vaporised metal, hearingdamage, eye damage such as blindnessfrom the ultraviolet light of the flash, aswell as many other devastating injuries.Depending on the severity of the arcflash, an explosive force known as anarc blast may also occur, which canresult in pressures of over 100 kiloPascal(kPa), launching debris as shrapnel at

Figure 1: DuPont’s “4Ps”-based approach to minimising arc flash risk.

speeds of up to 300 metres per second(m/s).

“Survivors of such injuries mayrequire extensive treatment andrehabilitation, and the cost of theseinjuries can be extreme, physically,emotionally, and financially. Whilelegislation requires businesses toperform risk assessments for all workactivities, electric arc risk is oftenoverlooked, because most people areunsure how to assess and manage thishazard effectively.”

Re-evaluateYES

Predict severity Results

Can we apply furtherpreventiontechniques?

NOSTART

Publishresults and

training

Applyprotectionmeasures

Residualrisk

Predict Prevent

ProtectPublish

Guide should be “an invaluable tool” to allthose charged with electrical safety in:r Giving guidance that will help avoid

worker injuries, equipment damage,and legal fines, via putting in place“appropriate control measures” for theseverity level of electrical arc hazard.

r Enhancing understanding of electricalarc hazard, risk prevention, andmitigation concepts.

r Assisting users to easily locate, identify,and engineer out, serious danger.

governing arc hazard risks. He explainedthat one of the difficulties facingengineers and electrical installers whenseeking to evaluate the risk of arc flashfrom any particular “kit” was that onepiece of electrical equipment thatappeared, overtly, to all intents, verysimilar to another, could pose verydifferent degrees of risk.

In addition to helping to protect thoseworking on electrical installations out inthe field, DuPont is keen that the guide be

used by design engineers to help themdesign out arc flash risk in any newequipment wherever possible.

Explaining briefly during the webinarthe fundamentals of what makes an arcflash incident happen, Mike Frain said:“An electrical arc is an electricalbreakdown of a gas (e.g. air) whichproduces an ongoing plasma discharge,resulting from a current flowing throughnormally non-conductive media such asair. It can occur where there is sufficientvoltage in an electrical system, and isusually caused by a short circuit ofenergised conductors. This initial shortcircuit is very often caused accidentally by electrical workers.”

From ‘inconsequential’ to disastrousEmphasising the potential severity of suchan occurrence, the DuPont Arc-Guidewebsite states: “An arc flash caused by an electrical arc with 1,000 amperes ormore can cause substantial damage, fire,or injury. The massive energy released in the fault rapidly vaporises the metalconductors involved, blasting moltenmetal, and expanding plasma outwardswith extreme force. A typical arc flashincident can be inconsequential, butcould conceivably easily produce a moresevere explosion. The violent event cancause destruction of equipment involved,fire, and injury, not only to the worker, but also to nearby people. Forces mayexceed 100 kPa, and debris is spread upto 300 metres/second, with temperaturesof up to 20,000˚C.”

The “public” site goes on to add that,“in addition to the explosive blast of sucha fault, destruction also arises from theintense radiant heat produced by the arc. The metal plasma arc producestremendous amounts of light energy –from far infrared to ultraviolet. Surfaces of nearby people and objects absorb this energy, and are instantly heated tovaporising temperatures, with the effectsof this seen on adjacent walls andequipment; they are often ablated and eroded due to the radiant effects. The thermal incident energy dissipatedonto the worker can cause severe skinburns, or have health consequences.”

Risk of loss of serviceIn addition, of course, to the potentialserious threat to employees, healthcareestates teams could also potentially face significant problems should, forexample, a generator or other keyelectrical appliance serving a hospital be out of action for any length of time,placing further emphasis on the need toensure that the arc flash risk from anygiven equipment is properly identified,and that, where feasible, appropriatemeasures to minimise the chances of an incident occurring are taken. :

Electrical safety

39Health Estate Journal

November 2011

Mike Frain, MD ofSheffield-based ElectricalSafety UK, which workedwith DuPont to developthe guidance, said: “Theteam that produced thisguide, including a numberof representatives fromacademia, collaborated for over two years to put it together.”

ARCBAN clothing from JK Ross incorporating DuPont Nomex. This layeringmethod of protective clothing is, DuPont says, “recommended for correct arc flashprotection”. It adds: “As a result of an arc flash study, the potential severity orincident energy level of an arc flash will be better understood, and therefore theamount of protection needed for any person working in this area can bedetermined. However, PPE is the last line of defence, and, if worn, the level ofprotection must always exceed the potential risk.”

into the arc, and the time ofexposure, will determine thelikely degree of injury and/ordamage to equipment.

“Using the tools provided,those responsible for majorelectrical installations cancalculate the arc flash riskfrom equipment such asswitchgear, motor controlcentres, and electricalpanels and cables, considerhow they might bestmitigate them and, wherethere is no opportunity toeradicate the risk altogether,how, for example, they canfield label particularequipment to ensure thatworkers are aware of therisk and take whateverpreventative measures theycan (such as wearing thecorrect personal protectiveequipment) to affordthemselves maximumprotection.”

As DuPont puts it, the

r Helping users “match thelevel of residual thermalrisks with the ratedperformance of a PPE tooptimise protection andcomfort for workers”.

r Enabling co-workersworldwide to have up-to-date information online,as well as access to thecalculation database.

r Providing access toreputable arc flash riskassessment partners.

A lack of specificlegislationMike Frain was at pains topoint out that one of themain reasons why DuPonthad felt the guide wasneeded was that, although,EU Directive 89/391/EECrequires employers toperform (regular) riskassessments for all hazards,there are currently nospecific regulations