Licht wissen 10 Emergency lighting safety lighting

Light and safety are closely linked. General lighting – lighting that is dependent on regular mains electricity – is widely understood by operators and users and documented accordingly in the relevant regulations and guidelines. In the case of mainsindependent emergency lighting – lighting which is activated only after a fall or failure of mains voltage – the same level of understanding cannot be expected.

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Emergency Lighting, Safety Lighting

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01

Light and safety are closely linked General lighting – lighting that is dependent on regularmains electricity – is widely understood by operators and users and documented accord-ingly in the relevant regulations and guidelines In the case of mains-independent emer-gency lighting – lighting which is activated only after a fall or failure of mains voltage – thesame level of understanding cannot be expected

Understanding emergency lighting is made more difficult by the multiplicity of standards, stipulations and guidelines relating to it As a result of the harmonisation of national and in-ternational norms, significant standardisation has taken place here in recent years – espe-cially with regard to terminology Emergency lighting is the umbrella term It denotes lightingthat is activated when general lighting fails Where emergency lighting is used to allow abuilding to be evacuated safely or to enable potentially hazardous work operations to besafely terminated (in the event of a mains power failure), it is referred to as safety lighting.That is the main topic of this booklet

Under the German Occupational Health and Safety Act (ArbSchG), employers are required

to conduct a hazard assessment of all work premises and workplaces Where this revealsthat a power failure and the resulting failure of general lighting would present a hazard for employees, a safety lighting system needs to be installed This booklet takes account of occupational health and safety requirements as stipulated in the new technical workplaceregulations (ASRs) and the relevant rules of the employers’ liability insurance associations

It also looks at the passages relating to safety lighting in building regulations and examinesthe contents of lighting and electrical standards

The development of the LED has radically transformed the products used for safety lighting.The LED light source is going to pervade every area of emergency lighting

In future, attention will need to be paid not only to this technological step change but also

to barrier-free escape routes and dynamic guidance systems Technical regulation is singly international Europe is (by necessity) growing together The primary focus must always be human needs and the primary purpose of safety lighting must be to help enablehuman beings to evacuate areas safely in the event of a failure of artificial lighting

increa-Prof Dr Bruno Weis

Editorial

[Titel + 01] No electricity, no light: powerfailures knock out lighting In hospitals,schools and places of assembly, mains-independent emergency and safety lightingneeds to kick in immediately It enablesbuildings to be evacuated safely, facilitatesorientation and reduces risk of accident

Light

in a power cut Page 8

Safety lighting Page 10

Escape route safety lighting Page 12

Safety lighting for work premises Page 16

Anti-panic lighting Page 20

Standby lighting Page 21

Safety signs Page 22

Escape signs

A white stick man on a green background or a stylisedgreen man on a white background? There are two escapesigns currently in use Which one is correct? Newlyinstalled emergency lighting systems should incorporatethe new sign (shown above), which complies with ASRA1.3 and DIN 4844-2

But the old escape sign (below) remains valid licht.deadvises against mixing old and new signs in an existingsystem

OLD

02

[02 + 03] Every power failure presents

haz-ards Sudden darkness triggers fear: the

rea-son for the blackout is unknown and people

have difficulty getting their bearings,

espe-cially those who are not familiar with the

building This is why it is mandatory for many

buildings to be equipped with

mains-inde-pendent escape route signs and

supplemen-tary safety lighting

A power outage can paralyse whole gions: trams stop running, computers crashand lights are instantly extinguished In re-cent years, two “extreme incidents” madeheadlines in Europe In late November

re-2005, masts carrying overhead power lines

in the Münster area collapsed under theweight of snow and ice, causing a blackoutthat lasted more than four days On 4 No-vember 2006, an event in the Emsland areagave rise to a power outage that left largeparts of Europe without electricity for hours:

a high-tension cable was shut down toallow a cruise vessel to sail down the EmsRiver to the North Sea from the Meyer ship-yards at Papenburg

Most power outages are more localised,however, and do not last for hours Ger-many has the best record in Europe formaintaining a reliable power supply Buteven it registers a rising number of outageincidents On 8 March 2011, for instance,the Bundestag and a number of govern-ment buildings in Berlin had to managewithout electricity for nearly 12 hours; on 13July 2011, around 600,000 people in andaround Hanover suffered a cut that leftthem with no power for up to an hour and ahalf Power failures occur for a wide variety

of reasons: violent storms, high winds,earthworks/excavation operations, fires andsystem overloads are just five of 27 possi-ble causes

Safety lighting

No electricity means no lighting This iswhen mains-independent emergency light-ing needs to kick in In a building suddenlyplunged into darkness, panic can quicklyspread – especially if a large number ofpeople are present and some are not famil-iar with the surroundings A blackout in anunknown place for an unknown reason trig-gers fear

Escape sign luminaires identify routes out of

a building, supplementary safety lighting

along escape routes facilitates orientationand reduces risk of accident Safety lighting

is a must Where safety lighting is required

by law, responsibility for installing and taining it resides with the operator of theestablishment; ensuring that a new or mod-ernised installation complies with regula-tions is the responsibility of the designer.Failure to comply with the stipulations setout in standards may be judged hazardousbuilding practice, which is an offence pun-ishable under paragraph 319 of the GermanCriminal Code

main-Different rulesDespite harmonisation efforts, the rulesabout where emergency lighting is requiredstill differ – in some cases from one part ofGermany to another but, in particular, be-tween Germany and other member states

of the European Union (EU) Retailers inGermany and Austria, for example, are onlyrequired to install emergency lighting insales premises over 2.000 m2 Blanket re-quirements are in place only in Belgium,Finland and Sweden

Compared to other European countries,Germany has relatively few blanket require-ments for emergency lighting Moreover,the thresholds above which emergencylighting is mandatory are relatively gener-ous

What this means is that there are moreplaces where employee safety is not guar-anteed in the event of a power failure Interms of emergency lighting standardsbased on building regulations, Germanylags behind most of the EU

In some cases, obligations are imposed byoccupational health and safety regulations:employers need to decide whether a failure

of general lighting exposes employees onthe premises to undue risk If safety lighting

is not installed, the employer is liable in theevent of loss or injury

Emergency lighting for safety

Lengthy power cuts – blackouts – are not rare And in an increasingly networked world, the risk of their occurrence will grow When general lighting fails due to a power outage, emergency lighting kicks in It guards against panic and accidents

Emergency and safety lighting ensures that

a minimum level of brightness is teed after a failure of the general lighting

guaran-But it also helps in other emergencies

Where a building needs to be evacuated,for example, it plays a key role in helpingpeople unfamiliar with the building to gettheir bearings and find their way to safeareas along escape routes

Emergency and safety lighting is covered

by a variety of standards, stipulations and guidelines Employers, facility opera-tors, lighting designers and installers need

to know the relevant requirements Theyalso need to be familiar with the terminol-ogy of this special area of supplementarylighting

In international standards and European rectives, ‘emergency lighting’ is now used

di-as the umbrella term for dent supplementary lighting It is activated

mains-indepen-whenever mains voltage fails or falls gency lighting includes

Emer-쐍 safety lighting and

쐍 standby lighting

The term ‘safety lighting’ is used to denotemains-independent supplementary lightinginstalled to ensure that a building can beevacuated safely or to enable potentiallydangerous work operations to be termi-nated Under the German OccupationalHealth and Safety Act, employers need toconduct a hazard assessment of the work-places they offer If this reveals that a gen-eral lighting failure is likely to present a haz-ard, safety lighting is required to beinstalled

Standby lighting denotes dent supplementary lighting that is installedwhere no hazard for employees is antici-pated It provides light where there is noactual risk after a power failure but light is

mains-indepen-Light in a power cut

When general artificial lighting fails after a power outage, the emergency lighting system takes over Where there is

a risk of accident after a power failure, safety lighting needs to be activated

Emergency lighting

Safety lighting where risk of accident

is present in compliance with ASR A3.4/3 occupational health and safety

regulations

Escape route safety lighting

in compliance with ASR A2.3

occupational health and safety

regulations

building regulations

Anti-panic lightingOverview of emergency and safety lighting

still needed to allow key operations to be

maintained

Subdivisions of safety lighting

Safety lighting, in turn, is divided into:

쐍 escape route safety lighting and signs,

쐍 safety lighting for particularly hazardous

work areas and

쐍 anti-panic lighting

The requirements that safety lighting needs

to meet are spread over various standards

DIN EN 1838 sets out the requirements for

safety lighting in emergency operation, i.e

in the event of a power failure The current

version of DIN 4844-1 deals with the

light-ing requirements for safety signs durlight-ing

normal mains operation

The electrical requirements for system

planning, installation and operation are

contained in the draft standard DIN V VDE

V 0108-100, published in August 2010

(for information [in German] about the

cur-rent status of normative requirements, see

www.dke.de, search term

„Sicherheits-beleuchtungsanlagen“) The safety and

electrical requirements that need to be met

by luminaires for emergency lighting are

defined in DIN EN 60598-2-22, published

October 2008

06Key laws and ordinances

Occupational health and safety regulationsOccupational Health and Safety Act (ArbSchG)

Workplace Ordinance (ArbStättV)Technical workplace regulations (ASR)Statutory accident insurers’ rules and regulations (BGV, BGR)

National building regulationsOrdinance Governing Places of Assembly(MVStättV)

Ordinance Governing Sales Premises(MvkVO)

Ordinance Governing Accommodation Establishments (MBeVO)

Ordinance Governing High-rise Buildings(MHHR)

Ordinance Governing Garages (MGarVO)Guideline for School Buildings

(MSchulbauR)Ordinance Governing Hospital BuildingsModel Guideline on Fire Protection Requirements for Conduction SystemsOrdinance Governing Electrical Operating Areas

Safety lighting ensures that work tions with a high accident risk potential can be terminated safely and persons un-familiar with the premises are able to exitthe affected rooms and areas safely in theevent of a general power failure Nationalbuilding regulations as well as occupationalhealth and safety rules need to be ob-served at the design and installationstages

opera-Safety lighting is divided into

쐍 escape route safety lighting, including escape route signs,

쐍 safety lighting for particularly hazardousworkplaces and

쐍 anti-panic lighting

Features of safety lighting

쐍 Luminaires for illuminating and identifying

an escape route need to be mounted

at least 2 metres above floor level

쐍 All escape signs at emergency exits and

at exits along escape routes are nated or back-lit

illumi-쐍 Where an emergency exit is not directlyvisible, one or more illuminated and/or

back-lit escape signs need to be tioned along the escape route

posi-The standard DIN EN 1838 requires morethan just good general illumination for es-cape routes It stipulates that supplemen-tary lighting should be provided for othersafety-relevant areas and potential hazardsites So safety luminaires also need to bepositioned at the following points:

쐍 at exit doors that need to be used in anemergency

쐍 near stairs, single steps or any otherchange of level

쐍 at emergency exits and safety signs

쐍 at any point where there is a change of direction

쐍 at any point where corridors or aislescross

쐍 near any First Aid post, fire-fighting facility

or alarm device

쐍 near final exits

쐍 outside the building up to a safe distancefrom each exit

DIN EN 1838 defines “near” as no morethan two metres away

Safety lighting

Safety lighting must come on whenever there is a failure of general lighting that may prevent the safe evacuation

of a building and thus present a risk of accident

07

[08] On escape routes up to 2 metres wide,

the horizontal illuminance on the central axis

must be at least 1 lx (measured at a height of

two centimetres above floor level)

Among other things, luminaires for safety

lighting need to be positioned …

level

to ensure direct illumination of each tread

First Aid post, fire-fighting facility or alarm

de-vice

metres from) every final exit

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14 1513

[14 + 15] Consistent luminaire design:

gen-eral and safety lighting can also be

incorpo-rated in a single unit Appropriate lighting

management systems ensure that the

gen-eral and safety lighting are separately

switched and dimmed

illumi-nance along the central axis must not

ex-ceed 40:1 This avoids light/dark contrasts

that interfere with the visual task

routes, luminous intensity must not exceed

certain limits at any azimuth angles between

60° and 90° to the vertical (see also the

table on page 15)

the limits must not be exceeded at any angle

To ensure that employees and visitors can reach safety as quickly as possible in

an emergency, escape route lighting andsignage need to be standard-compliant

This calls for:

쐍 escape sign luminaires or illuminated cape signs for marking the escape route

es-쐍 luminaires for illuminating the escape route

All employers are also required to positionescape and rescue plans where they areclearly visible to everyone: employees andvisitors must have an opportunity to memo-rise escape routes so that emergency stairsand emergency exits can always be found

Escape and rescue plans also serve as anorientation aid for emergency teams such

as the fire service

Lighting requirementsAccording to DIN EN 1838, escape routesafety lighting is the part of a safety lightingsystem that enables emergency facilities

to be clearly identified and safely usedwhere persons are present Workplace reg-

ulation ASR A2.3 also stipulates that wheresafe evacuation of the workplace is notguaranteed in the event of a general lightingfailure, escape routes need to be fitted withsafety lighting

Where the standards refer to an escaperoute, it is always a strip two metres wide.Wider routes need to be treated as morethan one two-metre strip or need to be fitted with anti panic lighting (see page 20) The most important lighting requirementsset out in DIN EN 1838 and technical work-place regulations ASR A3.4/3 are:

쐍 The horizontal illuminance along the tral axis of an escape route needs to be

cen-at least one lux – measured cen-at a point up

to 20 centimetres (ASR), preferably nomore than two centimetres (DIN EN 1838)above floor level On the left and right ofthe central axis, the illuminance is allowed

to decrease to 50 percent at a distance of

50 centimetres from the axis

쐍 Safety lighting must reach 100 % of itsrated output within 15 seconds of the

Escape route safety lighting

Escape route safety lighting needs to ensure adequate conditions for visual orientation along escape routes and in adjoining areas of the building Fire extinguishing and security equipment needs to be easy to locate and use.

general lighting failing Because mostgenerating sets with combustion engineshave a 15-second switchover time, how-ever, battery-based systems are the onlysuitable power source

쐍 The minimum colour-rendering index forescape signs is Ra40; this enablescoloured escape signs to be recognisedquickly and clearly

Lighting uniformity The ratio of highest to lowest illuminancealong the central axis must still not exceed40:1 –not even in the worst-case scenario,e.g between two luminaires at the end oftheir rated operating time This is becauseexcessively bright/dark patches make ob-stacles and the escape route ahead harder

re-be guaranteed for at least an hour Thetable on page 45 shows the times required

on other premises

Glare limitation – an often underestimated factor Excessively intense light can cause physio-logical (disability) glare In escape routelighting, it presents a problem in that it pre-vents obstacles or escape signs beingrecognised The risk is particularly acutewhere general diffuse lamps are used

In the case of horizontal escape routes, minous intensity must not exceed certainlimits at any azimuth angles between 60°and 90° to the vertical For all other escaperoutes and zones, the limits must not be

lu-19

exceeded at any angle (see illustrations on

page 13)

Escape route signage is also important

The lighting requirements in the event of a

power failure are set out in DIN EN 1838 It

should also be noted that the escape sign

luminaires defined in DIN 4844 must be

clearly identifiable even under general

light-ing conditions and therefore need to be

operated at a higher luminance level

For emergency operation, the luminance

at any point on the green surface should

be 욷 2 cd/m2; for mains operation, the

average luminance of the entire sign should

be 욷 200 cd/m2(see also “Safety signs:

quality is crucial” on page 22)

need to be standard-compliant

es-cape and rescue plan in line with ASR A1.3

Escape route safety lighting (DIN EN 1838)

to the vertical

Colour rendering: Ra욷 40Rated operating time

for escape routes: 1 hourPower-on delay: 50 % of required illuminance within 5 seconds

100 % of required illuminance within 60 seconds

20

Escape and rescue plan

Fire extinguisherFire hoseFire alarm, manualFire alarm phoneFire-fighting media and equipment

Direction indicatorEscape route/emergency exit

Emergency phoneEmergency showerEye wash stationDoctor

StretcherAssembly point

Location

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Occupational health and safety for em ployees is governed by EU-wide regula-tions In Germany, the relevant statute isthe Occupational Health and Safety Act(Arbeitsschutzgesetz – ArbSchG) Thisforms the basis for statutory instrumentssuch as the workplace ordinance Ar-beitsstättenverordnung (ArbStättV), whichsets out the basic health and safety stan-dards required Its individual stipulationsare concretised in technical workplace regulations (ASRs)

-The rules require employers to protect their employees from potential sources ofharm at the workplace This includesguarding against general accident risks

For if lights go off as a result of a powerfailure, even a janitor may be exposed todanger if he cannot find the way out in thedark or if he falls and sustains injury on theescape route as a result of being unable tosee Safeguards are provided here bysafety lighting

Responsibility resides with employersWhether safety lighting is necessary or notneeds to be established by employers onthe basis of a hazard assessment (para-graph 5 ArbSchG) This and the measuressubsequently taken need to be docu-mented (paragraph 6 ArbSchG)

The key question is whether safe tion of the workplace is possible And anaffirmative answer to that question can nor-mally be given only if sufficient light is avail-able even in the event of a power failure –i.e in work premises with windows or sky-lights during the day During winter, how-ever, it gets dark early, leaving insufficientlight for orientation even in the afternoon

evacua-So safety lighting is almost always sary It needs to deliver at least one lux illu-minance In rooms that can be safely evac-uated by every employee, only exits need

neces-to be signed

Employers must also ensure that ees and visitors can safely evacuate thebuilding after a power failure Where there

employ-is a heightened remploy-isk of accidents – e.g onstairs, because of obstacles that would

be hard to make out in darkness or cause the escape route is complicated –escape route safety lighting needs to be installed

be-At particularly hazardous workplaces, therisk of accident in a room suddenly plungedinto darkness is considerably higher Wheresuch workplaces are present, safety lightingsystems need to deliver at least 15 lux illu-minance to enable work operations to beterminated safely Where workplaces andescape routes could fill with smoke, an ad-ditional hazard is present in the event of afire An optical safety guidance systemneeds to be installed in such areas, in addi-tion to safety lighting

Secure against claims

An employer that complies with the relevantASRs can show authorities – especially inthe event of loss or damage – that every re-quirement of the Workplace Ordinance hasbeen observed If the measures taken differfrom those set out in the ASRs, the em-ployer faces the much more complex task

of proving that they were effective

Particularly hazardous work areasThe risk of accident is particularly high in

“particularly hazardous work areas” (ASRA3.4/3 paragraph 4.2) and at “particularlyhazardous workplaces” (DIN EN 1838).These include, for example:

쐍 Laboratories where risk is acute as a sult of experiments Acute risks may beexplosions or fire, the release ofpathogens or toxic, highly toxic or ra-dioactive substances in dangerous quan-tities

re-쐍 Workplaces that need to be kept dark fortechnical reasons

Safety lighting for work premises

Employers are obliged to protect the health and safety of their employees Among other things, this involves

conducting a hazard assessment at all workplaces One question it needs to address is whether all employees can safely evacuate their workplaces in the event of a lighting system failure

[21] Employers must ensure that

employ-ees and visitors are able to leave the building

safely after a power failure Safety lighting is

mandatory for “particularly hazardous

work-places”

Electrical operating areas and building

systems rooms that need to be accessed

in the event of the failure of artificial

light-ing

쐍 Areas with moving machinery that can

continue running for a long time after a

power failure Examples include facing

lathes, where additional accident risks

arise if lights fail

쐍 Control points for systems that require

constant monitoring, such as switchboard

galleries and control panels for power

sta-tions, chemical and metallurgical plants as

well as workplaces with isolating or

regu-lating equipment that needs to be

oper-ated to interrupt or terminate production

processes safely during normal or

dis-rupted plant operations

쐍 Workplaces near hot baths or casting pits

that cannot be properly secured by guard

rails or barriers for production reasons

쐍 Areas around work pits that cannot be

covered for operational reasons

쐍 Construction sites

21

Particularly hazardous workplaces (DIN EN 1838)

Illuminance: Emin= 10 % of the maintained illuminance required for the

task 쏜 15 lxUniformity: Emax: Eminⱕ 10 : 1Glare limitation:

h/m 쏝 2.5 2.5 울 h < 3 3 울 h 쏝 3.5 3.5 울 h 쏝 4 4 울 h 쏝 4.5 욷 4.5

Imax/cd 1,000 1,800 3,200 5,000 7,000 10,000The values in this table must not be exceeded at any azimuth angle between 60° and 90°

to the vertical

Colour rendering: Ra욷 40 Safety colours need to be clearly recognised

Rated operating time for escape routes: as long as a hazard existsPower-on delay: 0.5 seconds

22

23

Lighting requirements

Safety lighting in “particularly hazardous

work areas” needs to meet higher

require-ments Illuminance needs to be at least

15 lux Technical workplace regulation and

DIN EN standard both focus on that A

preferable level is 10 % of the illuminance of

the normal general lighting – which is what

the ASR recommends – because the

brighter the lighting, the more unlikely an

accident due to the prolonged darkness in

the wake of a power failure

This is also the reason for the stipulation

that the illuminance required needs to be

reached within 0.5 seconds For many light

sources, however, this is possible only with

safety lighting in maintained operation

Lighting uniformity in these work areas

should be lower than 10:1

The nominal operating time needs to be at

least as long as the hazard exposure after a

power failure This operating time is

estab-lished when a hazard assessment is

con-ducted

Construction sites

Construction sites are mentioned explicitly

in ASR A3.4/3 because of their particularly

hazardous nature as a workplace The

regulation states that safety lighting is

ab-solutely essential where daylight fails to

pro-vide a minimum of one lux illuminance for

escape route lighting and site workers thus

cannot evacuate their workplace safely

So any construction site where work tinues into the evening or night must atleast have escape route safety lighting in-stalled For basement levels, a higher light-ing level is required – e.g a minimum of

con-15 lux illuminance, which ASR A3.4/3 alsorequires for tunnelling work

Optical safety guidance systemsSafety lighting is usefully supplemented byoptical safety guidance systems, which facilitate escape if orientation in a room oralong escape routes is impaired by smoke

It is important to note that optical guidancesystems are not a substitute for standard-compliant safety lighting; they are installed

in addition to it

A distinction is made between:

쐍 photoluminescent guidance systems(signs),

쐍 electrical guidance systems (connected to

a safety power source),

쐍 dynamic guidance systems – ‘smart’ tems incorporating direction indicatorsthat change according to the location ofthe hazard site

sys-Direction signs and other guidance systemsare mounted on the wall at a maximumheight of 40 centimetres above floor level

This type of marking makes it possible toidentify escape routes with direction indica-tors In comparison to escape sign lumi-naires, optical safety guidance systemshave the disadvantage that they are not po-

[22 + 23] Safety lighting at “particularly

haz-ardous workplaces” is required to deliver at

least 15 lux illuminance Where there is a risk

of workplaces and escape routes filling with

smoke in the event of a fire, an optical safety

guidance system must additionally be

in-stalled

sitioned at eye level An evacuee’s view ofthe low level markers is obscured by thebodies of persons ahead

Where a risk of accidents exists, safetylighting is definitely necessary Nothing elsemakes differences in level, stairs and obsta-cles on the escape route identifiable andthus guards against dangerous falls Photoluminescent signs

In comparison to illuminated escape signs,photoluminescent signs have one disadvan-tage: they need to be sufficiently and con-stantly illuminated before the emergencyoccurs Despite this excitation light – which,incidentally, is not subject to any regulation– the time during which a photoluminescentsign is identifiable is limited Its luminance –i.e its brightness as perceived by thehuman eye - quickly diminishes So the dis-tance from which it is recognised de-creases

licht.de points out that, where a risk of dent exists, optical safety guidance sys-tems may be used only to supplement sig-nage and safety lighting with escape signluminaires Optical systems are mandatory– again as a supplementary measure –where the risk of smoke cannot be ruledout in the event of fire and escape routesare wider than 3.6 metres

acci-At sporting events, rock concerts or major

university lectures – wherever people

assem-ble in large numbers, panic can quickly arise

if the lights suddenly go out as a result of a

power failure People seeking to escape may

be injured or even killed in the ensuing crush

Anti-panic lighting makes for a greater

sense of security Its purpose is to reduce

the likelihood of panic and create the visual

conditions needed to enable people to

reach escape routes safely In Germany,

however, neither building nor workplace

regulations set out specific requirements

for the application of anti-panic lighting

So, as a general rule, anti panic lighting in

Germany is planned on the basis of one lux

illuminance on the free floor area and a

rated operating time of three hours

Anti-panic lighting needs to be installed

where escape routes are not clearly defined

– in large halls, for example – or where theentire hall space may be used as an escaperoute It is also required in conferencerooms with an area of more than 60 squaremetres and no signed escape routes aswell as in smaller enclosed spaces wherecrowding could give rise to panic Suchspaces include, for example, lift cabins

Lighting criteriaAnti-panic lighting should be directed straightdownwards and illuminate obstacles up totwo metres above the reference plane

Furthermore, DIN EN 1838 stipulates that

쐍 because of persistence of vision, the ratio

of highest to lowest illuminance should be

no greater than 40:1; this avoids sive differences in brightness that interferewith the visual task;

exces-쐍 the colour rendering index of light sourcesshould be at least Ra40 so that safety

signs and their colours can be clearlyidentified;

쐍 50 % of required illuminance must bereached within five seconds, 100 % within

60 seconds;

쐍 glare limitation requirements are the same

as for escape route safety lighting (seetable on page 15)

Anti-panic lighting

Anti-panic lighting is the third category of safety lighting alongside escape route safety lighting and safety lighting for particularly hazardous workplaces The light it provides is intended to reduce hysteria and panic in an emergency.

24

Standby lighting is the second type ofemergency lighting alongside safety lighting(see diagram on page 8)

Safety lighting must always be installedwhere a risk of accidents exists Standbylighting, on the other hand, may be installedonly if a hazard for employees and visitorscan be categorically ruled out Under theGerman Occupational Health and SafetyAct, employers are required to conduct ahazard assessment of workplaces – andtake appropriate action depending on thefindings

So standby lighting systems are not rily designed to avoid accidents They areinstalled for operational reasons, e.g toavoid production downtime due to a failure

prima-of the general artificial lighting In that event,mains-independent standby lighting guar-antees that light remains available

If a standby lighting system is to performthe tasks of emergency lighting, it needs tomeet all the relevant requirements Essentialactivities can then continue However, if thelighting level is lower than the minimum illu-minance of the general lighting, the standbylighting may be used only to power down orterminate work processes

outbreak of panic in the event of a power

failure

produc-tion downtime in the event of a failure of

the general artificial lighting due to a power

[26] Safety signs clearly indicate the

direc-tion to take – provided the pictogram is

cor-rectly dimensioned for the required viewing

distance

Safety signs mark escape routes and tify the location of fire protection equip-ment According to ASR A1.3 and DIN4844-1, a safety sign is a sign that com-bines geometrical shape and colour with agraphical symbol to convey a particularhealth and safety message Safety signsfor escape routes are referred to as es-cape signs They are used to mark thecourse of escape routes and indicateemergency exits and First Aid stations It isimportant to ensure that at least one es-cape sign is identifiable from every possi-ble observation point

iden-In 2007, a new escape sign was

approv-ed by ASR A1.3 and DIN 4844-2 duced for safety reasons, it features a pic-togram in which the direction arrow isclearer and more instantly recognisable

Intro-Existing old signs based on BGV A8 need

not be replaced but should not be porated in new installations licht.de ad-vises against using the two signs together,

incor-at least within the same part of a ing

build-Lighting parametersDIN EN 1838 and the current DIN 4844-1present different requirements for illumi-nated and back-lit safety signs in terms ofthe lighting parameters to be met for thedifferent operating conditions For escapesign luminaires in emergency operation,DIN EN 1838 requires a much lowerbrightness for the sign as a whole thanDIN 4844-1 DIN 4844-1 deals with normaloperation and takes into account thatwhen the general lighting is on, escapesigns need to stand out against brightly litsurroundings, so they need to be brighterthan in emergency operation

Safety signs: quality is crucial

Safety signs for escape routes can be either illuminated escape signs, i.e with an external light source, or back-lit escape signs with an internal light source

26

Luminance, uniformity of illumination and

contrast are key criteria for judging a good

escape route luminaire and thus the safety

it affords The table on the right

sum-marises the requirements of the two

rele-vant standards

Mounting height of escape signs

Because a back-lit sign is easier to

recog-nise from a greater distance than a sign

that is only illuminated, DIN EN 1838 and

DIN 4844 stipulate that different distance

factors need to be applied to establish the

standard-compliant viewing distance (see

Fig 27)

To be equally recognisable from the same

distance, an illuminated sign needs to be

twice as high as a back-lit sign Back-lit

signs are always the better choice because

they are also recognisable for much longer

and from a greater distance if smoke is

present Illuminated or backlit escape signs

should not be mounted more than 20

de-grees above horizontal sight lines

(mea-sured at the maximum viewing distance)

The formula for calculating the height of

back-lit signs is:

I = z x h (where z = 200)

e.g height = 15 cm Ⳏ viewing distance 30 m

The formula for calculating the height of illuminated signs is:

I = z x h (where z = 100)e.g height = 15 cm Ⳏ viewing distance 15 m

Comparison of lighting requirements

DIN 4844-1 DIN EN 1838Environment bright dark and dark

Mains/emergency power mains emergencyMaintained operation yes not specifiedGreen safety colour acc to DIN 4844-1 acc to ISO 3864-4White contrast colour acc to DIN 4844-1 acc to ISO 3864-4

Uniformity of Lmin Lmin

g 욷 –––– 0.2 g 욷 –––– 0.1green/white surfaces Lmax LmaxLuminance contrast between Lwhite

k = –––––– = 5 :1 to 15 :1green and white surfaces Lgreen

Average luminance of white contrast colour 욷 500 cd/m2 not specifiedLuminance of green

safety colour not specified 욷 2 cd/m2

Calculated average luminance

of the sign as a whole 욷 200 cd/m2 욷 5 cd/m2

Illuminance of the 욷 50 lxilluminated sign (preferably 욷 80 lx) not specified

27

Formula for calculating sign height

Explanation of symbols: I = viewing distance h = height of pictogram z = distance factor

© licht.de

[28] Escape sign luminaire in maintainedoperation

The minimum luminance of the white

EN 1838

ex-posed to a charging light source

The minimum luminance of the white

ASR A3.4/3

Escape sign luminaires are easily and rectly identified The green safety colour isclearly recognisable even in emergency operation, as required by ASR A3.4/3 andDIN EN 1838 Standard signs with photo-luminescent pigments, however, appeardark after a power failure: the green safetycolour is usually no longer recognisable as

cor-a colour cor-and the white contrcor-ast colour erally has a yellowish green appearance

gen-Efficiency Emergency powered luminaires operate re-gardless of the operational status of thegeneral lighting Photoluminescent materi-als, on the other hand, need to be suffi-ciently and continuously charged ahead of

an emergency Light sources with a dominantly red spectral content (e.g incan-descent lamps) and high-pressure sodiumvapour lamps are not suitable sources forcharging

pre-Luminance The luminance of an escape sign luminaireremains constant from the beginning to theend of the operating time, which is at leastone or three hours The impression ofbrightness created by a photoluminescent

sign, however, diminishes within minutes.After 60 minutes of operation, the lumi-nance of an escape sign luminaire is up to athousand times greater than that of a pho-toluminescent sign

Viewing distance

As luminance decreases, so does visualacuity and identifiability A 20 centimetrehigh illuminated escape sign luminaire isclearly identifiable from a distance of

20 metres; an escape sign luminaire of thesame height achieves the same degree ofidentifiability at twice that distance: it can

be easily recognised from a distance of

40 metres

By contrast, the afterglow of a similarlysized photoluminescent sign weakens sofast that the viewing distance usually decreases to around five metres within

10 minutes; after 60 minutes, the content

of the sign can generally be recognised only from immediately in front of the sign.The luminance of the white areas of thesign needs to be at least 0.012 cd/m² forcompliance with ASR A3.4/3 With an es-cape sign luminaire, the viewing distanceremains constant

Escape sign luminaires

Escape sign luminaires are easier to recognise than ordinary photoluminescent signs There are several reasons for this, one of which is that the green safety colour is clearly identifiable even in emergency operation

Safety lighting is necessary

“Photoluminescent safety guidance systems do

not meet the requirements in terms of colour

rendering or illuminance They can only be used in con

-junction with a standard-compliant safety lighting

system, e.g as floor markings, or as a

supplemen-tary safety measure in areas where safety lighting

is not required.”

Runner 68 in Opfermann, Streit, Pernack

commen-tary on the 2004 German Workplace Ordinance

(ArbStättV)

Luminaires for safety lighting systems

Safety lighting is safe only if the luminaires used are of the highest quality Standard-compliant products

and professional installation protect lives This chapter provides information on luminaire types, classification

and labelling

The requirements that safety luminairesneed to meet in terms of design and oper-ational reliability are set out in DIN EN60598-1 “Luminaires – General require-ments and tests”, DIN EN 60598-2-22

“Particular requirements – Luminaires foremergency lighting” and DIN EN 62034

“Automatic test systems for battery ered emergency escape lighting”

pow-CE marking The CE mark is not a test symbol but ismandatory for products marketed withinthe EU In applying it, manufacturers andimporters confirm that their products meetthe “basic requirements” of various relevant

EU directives These include, for example,the Ecodesign and EMC directives Manu-facturers and importers must furnish evi-dence of conformity to the relevant authori-ties on demand

Field 1: Design

The first field on the rating plate contains

a letter of the alphabet indicating the

de-sign of the unit

X = with built-in single battery

Z = for central power supply systems

Field 2: Operating mode

The second field on the rating plate

con-tains a numeral indicating the operating

mode of the unit

0 = emergency luminaire in

* 10 = for a specified operating time of

identify-A = features test system

B = features remote control for idle time

C = offers possibility of remote deactivation

D = luminaire for particularly hazardousworkplaces

E = luminaire with non-replaceable lamp(s)and/or battery

ENEC/VDE test mark The ENEC mark (ENEC = European NormElectrical Certification) shows that lumi-naires and built-in operating devices com-ply with current standards The numberafter the mark identifies the test and certifi-cation institute responsible In Germany,this is VDE (Verband der ElektrotechnikElektronik Informationstechnik e.V.), whichcombines its test mark with the ENECmark VDE not only tests products but alsomonitors their production

Safety luminaire labellingFor standard compliance, all safety lumi-naires need to be labelled in a particularway A rectangular bar divided into three orfour sections provides coded information

on type (single battery or central supply),operating mode (e.g 0 for safety luminaires

in non-maintained operation), built-in

equip-Labelling of safety luminaires

X 1 AB*** *60

36