Emergency Lighting Definitions
ANTI-PANIC LIGHTING
is the part of the emergency escape lighting provided to avoid panic
and provide illumination to allow people to reach a place where an
escape route can be found.
BALLAST
The component that controls the operation of a lamp from a specified
low or high voltage AC or DC source (Typically between 12 and 240 volts)
BALLAST LUMEN FACTOR (BLF)
The ratio of the light output of the lamp when the ballast is
operated at its design voltage compared with the output of the same lamp
operated with the appropriate ballast supplied at its rated voltage and
frequency.
BATTERY
Secondary cells providing the source of power during mains failure.
BATTERY -
RECOMBINATION
A battery that is designed to recombine the electrolyte, constructed
so that no provision is made for replacement of electrolyte (sometimes
called sealed).
BATTERY - VENTED
A battery that requires replacement of electrolyte at regular
periods.
BATTERY CAPACITY
The discharge capability of a battery, being a product of average
current and time, expressed as Ampere-hours (Ah) over a stated duration.
Note: At fast rates of discharge the full ampere hour capacity of the
battery is not available.
BS5266
The British Standard for emergency lighting, it has now been revised
to conform with the European Standard EN1838. It is now issued in the UK
under the reference BS EN 1838/BS5266 Part 1/7/8
BS EN60598-2-22:1999
This is British/European luminaire product standard.
CANDELA (CD)
The unit of luminous intensity.
CENTRAL BATTERY SYSTEM
is a system where the batteries for a number of fittings are housed
in one location, usually for all of the fittings in one subcircuit.
CENTRAL TEST
A testing system for a wide range of applications operating on 24v,
50v or 110v as well as 230v AC Static Invertor projects.
COLOUR RENDERING INDEX
(CRI)
A measure of the degree to which the appearance of a surface colour
under a given light source compares to the same surface under a CIE
reference source. The index has a maximum value of 100.COLOUR
TEMPERATURE (°K)
All materials emit light when heated (e.g. metal glows red through to
white as the temperature increase). The temperature to which a full
radiator (or ‘black body') would be heated to achieve the same
chromaticity (colour quality) of the light source being considered,
defines the correlated colour temperature of the lamp, quoted in degrees
Kelvin.
COMBINED EMERGENCY
FITTING (SUSTAINED)
is a light fitting containing two or more lamps at least one of
which is energised from the emergency supply, the remaining lamps are
supplied from the normal supply.
CONVERSION KIT
A product used to provide standard mains luminaries - including low
voltage - with an emergency back up should the mains power fail.
DESIGN VOLTAGE
The voltage declared by the manufacturer to which all the ballast
characteristics are related.
DISABILITY GLARE
Glare produced directly or by reflection, that obscures or impairs
vision of an object, but does not necessarily cause any discomfort.
DISCOMFORT GLARE
Glare which causes visual discomfort.
DOWNWARD LIGHT OUTPUT
RATIO (DLOR)
The ratio of luminaire light output below the horizontal, compared
with total lamp light output.
EMERGENCY EXIT
is a way out intended to be used at any time. Final Exit is the
terminal point of an escape route at which persons are no longer in
danger from any hazard requiring evacuation of the building.
EMERGENCY LIGHTING
is the lighting provided for use when the normal lighting mains
supply fails, or when local sub circuit failure occurs.
ESCAPE ROUTE LIGHTING
is provided to ensure the means of escape can be effectively
identified and used.
EXTERNALLY ILLUMINATED
SAFETY SIGN
A sign that is illuminated, when it is required, by an external
source within 2m.
F ' MARK
Shows the luminaire can be mounted on flammable surfaces.
FINAL EXIT
The terminal point of an escape route, beyond which point persons
are no longer in danger from fire or any other hazard requiring
evacuation of the building.
GLARE
The discomfort or disability that occurs when there is an excessive
change of luminance in the field of vision.
HIGH RISK AREA LIGHTING
The part of escape route lighting provided at a potentially
dangerous location to enable proper shutdown procedures for the safety
of the operator and other occupants of the building.
HOUSING 850ºC TEST
Mandatory test for emergency luminaires used on escape routes, to
establish that materials do not burn at given temperature.
Self-extinguishing grades of plastic must be used, or alternatively
glass and/or steel.
ICEL 1001 REGISTRATION
The industry standard for the approval of photometric performance
and claimed data of emergency lighting equipment, which is tested by the
British Standards Institute.
ICEL 1004
The industry standard and accepted practice for the conversion of
mains luminaries to having an emergency battery powered back up.
ILLUMINANCE (LUX)
The luminous flux density at a surface, indicated in lm/m2.
INGRESS PROTECTION (IP) NUMBER
Classification of the degree of protection a luminaire provides
against the entry of solid foreign bodies and moisture.
INTERNALLY ILLUMINATED SAFETY SIGN
A sign that is illuminated, when it is required, by an internal
source.
ISOLUX DIAGRAM
Diagram showing contours of equal illuminance.
K FACTOR
The ratio between the light output from the lamp in the worst
condition, normally at end of discharge and with cable volt drop, to the
light output at nominal voltage.
LAMP LUMEN MAINTENANCE FACTOR (LLMF)
The proportion of light output of a lamp after a stated period,
compared with initial lumen output.
LAMP SURVIVAL FACTOR (LSF)
The proportion of functioning lamps in an installation after a
stated period.
LIGHT LOSS FACTOR (LLF)
See Maintenance Factor.
LIGHT OUTPUT RATIO (LOR)
The ratio of the total light output of a luminaire, compared with
total lamp light output.
LUMEN (LM)
The unit of luminous flux used to describe the quantity of light
emitted by a source or received by a surface.
LUMINAIRE
Apparatus which distribute the light given by a lamp or lamps,
including all the items necessary for fixing and protecting the lamps
and for connecting them to the electrical supply.
LUMINAIRE MAINTENANCE
FACTOR (LMF)
The proportion of light output from a luminaire with dirt deposition
after a stated period, compared with the initial light output when
clean.
LUMINANCE (CD/M2)
The perceived brightness of a surface, measured by the intensity of
light emitted or reflected from a surface area in a given direction.
LUMINOUS EFFICACY (LM/W)
The ratio of light emitted, to the power consumed by a lamp.
LUMINOUS FLUX (LM)
The total light emitted by a lamp, measured in lumens.
LUMINOUS INTENSITY (CD)
The power of a light source or illuminated surface to emit light in
a given direction, measured in candela.
LUX
The unit if illuminance, equal to one lumen per square metre
(lm/m2).
MAINTAINED EMERGENCY LIGHTING
is a light fitting containing one or more lamps all of which operate
from both the normal and emergency supply at all times.
MAINTENANCE FACTOR (MF)
The ratio of the illuminance provided by an installation at a stated
period, compared to the installation when new. Calculated as a product
of lamp lumen, lamp survival, luminaire and room surface maintenance
factors.
MOUNTING HEIGHT
is the vertical distance between the light fitting and the floor.
NON-MAINTAINED EMERGENCY LIGHTING
is a light fitting containing one or more lamps all of which operate
from the emergency supply only following the failure of the mains supply
or local sub circuit.
NORMAL LIGHTING
is all permanently installed artificial lighting operating from the
mains supply for use when inadequate lighting is available during
occupation of the building.
RATED DURATION
is the manufacturer's declared duration for a battery operated
emergency light. Typically one to three hours when fully charged.
RATED LOAD
The maximum load which may be connected to the system which will be
supplied for the rated duration.
RE-CHARGE PERIOD
The time taken for the batteries to regain sufficient capacity to
achieve their rated duration.
ROOM INDEX (K)
Index defining the relationship between the height, length and width
of a room. Used for illuminance calculations.
ROOM SURFACE
MAINTENANCE FACTOR (RSMF)
The proportion of illuminance provided by a lighting installation
with dirt deposition on the room surfaces after a stated period,
compared with the illuminance when the room was clean.
SAFETY SIGN
A sign which gives a general safety message, obtained by a
combination of colour and geometric shape and which, by the addition of
a graphic symbol or text, gives a particular safety message (ISO 3864:
1984).
SELF CONTAINED EMERGENCY LIGHT FITTING
is a fitting or sign providing maintained, nonmaintained or combined
emergency lighting in which all of the operating components are within 1
meter of the housing.
SELF TEST
A testing system for a wide range of self contained luminaries.
SLAVE FITTING
is an emergency light fitting without it's own batteries that is
designed to work within a central battery system.
SPACING TO HEIGHT RATIO (SHR)
The ratio of the distance between luminaire centres in relation to
their height above the working plane. Maximum spacing to height ratio (SHRmax)
is the maximum spacing of an array of luminaires that will achieve a
ratio of min/max direct illuminance of at least 0.7.
STANDBY LIGHTING
That part of emergency lighting provided to enable normal activities
to continue substantially unchanged (IEC 50 - Chapter 845).
STATIC INVERTOR
A central system which enables mains luminaries to be utilised as
emergency fittings without the need for additional wiring.
SUSTAINED EMERGENCY LIGHTING
See combined emergency lighting.
UNIFORMITY RATIO
The ratio between maximum to minimum illuminance measured at the
working plane.
UTILISATION FACTOR AT ZERO REFLECTANCE (U.F.O.)
Determines the proportion of light output from a lamp that falls
directly on the floor for different room indexes and types of diffuser.
UNINTERRUPTIBLE POWER SUPPLY (UPS)
A versatile method of providing back up power and or steady,
constant mains supply to specific applications such as I.T & telephones
as well as being used to provide an emergency lighting facility in
certain installations.
UPWARD LIGHT OUTPUT
RATIO (ULOR)
The ratio of luminaire light output above the horizontal, compared
with total lamp light output.
UTILANCE (U)
The proportion of luminous flux emitted by a luminaire which reaches
the working plane.
UTILISATION FACTOR (UF)
The proportion of luminous flux emitted by a lamp (or lamps) which
reaches the working plane.
