LIGHTING DESIGN
& APPLICATION
W
ith the energy crisis and its effects experienced since
January 2008, the need for good quality compact
fluorescent lamps became more urgent.
Compulsory performance requirements for
compact fluorescent lamps (CFLs)
In support of the national energy saving
drive it was clear that these lamps must
comply with not only safety standards,
but also with acceptable minimum
performance standards.
We are all aware of the claims made for
the light output (luminous flux) and life
of these lamps, but we also know that
in many cases the lamps have very low
light output values and the life of the
lamps do not come close to the claimed
values. The consumer also experiences
regular problems with the starting of
the lamps.
It has been proposed that a specification
including both safety and performance
requirements like lamp efficiency,
lumen maintenance, power factor,
starting, EMI and life are declared
compulsory to protect the consumer
and to support the general effort to
save energy.
The performance requirements and
test methods included in the draft
specification as well as the motivation
to include the specific requirement and
the test method will be discussed in this
paper.
Standards South Africa (STANSA) has
proposed to amend the South African
standard SANS 60901/IEC 60901
"Single-capped fluorescent lamps –
performance specifications" to include
the national requirements for energy
efficiency. The details of the national
modifications will be given in an annex
with the title: National Annex AA
(normative), South African requirements
for efficiency of lamps.
by Margaret Budzinski and Elsie Coetzee,
National Metrology Institute of South Africa (NMISA)
The following paragraph
has been added to the
national foreword of SANS
60901 (due to the inclusion
of national requirements
the dual numbering of the
standard falls away):
“To encourage users to
replace incandescent lamps
with compact fluorescent
lamps (CFLs), committee
SC64A decided to modify
the international standard
Fig. 1: IESSA delegates to CIE 2007 visiting the
IEC 60901 to include energy
ELI Quality Certification Institute at the
China Standard Certification Centre.
efficiency requirements
suitable for South African
conditions.
National Amendment 1 to SANS 60901/
The international standard allows the
IEC 60901 "Single-capped fluorescent
manufacturer to select his own ratings
lamps – performance specifications" are
and the lamps are then tested to those
discussed in this section.
ratings. The national modifications
Most of the requirements on energy
require the tests to be conducted at the
efficiency included in the amendment
SA standard voltage and specify specific
are based on the Efficient Lighting
values for starting, luminous efficacy
Initiative (ELI) technical specification for
and life.”
CFLs. ELI is a voluntary international
The Regulatory Department of the SABS
programme for certifying the quality
will compile a standard that refers to the
and efficiency of lighting products. A
South African performance requirements
working group of IESSA investigated the
included in Annex AA in SANS 60901
national requirements to be included in a
and the standard on the safety of CFLs
compulsory standard and decided that the
SANS 61199. This standard will be
ELI requirements were the most suitable.
submitted to the Minister of Trade and
Requirements
Industry to be declared compulsory.
National requirements for
energy efficiency
The national requirements as in draft
June 2008 - Vector - Page 22
AA.1 Starting
At the test voltage the lamp shall start
within 1,5 s.
One of the most common problems
experienced with compact fluorescent
lamps is the starting of the lamps
especially during winter or rainy
weather. It is not possible to simulate
all the different weather conditions
in a laboratory. In accordance with
IEC standards, fluorescent lamps are
tested at the following temperatures:
l For testing the starting characteristics
of single-capped and double-capped
fluorescent lamps, these standards
require an ambient temperature of
between 20°C and 27°C.
l Fo r t e s t i n g t h e p h o t o m e t r i c
characteristics of single-capped and
double-capped fluorescent lamps,
these standards require an ambient
temperature of 25°C ± 1°C.
The humidity of the laboratories is
maintained between 35% and 65%. The
minimum of 35% (in accordance with
the SANAS requirements for photometry
and radiometry laboratories) is usually
specified as a minimum, because
at values less than 35% problems
are experienced with static electricity.
Generally a maximum of 65% humidity
is specified where electrical measuring
1
2
Lamp power rating
W
Lamp efficacy
lm/W, Min
<15
45
>15
55
<14
with translucent cover
40
15 – 19
with translucent cover
48
>20
with translucent cover
50
Table AA.1: Lamp efficacy.
instruments are used, because corrosion
could develop on the electrical contacts
inside the instrument as well as on the
external connections.
The test voltage for the starting test is
230 V – 10 % (207 V). The South African
standard voltage is 230 V + 10% and it
is therefore required that the lamp shall
start at the minimum supply voltage.
AA.2 Luminous flux
The lamp efficiency, calculated from the
initial luminous flux and initial power
measurements, shall be as given in
table AA.1
In most of the standards e.g. SANS
60901/IEC 60901 requirements for
the initial luminous flux and initial
power are stipulated separately. The
Fig. 2: Compact fluorescent lamps in the cap-up position.
Fig. 3: Power factor correction vector diagram.
luminous flux is usually stated as a
minimum percentage (e.g. 90% min) of
the rated value as per the data sheet.
As far as the initial power is concerned,
the requirement is also stipulated in
terms of the rated wattage. In SANS
60901/IEC 60901 it is stated that the
initial power reading shall not exceed
the rated power by more than 5%
(+ 0,5 W).
Since lamp efficiency became
critical in the energy saving drive,
requirements for minimum lamp
efficacy, expressed as lumen per watt,
make more sense. It also simplifies the
determination of compliance criteria
for testing laboratories.
Claims regarding the CFL efficiency
versus the efficiency of incandescent
lamps made by CFL suppliers and even
by government are in many cases not
true. Ridiculous statements like “8 x more
light” are quite common. In practice we
know that we have a different situation
and that the light output of many CFLs
is far below the claimed values. Some
results obtained in the laboratory are
given in Table AA1.
It is not uncommon to get efficacies
June 2008 - Vector - Page 24
as low as 32 lumens per watt for
CFLs (15 - 22 lm/W for incandescent
lamps). In cases like this the incentive
to replace an incandescent lamp with
a CFL is lost especially if the price
difference is taken into consideration.
The drive to convince the consumer
to fit luminaires with CFLs loses
momentum at an early stage if low
illuminance levels are obtained and
the energy saving performs far below
the optimum targets that could be
achieved.
As far as the test method for luminous
flux is concerned, it is proposed that
the CFLs are tested in an integrating
sphere after an aging period of
100 hours with the lamp in the
vertical cap-up position that is the
normal operating position for these
lamps. The measurements are done at
230 V.
AA.3 Power factor
The power factor of a lamp shall be
0,5 or higher.
Leading power factors varying between
0,52 and 0,56 were measured on wellknown trade name self-ballasted CFLs.
least 50% of the lamps in the sample
shall remain burning.
Fig. 4: Lumen depreciation versus burning hours.
The problem with leading power factor
in installations is that consumer power
systems are designed and constructed
assuming lagging power factors.
Installations so designed which are
suddenly changed from a resistive
circuit to a capacitive circuit usually
experience problems characterised
by switching problems as a result of
large inrush currents and switching
oscillations.
This stresses the installation reducing
the lifetime of components including
capacitors which are commonly used
in most appliances and UPS systems as
well as contactors and switches.
Many electrical loads incorporate
elements that can impose a leading
power factor on the power source. While
these loads are typically not a problem
for utility power sources, it can cause
generator set failures or the failure of
certain loads to operate properly.
When a leading power factor load
is applied, the voltage of the genset
or genset bus rises, and the voltage
regulation system reduces exciter power,
reducing the strength of the magnetic
field. If the field fails, the generator
set may slip a pole, which results in
potentially catastrophic alternator
damage.
Alternators are physically limited in
their ability to both produce and
absorb power. When a leading power
factor load is applied to an alternator,
disoperation of the generator, over
voltage, load disoperation, and
alternator damage can occur.
To resolve this type of problem a
system designer needs to understand
the nature of the problem and the
limits of the machines as installed.
Most of the solution will come from
changes in the system sequence of
operation, or hardware changes that
prevent disruptive leading power
factor (reverse VAR) conditions from
affecting the generator.
AA.4 Electromagnetic
interference suppression.
The lamp shall comply with CISPR 15
(SANS 215).
With the advances in power-electronics
technology, devices such as fluorescent
lamps incorporate inverter technology to
bring about energy saving by switching
at high frequencies. However, a
considerable amount of electromagnetic
interference is generated by fluorescent
lamps. Techniques to suppress the
electromagnetic interference are
vital especially in environments with
precision devices such as medical and
aircraft instruments that are sensitive
to the irradiation of electromagnetic
interference and where the operation
of the device could be influenced by the
interference.
CISPR 15 is the international standard
specifying the limits and methods of
measurement of radio disturbance
characteristics of electrical lighting and
similar equipment.
AA.5 Lumen maintenance
After 2000 h operation, the luminous flux
of the lamp shall be not less than 80%
of the initial value.
The luminous flux of fluorescent lamps
decreases rapidly during the first 2000
hours of operation. After this period
the light output of the lamp stabilises
and the decrease occurs at a slow rate.
In the case of bad quality lamps with
an incorrect gas mixture, the reduction
in luminous flux is more than the
maximum of 20% allowed. Although
the initial luminous flux could have
been acceptable, the result of this is
the lamp operates for the greater part
of its life at low efficiency.
AA.6 Life
Each lamp shall have a life of at least
2000 h, and after 6000 h operation at
June 2008 - Vector - Page 25
The sample size of the lamps tested
for life shall be at least 10 lamps. The
lamps are operated in the vertical capup position at a 230 V supply and are
switched off for 15 minutes after each
2 h 45 min of operation. They are
operated at an ambient temperature
between 15ºC and 50ºC.
This amendment only covers lamps
with a nominal life of 6000 hours. It
was decided not to include the 3000
hour lamps, because the costs of the
lamps and maintenance versus the
costs involved with incandescent lamps
do not make the CFL choice a feasible
one.
Claims were made by government that
CFLs last 10 x longer. Theoretically
an incandescent lamp’s rated life is
1000 hour which gives us a factor of
6 x. However, we have all experienced
that many CFLs do not outlive the
incandescent lamps by many hours.
Once again, CFLs with short lives do
not support the energy saving drive.
Conclusion
South Africa needs compact
fluorescent lamps complying with not
only compulsory safety standards, but
also with these compulsory minimum
performance standards in support of
the energy saving drive. However,
it is important that the compulsory
requirements must be regulated and
the quality of the CFLs sold in our
country monitored for compliance with
the compulsory standard. Otherwise
the work done to compile and issue
the standard was in vain.
References
[1] NTT Energy and Environmental Systems
Laboratories – http://kankyo.lelab.ecl.ntt.
co.jp/eng/research/energy/emc.html
[2] Howstuffworks Electromagnetic Interference
– http://electronics.howstuffworks.com/
question230.htm
[3] Draft South African National Standard,
SANS 60901, “Single-capped fluorescent
lamps – performance specifications”,
2008.
[4] Draft National amendment 1 to SANS
60901/IEC 60901.
Acknowledgements
Adolf Claasen, - Fellow of IESSA,
Technical Specialist, STANSA
Greg Marcia - Chairman Development
Committee, IESSA, Technical Manager,
Nordland
Contact Elsie Coetzee, NMISA,
Tel 012 841 3047,
emcoetzee@nmisa.org D