Have candle systems become too complicated?

Have candle systems become too complicated?
Increasing demands on candle performance using todays raw
materials – a wick perspective with solutions and possibilities
Presented at the 3rd World Candle Congress, 2010
Contents
1. Definition of candle system
2. Parameters influencing burning performance
- Materials
- Manufacturing
- Ambient conditions
3. Increasing demands on burning performance
4. Possibilities and limits
5. Summary and conclusion
„Everything should be
made as simple as
possible, but not
simpler.“
Albert Einstein, 1879 - 1955
Definition of candle system
272 years ago
Translation from the Leipzig Universal
Encyclopeadia of 1738:
„ a wick of thread coated with tallow or
wax, which when ignited gives forth a
bright glow to illuminate a dark place.“
Definition of candle system
2 years ago
(CEN) Specification for fire safety european standard EN 15439 [Para. 3.4]
„one or more combustible wicks supported
by a material that constitutes a fuel, which is
solid, semisolid or quasi-rigid at room
temperature (20°C to 27°C)... It can also
contain additives which are used for colour,
odour, stability, or to modify the burning
characteristics; the combined function of
which is to sustain a light-producing flame.
Definition of candle system
candle components
A candle is a system comprising
-
Various materials
Various geometric shapes and structures
= complex interaction of chemical properties and physical laws.
Definition of candle system
candle components
Base materials
• Paraffin wax
• Microcrystalline wax
• Bees wax
• Fatty acids
• Edible fats
Effect materials
• Lacquers
• Colours
• Decorative items
• Fragrances
Additives
• Polymers
• Antioxidants
• UV absorbers
• Self extinguishing agents
• Adhesives
Wicks
• Flat wicks
• Round wicks
• Special wicks
Definition of candle system
classification of candle types
Candles/Lights
burning outdoors
fuel in containers
burning indoors
fuel freestanding
fuel in containers
fuel freestanding
grave lights
container candles
cylindrical candles
other lights
votives
floating candles
tea lights
non cyl. candles
Definition of candle system
the main aim
Trainee
Houston – this
candle is burning
upside-down – beep.
Definition of candle system
the wick as performance indicator
Smoking
Dripping
Carbon deposits
Afterglow
Ash
Flame too small
Parameters influencing burning performance
variables
Materials
Manufacturing
Burning conditions
Parameters... materials
particular influences
Which material properties influence burning and therefore also wick selection?
• Composition – e.g. acid value indicates level of aggressivity towards cotton in
in the wick – wick chemical treatment.
• Viscosity -
flame size – wick size.
• Ash content - ash formation (anorganic substances present)
can sometimes be limited by using special wicks.
• Hardness -
can influence wick curvature - wick size/type.
• Flashpoint -
safety aspect – wick size.
Parameters... materials
acid value
Wicks chemically treated for materials in question
Paraffin candle
with wick
treated for
stearic acid.
Stearic acid
candle. Wick
treated for
paraffin wax.
Parameters... materials
acid value
Wicks chemically treated for materials in question
Stearic acid
candle. Wick
treated for
stearic acid.

Paraffin
candle with
wick treated
for paraffin

Parameters... materials
viscosity
Paraffin, stearic acid and palm fat - viscosity and temperature
45,000
Viscosity in "cst"
40,000
39,903
35,000
palm fat
30,000
27,403
25,000
20,000
20,748
stearic acid
15,000
15,623
15,84
12,446
11,859
10,025
9,251
10,000
paraffin
5,000
7,381
6,51
5,315
8,248
6,002
4,425
4,962
3,745
3,206
0,000
40,00
50,00
60,00
70,00
80,00
Temperature in "°C"
90,00
100,00
Parameters... materials
acid value + viscosity
Paraffin dinner candle, diameter 22mm
Standard wick Flatwick 3x10 SU
• „3x10“ = 30 threads
• „SU“ = chemical treatment for paraffin wax candles
Stearic acid dinner candle, diameter 22mm
Standard wick Flatwick 3x14 STP
• „3x14“ = 42 threads
• „STP“ = chemical treatment for stearic acid candles
Parameters... materials
acid value + viscosity
All wick examples with treatment for paraffin
Stearic
Fat / stearic
Paraffin
Parameters... materials
wick selection ???
100 % Paraffin
100 %
stearic
100%
Paraffin
100 % Palm
100%
Palm
SU?
STP?
100%
Stearic
STP? SU?
100%
Paraffin
100 % Paraffin
Various material combinations
Parameters... materials
others
Hardness
Ash content
Flashpoint
Parameters... materials
wicks
The dark ages
Flat!!!
Flat wicks
mainly for candles
smaller than  25mm
Round!!!
Round (US–square) wicks
mainly for candles
larger than  25mm
Parameters... materials
wicks
More recent developments
Flat wicks
Round wicks
R- wicks
Special wicks
1980
60 basic wicks
3 chemical treatments
2009
365 basic wicks
12 chemical treatments
Parameters influencing burning performance
variables
Materials
Manufacturing
Burning conditions
Parameters... manufacturing
wick positioning
Wick stance - the wick must be centered and kept straight during and after
wax pouring – see diag. A. Otherwise B, C, D and E can occur.
Direction of natural curve
A
B
D
E
C
Example
Parameters... manufacturing
wick positioning
If the wick tension in a
press is too slack, the
wick ends up like this.
Parameters... manufacturing
wick positioning
Parameters... manufacturing
wick positioning
Twisted wicks and over-stretched
wicks
Parameters influencing burning performance
variables
Materials
Manufacturing
Burning conditions
Parameters... burning conditions
overview
Temperature, air movement, humidity, surface, burn cycles
Parameters... burning conditions
temperature
Ambient conditions
Flame height measured = 380mm
Parameters... burning conditions
surface
1. Tested on upturned glasses
Average burn time = 4 hours 36 mins
Average weight of residual material
including tealight cup = 1,72g
2. Tested on glass sheet on metal
Average burn time = 3 hours 47 mins
Average weight of residual material
including tealight cup = 2,84g
3. Tested on raised glass sheet
Average burn time = 4 hours 33 mins
Average weight of residual material
including tealight cup = 1,45g
WEDO test method
All tested „on glass“
Parameters... burning conditions
burn cycles
Candle burned
continuously
for 10 hours
Candle burned
for 2 x 2 hour
cycles
Candle burned
for 4 x 5 hour
cycles
Increasing demands on burning performance
the past
- Flame shouldn‘t smoke
- Candle shouldn‘t drip
- Flame had to be bright enough
Increasing demands on burning performance
todays regulations and recommendations
Bodies/authorities
Motivation
• National standards (e.g)
- ASTM
- CEN
• Safety
• Health
• Environmental considerations
• Quality
• Marketing
• Quality „seal“ (e.g)
- RAL
- Swan label
• Retailers (e.g)
- Retailers own regulations
- Use of testing houses
Increasing demands on burning performance
todays regulations and recommendations
- Candle must not drip (continuous burn)
- Candle must not drip (burn cycles)
- Burn time exactly X hours
- Uniform flame height & stability
- Maximum / minimum flame height
- Amount of material residue
- Afterglow period
- Wick position
- Carbon deposit (size)
- Temperature of container
- Sooting index
- etc. etc.
Possibilities and limits
burn tests with good candle systems
"There is not a law under which
any part of this universe is
governed which does not come
into play and is touched upon in
these phenomena. There is no
better, there is no more open
door by which you can enter into
the study of natural philosophy
than by considering the physical
phenomena of a candle."
Michael Faraday, 1791 - 1867
Possibilities and limits
burn tests with good candle systems
The big question
How well and consistently can a good candle
system actually burn?
Possibilities and limits
burn tests with good candle systems
digital video
size and shape of
the flame
computer controlled
scales
hourly fuel flow
drip loss
digital thermometer
temperature
Possibilities and limits
burn tests with good candle systems
wire mesh cylinder &
detection index
soot index
Burn tests with good candle systems
- flame heights
How constant does flame height remain during burning?
How constant is the fuel flow during the burn cycle ?
How constant is the temperature of the liquid in the bowl?
0:00:01:53
15,30mm
0:00:15:26
17,70mm
0:00:52:35
17,90mm
0:01:41:03
17,20mm
0:02:29:03
15,70mm
0:03:58:19
14,40mm
Burn tests with good candle systems
- flame heights
Critical relighting phase
Stearic acid
No glow point at
wick tip.
Wick does not trim
immediately
Glow point appears
at wick tip.
Wick trims
Paraffin
Glow point appears
immediately at wick
tip.
Wick trims
Glow point
disappears as wick
becomes saturated.
(Once saturation
phase has passed,
wick continues to
burn with glow point)
Burn tests with good candle systems
Results of burn tests carried out on a number of different types of
candle will be inserted here. As the testing schedule will continue
beyond the deadline for inclusion in the printed handout, results
presented at the conference will be available in printed form
seperately.
Burn tests with good candle systems
- changing candle parameters
Three variables – only two can be changed at a time.
Flame height
Weight
Burn time
Weight
+
Flame height =
Burn time
+
Weight
=
Flame height
Burn time
=
Weight (necessary)
Flame height +
Burn time
Conclusion
This presentation has left us with a number of questions:
• What are the correct requirements and parameters?
• How can we measure these?
• Which requirements are sensible and useful to consumer and environment?
• How can we differentiate between important and not so important
requirements?
To find the answers, the following is necessary:
• Candle manufacturers, their suppliers and customers will have to work
closely together.
• Parameters and quality indicators relevant to candles must be defined.
• It may be necessary to develop new testing methods and procedures.
•This is a technical task best coordinated by the candle associations.