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TECHNICAL
INFORMATION
250
Plastics
A plastic is a material that can be formed and shaped into finished
articles using heat (thermoformed). It has a molecular structure that
consists of very long chains of polymers formed by the interaction of
many molecules (monomers) or molecular pairs.
A distinction is made between thermoplastics and thermosettings.
Thermoplastics
Made by injection of the molten plastic into a cool mold.
Parts formed from thermoplastics can be repeatedly softened by an
increase of temperature. Most thermoplastics are soluble in a suitable
organic solvent.
Thermosettings
Made by forming the plastic objects in a hot mold.
Once formed, it becomes substantially infusible and also insoluble
because of the crosslinked molecular structure.
Thus products from materials made using thermosettings do not melt
upon heating and are practically insoluble to most commercial
solvents.
Some softening under the effect of commercial solvents is however
possible.
Advantages of Non-Metallic
Double insulation ensures perfect safety against direct and indirect
contact.
Enclosure does not need to be grounded.
Unlike metals, plastics are non-corrosive.
The enclosures are homogenous, thus they do not require any
maintenance even when scratched, as only more of the same
material will be exposed.
Due to their light weight, non-metallic enclosures can be very easily
handled and installed.
Special features
Polyester
A thermoset derived from unsaturated polyester resins reinforced with
glass fibers. Readily worked with common tools such as drills,
punches and saws. Polyester enclosures are ideally suited for outdoor
installations and use in hot, humid and/or chemically aggressive
environments.
Polycarbonate
A bisphelon A based thermoplastic. It meets the highest mechanical
requirements. Its resistance to most chemical vapors is good and it is
used in a corrosive environment. Outdoor exposure may cause
yellowing.
Technical data of plastics
Properties Standards
Mechanical
Impact strength ISO 179
Notched impact strength ISO 179
Flexural strength ISO 178
Tensile strength ISO 3268
Electrical
Tracking resistance IEC 112
Surface resistivity IEC 93
Special resistivity IEC 93
Dielectric strength IEC 243
Physical
Deflection temperature ISO 75/A
Vicat softening point ISO 306/B50
Temperature resistance continuous
Color fastness ISO R879
Tropicalization and resistance to mold IEC 68-2-3
and fungus growth
Water absorption ISO 62/1 96h
Density ISO R1183
Flame resistance
Limit oxygen index ISO 4589
Flammability UL 94 (3mm)
Hot wire resistance IEC 695-2-1
Toxicity of fumes ISO 4615
Chemical resistance
a. Resistance to splashes and vapors
Acids 10% (any concentration
Bases 10% that is not harmful to
Salts mankind)
Organic solvents
Oils and fats
Combustibles
b. Longlasting contact (not harmful to people)
Acids 10%
Bases 10%
Mineral oils and combustibles
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Unit FRP Polycarbonate Polycarbonate PPO PA6 PVC
glassfiber reinforced (2.5% humidity)
kJ/m
2
55 no rupture 50 40 40 25
kJ/m
2
55 30-50 15 15 25 20
MPa 150 no rupture 160-170 no rupture no rupture no rupture
MPa 50-60 65-70 100 37 60 65
V/50dr KC600 KC200 KC175 KC175 KC600 KC600
Comparative fig. 12 15 15 >12 12 15
cm 10
12
10
16
10
16
10
14
10
12
10
13
kV/mm 18 35 39 16 34 30
°C >250 135 145 95 60 50
°C - 145-150 160-165 109 210-220 70
°C -50 to +150 -50 to +130 -50 to +130 -50 to +100 -40 to +100 -20 to +60
Blue wool scale 7-8 4 4 4 8 4
- no degradation no degradation no degradation no degradation no degradation no degradation
mg 45 10 10 7 320 5
kg/dm
3
1.75 1.2 1.33 1.1 1.14 1.38 to 1.40
% 0
2
26 24.3 34.4 27.5 23 43 to 47
94HB 94 V2 94 V1 94 V1 94 V2 94 V0
°C 960 850 960 960 650 960
% CI halogen-free halogen-free halogen-free halogen-free halogen-free halogens
good resistance good resistance (1) good resistance (1) good resistance (1)
fair resistance good resistance
good resistance good resistance
good resistance good resistance
good resistance fair resistance
good resistance good resistance
good resistance good resistance
limited fair resistance fair resistance fair resistance excellent chemical good resistance
not recommended no degradation no degradation fair resistance resistance except to good resistance
resist fair resistance fair resistance fair resistance effect of acids and good resistance
phenols
(1) except to organic and aromatic hydrocarbons
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TECHNICAL
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Chemical resistance for hot
compression-molded
fiberglass reinforced
polyester (FRP) enclosures
SALTS
Ammonium sulfate +
Potassium ammonia sulfate +
Ammonium bichromate 20% 0
Ammonium carbonate 10% 0
Ammonium chloride +
Ammonium nitrate 0
Ammonium sulfate 10% +
Ammonium acetate Aniline sulfate +
Carbonate of barium Chloride of barium +
Calcium chloride, saturated sol. +
Calcium hypochlorite 0
Calcium sulfate +
Copper (II) chloride +
Copper (III) sulfate +
Iron (III) chloride +
Iron (III) nitrate +
Iron (III) sulfate +
Iron (II) chloride +
Iron (II) sulfate +
Magnesium chloride +
Magnesium sulfate +
Mercuric (II) chloride +
Nickel chloride +
Nickel nitrate +
Nickel sulfate +
Potassium carbonate 0
Potassium chloride +
Potassium nitrate +
Potassium sulfate +
Nitrate of silver +
Sodium acetate +
Sodium bicarbonate 10% +
Sodium carbonate 10% 0
Sodium chloride +
Sodium hypochlorite 5% 0
Sodium nitrate +
Zinc chloride +
Sulfate of zinc +
OTHER AGENTS AND MEDIA
Ethylene glycol solution of 0 to 100% +
Glycerine +
Chlordioxide (bleaching agent) Saturated chlorinated water +
Formaldehyde 10 to 40% +
Hydrogen peroxide 5 to 10% +
Normal water +
Distilled water +
Sea-water +
Phenol 0
List of conventional symbols
+ = resistant
0 = resistance limited
- = non resistant
ACIDS
Acetic acid +
Benzoic acid +
Boric acid +
Chromic acid 30% Citric acid +
Formic acid 25% 0
Hydrochloric acid 10% +
Conc. hydrochloric acid 0
Lactic acid 1% +
Nitric acid 5% 0
Nitric acid 50% Concentrated nitric acid Phosphoric acid 25% 0
Phosphoric acid 50% Sulfuric acid 25% +
Sulfuric acid 50% Tartaric acid +
Oxalic acid, saturated solution +
BASES
Ammonia 5% 0
Ammonia 25% 0
Barium hydroxide 10% Calcium hydroxide Hydroxide of sodium 5% 0
Hydroxide of sodium 20% -
OILS AND GREASES
Fatty acids +
Oleic acid +
Stearic acid +
Lubricating oil +
ORGANIC SOLVENTS
Acetone Amyl alcohol 0
Methanol 0
Ethyl alcohol 0
Benzene 0
Butyl acetate Carbon bisulphide Carbon tetrachloride +
Gasoline +
Petroleum +
Naphta +
Perchlorethylene 0
Toluol 0
Ethyl acetate 0
Dichlorethylene 0
Ether 0
Chemical resistance for
polycarbonate covers
ACIDS
Acetic anhydride Acetic acid (low concentration) +
Hydrobromid acid +
Hydrochloric acid 10% +
Concentrated hydrochloric acid +
Chromic acid +
Citric acid +
Hydrofluoric acid 20% +
Phosphoric acid 86% +
Carbonic acid +
Lactic acid 20% +
Oxalic acid +
Nitric acid <10% +
Nitric acid 25% +
Concentrated nitric acid Sulfuric acid <50% +
Sulfuric acid 70% Sulfuric acid 95% -
BASES
Ammonia Sodium hydroxide (strongly diluted) Sodium hydroxide (diluted) Sodium hydroxide (concentrated) -
SALTS
Aluminum chloride +
Ammonium chloride +
Ferric chloride +
Ferrous chloride +
Ferric sulfate +
Ferrous sulfate +
Copper salt +
Solution of sodium carbonate +
Sodium phosphate +
Sodium hypo-chlorite 0.5% +
Sodium nitrate +
Sodium sulfide Calcium chloride +
ORGANIC SOLVENTS
Acetone Alcohols +
Aliphatic hydrocarbons Amyl acetate Aromatic solvents Carbon disulfide Carbon tetrachloride Trichlorethylene -
OILS AND GREASES
Minerals oils +
Vegetable oils +
Fatty acids >C6 +
OTHER CHEMICALS
Aniline Phenol Formaldehyde 40% +
Sea water +
Hydrogen peroxide 3% +
Chlorine water solution -
ALCOHOLS
Does not resist: methyl alcohol,
benzylalcohol, furfurylalcohol, amylalcohol
Above based on total immersion tests and
are thus extremely conservative.
In most applications, fiberglass reinforced
polyester offers the best all around
performance in corrosive environments. The
only reagent likely to cause severe problems
is hydrofluoric acid. If likely to be
encountered, refer anticipated concentration
to Vynckier Enclosure Systems.
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Chemical Resistance for PPO
(polyphenylene oxyde)
Temperature
(°C)
Ethanol 20 +
Benzol 20 Soldium chloride 80 +
Acetic acid 10% 80 +
Dichlorethylene 20 Ammonia 80 +
Sodium hydroxyde 80 +
Oleic acid 20 +
Hydrochloric acid 10% 80 +
Hydrochloric acid 37% 20 +
80 Sulfuric acid 10% 80 +
Toluol 20 -
Resistance To Weathering
Regardless of the product range or
the manufacturer, it is known that hot
compression-molded FRP is subject to
erosion when used. Due to the
combined action of rain, wind and UV
rays the polyester matrix is only
superficially eroded and glass fibers
become apparent, the depth of the
erosion is only 7 µm.
This slight erosion is unavoidable
unless a surface coating (eg. varnish) is
applied (which brings with it additional
problems such as adhesion). It is
important to note that any erosion is
very superficial and has no effect on the
physical characteristics of polyester
(electrical, mechanical or chemical).
Vynckier fiberglass enclosures have
been successfully used outdoors since
1958 and tests on field samples support
laboratory results.
Painting of Fiberglass Enclosures
Because of the presence of mold
release agents, painting of hot molded
fiberglass generally requires surface
preparation prior to painting.
To ensure a good bond, the following
points are important:
- adequate surface cleaning or
preparation
- use of an appropriate primer. This
is recommended, but satisfactory
results can be obtained without it.
The surface preparation can be one
of several ways:
- roughening of the surface with an
abrasive such as pumice or waterproof
carborundum paper. This ensures good
adhesion but the operation can be time
consuming.
- degreasing the surface with an
organic solvent such as trichlorethylene.
This by itself, however, is not the
preferred method as attention is
required to prevent the evaporating
solvent from leaving mold release
residue which could interfere with a
good bond.
- degreasing and cleaning with
alcohol. This normally gives satisfactory
results.
- degreasing with a water solution of
alkaline or caustic salts such as sodium
carbonate or trisodium phosphate. The
solution can also contain a detergent or
other domestic cleaning products.
- industrial solvents: aromatic
hydrocarbon eg. benzene, toluene,
xylene, butyl acetate, glycol acetate
EMI-RFI Protection
Foreward
Electromagnetic pulses (EMPS) may
adversely affect electronic and other
control systems. These disturbances
may be such that they cause erratic
operation, component failure or a
reduction in component life. This
electromagnetic energy, called EMI, has
become an added pollutant in the radio
spectrum.
Vynckier can provide EMI-RFI shielded
enclosures which give effective
protection against electromagnetic and
radio frequency interference, hence the
designation EMI-RFI.
Application
The EMI-RFI enclosures have been
especially designed to overcome the
problems frequently arising from power
supplies featuring non-sinusoidal input
current waveforms, such as those
produced by energising and
deenergising transformers and
regulators, the on and off switching of
digital electronic controls, etc.
The EMI-RFI enclosure is made of
insulating molding material, suitable for
installation outdoors or indoors, that
serves a double duty:
— it attenuates the radiation of
enclosed EMI generating
appliances from getting OUT
and
— it guards sensitive equipment
from breakdowns and
destruction due to EMI
radiation getting IN.
Specification:
Vynckier procedures for coating are
providing an attenuation level of 60 to
65 db at 2 mils of thickness per ASTM
ES 7-83.
The gasket is a continuously extruded
silicone elastomer fill with silver-plated
inert particles.
After cleaning the product must be
carefully rinsed and dried.
Once the surface has been prepared,
an appropriate primer and top coat,
based on polyurethane or epoxy, should
give satisfactory results. Recommendations for use of a specific paint should
be obtained by reference to the paint
manufacturer.
Attention should be taken to ensure
appropriate ventilation is utilized and
manufacturers recommendations are
followed to prevent any toxic effects of
any chemicals used in this process.
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Hazardous Gases or Vapors
The chart below shows the differences in the way specific gases or
vapors are designated.
These global products consist of flameproof components with increased
safety terminals which are enclosed in non-metallic housings.
1) IEC Term NEC Term IEC Symbol IEC Suitability
Flameproof Explosion-proof “d” Zone 1, 2
Description: Sources of ignition are contained within enclosures which
can contain an internal explosion without igniting the surrounding
atmosphere.
2) IEC Term NEC Term IEC Symbol IEC Suitability
Increased NA “e” Zone 1,2
Safety
Description: Additional measures are taken to prevent excessive heat,
arcs, or sparks from occurring in equipment where this does not
normally occur, i.e., terminals.
Classification of Maximum Surface Temperatures
The IEC has a system of “T” codes which are used to designate the
maximum operating temperatures on the surface of the hazardous
location equipment.
Maximum Degrees °C IEC/NEC “T” Code
450 T1
300 T2
200 T3
135 T4
100 T5
85 T6
Product Marking
In addition to traditional NEC product markings for NEC hazardous
location suitability, these products also carry CENELEC markings. A
breakdown of the symbols is shown below.
NEMA Ratings/IP Codes
NEMA ratings are standards which define the hazardous or hostile
environments which may face a particular electrical installation. Under
IEC publication 529, the degree of protection required for a given
enclosure is defined as IP (Ingress Protection) codes. IP codes are two
digit numerals which can be derived from the following chart.
Ingress Protection (IP) Codes
First Numeral Protection against Symbol description
Solid Bodies
0 No protection
1 Objects greater than 2.0"
2 Objects than .47"
3 Objects greater than .10"
4 Objects greater than .04"
5 Dust protected
6 Dust tight
Second Numeral Protection against Symbol description
liquid
0 No protection
1 Vertically dripping water
2 75° to 90° angled dripping
water
3 Sprayed water
4 Splashed water
5 Waterjets (Hose)
6 Heavy seas
7 Effects of immersion
8 Indefinite immersion
Example: IP65
Hazardous areas under CENELEC European Norms
Zone 0 = Zone in which an explosive gas/air mixture is continuously
present or present for long periods.
Zone 1 = Zone in which an explosive gas/air mixture is likely to occur in
normal operation.
Zone 2 = Zone in which an explosive gas/air mixture is not likely to occur
in normal operation and if does, will only last for a short period.
EXPLANATION OF CERTIFICATE SYMBOLS
The following tables can be used as practical quick guides.
The different EX protection types specified are:
Protection type Symbol Test Standard
Increased safety e EN 50019
Non-sparking n
Flameproof d EN 50018
Intrinsically safe i EN 50020
Special protection s
Encapsulation m EN 50028
Oil immersion o EN 50015
Pressurisation p EN 50016
Sand or powder filled q EN 50017
Explosive Explosive
Gas Group (NEC) Group (IEC) Comment
Acetylene A Acetylene is IIC
Hydrogen B Hydrogen is IIC
Ethylene C Ethylene is IIB
Propane D Propane is IIA
IIC
IIB
IIA
EEx de IIC T6
Designates being built to European
standard.
Apparatus type-flameproof components
“d” with increased safety “e” terminals.
Gas Group.
Temperature code.
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