Information

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ELECTRICAL SOLUTIONS
B1.99
B2.
Cable
Accessories
C1.
Wiring
Duct
C3.
Abrasion
Protection
C4.
Cable
Management
D1.
Terminals
D2.
Power
Connectors
E1.
Labeling
Systems
E2.
Labels
E3.
Pre-Printed
& Write-On
Markers
F.
Index
B3.
Stainless
Steel Ties
C2.
Surface
Raceway
E5.
Lockout/
Tagout
& Safety
Solutions
B1.
Cable Ties
A.
System
Overview
D3.
Grounding
Connectors
E4.
Permanent
Identification
Over a period of time, ultraviolet light (a component of sunlight) attacks most plastic materials and reduces their
properties by breaking the molecular chain. The material breakdown is accompanied by reductions in tensile
strength and elongation, increased brittleness, color changes and loss of surface gloss.
Carbon black, which is used in Panduit nylon, polypropylene, and acetal cable ties, is one of the most effective
stabilizers known today. A uniform dispersion of carbon black provides good ultraviolet light resistance without
adversely affecting physical properties. The addition of carbon black, or any other ultraviolet light stabilizer,
prolongs the useful outdoor life of plastic products, but it does not totally eliminate the destructive effects of the
light. Some plastics, such as TEFZEL
■
or HALAR
▲
, are intrinsically very resistant to ultraviolet light
and do not require stabilizing additives.
Weathering Test Methods
In order to monitor the effects of ultraviolet light and the effectiveness of ultraviolet stabilizers, Panduit,
in conformance with industry standards, adopted two methods of weatherability testing: Outdoor Aging and
Accelerated Weather Aging.
Outdoor Aging
The Outdoor Aging method is probably the best and most realistic method of the two. It is conducted in
accordance with ASTM D 1435 Standard Practice for Outdoor Weathering of Plastics, and allows the
material to be affected by not only ultraviolet light, but by all other outdoor elements as well. Although this may
more closely approximate an actual application, two drawbacks do exist. The period of time required to
produce property decay and material failure may be quite long, and varying adverse chemical environments
cannot be tested.
Accelerated Weather Aging
Accelerated weathering tests are conducted to estimate the rate of degradation due to a combination of
ultraviolet light, temperature, and moisture. The methods used are in accordance with the following standards:
• ASTM D 1499, Operating Light and Water Exposure Apparatus (Carbon-Arc type) for exposure to plastics
• ASTM G 154-04, Operating Light and Water Exposure (Fluorescent UV Condensation type) for exposure
of non-metallic materials
The condition specified in ASTM D 1499 utilizes a water spray and a carbon arc to simulate natural sunshine.
The test chamber is operated 20 hrs./day with a two-hour cycle of 108 minutes of simulated sunshine and twelve
minutes of sunshine and water spray. The temperature of a black body inside the chamber is approximately
63°C (145°F) during the “sunshine only” portion of the cycle. Humidity is not controlled inside the chamber.
The test chamber per ASTM G 154-04 uses fluorescent sun lamps to generate ultraviolet light only. A heated
water pan produces condensation during a portion of the cycle. The daily cycle is composed of 20 hours of light
followed by 4 hours of condensation. Black body temperatures during the light cycle are 50°C (122°F) and
40°C (104°F) during the condensation cycle.
Panduit has also designed a special chamber, which is used to simulate the effect of acid rain and ultraviolet
light on cable tie materials. The effects of other common chemicals, such as road salt, are also evaluated
in this chamber.
These methods are effective in quickly determining the ultraviolet light resistance of the various cable tie
materials, but it must be emphasized that there are no exact correlations between accelerated aging and
actual outdoor exposure.
■
TEFZEL is a registered trademark of E.I. du Pont de Nemours and Company.
▲
HALAR is a registered trademark of Ausimont USA, Inc.
Weathering