Tài liệu KRONE - White paper - TrueNET - Moisture Ingress - 2003 docx

To put this issue to the test, we submerged a sample of AirES cable in a water solution with a dye tracer.. For the test we needed a control sample as well and used a competitors cable w

This white paper will focus on issues

related to moisture and its effects on

UTP Plenum cabling solutions For the

purpose of argument we will be looking

beyond standards and testing for issues

that, quite frankly, should never happen

under normal circumstances However,

as many of us who have been in the

industry for a number of years realize,

sometimes the unlikely becomes reality!

The industry bodies have this to say about wet and

dry locations:

BICSI TDM manual, 9th edition, Chapter 4 –

Horizontal Distribution Systems, Section 1 –

Horizontal Pathway Systems, final paragraph of page

4-5, which states:

Wet Locations

Intrabuilding horizontal pathways shall be installed

in "dry" locations that protect cables from

mois-ture levels that are beyond the intended operating

range of "inside" premises cables For example,

slab-on-grade construction where pathways are

installed underground or in concrete slabs that are

in direct contact with soil (e.g., sand, gravel, etc.)

are considered to be "wet locations." In the

United States, see the NEC, Article 100, for

defini-tions of damp, dry and wet locadefini-tions.

NEC Article 100 – Definitions

Locations:

Damp locations: Partially protected locations under canopies, marquees, roofed open porches, and like locations, and interior locations subject to moderate degrees of moisture, such as some basements, some barns, and some cold-storage warehouses.

Dry Locations: A location not normally subject to dampness or wetness A location classified as dry may be temporarily subject to dampness or wetness,

as in the case of a building under construction Wet Locations: Installations underground or in concrete slabs or masonry in direct contact with the earth or other liquids, such as vehicle washing areas, and locations exposed to weather and unprotected.

The above being said, let's have some fun.

The AirES cabling innovation incorporates air pockets around the primary conductor They run the entire length of the cable (a bit like rifling) These air pock-ets allow AirES to achieve unparalleled electrical per-formance to overall size This perper-formance is achieved through mixing the dielectric constant of Air and FEP together to make an overall dielectric constant better than that of FEP alone (for more information please see our "Electrical Attributes" white paper on this subject) It is worth noting the dielectric constant of water is terrible when com-pared with most insulation materials Additionally, as many people know, mixing amperage with water is never a good idea For this reason BICSI and the NEC have mandated that UTP cabling be placed in

"dry" locations

The Effect of Moisture Ingress

on AirES™

Cable

However we have decided to test how AirES would perform in a "wet" environment Because of Krone's ingen-ious use of air pockets to improve electrical performance, a query has arisen with regards to moisture traveling down the air channels themselves

To put this issue to the test, we submerged a sample of AirES cable in a water solution with a dye tracer For the test we needed a control sample as well and used a competitors cable with solid FEP insulation over the copper conductor As in the image below, both cables were cut to the same length The same amount of solution (5ml) was used for each

We then placed both samples (Green AirES and White Competitor) into the solution for a period of 2 hours It's worth noting that the fluid level in the AirES graduated cylinder with the cable sample was at 5.95ml The com-petitor sample fluid level was at 6.1ml This can be attributed to reduced displacement of fluid with AirES, because of the smaller OD/cross sectional area of the cable

After soaking in the solution for 2 hours the cables were removed and the fluid levels were measured to deter-mine how much had soaked into each cable

The competitor sample soaked in 0.15ml of fluid AirES soaked in 0.05ml of fluid

The reason for the fluid absorption difference was obvious once both samples were cut open In order to achieve Cat 6 performance a "star" filler has been used on the competitor cable to separate the pairs (which makes the cable larger) This allows for more "free space" within the cable Therefore, more fluid to be absorbed The AirES cable, by introducing air between the copper conductor and the insulation, has less need for pair separation This allows for the smaller cable size and less absorption

The conductors were then inspected to see how much of the solution was absorbed by the conductors themselves.

Above are all 4 pairs of the competitor sample It would be fair to say that none of the solution absorbed was attributed to the conductors themselves No penetration was evident

Even though the amount of fluid absorbed by the airES cable was less, fluid did penetrate the air pockets within the insulation due to capillary action It flowed up to the level of the fluid within the cylinder

This is most evident in the orange and green pairs, white conductor, with a color change to blue where the dye has penetrated

Although a fascinating result, it is actually quite meaningless in a real life installation This did, however, prove that the air pockets do exist

We then tested the cable as it is installed e.g with a jack attached A little bit of history about KRONE connectivity first One of our claims has been the 45° IDC With the use of this technology KRONE has been able to achieve

a gas tight seal around the contact and in doing so sealed the cabling conductor to that contact

In the example above, ribs (arrow 1) on either side of the connection point squeeze (hold) the insulation to take any disturbance through movement of the cable away from the contact itself These ribs also help to seal the insulation around the conductor The IDC, or Insulation Displacement Contact, does just that It displaces the FEP insulation around the connection point, which completely seals the junction from gas and/or water ingress

To simulate what might happen if a KRONE jack with AirES cable were to be subjected to direct contact with water we submerged a terminated jack into the same water/dye tracer liquid as the first test In this test we let the cable soak for 14 hours This was 7 times longer than the first test

The results were astounding We rinsed the excess dye tracer off of the jack after removal from the liquid (as in the first test conductors) As you can see below, the label to the jack wiring scheme was completely tinted blue

from soaking None of the tracer was evident on any of the pairs The 45° IDC contacts had completely

stopped any penetration whatsoever

For the next part of our investigation we subjected AirES cable to a harsh humid environment and measured the effects To understand the effects, we used an industry standard construction Cat 6 cable with a star filler as a control

For the purpose of extreme conditions 70°C (158°F) at 95% rH were selected as the temperature and humidity The cables were placed into the environmental chamber for a period of 5 days Testing was conducted before the samples were placed in the chamber and one-hour after completion The results were then compared to show any effect the moist heat may have had on the electrical integrity

Results for AirES Category 6 cable to TIA/EIA 568B.2.1:

Although Attenuation, NEXT and Return Loss were effected slightly by the moist environment, the AirES cable tested passed Category 6 requirements

The control sample was then tested in the same manner as the AirES sample.

The results were very surprising As in our original

moisture ingress testing, using tracer dye, the control

sample seems to have "taken up" more moisture

during the humidity testing Both the Attenuation

and NEXT differences looked similar to that of AirES

The Return Loss, however, suffered greatly

We thank our competitor for sparking this

investiga-tion Through it we've found yet another advantage

to AirES Moisture ingress appears to be less through

hot humid environments, due to the reduced "free

air" space inside the cabling jacket This is evidenced

in the Return Loss results before and after humidity

testing on "Industry Standard" star filler design

Category 6 cable and that of cable integrating AirES

technology

Even though these were interesting experiments, it is important the user does NOT use this information as

a reason to install cabling in a wet or moist environ-ment! In short, water and networking don't mix With that said, it is worth noting the KRONE cabling solutions will attract less moisture, due to a reduced cabling size The connectors will block any moisture ingress on the conductors at the cable end

Please remember, we do not recommend running your computer while swimming, bathing or taking a shower If you must, please use wireless

KRONE™ Confidential Publication, not for reproduction without expressed written consent

Author: Tim Takala - Director, Support Technologies KRONE Inc