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

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 locations. 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. Dr y 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. W et 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 performance 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: [...]... 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 investigation Through it we've found yet another advantage to AirES Moisture ingress appears to... 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... 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 . This white paper will focus on issues related to moisture and its effects on UTP Plenum cabling solutions "Electrical Attributes" white paper on this subject). It is worth noting the dielectric constant of water is terrible when com- pared with most insulation