This page contains a Flash digital edition of a book.
CLEANROOMS: CABLING


 Cleanroom cables are available with different levels of EMI shielding, below; it is important to specify the right kind of cabling for the environment in which it will be used


wide variety of highly-demanding applications, including Class 1 cleanroom environments,medical grade applications when sterilised and chemical processing, as well as food and beverage wash-down applications. I spoke to David Cairns of


A


Aerco to understand what makes this cable suitable for use in cleanrooms and discovered that it’s all about the jacketing. Instead of using the usual PVC, polyurethane or polyethylene coating, Xtra- Guard 5 uses fluorinated ethylene propylene (FEP), a Dupontmaterial similar to Teflon but which is able to be extruded into forms such as cable jackets. The benefit of thismaterial


is that it is chemically inert. According to Cairns, it is important formaterials used for cleanroomcables to have a number of vital properties: “Theymust be resistant to harsh cleaning agents, as every nowand again the cleanroomitself has to be cleaned. PVC is not suitable as itwill break down and small particlesmay flake off and contaminate the cleanroom.” Similarly, Xtra-Guard 5


cabling contains no materials that canmigrate anywhere else, there is no shedding or outgassing. Also, Alpha-Wire Xtra-Guard 5 doesn’t absorb contaminants in the way PVC does. PVC is hydroscopic and will absorb water and other particles.


WIDE APPLICABILITY I asked Cairns if theXtra-Guard 5 is a Cat 5 data cable or whether there are other applications it can be used for.He toldme it’s available in 16-24 gaugemulti-core or 18-24 gaugemulti-pair, depending on the


34 /// Environmental Engineering /// February 2017


application. It is also available unshielded or with 1.5mmaluminium/polyester shielding for EMC protection. There is also the option to have increased EMI shielding with the Alpha Supra-Shield system, which uses a combination of aluminiumfoil, polyester and copper braid to provide high levels of shielding frominterference and emissions. According to Cairns, there is also an


advantage in terms of cable size which results fromthe use of FEP. Due to its


Clean looms


erco is stocking the Xtra-Guard cable range fromAlphaWire, which includes the top-of-the- range Xtra-Guard 5 cabling that’s designed to be used in a


Jonathan Newell talks to UK company Aerco about its range of specialist cabling designed to be used in FED STD 209E Class 1 cleanrooms


excellent dielectric strength, thematerial enables the cables to bemade typically 20-30 per cent smaller than equivalent conventional cable.


CHANGING ENVIRONMENTS With the greener cleanroomenvironment that now exists with the banning of fluorocarbon cleaning agents, I asked Cairns whether or not the absence of such aggressive chemicals provided a continued need for cabling that is chemically inert. “It’s important in such environments to have materials that aren’t going to chemically change when cleaned using whatever cleaning agent. For example, PVC can be affected even by soap and water.” He went on to say that


there are other environmental factors that are often encountered in cleanrooms which can have a bad effect on polymers. The example he used was UV light, which doesn’t affect FEP.


COLOUR The cores of the Xtra-Guard 5 cable are coloured but have no exposure to the outside world and the colouring eases the task of wiring. The outer jacket is uncoloured and although colours are available, Cairns recommends the use of cable tags to identify cables rather than risking


outgassing of the pigment in harsh environments.


COST There is a premiumto pay for the Xtra- Guard 5 cable when compared to other cables in the same range, something which Cairns says can be avoided in some less stringent applications by knowing what the cable is for and what environment it will be placed in. EE


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60