Standards support proper design and installation
Electrical contractors have been cabling or wiring the industrial environment for years. Today, careful and professional connection is imperative because information on the factory floor collected by those networks can be input to the office network system for information reporting. The industrial cabling standard being developed by the Telecommunications Industry Association (TIA) is meant to give support for a proper design and installation that enables expected network performance. The standard, TIA-1005 for Industrial Cabling, could be ready in late 2007.
TIA-1005 says it “specifies minimum requirements for the telecommunications infrastructure, including pathways and spaces within and between industrial buildings and structures ... , specifies cabling requirements, cabling distances, telecommunications outlet/connector configurations, and topologies ... cabling specified by this standard is intended to support a wide range of different sites and applications (e.g., voice, data, text, video, industrial and building controls, security, fire alarm and image) within industrial environments that can include wide ranges of temperature, humidity, electrical noise, shock, vibration, corrosive gases, dust and liquids.”
As usual, the standard also specifies generic telecommunications systems to support multivendor and multiproduct installations. In addition, it provides manufacturers with the information they need to design telecommunications products, such as cables and connectors, for the industrial premises and gives them basis for further product development.
The MICE tables
A new way of looking at the industrial environment started with this standard. The so-called MICE tables describe the environmental classifications within the industrial premises, and the parameters for each kind (level) of environment. There are four primary elements used to classify an environment:
- M: mechanical characteristics
- I: ingress protection
- C: climatic/chemical
- E: electromagnetic
The MICE environment levels are the following: M-1 for mechanical specs for a commercial-type environment, M-2 for the mechanical specs for a light industrial environment and M-3 for the mechanical specs for a heavy industrial environment.
When buying components in the future, this kind of knowledge about your own working environment will make it easier to describe what you want.
The reason the industrial environment was broken down in the MICE tables was because those environmental conditions in industrial premises could be further described by the levels of harshness and types of conditions. The conditions affecting the environments were mechanical shock and vibration, dust and liquid ingress, temperature and humidity levels, chemicals and levels of EMI.
Again, the classification is a three-level classification where MICE-1 is equivalent to a commercial premises, MICE-2 to a light industrial premises, and MICE-3 to a heavy industrial premises.
There are three basic industrial areas within the industrial premises: the factory floor, the automation/work area and the automation island. The MICE classifications describe the possible environmental conditions within these industrial areas. Above is an illustration of the industrial/factory floor areas that are defined by environmental classifications with examples of basic MICE classifications.
MICE tables do two things. First, they help designers and planners specify and purchase components or protection methods (mitigation or isolation). Second, they provide information for the user to apply an environmental classification to the hardware they are buying. In fact, the term MICE is a way of classifying the cabling channel environment.
Each of the four primary environmental elements (M, I, C or E) is divided into specific parameters and levels for those parameters. Each sub-suffix for the four primary environmental criteria is either a 1, 2 or 3. For example, the most benign environment is described as M1 I1 C1 E1 whereas the harshest environment within the scope of this standard would be defined as M3 I3 C3 E3.
To further complicate things, the applicable MICE classification may be different along the length of the cabling channel. The ingress protection characteristics of the environment in the automation/work area and at the automation island are different and more severe than those characteristics on the factory floor or in the telecommunications room. Note: This concept is not a basis for testing the local environment. Neither is it a series of environmental criteria for testing components used within those environments.
Annex C of the future TIA 1005 will contain a tutorial on the MICE table.
Applying MICE information
When you want a component that meets the specs listed in an applicable MICE table, all you have to do is choose what type of environmental condition (i.e., mechanical, ingress, climatic or electromagnetic) is of concern to you, then look up the appropriate table showing the standard’s boundaries for that condition. For example, if your environment has some particularly harsh or significant environmental conditions that would cause you to want a sturdier or better operating component, look for the condition that exists in your area (see illustration on page 200 for an example of MICE environmental conditions).
Example of a ‘mechanical’ concern: Some mechanical concerns include shock/bump, vibration, crush and/or tensile force. If your concern is tensile force, then you would look at the MICE table for mechanical conditions and find the level of protection you want (M1, M2 or M3). If you decide on Level M1 for tensile force, you would see from the table that the parameter was “application specific” across all mechanical classification levels. You would then look to the manufacturer for its recommendation.
Example of an ‘ingress’ concern: If your concern falls under “ingress,” then you would look at the applicable MICE table and find the level of protection (I1, I2 or I3) you would want. If you decide on Level 2 (I2) protection for particulate ingress, you would see from the table that 50 m would be the maximum diameter for a product to meet regarding its ability to protect against ingress of particulates.
Example of a ‘climatic’ concern: Some “climatic” concerns would be ambient temperature, rate of change of temperature, humidity and ozone. If your concern falls under the “climatic” classification, then you would look at the MICE table under climatic and chemicals and find the level of protection (C1, C2 or C3) you would want. If you decide on Level 2 (C2) protection for a rate of change of temperature, you would see from the table that the level of protection needed for a product you would buy would be a rate of change of temperature at 1.0°C per minute.
Example of an ‘electromagnetic’ concern: Some “electromagnetic” concerns would be surges, a magnetic field or radiated radiofrequency. If your concern falls under the “electromagnetic” classification, then you would look at the MICE table under electromagnetic conditions and find the level of protection (E1, E2 or E3) you would want. If you decided on Level 2 (E2) protection for a surge, you would see from the table that the level of protection needed for a product you would buy would be its ability to handle a 1,000V surge.
Beyond the MICE
The standard also covers ways to enhance products to handle some industrial floor environmental conditions. For instance, you can use a cabling system designed with special materials to enable its use in high UV radiation MICE environments, use additional separation in an environment where a relay contactor is found to cause interference to reduce the magnitude of coupling, pressurize the enclosure to produce positive venting, and separate the cabling system inside a pathway to reduce the influence of the high MICE (EMC) zone on the rest of the pathway.
Keep in mind that industrial segment cabling is similar to the familiar term “horizontal” cabling. The main difference is that there is not usually a person inhabiting the industrial work area—that area could be out on the factory floor, or it could be the whole factory floor.
Some of the latest changes made to this standard occurred in February 2007. They include the following:
- The “horizontal” distance would remain 100 meters for copper, with the exception of 300 meters when installing “centralized” cabling.
- Designers would be given leeway when designing with fiber in the horizontal (the automation island area) because they took out the words “automation specific” from the description of the horizontal channel distance so people could do what they want.
- The new pieces of hardware added to the standard were the industrial equipment room and the industrial enclosure.
- Requirements for the industrial enclosure and equipment room would be the same as those related spaces in TIA 569-B.
- Specs for pathway separation for E2 and E3 environments were to be included in the next draft.
However, there is still work to be done on this standard. Remaining work includes the following:
- Decide if the MICE environments actually were to be used to define a cable’s performance.
- Include specs on sealed optical fiber connectors.
- Decide if Power over Ethernet (PoE) could be supported by two-pair cabling.
- Figure out how and whether to describe the horizontal “channel” for both copper and fiber.
- In the connecting hardware section, decide whether a Category 5e or 6 modular jack was necessary for all industrial automation outlets (AOs).
MICHELSON, president of Jackson, Calif.-based Business Communication Services and publisher of the BCS Reports, is an expert in TIA/EIA performance standards. Contact her at www.bcsreports.com or firstname.lastname@example.org.