Electrical equipment can and does cause explosions in some atmospheres. As cameras and senor capabilities increase, these cameras are being used in more areas than ever.  In the past, one of the limiting factors was placing a camera in a critical area defined as hazardous.   Hazardous areas are environments in which the atmosphere contains, or may possibly contain, flammable or explosive gases and, in the right conditions, may cause a fire or explosion.  The frequency of occurrence determines the level of hazard for a location. The longer the material is present, the greater the risk. These areas present many challenges in terms of where you can place, maintain, and use a sensor. Explosion-protected cameras address some of these concerns and regulations. 

To help define hazardous areas, a rating system was devised for definition of what can be used in a Hazardous Area.  In short, areas that produce a certain level of gas, vapor or liquid that are present in normal operation conditions.  Class/Division/Zone is the classification system set up in the US.  For this discussion we will use the Class I Division I hazardous areas. 

Class I, Division 1: There are three different situations that could exist to classify an area as a Class I, Division 1 location:

1.     Ignitable concentrations of flammable gases or vapors may exist under normal operating conditions.

2.     Ignitable concentrations of such gases or vapors may exist frequently because of repair or maintenance operations or because of leakage.

3.     Breakdown or faulty operation of equipment or processes might release ignitable concentrations of flammable gases or vapors and might also cause simultaneous failure of electric equipment.

The control and monitoring of equipment to ensure sustained processing activity is essential in refineries and industrial plants to control production and operational cost.  Companies are always looking to increase production, drive down the cost of production and improve environmental performance in refineries.  In the past, most of the monitoring relied on individual people walking an area to be the eyes and ears for any problems. Sensors were introduced and embedded in processing areas to monitor vibration, heat, and the like. Verification once a sensor alarmed was confirmed by still having to send in a person to validate the alarm. Cameras today can be the eyes and ears of a human to validate remotely without disruption to process operation or production thus reducing production costs. 

As we investigate a typical oil and processing area, we see the hazardous area and the CID1 with ignitable concentrations present as defined. We also see many process monitoring applications present. Such applications include:

·       Rotating equipment – equipment that could come out of balance triggering a vibration sensor

·       A thermal couple area – areas that could heat up too fast or exceed processing limitations. Many products are developed by mixing and adding chemical at a precise temperature for the chemical reaction to occur properly. I.e. antifreeze 

·       Valves and seals – junction points controlling volume tend to leak and fail. 

·       Settling tanks – used for separations during process. Monitored by thermal couples 

·       Pumps and pumping stations – looking for seal failure and early leaks

·       Piping – miles and miles of pipes can be monitored for leaks and wear or damage 

Using sensors such as visible and thermal cameras can help in monitoring and verify problems in some of these applications, remotely without shutdown or the risk of sending a person in that area. 

Challenges in remote monitoring in hazardous areas

Some challenges in remote monitoring in hazardous areas involve access to equipment for maintenance and reducing failure points.  Shut down for maintenance is costly in lost production.  Unscheduled shutdowns are very costly.  Easy quick installations with reduced crews because of lighter camera systems and no additional equipment needed to boost or extend network signals help reduce production downtime. New cabling solutions like the GameChanger Cable^TM from Paige, deliver 1Gb/s Ethernet and PoE+ up to 656 feet or 10Mbs/s up to 850 feet reducing costs, simplifying installs and saving money.  By extending the distance limitation with cable alone, installers are also avoiding the need to install (and later service) equipment in remote and hazardous areas, saving money and keeping workers safe.

Preventive maintenance 

Remote monitoring of these applications listed could help establish trend analysis and facilitate predictive maintenance thus allowing intelligent scheduling for preventive maintenance.  Explosion-protected cameras are IP cameras that can be configured remotely, health monitored remotely and rebooted remotely reducing the need for human interaction in the hazardous areas. 

Processing applications

Process capabilities of these cameras have increased significantly in the past several years. The ability to take an unacceptable image and process to get an acceptable usable image has never been more available than today.  These sensors are now a computer with a lens. Users are seeing more in challenging conditions using this technology to verify and confirm before costly intervention.

On the edge analytics

The ability to run multiple event-driven edge analytics reduces bandwidth use lowering costs and automates our monitoring process for implementation of AI (Artificial Intelligence) and ML (Machine Learning). Edge based analytics can not only tell you if a person is entering an area that is restricted (safety, security) but can also notify if it see a rise in temperature of a failing component or detect a leaking pipe or emissions. 

New markets and applications  

As we see the cost of explosion-protected cameras go down, we see other verticals opening such as agriculture (processing plants, storage facilities, transportation lines, fuel distribution terminals), chemical (fertilizer plants, chemical facilities) transportation and water treatment facilities all having hazardous areas associated. These verticals also have common applications within their own plants requiring explosion-protected cameras and sensors. Automating critical monitoring not only reduces overall production costs but positions companies for the new digital age to come. 

In the Zone

Intelligent Buildings have changed the landscape of low-voltage infrastructure layout. One of the biggest changes is selecting the proper cable and topology to deliver network data and power (PoE) to devices, which had previously run on many different disparate cabling types and automation systems. These include security cameras, access control, wireless access points, HVAC, lighting and many more. Location of these devices vary greatly since they do not attach to typical telecommunications outlets installed 15” above the floor. These applications are fixed in ceilings, on walls, by doors, as well as outdoors in garages and parking lots. Gaining attention to connecting IP cabling to these devices is to employ a flexible zone cabling layout.

The major benefit of a zone cabling design is that it provides easy-to-manage cabling between the TR and the devices, without having to homerun cable from all the way back to the TR.  A zone layout also reduces labor and material costs during reconfiguration because the cabling from the TR to the HCP stays intact, especially when adding future devices that will only require cable or patch cords from the HCP. 

Zone Cabling Guidelines

There are two standards that provide well-defined guidelines for the design, planning and installation of a zone cabling layout as an integral part of an intelligent building infrastructure — TIA-862-B-2016 Structured Cabling Infrastructure Standard for Intelligent Building Systems and ANSI/BICSI-007-2020 standard, Information Communication Technology Design and Implementation Practices for Intelligent Buildings and Premises. Together these two documents complement each other to provide cabling installation planning but may vary in some of the recommendations.   

For twisted-pair copper cabling, both TIA and BICSI recommend Category 6A for new installations or Category 6 at minimum in an existing building or as a retrofit.  In addition, BICSI also recognizes that in existing installations of intelligent building systems, the use of non-recognized horizontal cabling shall be allowed if the following conditions are met:  use of non-recognized cabling does not violate current Code or AHJ requirements;  the need for cabling is a result from the movement, expansion, or other alterations to an existing system; or the non-recognized cabling meets or exceeds the performance of the existing cabling in use by the specific system.    

TIA provides guidelines for cabling types, pathways, terminations and installation best practices. A zone enclosure or HCP is defined by TIA to house one or more of the following: a) a consolidation ; b) a horizontal connection point; or, c) intelligent building system outlet.  For twisted-pair cabling, in order to reduce the effect of multiple connections in close proximity on NEXT loss and return loss, the HCP should be located at least 15 m (49 ft) from the TR (or “Distributor”) that houses the active equipment.  When cross-connections are used at the HCP, an equipment outlet shall not be installed as part of Cabling Subsystem 1 to ensure that the cabling channel contains no more than four connections.  The zone enclosure should be sized to accommodate immediate requirements and long-term growth but not more than 96 connections.  

The BICSI standard leverages the requirements by TIA but delves more granular into the best practices for planning spaces, topology and media selection for the additional building applications.  The revised BICSI-007-2020 has expanded the section on design considerations for zone enclosures to include more options and topologies for horizontal cabling and contains diagrams and layouts that depict examples of a star topology (point-to-point), different coverage area patterns, and tree topology. 

Although TIA recognizes zone enclosures as only housing passive cross connections (or interconnections) for data or building devices, BICSI’s 007-2020 version states, “Unlike a consolidation point, an HCP may be either active or passive.”  Allowing active equipment, such as PoE extenders, midspan injectors, AC outlets, fans or switches within the HCP expands the design of the zone boxes. Spare capacity for future expansion is considered when determining the size of the HCP.  Manufacturers of ceiling boxes are now offering different configurations, sizes and features. (See photo for a ceiling box with electrical connections and accommodation for both patching fields and active components)

Zoning Out

A zone cabling horizontal channel distance is limited by TIA to 100m for twisted pair cabling from the equipment in the TR to the device itself, including patch cords.  This means that if the HCP is located at least 15m from the TR, that the end device can not run further than 85m from the zone enclosure (including the patching field)   (See Figure 1).  Since most of building devices are beyond 100m, there are options – add PoE extenders, which would require AC power for the active components, or use a  hybrid fiber/copper cable which would include employing media converters and PoE extenders and AC power, which greatly increases the material and installation costs, or simply specify the long-distance GameChanger Cable™.  The patented 22 AWG GameChanger cable more than doubles the distance of a Category 6 or 6A cable (unshielded or shielded) out to 260m (850 ft.) from the TR to the device if the zone box only houses a cross connection.  If  active PoE midspans or digital building PoE switches are installed in the HCP, then the GameChanger cable can run out to 260m from that point which drastically extends the total horizontal cable run. (See Figure 2).   

Figure 1: TIA-862B-2016 - Example of a Cabling Subsystem 1 using a star topology to coverage areas

 

Figure 2: GameChanger Cable extends the cable channel distance to 260m/850 ft. without zone cabling or at least 275m/899 ft with an HCP containing active equipment.

 

 

A properly executed zone cabling plan has many immediate and long-term benefits. It results in a more manageable and accessible cabling topology, which has a direct impact on material costs, labor, and future MACs and maintenance.  Smart building designers and installers will think outside of the box in selecting the appropriate cabling infrastructure to specifically address the application requirements and endpoints.  To see how GameChanger is the smart choice for intelligent buildings, check out our resources and our white paper.

 

A major safety concern defined in "hazardous locations" is the occurrence of fires and explosions due to presence of flammable gases, vapors, dusts or fibers. Hazardous locations (HL) are usually found in industrial facilities where explosive liquids, gases or dusts are present. No other aspect of industrial safety receives more attention in the form of codes, standards, technical papers, and engineering design.

Regulatory bodies like the Occupational Safety and Health Administration (OSHA), National Electrical Code (NEC) and the NFPA 70 have established classification systems for locations which exhibit potentially dangerous conditions and hazards.  They define the types of hazardous substances that are, or may be, present in the air in quantities sufficient to produce explosive or ignitable mixtures.  Hazardous location requirements exist not only to prevent a fire or explosion, but also to contain the fire or explosion should it occur.  OSHA provides guidelines for specially designed equipment and special installation techniques must be used to protect against the explosive and flammable potential of these substances.

Hazardous locations are broken into different categories called “Classes” and “Divisions” in NEC’s Article 500 Hazardous (Classified) Locations – Classes I, II, and III, Divisions 1 and 2. The NEC imposes strict requirements for cabling methods in these locations which are permissible by the code-making bodies, also known in the ICT industry as the Authority Having Jurisdiction (AHJ), with safety being the most critical consideration. The “Classes” define the type of explosive or ignitable substances which are present in the atmosphere or could be present.  The “Groups” define substances within the Classes and are rated by their flammable nature in relation to other known substances. The “Divisions” apply to the specific conditions and the likelihood of the specific substances in the Groups to exist in the areas.  

The process of classifying an area is often complex, so it is generally determined by the facility’s engineering staff. Buildings are not classified, but areas within the building are.  “Class I, Division 1” is the most hazardous classification. Notice that the ignitables  get bigger as the class number increases. Unfortunately, there isn’t always a clear boundary.  Often there are areas that have a mix of particle sizes.

Some examples of Class 1 areas are:

• Petroleum refineries, and gasoline storage and dispensing areas;
• Dry cleaning plants where vapors from cleaning fluids can be present;
• Spray finishing areas;
• Aircraft hangars and fuel servicing areas; and
• Utility gas plants, and operations involving storage and handling of liquified petroleum gas or natural gas.

Selecting Proper Cable and Following Best Installation Practices 

Each type of hazardous location requires specific types of cable and installation methods. Approved wiring methods range from a rigid, highly impenetrable type of cable, such as Type MI (mineral insulated cable), to a raceway system such as metallic conduit. Cable glands (cable entry devices) used in hazardous locations are intended to provide the safe connection of suitable cables to enclosures, maintaining the explosion protection and ingress properties of equipment.  Cable glands provide a degree of environmental and ingress protection required for the equipment they are being connected to and the hazardous location for which they are being installed in. NEC prescribe the requirements for both cable glands and cables.

The NEC defines the types of cables that can be used in hazardous locations, and UL provides the means to approve cables for the US. The various cable types, in conjunction with the appropriate terminations, must provide a system that significantly limits or completely eliminates the possibility of an electrical arc or spark igniting the surrounding flammable gases, vapors, dusts or fibers. The approved cable types range from extremely rigid and impermeable mineral-insulated, metal-sheathed Type MI cables and MC-HL and ITC-HL cables with gas/vapor-tight continuous corrugated metallic sheaths to unarmored, highly flexible Type TC-ER-HL cables and flexible cords.

Cable allowed for use in Class I Division 1 are limited, with a few exceptions, to type MC-HL, ITC-HL, and TCER-HL under special conditions.  NEC provides requirements for equipment (including cables) installed in HL areas which includes:

• Identification for use in the Class and Grouping of the location
• Meets specific eternal or exposed surface temperature requirement
• Marked to show its temperature range and the environment for which it has been evaluated 

In jurisdictions following IEC requirements, there are product standards for hazardous location cable glands. However, unlike NEC, IEC does not identify specific product standards for hazardous location cables, but provides installation cable requirements according to the IEC 60079-14. And although this standard provides guidance for the minimum requirements for cable installation, it does not define specific tests or construction specifically for hazardous location cable.  IEC recommends certain cable properties, such as jacketing materials not to be an “easy tear” type (i.e. with low tensile strength sheaths) unless installed in conduit, jacketing to be extruded and constructed of  thermoplastic, thermosetting or elastomeric materials and any fillers need to be water blocking.  

Tough Cable Challenges and an Easy Solution

In addition to the cable’s robust construction needed to perform in severe environments,  one of the biggest challenges for Ethernet cable is the 100m distance limitations.   In harsh environment locations, such as the Class I areas mentioned above, the distances from the telecommunications room (TR) to the devices often exceeds 100m.  Adding an additional termination point, whether a telecom enclosure or an additional TR is just not feasible or cost effective.

The GameChanger™ Cable, which was designed to deliver both data and power (PoE) far beyond the Ethernet distance limitations for Category cable, is now available in a version specifically developed for harsh locations.  This cable is classified as ITC-HL (instrumentation tray cable for hazardous locations), meeting UL2250 and UL2225 listings for 300V copper conductors for use in Class 1, Division 1 (CI/DI) hazardous locations.

This GameChanger cable consists of 22 AWG copper conductors with FEP insulation and manufactured with an inner jacket covered by a continuously corrugated welded (CCW) armoring and then sheathed with an outer PVC jacket.   This cable is ROHS-2 compliant, sunlight resistant and can be direct buried.  The operating temperature has a wide range of -50°C to +90°C which assures reliable performance in all severe environments. With the CI/D1 rating this armored cable allows installers to skip the expensive and time-consuming installation of rigid pipe or conduit, and with a reach that goes well over two times traditional cable, saving a significant amount of time and money. 

All  GameChanger cables deliver 1Gb/s Ethernet and PoE+ up to 656 feet (200 meters) and 10Mb/s Ethernet and PoE+ up to 850 feet making it an ideal pairing for explosion proof cameras, WAPs and other edge devices. This cable eliminates intermediate IDF requirements and the need to install repeaters, power supplies and other equipment, which are costly and introduce additional points of failure.