How should isolation safety barriers be installed and maintained?

　　At demanding industrial sites, isolation safety barriers are almost invariably employed as the primary intrinsically safe explosion-proof instrumentation. Isolation-type safety barriers have gradually replaced Zener safety barriers and are now widely used in the field of explosion protection. Regardless of the specific role of a safety barrier, it is our hope that everyone who becomes familiar with them will be able to use them effectively, thereby maximizing the benefits of Chengdu’s safety barriers.

　　Isolation safety barriers offer outstanding advantages and a broader range of applications. When factoring in the costs of design, construction, installation, commissioning, and maintenance, their overall life-cycle cost is relatively low. As a rule, isolation safety barriers are invariably employed as the primary intrinsically safe explosion-proof instrumentation in demanding industrial environments, enjoying widespread adoption in the field of safety and explosion protection.

　　The application of safety barriers and the concept of intrinsic safety for explosion protection have been thoroughly implemented and widely adopted in hazardous industries such as chemical processing. Chemical instrumentation personnel must master their fundamental principles and operating procedures to ensure the intrinsic safety of on-site production.

　　Functions of the isolation safety barrier:

　　1. Thanks to the use of three-terminal isolation, a system ground connection is not required, which greatly simplifies both design and on-site installation.

　　2. The requirements for instruments in hazardous areas are significantly reduced, eliminating the need for isolation instruments on site.

　　3. Since the signal lines do not require a common ground, the stability and anti-interference capability of the detection and control loop signals are significantly enhanced, thereby improving the overall system reliability.

　　4. The isolation safety barrier features enhanced input signal processing capabilities, enabling it to receive and process signals from thermocouples, resistance temperature detectors, frequency sensors, and more.

　　5. This isolation safety barrier can provide two mutually isolated signals for two devices powered by the same signal source, ensuring that the signals from the two devices do not interfere with each other and enhancing the electrical safety and insulation performance of the connected equipment.

　　Precautions for installing an isolation safety barrier:

　　1. The isolation safety barrier shall be installed in a safe location, and the ambient conditions shall comply with the “Operating Conditions” requirements specified in the “Safety Barrier Selection Catalog.”

　　2. The connecting cables for the intrinsically safe side (blue terminal) and the non-intrinsically safe side of the isolation safety barrier shall be routed separately within cable trays, with each side using its own independent protective conduit. No other power cables, including those supplying power to the intrinsically safe circuit, are permitted in the wiring conduits on this side.

　　3. Wiring leading to hazardous locations shall be intrinsically safe wiring with blue markings. The cross-sectional area of the flexible copper conductors shall be greater than 0.5 mm², and the insulation strength shall exceed 500 V.

　　4. Before energizing and commissioning an intrinsically safe barrier, it is imperative to verify that the barrier’s model, wiring configuration, and circuit polarity comply with the requirements specified in the design documentation and product specifications; failure to do so may result in injury to personnel and damage to equipment.

　　5. It is prohibited to use a megohmmeter to test the insulation strength between the terminals of an isolation safety barrier. If the system’s insulation strength is to be checked, all isolated safety barriers must first be disconnected; otherwise, the internal circuitry of the safety barriers may be damaged. 6. Before programming a safety barrier on-site, all wiring must be disconnected, the programmer must then be connected, and power must be applied for programming; otherwise, adverse consequences may result.

　　7. Field instruments connected to isolation safety barriers shall be certified as explosion-proof by a nationally recognized explosion-proof inspection authority and shall possess the corresponding explosion-proof certificate.

　　8. When designing, installing, using, and maintaining isolation safety barriers, the relevant operating requirements shall be observed concurrently.

　　Isolation safety barriers are devices used in intrinsically safe explosion-proof systems to provide electrical isolation for field instruments. In explosion-proof systems and explosion-proof electrical equipment, intrinsically safe explosion-proof systems are designed with intrinsically safe safety barriers. These barriers are installed in a safe location and comprise both intrinsically safe circuits and non-intrinsically safe circuits. Within the circuit, the energy delivered to the field’s intrinsically safe circuit is limited by current- and voltage-limiting circuits, thereby preventing hazardous energy from the non-intrinsically safe circuit from entering the intrinsically safe circuit. In intrinsically safe explosion-proof systems, such barriers are referred to as associated equipment and constitute an essential component of the intrinsically safe system.