1. The name of the standard was changed from "design specification" to "design standard";
2. The scope of toxic gases is expanded from those listed in the Catalogue of Highly Toxic Substances to ordinary toxic gases;
3. Requirements for design compatibility, independence and reliability of combustible gas and toxic gas detection and alarm system (GDS for short) have been added; ?
4. The requirement that the flammable gas and toxic gas detection and alarm system (GDS for short) should be set separately from the fire and fire monitoring system is added;
5. An open-circuit (laser, infrared) detector and a noise detector are added, which further improves the requirements for detector layout;
6. Five normative standard appendices, such as selection guide of common gas detectors and GDS configuration diagram, have been added; ?
7. Some chapters and clauses of the standard have been revised and improved, and mandatory clauses have been cancelled.
Original name: GB50493-2009 Code for Design of Detection and Alarm of Combustible and Toxic Gases in Petrochemical Industry.
◆ Now: Name GB/T 50493-20 19 Design Standard for Detection and Alarm of Combustible and Toxic Gases in Petrochemical Industry.
◆ Description of terms:
According to the latest national standard, as normative documents, they must all be mandatory, and as recommended standards, there is no mandatory provision.
◆ Original text: GB50493-2009 3.0.6: The physical detection (detector) of combustible gas should adopt the products with manufacturing certification, explosion-proof performance certification and fire-fighting certification of measuring instruments of the national designated institutions or their authorized inspection units.
◆ Now: GB/T50493-20 19 3.0.5: The combustible gas detector must obtain the type approval certificate of measuring instruments, explosion-proof certificate and type test report of fire protection products from the national designated institution or its authorized inspection unit; The alarm control unit participating in the fire fighting linkage shall adopt a special combustible gas alarm controller that has obtained the type test report of the National Fire Electronic Product Quality Supervision and Inspection Center; The toxic gas detector required by national laws and regulations must obtain the type approval certificate of measuring instruments from the national designated institution or its authorized inspection unit. Toxic gas detectors installed in explosive dangerous places shall also obtain explosion-proof certificates from state-designated institutions or inspection units authorized by them.
◆ Description of terms:
20 17 12.26 The National People's Congress has approved that the new measurement law will be implemented on 20 17 12.28. The main contents of the revision: cancel the administrative license for manufacturing, repairing and measuring (that is, cancel the certification for measuring manufacturing), and strictly implement the type approval license for measuring instruments.
Combustible gas detectors do not need CCCF certification at present, but they must obtain fire-fighting product type test report (necessary) and fire-fighting product certification certificate (voluntary certification by enterprises) when selling.
◆ Original: GB50493-2009 3.0.9: combustible gas and toxic gas detection and alarm system shall be set independently.
◆ Now: GB/T50493-20 19 3.0.8: The combustible gas and toxic gas detection and alarm system shall be set independently of other systems.
◆ Description of terms:
The combustible gas and toxic gas detection and alarm system may not be combined with the production process control system to ensure that the combustible gas and toxic gas detection and alarm system can still work normally when the production process control system of the process device fails or stops. ?
In 20 14, the document No.3 of the State Administration of Work Safety [2014]16 also explicitly required to set up an independent flammable gas and toxic gas detection and alarm system. Therefore, when revising the standard, the requirements for setting GDS were revised with reference to the relevant requirements of GB50 1 16 and Document No.3 of the State Administration of Work Safety [2014]16.
◆ Original: GB 50493-2009 3.0.11:The combustible gas and toxic gas detection and alarm system fixedly installed on the site of process units and storage and transportation facilities shall be powered by UPS. The combustible gas and toxic gas detection and alarm system of gas stations, filling stations and scattered or independent toxic, flammable and explosive business facilities can be powered by ordinary power supply.
◆ Now: GB/T50493-20 19 3.0.9: The power supply load of gas detector, alarm control unit and on-site alarm of combustible gas and toxic gas detection and alarm system should be considered as the particularly important load in the first-class electricity load, and UPS power supply device should be adopted.
◆ Description of terms:
Dispersed or independent facilities of toxic, flammable and explosive substances such as gas stations and filling stations generally adopt tray-type or wall-mounted facilities, and the power supply is small, so it is stipulated that the detection and alarm system can also use ordinary power supply.
◆ Original text: GB50493-2009 3.0.4: The alarm signal shall be sent to the on-site alarm and indicator alarm equipment in the manned control room or the on-site operation room, and an audible and visual alarm shall be given.
◆ Now: GB/T50493-20 19 3.0.3: The detection and alarm signals of combustible gas and toxic gas shall be sent to the on-site control room and the central control room on duty for display and alarm; The secondary alarm signal of combustible gas and the fault signal of alarm control unit of combustible gas and toxic gas detection and alarm system shall be sent to the fire control room.
◆ Description of terms:
The fire control room also needs to monitor the secondary alarm signal of combustible gas and the fault signal of the alarm control unit of combustible gas and toxic gas detection and alarm system.
◆ Original: GB50493-2009 3.0.8: The detectors (detectors) in combustible gas or toxic gas places should be fixed.
◆ Now: GB/T50493-20 19 3.0.6: Stationary detectors should be used in places where combustible gas and toxic gas detectors are needed; Places that need temporary detection of combustible gas and toxic gas should be equipped with mobile gas detectors.
◆ Description of terms:
For some places without fixed combustible gas or toxic gas detectors, mobile combustible gas or toxic gas detectors can usually be installed to ensure the safety of production and maintenance. For example, the ambient humidity is too high; The ambient temperature is too low; Or it is regarded as a non-explosive or non-toxic area under normal circumstances, and may be an explosive or toxic dangerous area during production and maintenance. Due to the limitation of the performance of the tested products, mobile combustible gas or toxic gas detectors can usually be installed to ensure the safety of production and maintenance.
◆ Original text: GB50493-2009 2.0.2: Toxic gas: refers to the gas that can cause acute or chronic harm to health through physical contact of workers in occupational activities. The scope of toxic gas in this specification refers to the toxic vapor or toxic gas listed in the Catalogue of Highly Toxic Substances (No.2003142). Common ones are: nitrogen dioxide, hydrogen sulfide, benzene, hydrogen cyanide, ammonia, chlorine, carbon monoxide, acrylonitrile, vinyl chloride, phosgene (carbonyl chloride) and so on.
◆ Now: GB/T50493-20 19 2.0.2: Toxic gas refers to toxic gas or vapor that can cause death or permanent injury to workers through skin contact or breathing in occupational activities.
◆ Description of terms:
Gases that cause death or permanent injury through skin contact or breathing are called toxic gases. Requirements conform to this specification.
◆ Original text: GB50493-2009 3.0.5: The layout of on-site alarms in the device area should be comprehensively determined according to the area of the device area, the layout of equipment and buildings, the physical and chemical properties of release sources and the characteristics of on-site airflow. On-site alarm can choose stereo or alarm light.
◆ Now: GB/T50493-20 19 3.0.4: audible and visual alarm for combustible gas and toxic gas should be set in the operation area of the control room; The on-site area alarm should be set according to the occupied area of the device, the layout of equipment and buildings, the physical and chemical properties of the release source and the characteristics of the on-site airflow. On-site area alarm shall have sound and light alarm function.
◆ Description of terms:
When the number of combustible and/or toxic gas detectors on site is less than 65,438+00, the noise of the site environment is less than 85dBA, and the detectors are equipped with integrated audible and visual alarm, there is no need to set up a site area alarm without affecting the alarm effect on site.
When the environmental noise of the site exceeds 85dBA, and it is difficult for the detector integrated with audible and visual alarm to achieve the alarm effect, in order to warn the site staff, it is necessary to set up site area alarms at the main entrances and exits of the production site and high-noise areas.
◆ Original text: GB50493-2009 3.0. 10: The equipment of portable combustible gas and/or toxic gas detector should be comprehensively determined according to the site conditions of production devices, flammable and explosive characteristics and toxicity of industrial media and the number of operators.
◆ Now: GB/T50493-20 19 3.0.7: Field workers entering explosive gas environment and/or toxic gas environment should be equipped with portable combustible gas and/or toxic gas detectors. When explosive gas and toxic gas exist in the environment at the same time, portable combustible gas and toxic gas detectors can adopt multi-sensor type.
◆ Original text: GB50493-2009: Gas density is greater than 0.97kg/m? It is considered to be heavier than air (in standard state); The gas density is less than 0.97kg/m? It is considered lighter than air.
◆ Now: GB/T50493-20194.1.2: To judge whether the leaked gas medium is heavier than air, the ratio of the molecular weight of the leaked gas medium to the molecular weight of ambient air should be ≥ 1.2, and the leaked gas medium is heavier than air; The ratio of 1.0 ≤ is less than 1.2, and the leaked medium is slightly heavier than air; 0.8