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Question 1: Is it acceptable to use a non-explosion-proof phone for on-site inspections of flammable and explosive areas, taking photos with the phone in flight mode? 【Answer】First, it is necessary to determine whether the flammable and explosive area is an explosion-proof zone. If in a non-explosion-proof area, it is theoretically possible to take photos in flight mode. If in an explosion-proof area, non-explosion-proof electrical equipment must not be used. Places where flammable and explosive materials are present pose extremely high safety risks, as sparks and static electricity can trigger explosions or fires. Non-explosion-proof phones do not incorporate specialized explosion-proof measures in their design and manufacturing; their internal circuits and batteries can still generate tiny electric sparks or release static electricity while in use, thus becoming potential sources of ignition. Flight mode only turns off the phone’s communication functions, but it does not change the phone’s inherent electrical characteristics or potential hazards. To ensure the safety of personnel and the security and stability of the premises, specialized equipment certified for explosion protection should be used for tasks such as taking photographs. Question 2: How are the explosive hazard zones in the gas boiler room (Class D, open flame) classified? How to select explosion-proof electrical equipment? 【Answer】In accordance with Article E.0.6 of GB 50028-2006 \"Code for Design of Urban Gas (2020 Edition)\", the following electrical installation areas can be classified as non-explosion hazardous areas: 3. Areas near equipment that uses an open flame during the production process, or near equipment whose heated surface temperature exceeds the ignition temperature of the combustible gases present in that area. Such as boiler rooms, hot water heater rooms, etc. In accordance with Article 15.3.7 of GB 50041-2020 \"Code for Design of Boiler Rooms\": Boiler rooms for oil or gas boilers located within other buildings shall be equipped with independent ventilation systems, and the ventilation equipment must be explosion-proof. Therefore, it is not necessary to divide the gas boiler room into explosion-hazardous areas. The ventilation equipment in the gas boiler room shall be explosion-proof. Question 3: Does the motor of the transfer pump for the hydrogen peroxide storage tank need to be explosion-proof? How to determine the explosion protection rating? 【Answer】For a simple hydrogen peroxide storage tank, explosion protection is not required within the cofferdam area. For storage tanks, the spacing between them can be determined in accordance with Class A standards; a fire protection distance should be maintained between the tank area and the production facilities, while the electrical systems in the tank area do not need to be explosion-proof ； In an environment with only hydrogen peroxide and no other gases or dusts, it is sufficient to select an appropriate corrosion protection rating; explosion-proof measures are not very necessary. Question 4: Is sodium dithionite a combustible dust? 【Answer】Sodium dithionite is not included in the \"List of Key Flammable Dusts in the Industrial and Trade Sectors (2015 Edition)\". For dusts that are not listed in this directory nor covered by any explosion protection standards, their evaluation is carried out in accordance with the standard GB/T 3836.12-2019 \"Explosive atmospheres – Part 12: Test methods for the characterization of flammable dusts\". Question 5: Do Class C installations require the division of explosion hazard zones? In what situations should electrical equipment design for explosive gas environments be carried out? 【Answer】For Class C operations, even if the operating temperature is above the flash point, an explosive hazard area still needs to be designated. As for whether electrical equipment needs to be explosion-proof, reference should be made to GB 50058-2014 \"Code for Design of Electrical Installations in Explosive Atmospheres\" 3.1.1. Electrical installation design in explosive gas environments is required when one of the following explosive gas mixture environments exists or may exist during production, processing, handling, transportation, or storage: (1) Under atmospheric conditions, combustible gases mix with air to form explosive gas mixtures ； (2) Vapors or mists of flammable liquids with a flash point equal to or below the ambient temperature, when mixed with air, form explosive gas mixtures ； (3) When the operating temperature of the material is higher than the flash point of the flammable liquid, and there is a possibility of leakage of such liquid, its vapors or mist mix with air to form an explosive gas mixture. Question 6: Can graphite powder be considered a combustible and explosive dust? 【Answer】Graphite powder is a Class IIIC flammable conductive dust. Question 7: What common issues are there with gas alarms during on-site inspections? 【Answer】Generally, the following situations may occur: (1) Missing: It has not been configured in the area where installation is to take place ； (2) Incorrect position: The height or coordinates do not cover the effective range ； (3) Incorrect selection: Incompatible explosion protection rating ； (4) Configuration error: When both toxicity and flammability are present, the two functions are not provided simultaneously ； (5) Range error: The range does not match the applicable gas ； (6) Range accuracy: The accuracy required for the range does not meet the standards ； (7) Quantity issue: The quantity is too low, resulting in insufficient coverage ； (8) Testing issue: Testing, verification, or calibration not carried out on a regular basis ； (9) Alarm issues: Alarms are recorded, but not addressed ； (10) Installation issue: The alarm systems are installed by the companies themselves, without professional design ； (11) Alarm function: Sound and light alarms, as well as area alarms, are not installed or used properly ； (12) Maintenance management issues: Whether it is operating properly, and whether regular inspections, maintenance, and calibration are carried out. Question 8: Are there any regulations specifying that laboratories cannot be installed in Class A and Class B factories? 【Answer】Reference 1: According to Article 5.2.17 of GB 50160-2008 (2018 edition), the Fire Protection Design Code for Petrochemical Enterprises, the control rooms, laboratories, offices, etc. of a plant should be located outside the plant itself, and it is advisable to have them arranged in a unified manner across the entire plant or in specific areas. Item 4 of Article 5.2.18 states that the exterior walls facing the equipment that poses a fire hazard in laboratories, offices, etc., should be solid walls made of non-combustible materials without any doors or windows. When it is indeed necessary to install doors and windows, fire-resistant ones should be used. Basis 2: According to Item 3, Section 8.3.1 of GB 51283-2020 (2020 revised edition), “Fire protection design code for engineering projects of fine chemical enterprises”: Offices, rest rooms, control rooms, laboratories, etc. shall not be located within Class A or Class B factories. Should it be necessary for them to be situated adjacent to such factories, their fire resistance rating must be no lower than Grade II. They must also be separated from the factory buildings by explosion-proof walls with a fire resistance limit of at least 3.00 hours and having no doors, windows, or openings. Additionally, independent emergency exits must be provided. Question 9: Can using cable conduits or explosion-proof hoses provide explosion protection? 【Answer】It can provide mechanical protection and energy suppression, but it cannot prevent explosions; measures at the electrical interfaces of the equipment itself are what serve to prevent explosions. Question 10: Can explosion-proof electrical equipment for gas-filled environments be used in areas at risk of dust explosions? 【Answer】No. (1) Only explosion-proof equipment with dual certification for gas explosion protection and dust explosion protection can be used in both gas-filled and dusty environments ； Equipment with only gas explosion-proof certification cannot be used in dusty environments, while equipment with only dust explosion-proof certification cannot be used in gas environments. (2) Attention should be paid to the environmental group and the application scope of explosion-proof areas. In accordance with the requirements outlined in the interpretation of Clause 5.2.3 of GB 50058-2014 \"Code for Design of Electrical Installations in Explosive Atmospheres\", in areas where both explosive gases and dust are present, the selection of explosion-proof electrical equipment must meet both the explosion-proof requirements related to explosive gases and those related to explosive dust; the explosion-proof marking on such equipment shall include indicators for both types of hazards.