# Technical Specifications for the Design and Installation of Welding Fume Purification Systems ## I. Design Basis and General Principles Core Standards: In addition to complying with general ventilation and dust removal specifications, the design, installation, and operation of this system must give priority to the following national ecological and environmental standards: GB 16297-1996 "Integrated Emission Standard of Air Pollutants": Specifies the maximum allowable emission concentration and emission rate of particulate matter (the main component of welding fume). The chimney height and emission concentration must meet the requirements of this standard. GB 28664-2012 "General Technical Conditions for Welding Fume Purifiers": Provides specific technical requirements for the performance, safety, noise, and other aspects of welding fume purification equipment, serving as the core basis for equipment selection. Design Objectives: The system shall effectively capture and purify fume generated during welding operations. It must ensure that the air quality in the workplace meets the limit requirements for metal fume (such as compounds of manganese, chromium, nickel, etc.) specified in GBZ 2.1-2019 "Occupational Exposure Limits for Hazardous Agents in the Workplace" and achieve compliant emission. ## II. Design Specifications for Exhaust Pipes and Chimneys Height and Emission Requirements: Decentralized In-plant Systems: For mobile or centralized welding fume purifiers used for workstation purification, the exhaust pipes extending through the roof shall be 1.5 meters above the roof. When adjacent to sensitive buildings, the height shall be increased to ensure diffusion. Centralized External Emission Systems: If the purified gas needs to be discharged externally, the chimney height must be calculated in accordance with GB 16297-1996 to ensure that both the particulate matter emission rate and concentration meet the standards. The design shall consider utilizing chimney draft for energy conservation. Safety Exception: When welding galvanized or painted workpieces or when harmful gases such as carbon monoxide may be generated, the exhaust pipe shall be at least 4 meters higher than the surrounding buildings. Roof and Pipe Construction: Pipes penetrating the roof must be securely fixed. The opening diameter shall be 40~100mm larger than the pipe, and waterproof sealing shall be properly done to prevent rainwater infiltration. Pipes should be made of smooth and wear-resistant materials (such as galvanized steel sheets, spiral ducts). Horizontal pipes shall be provided with sufficient slope and ash cleaning ports at low points to adapt to the easy deposition characteristics of welding fume dust. Safety Measures: Outdoor chimneys must be equipped with lightning protection and grounding in accordance with regulations. For systems capturing explosive dust (such as aluminum-magnesium alloy welding fume), the pipes shall be designed with anti-static and explosion relief measures. ## III. Specifications for Valves, Regulation, and Control Systems Air Volume Balance and Energy Conservation: Multi-station centralized systems must be equipped with regulating valves or reducing pipes on each suction branch pipe. Commissioning shall be conducted through rigorous air volume balance calculations to ensure balanced suction at each welding point. Low-resistance design is preferred. It is recommended to install differential pressure sensors or air volume monitoring devices on main branch pipes or main pipes to monitor the system status in real time. Interlocking and Automatic Control: Each branch pipe of the welding fume suction arm or hood opening must be equipped with a pneumatic or electric closed valve. The valve must be interlocked with the welding power source to achieve "valve opening and fan high-speed operation when the welding torch starts; valve closing and fan low-speed operation or delayed shutdown when welding stops"—this is the key to energy-efficient and high-performance operation of the welding fume system. System Redundancy and Maintenance: When dust removal systems of multiple production lines or large workshops are adjacent, connecting pipes and switching valves can be installed to realize standby in case of failure and ensure production continuity. The pipe system shall be designed with inspection ports for easy cleaning and testing. Simplified Equipment Start-stop: For the main fan of welding fume purification with a motor power ≤75kW, if the power supply conditions permit, a dedicated fan start valve may not be installed. 要不要我帮你整理一份**英文版本的规范要点对照表**，方便快速查阅核心技术要求？