A ducted fume hood draws room air inward to help contain airborne contaminants generated inside it and carries them to a suitable exhaust system. It has a different purpose from a clean bench, which supplies clean air to protect work and may direct that air towards the user.
Describe the procedure inside the enclosure
Identify substances, quantities, heat sources and equipment dimensions. Large apparatus can obstruct the internal air path or force work too close to the opening. Choose the liner and work surface for the chemical and thermal conditions.
Special processes may require dedicated equipment and exhaust design. A general-purpose hood should not be assigned perchloric-acid, highly reactive or other exceptional duties merely because it has a stainless interior.
The sash is part of the operating arrangement
Define the normal working opening and provide room for the task at that position. Opening the sash changes the air demand and containment conditions. Air velocity is one useful parameter, but a single face-velocity reading is not a complete demonstration of containment.
Cross-draughts, supply-air jets and people moving past the opening can interfere with performance. Locate the hood with the room ventilation and circulation in mind.
Include the exhaust and acceptance work
The duct, fan, discharge and replacement air must be coordinated. State whether treatment is needed and who supplies each component. The HSE's commissioning guidance calls for demonstrating effective exposure control in use and establishing a performance benchmark for later checks.
Labconco's comparison of laboratory enclosures explains why fume hoods, biological safety cabinets and clean benches should not be treated as interchangeable.
Specify airflow indication, service access and the responsibilities for commissioning and user instruction. A cabinet-only price can omit a substantial part of the functioning installation.
Send the procedure and exhaust-system brief to shengtongJH for a fume-hood configuration coordinated with the laboratory's requirements.