Why does an integrated unit still leak fumes?

Common causes include improper hood height, insufficient airflow or static pressure, reversed fan rotation, blocked filters, leaky ducts or inadequate makeup air. Ensure proper makeup air first, then check hood-face velocity and purification-section resistance. Checklist: Define capacity, accuracy, materials and operating environment before requesting quotes on a uniform basis. Request specification sheets, test reports, certificates, maintenance manuals and spare-part lists. During acceptance, verify appearance, dimensions, functions, safety protection and packaging, and keep test records. Do not compare unit price alone; include customization, freight, spare parts, after-sales support and downtime risk. Keep written records of inquiries, confirmations, FAT, acceptance and warranty commitments.