Ducted Vertical Laminar Flow Cabinet

What is the Ducted Vertical Laminar Flow Cabinet?

A ducted vertical laminar flow cabinet exhausts its downward air stream to atmosphere through a duct. It is chosen when exhaust must leave the room and downward product protection is preferred rather than recirculate.

Overview

This model adds a duct to the vertical design so the air leaving the front of the work zone is carried outdoors. Supply is HEPA filtered and descends at 0.3–0.5 m/s, protecting the work from particles above. The duct must be sized for the cabinet airflow, and a volume control or fan speed adjustment keeps downflow velocity in range if building exhaust pressure varies. The body is typically stainless steel with a smooth interior. Removal of exhaust air suits processes that release fine dust or odour, and rooms where recirculation is not permitted. An airflow alarm and filter pressure gauge are standard, and the exhaust fan is normally dedicated to the cabinet so other users do not alter its performance.

How does it work?

In a vertical laminar flow cabinet, room air is drawn through a prefilter and a HEPA filter located at the top, and a plenum and diffuser distribute it as a unidirectional stream that descends at 0.3–0.5 m/s over the work zone. Particles shed by the work are swept downward and away rather than towards the operator, and because the flow is vertical, taller items disturb it less than in a horizontal cabinet. Air leaves at the front of the work area and may be exhausted to the room or ducted, and some models recirculate most of the air. The supply filter removes at least 99.97 % of 0.3 µm particles for HEPA and 99.999 % for ULPA, giving ISO 5 or better at the work surface. Face velocity, filter integrity and particle counts are verified, and the cabinet must be sited away from draughts that could break the laminar stream.

What are the key features?

• Ducted exhaust of the downward air stream
• Vertical HEPA supply at 0.3–0.5 m/s
• Volume control to protect downflow velocity
• Stainless steel, smooth interior
• Suited to dusty or odorous work
• Airflow alarm and filter pressure gauge

What are the technical specifications?

A typical ducted vertical laminar flow cabinet configuration offers flow direction of Vertical, top to work surface, filter class of HEPA H14, ≥ 99.97 % at 0.3 µm, downflow velocity of 0.3–0.5 m/s, exhaust of Ducted to atmosphere, duct diameter of 200–300 mm and airflow of 400–1200 m3/h. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Ducted Vertical Laminar Flow Cabinet is used in fine-dust handling, odorous or abrasive processes, rooms where recirculation is not allowed and cleanroom exhaust applications. Across the wider Vertical Laminar Flow class, laboratories also deploy it for cell culture and sterile handling, electronics and semiconductor assembly and media preparation and plating.

Which standards and certifications apply?

Relevant standards and methods include ISO 14644-1 (cleanroom classification), ISO 14644-3 (test methods), IEST-RP-CC002 (unidirectional flow clean-air devices), EN 1822 (HEPA and ULPA filters), EU GMP Annex 1 (sterile manufacturing) and GB 50073 (cleanroom design code). Certification candidates for this model are CE and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Site the cabinet away from doors, air diffusers and people traffic, since draughts above about 0.2 m/s disturb the downward stream. Verify filter integrity and face velocity at installation and at least annually, and change prefilters every 3–6 months. Place tall items so they do not block the diffuser, and keep the front opening clear so air can exit. Clean surfaces with compatible agents and avoid generating aerosols that load the filter. The cabinet protects the work rather than the operator, so do not use it for hazardous aerosols or chemical vapour. Record requalification results, and confirm the recirculated or ducted exhaust path meets room requirements.

How do I select the right Ducted Vertical Laminar Flow Cabinet?

Choose the ducted vertical model when exhaust must leave the room while downward protection is preferred. Confirm duct sizing and that building exhaust changes do not alter downflow velocity. RFQ: airflow, duct route and diameter, fan details and width.

How does it compare with other Vertical Laminar Flow variants?

Choose vertical laminar flow when the work is tall, when the cabinet contains a central obstruction such as a jig, or when downward flow is preferred so that particles do not travel towards the operator. Decide whether the cabinet recirculates, exhausts to the room or is ducted, and select HEPA H14 for ISO 5 or ULPA for ISO 4 or better. Match internal height and working depth to the equipment, and consider a sash or partial front for increased operator comfort. For regulated or aseptic work, choose stainless steel with cleanable surfaces and documentation. Confirm face velocity and cleanliness at commissioning. Vertical designs are often preferred in cell culture and sterile handling where a downward draught over open vessels reduces contamination from above.