Walk-In Perchloric Acid Hood

What is the Walk-In Perchloric Acid Hood?

A walk-in perchloric acid hood provides floor-level access and full washdown for large digestion racks and tall glassware. It is used for high-throughput perchloric acid digestions in environmental and geological research laboratories.

Overview

The hood extends to the floor so multi-level digestion racks and carboys can be wheeled in. Construction is smooth, non-combustible polypropylene or stainless steel with coved internal corners and a stainless or ceramic floor. Internal height is 2000–2500 mm, depth 900–1500 mm and width 1500–2400 mm. A full-height sash or interlocked door allows loading, and the washdown system wets the walls, baffles, floor and entire duct each cycle. Airflow of 1000–2500 m3/h holds face velocity at 0.4–0.6 m/s across the larger opening. Drainage flows to a dedicated chemical waste line with an acid-resistant trap. Lighting, power outlets and airflow alarms are provided, and the exhaust remains dedicated to perchloric acid service.

How does it work?

Perchloric acid hoods work like other fume hoods but add a washdown system that periodically sprays water through the interior, the rear baffle and the entire exhaust duct. Heated perchloric acid vaporises, and its vapour can condense with organic material to form perchlorate salts in the duct, which are shock-sensitive and can explode. Water washdown dissolves these deposits before they accumulate. The hood and duct are constructed from non-combustible, chemically resistant materials with smooth, coved and crevice-free interiors and no sharp bends or horizontal runs where liquid or salt could collect. The washdown cycle runs for several minutes, typically daily or after each use, and drains to a dedicated chemical waste line. A dedicated exhaust system, separate from other hoods, prevents cross contamination and dilution problems.

What are the key features?

• Floor-level access for large racks
• Smooth non-combustible PP or stainless construction
• Full washdown of walls, floor and duct
• Height 2000–2500 mm, width 1500–2400 mm
• Airflow 1000–2500 m3/h at 0.4–0.6 m/s
• Dedicated exhaust with waste drainage

What are the technical specifications?

A typical walk-in perchloric acid hood configuration offers body material of Polypropylene or 316L stainless, height of 2000–2500 mm, width of 1500–2400 mm, depth of 900–1500 mm, face velocity of 0.4–0.6 m/s and airflow of 1000–2500 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 Walk-In Perchloric Acid Hood is used in high-throughput perchloric digestion, geological and mining assay, environmental batch analysis and large composite sample digestion. Across the wider Perchloric Acid Hoods class, laboratories also deploy it for trace-metal digestion with perchloric acid, environmental and geological analysis and food and biological sample decomposition.

Which standards and certifications apply?

Relevant standards and methods include EN 14175-2 (fume cupboards, safety and performance), EN 14175-3 (type test methods), ASHRAE 110 (method of testing performance of laboratory fume hoods), NFPA 45 (fire protection for laboratories using chemicals), GB/T 34269 and IEC 61010-1. 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.

Never share the duct with other hoods, and never use the hood for organic solvents or for drying organic material, since perchloric acid and organics can form explosive mixtures. Run the washdown cycle before and after work and keep a log of cycles and cleaning. Inspect the duct interior for salt deposits on a defined schedule, using a borescope where needed, and clean any deposit with water rather than scraping. Keep all surfaces smooth and free of ledges, gaskets or insulation that could collect salts. Verify face velocity and alarms regularly, and train users to keep glassware away from baffles. Treat washdown effluent as acidic waste and confirm the trap and drain are compatible.

How do I select the right Walk-In Perchloric Acid Hood?

Choose a walk-in design for multi-level racks or heavy carboys that cannot be lifted. Confirm floor loading, trolley access and washdown coverage of the larger interior. RFQ: rack dimensions, acid volumes, duct route, drainage and door clearance.

How does it compare with other Perchloric Acid Hoods variants?

Every perchloric acid hood must have a full washdown system covering the interior and the whole duct, because partial washdown leaves deposition sites. Choose a dedicated exhaust path with no shared ductwork, and specify smooth, all-welded construction with coved corners and no internal fasteners or ledges. Select the liner for the acids used: polypropylene or PVC for mixed acid work, and stainless steel or special alloys where hot concentrated perchloric acid is handled. Match the internal height to reflux glassware and the digestion block, and select airflow so face velocity stays at 0.4–0.6 m/s. Include a washdown timer or automatic cycle, drainage with an acid-resistant trap, and airflow monitoring with an alarm. Confirm the duct material, slope and washdown coverage in writing.