Fume-Hood-Selection-Guide
Face velocity
0.4-0.6 m/s
Airflow
Uniform
Control
VAV ready
01 / Risk foundation
Selection begins with risk.
Cabinet type, liner, sash and control follow from chemical hazard, volatility, concentration and operator exposure.
Chemical toxicity & volatility
Identify GHS hazard class, TLV/PEL, boiling point and vapor pressure. High-toxicity or volatile substances require proven containment and may trigger perchloric acid or radioisotope specification.
Process & quantity
Heating, stirring, transfer and scale affect vapor generation. Batch analytical work differs from continuous synthesis or high-volume industrial testing.
Operator exposure scenario
Frequency, duration and hand access depth matter. Demonstration hoods tolerate higher velocity; precision manipulation benefits from low turbulence and adjustable sash.
Regulatory & testing requirement
Tender may specify ASHRAE 110, EN 14175 or AS/NZS 2243.8 acceptance. Confirm whether type testing, as-installed field test or both are required.
02 / Cabinet types
Match cabinet to application.
Four primary variants address general chemistry, high-heat, perchloric acid and radioisotope work.
General chemistry
For routine analytical, organic and inorganic work. Epoxy resin or stainless steel liner. Suitable for most solvents and acids at normal concentration and temperature.
- Epoxy resin or SS304/316L liner
- Vertical or horizontal sash
- ASHRAE 110 / EN 14175 compatible
Walk-in & digestion
For large equipment, furnace, digestion block or continuous high-temperature process. Stainless steel interior, reinforced structure and often floor-mounted.
- Stainless steel interior and baffle
- Walk-in width typically ≥1800 mm
- Heavy-duty fan and duct material
Perchloric acid
Dedicated cabinet with wash-down interior, stainless steel, integrated spray system and separate duct. Prevents explosive perchlorate crystal accumulation.
- SS316L with coved corners
- Internal wash-down nozzles
- Isolated stainless exhaust
Radioisotope
Containment for radioactive material handling. Stainless steel, sealed joints, HEPA filtration and shielding as required by radiation safety authority.
- Stainless steel sealed construction
- HEPA exhaust filtration
- Shielding and monitoring provision
03 / Materials & sash
Liner and sash govern durability.
Chemical resistance, temperature tolerance and operator access depend on interior material and sash design.
| Liner material | Chemical resistance | Temp. limit | Typical use |
|---|---|---|---|
| Epoxy resin | Acids, bases, solvents (moderate conc.) | ≤90°C | General analytical & organic chemistry |
| Stainless steel 304 | Acids, bases, solvents; avoid chloride | ≤200°C | High-temperature, heavy-duty, wash-down |
| Stainless steel 316L | Acids, bases, chlorides, perchloric acid | ≤200°C | Perchloric acid, coastal & corrosive env. |
| Polypropylene (PP) | Strong acids, bases; avoid oxidizers | ≤80°C | Wet chemistry, strong acid/base bench work |
Vertical sash
Counterbalanced or cable-suspended. Full-width opening, suitable for tall equipment and general manipulation. Single or combination (vertical + horizontal).
- Wide clear access when raised
- Reduces face velocity at full height
Horizontal sliding sash
Panels slide left-right. Fixed sash height maintains face velocity. Ideal for demonstration, teaching or applications where full opening is not needed.
- Constant face velocity
- Limited vertical clearance
04 / Airflow engineering
Containment is system performance.
Face velocity, airflow, static pressure, fan selection and VAV control must align with room HVAC and testing standard.
Face velocity
Typical range 0.4-0.6 m/s (80-120 fpm). ASHRAE and EN standards recommend 0.5 m/s nominal. Higher velocity does not guarantee better containment and may cause turbulence.
Verification
Measure at 16 points across sash opening per ASHRAE 110. Uniformity ±20% of mean required for robust containment.
Airflow & static pressure
Volumetric flow (CFM/CMH) = face velocity × sash area. System static pressure (Pa / in wg) = hood entry loss + duct + filter + outlet resistance. Fan must overcome total at design flow.
Design margin
Allow 20-30% pressure margin for filter loading. Verify fan curve and motor power at expected duty point.
Fan & motor selection
Centrifugal fans preferred for general chemistry. Corrosion-resistant material (epoxy-coated, FRP, SS) for acid/solvent vapor. Direct-drive EC motor supports VAV and reduces maintenance.
Location
Roof or penthouse-mounted exhaust fan minimizes contaminated duct length inside lab and simplifies isolation.
Variable Air Volume (VAV) control
VAV reduces exhaust when sash closes, saving energy and conditioning cost. Sash position sensor modulates damper or fan speed to maintain target face velocity. Requires room supply compensation and monitoring to prevent negative pressure hazard.
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Energy efficiency
Reduces fan runtime and HVAC load 30-50% in typical research lab.
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Face velocity stability
Pressure-independent control maintains 0.5 m/s ±10% across sash positions.
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Room coordination
BMS must track hood exhaust and adjust supply to maintain room differential.
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Alarm & monitoring
Face velocity, airflow and fan status monitored; audible/visual alarm on failure.
05 / Standards & testing
Performance verified by test.
ASHRAE 110, EN 14175 and AS/NZS 2243.8 define containment test procedures. Type testing and field testing address different stages.
ASHRAE 110
North American and international reference. Tracer gas (SF₆) quantifies containment. Reports AM (as-manufactured), AI (as-installed) and AU (as-used) concentration at mannequin breathing zone.
Acceptance: ≤0.10 ppm at 0.5 m/s (common)
Robustness test: cross-draft challenge
Type test provides product baseline
EN 14175
European standard series (EN 14175-1 to -7). Part 3 (type test) and Part 4 (on-site test) define containment, face velocity uniformity, airflow stability and operator exposure.
Tracer gas or visual smoke test
Acceptance: containment class per Part 3
Part 4 used for commissioning and periodic
AS/NZS 2243.8
Australia and New Zealand standard for fume cupboard commissioning and use. Specifies face velocity, smoke visualization, annual recertification and operating procedures.
Face velocity 0.4-0.6 m/s, uniformity ±20%
Smoke test mandatory at commissioning
Annual performance verification required
Type testing vs. field testing
Type test (AM) conducted by manufacturer or independent lab on standardized configuration. Demonstrates design capability. Results apply to tested model and configuration only.
As-installed (AI) or on-site test performed after installation in final location. Verifies hood, duct, fan, room interaction and control. Required for compliance in regulated facilities.
Critical
Type test report provides product evidence. Field test confirms actual project performance. Both serve different stages of risk reduction.
Acceptance criteria
Tender or project specification defines pass/fail threshold. Common ASHRAE 110 acceptance: ≤0.10 ppm average, ≤0.15 ppm single-point. EN 14175 and AS/NZS criteria vary by application risk.
Periodic retest interval typically annual or per local safety authority. Corrective action triggered by face velocity deviation, visible leakage or alarm frequency increase.
Documentation
Test certificate must identify hood serial, test date, standard version, actual readings, tester qualification and equipment calibration traceability.
06 / Decision support
Selection decision tree
Follow risk assessment to cabinet type, liner, sash and system requirements. Confirm testing standard and acceptance criteria before finalizing specification.
Step 01 · Identify chemical hazard
Review GHS classification, TLV/PEL, volatility and quantity. High-toxicity or perchloric acid → specialty cabinet. General chemistry → standard cabinet.
Step 02 · Select cabinet type & liner
Standard: epoxy or SS304 for general work. High-heat/walk-in: stainless steel. Perchloric: SS316L + wash-down. Radioisotope: sealed SS + HEPA.
Step 03 · Choose sash configuration
Vertical sash for tall equipment and general manipulation. Horizontal sash for fixed-height demonstration or teaching. Combination sash for flexibility.
Step 04 · Calculate airflow & fan
Target face velocity 0.5 m/s. Calculate CFM/CMH = velocity × sash area. Add duct + filter pressure loss. Select fan and motor with 20-30% margin.
Step 05 · Specify control & monitoring
VAV for energy efficiency. Face velocity alarm and airflow monitor mandatory. Integrate with room BMS for supply compensation and pressure control.
Step 06 · Define testing & acceptance
Specify ASHRAE 110, EN 14175 or AS/NZS 2243.8 as applicable. Require type test report and as-installed field test. Set acceptance threshold and periodic retest.
Ready to specify
Request technical inquiry
Submit your project parameters, chemical list, testing requirement and local standard. Our technical team will review and provide cabinet recommendation, airflow calculation, fan selection and testing pathway within 2-3 business days.
Specification review
Chemical list, process, cabinet type, liner, testing standard
Airflow calculation
Face velocity, CFM/CMH, static pressure, fan curve
Testing pathway
Type test report, field test procedure, acceptance criteria
Response time: 2-3 business days. Complex multi-hood projects may require additional coordination.