- Available Certified ISO Grade Designs: ISO 8
• Certified ISO Grade Design: ISO 8
• Unit of Measure: of 1
• Certified ISO Grade Design: ISO 8
• Unit of Measure: of 1
Laboratory hoods serve a number of critical purposes in the lab environment.
Such hoods, often called laminar flow workstations or clean benches, use a flow of HEPA-filtered air to prevent influx of viable and non-viable particles into the enclosure and to sweep away any contaminants generated by the work process.
For fume containment, laboratory fume hoods use a ducted ventilation system that maintains negative pressure. Where ducting is impractical, ductless hoods are also available for removal of non-hazardous contaminants (fumes or particles), using either HEPA or activated carbon filters.
Biological safety cabinets combine aspects of both hood types: a laminar flow of micro-filtered air and negative-pressure containment of bio-hazard fumes.
Laminar flow hoods (also called laminar flow clean benches) force air through a HEPA or ULPA filter to create a clean work area free of nearly all contaminating particulates, including bacteria, mold spores and many viruses. These hoods use a vertical or horizontal airflow design. Both provide excellent protection of products from particulates and cross-contamination, but do not protect the operator or environment.
So why choose one over the other? Vertical laminar flow hoods (VLF Hoods) require less floor space, but more overhead clearance. In addition, a sash at the front of the VLF hood provides a barrier between air exiting the hood and the operator’s face. VLF hoods create turbulent air flow when air strikes the work surface, requiring sterile work to be performed above the work surface.
HLF hoods minimize air turbulence (and particle backflow) on the work surface except where equipment disrupts the horizontal airflow. However, they direct the airflow directly at the operator’s face and require more depth to accommodate placement of the fan filter unit at the rear of the hood.
Read more about the differences between horizontal and vertical laminar flow hoods
Laboratory fume hoods draw air from the environment through the opening of the hood, allowing environmental contaminants into the work area. Thus, lab fume hoods do not offer a sterile environment or product protection. Instead, chemical fume hoods are designed to protect the operator from dangerous or irritating fumes and powders generated from work performed inside the hood.
In ducted fume hoods and canopy fume hoods, air passes out of the hood through a duct leading to an in-house ventilation system that contains and/or neutralizes hazardous materials.
In ductless fume hoods, fans draw exhaust air through a series of filters that remove irritating substances before release back into the room. Since these filters are not 100% efficient in removing all substances, ductless fume hoods are not advised in the presence of biohazards; however, they provide a convenient, cost-effective solution for operations involving irritating but non-hazardous fumes in facilities where an in-house HVAC system cannot be accessed.
Biological Safety cabinets combine design aspects of both laminar flow and fume hoods. Filtered air is directed downward onto the work surface and then travels into a plenum through openings on the front and sides of the hood. Depending on the classification of the biosafety hood, some percentage of air is recirculated through a HEPA filter while the rest is directed out of the hood through an exhaust system. Thus, biosafety cabinets offer operator, environmental and product protection.
These laboratory safety cabinets (sometimes called IV hoods or compounding hoods) are ideal when preparing sterile medications such as chemotherapeutic agents that may pose a risk to the operator.
When it comes to working with hazardous or potentially infectious material, protecting personnel must be the primary concern. However, offering personnel protection does not have to come at the cost of risking product integrity. Class II BSCs provide protection to both personnel and product simultaneously. They maintain an ISO class 5 clean work area for product manipulation, while ensuring that exhaust air is filtered and ducted out of the environment. Thus, a class II BSC is the ideal solution when working with moderately hazardous material and both personnel and product safety are required.
Read more about these lab hoods here regarding their biological safety rating
• Certified ISO Grade Design: ISO 8
• Unit of Measure: of 1
Laminar is derived from the Latin lamina, a thin sheet of material. When used to describe a laboratory hood, the term "laminar flow" refers to air exiting a filter in parallel layers that move at the same speed and in the same direction, vertically or horizontally across the enclosure. Any particles introduced in a laminar flow of air during a work process are predictably swept in the direction of the flow and removed from the enclosure, downstream of critical processes.
Disruption to laminarity results in turbulence, a randomized flow that suspends particles in eddies rather than removing them. Because they can remain in the system, carried by “second-pass” air that swirls around the critical work area, contaminants are deposited unpredictably, often with disastrous results.
Vertical laminar flow (VLF) hoods position the fan filter unit on top of the hood, a space-efficient design that accommodates most facilities as long as overhead clearance isn’t a problem. Horizontal laminar flow (HLF) hoods position the fan on the back of the hood, necessitating as much as 18” or more additional floor or bench space for fan, filter and make-up air flow. In a cleanroom or lab where space is at a premium, that difference alone could determine your choice. Footprint Advantage: VLF Hood
VLF hoods often have an adjustable sash at the front of the hood to maintain the downward laminar air flow. HLF hoods are generally open at the front of the hood to ensure unrestricted horizontal air flow. The larger opening of an HLF hood makes placement of large objects and instruments easier when compared to a VLF hood although, without a sash to serve as a shield, chemical fumes or powders inside the work area may blow into the operator's face. Sash Advantage: VLF Hood (operator safety); HLF Hood (transferring large materials)
Although both hoods are effective at sweeping particles from the hood, air eventually encounters obstacles that disrupt laminar flow. In most VLF hoods, the work surface creates turbulence, so critical processes must be performed above the surface to avoid contact with “second-pass” air that could contaminate a sensitive operation. Some VLF designs include a perforated floor with sub-surface plenum to reduce this obstruction, but these measures add cost. HLF hoods generally minimize this airflow disruption. However, large objects placed on the work surface can cause swirling or contaminate downstream materials, so critical operations should take place adjacent to the filter face. Laminar Flow Advantage: HLF Hood
We end with a tie; your working conditions will help you determine which of these advantages matter most in your operation.
Safety Alert: Under no circumstances should laminar flow hoods be used in the presence of hazardous materials. Use a fume hood or biological safety cabinet for safe biohazard containment.
Model | Horizontal Laminar Flow (HLF) Station | Vertical Laminar Flow (VLF) Station | ValuLine™ VLF Station | ValuLine Whisperflow Hood | Portable CleanBooth |
---|---|---|---|---|---|
Flow | Horizontal | Vertical | Vertical | Vertical | Vertical |
Nominal Widths | 7', 6', 4' (2.1 m, 1.8 m, 1.2 m) | 8', 6', 5', 4' (2.4 m, 1.8 m, 1.5 m, 1.2 m) | 8', 6', 5', 4' (2.4 m, 1.8 m, 1.5 m, 1.2 m ) | 6', 5 ', 4', 3 ', 2 ' (1.8 m, 1.5 m, 1.2 m, .9 m, .6 m) | 6', 4' (1.8 m, 1.2 m) |
Nominal Overall Depth and Height | 44"D x 63"H (1118 mm x 1600 mm) | 41"D x 90"H (1041 mm x 2286 mm) | 41"D x 90"H (1041 mm x 2286 mm) | 24”/30”D x 41”H (610/762 mm x 2286 mm) | 30"D x 82"H (762 mm x 2083 mm) |
Nominal Working Space | 30"D x 28"H (762 mm x 711 mm) | 27"D (686 mm); height depends on workbench used | 27"D (686 mm); height depends on workbench used | 24”/30”D x 23”H (610/762 mm x 584 mm) | 24"D (610 mm); height depends on workbench used |
Construction Material / Options | Powder Coated Steel Frame | ||||
Work Surface Options | Workbench sold separately; many top materials available. 2-piece frame isolates fan vibration. | 304 Stainless Steel work surface included | Placed on user-furnished bench (stands available) | Workbench sold separately; many top materials available. 2-piece frame isolates fan vibration. | |
Blower Type | Integrated Fan/Filter Unit | Integrated Fan/Filter Unit | Integrated Fan/Filter Unit | Integrated Fan/Filter Unit | Integrated Fan/Filter Unit |
Air Flow, | 7' (2.1 m) 6' (1.8 m) 4' (1.2 m) | 8' (2.4 m) 6' (1.8 m) 5' (1.5 m) 4' (1.2 m) | 8' (2.4 m) 6' (1.8 m) 5' (1.5 m) 4' (1.2 m) | 6'(1.8 m) 5'(1.5 m) 4' (1.2 m) 3 ' (.9 m) | 6' (1.8 m) 4' (1.2 m) |
CFM (m³/hr) | 1130 (1920) 960 (1632) 650 (1104) | 1300 (2209) 960 (1632) 840 (1427) 650 (1104) | 1300 (2209) 960 (1631) 840 (1427) 650 (1104) | 960 (1632) 840 (1427) 650 (1104) 558 (948) | 960 (1632) 650 (1104) |
Filter Types | HEPA or ULPA | HEPA or ULPA | HEPA or ULPA | HEPA or ULPA | HEPA or ULPA |
Prefilter | Washable Polyurethane Foam | Washable polyurethane Foam | Washable polyurethane Foam | Washable polyurethane Foam | Washable polyurethane Foam |
Portability / Installation Access | Not portable | Not portable. Wider than standard door frame | Not portable. Wider than standard door frame | Portable | Portable: CleanBooth frame uses casters. |
Front Sash Configuration Options | Take-up air slots and plenums on three sides of the work area | Tilt-Up | Uses softwall panel kits: vinyl, anti-static vinyl, or non-outgassing polyurethane | ||
Lighting | LED | LED | LED | LED | Optional fluorescent lighting |
Noise Level, Measured 30" (762mm) from filter face at 90 FPM (.46m/s) | <50 dBA | <50 dBA | <50 dBA | <50 dBA | <50 dBA |
Airflow Monitor Options | Minihelic gauge monitors backpressure across filter | Includes touch screen controls with backpressure indicator | Optional: air velocity meter and differential pressure gauge for filter backpressure | Optional swing-vane anemometer | Optional: air velocity meter and differential pressure gauge for filter backpressure |
Power Requirements | 120 VAC, 50/60 Hz or 220VAC, 50 Hz | 110 VAC, 50/60 Hz or 220VAC, 50 Hz | 110 VAC, 50/60 Hz or 220VAC, 50 Hz | 110 VAC, 50/60 Hz or 220VAC, 50 Hz | 120 VAC, 50/60 Hz or 220VAC, 50 Hz |
Price Range | $9,300 – $14,300+ | $6,000 - $14,000+ | $5,000 - $10,000+ | $1500 | $2,000 - $4,500+ |
Application Synopsis |
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Bel-Art Desiccator Styles and Configuration
Bel-Art Benchtop Desiccator Cabinets feature removable, tray-like shelves with perforated bottoms that slide in/out on pre-set rails.
Bel-Art Vacuum Space-Saver Desiccator Chambers include a clear, chemical-resistant polycarbonate base with interlocking ridges for stacks up to 3 units high. Space Saver Desiccators use either high-heat desiccator plates or desiccant cartridges to quickly dry samples or degas parts
Bel-Art Portable Vacuum Desiccators provide reliable and economical drying chambers for classrooms and research laboratories.
Vacuum Space-Saver desiccators use high-heat desiccator plates or desiccant cartridges to quickly dry samples or degas parts
Non-vacuum desiccators are feasible as a drying chamber for thin-layer chromatography plates, dried materials, and chemical standards.
Can I Use a Desiccator Cabinet to Bake or Actively Dry Materials?
Typically, a desiccator is appropriate for maintaining low levels of moisture, but not a meaningful replacement for removing moisture from already saturated items. A desiccator cabinet maintains dry conditions that prevent trace moisture from degrading sensitive parts from absorbing moisture during storage or assembly workflows.
Moisture is removed from the chamber product via silica desiccant, active drying, or purged via an inert gas or vacuum to prevent adsorption. Adsorption is the adhesion of atoms, ions or molecules which originate from a gas, liquid or dissolved solid to a surface.
Desiccant Packages for Secador Desiccant Cabinets
Desiccant drying packages are Ideal for use with Secador 1.0 or 2.0 desiccators, these desiccant cartridges reduce moisture and the silica gel beads turn pink when saturated with moisture. The transparent polystyrene dish allows silica gel examination without requiring access or opening of the chamber. Beneficially, the desiccant is non-toxic, non-corrosive and inert.