Laminar Flow Hood
Laminar flow hoods are designed to supplement cleanrooms; which can be costly to build. Using a laminar airflow workstation can be an economical solution for companies requiring a sterile and contamination-free or ISO class 5 working environment.
Laminar flow workbenches (LAFWs) are used in applications where clean air is necessary to prevent airborne contamination of parts, samples or materials.
The use of the laminar flow hoods has spread to a wide range of industries from R&D, Medical & Research laboratories to manufacturing, electronic part assembly, data recovery, aerospace, food processing, bio-science, and pharmaceutical production.
It is important to note that laminar flow hoods are only recommended for work with non-hazardous materials. They do not provide protection for your personnel. If you need the protection of personnel and samples, you need a biological safety cabinet.
These are two different types of laminar flow hoods. The types are differentiated according to the air flow direction inside the hood.
Laminar Flow hood-Horizontal Airflow Diagram
Laminar Flow hood-Vertical Airflow Diagram
1. Horizontal Laminar Flow Hood
These hoods are typically wider especially when the filter is in the back of work zone, so they require more clearance and more floor space compared to a vertical flow hood.
They are usually preferred for plant tissue culture, electronics inspection and assembly, and pharmacy drug preparation. They will not have a front sash so the air stream is going toward the operator.
Horizontal Laminar Flow Single Filter
Horizontal Laminar Flow Double Filters
2. Vertical Laminar Flow Hood
Vertical laminar flow hoods are often selected because they work like a laminar flow clean room but on a smaller scale. These filters are typically positioned in the ceiling directing the clean air downward, purging particles out of the work zone and through a front-access opening.
They feature front sash for personnel protection and act as a physical barrier when working with chemicals. Vertical flow hoods are preferred in data recovery, medical laboratories, forensic, microbiology etc.
A solid worksurface in vertical laminar airflow hoods is an obstacle, therefore the vertical hoods have better performance when particle-sensitive process is performed about one foot above the work surface or closer to the filter surface. However, using a perforated top worktable or work surface can improve the situation.
Benchtop laminar Flow Hood
Laminar Flow Booth
Portable Laminar Flow Hood
Laminar Flow Isolator
Laminar Flow Hoods Performance
Regarding the hood cleanliness performance, most popular laminar flow hoods are in two classes: ISO 4 (Class 10) and ISO 5 (class 100). Classifications are based on particle counts taken at a location within the clean zone of a workstation.
e.g. in Class 100 (ISO 5) laminar flow hoods particle count should not exceed a total of 100 particles per cubic foot of a size 0.5 micron and larger.
The major part of a laminar flow hood is HEPA filter. HEPA filters depend on the performance quality, and can eliminate 99.97% to 99.99% of particulates for 0.3 micron or larger. Unidirectional laminar air flow across the filter surface is supplied to the work zone to maintain sterile conditions and to avoid turbulence.