Laminar Airflow Workbench (LAFW)
A Laminar Airflow Workbench (LAFW) is a sterile compounding device that uses HEPA-filtered unidirectional airflow to provide an ISO Class 5 environment for preparing sterile preparations such as IV admixtures and ophthalmic solutions.
Exam Tip
LAFW supplies ISO Class 5 first air for nonhazardous sterile compounding. Protect critical sites from airflow obstruction. Use validated startup/recovery and cleaning procedures. Hazardous compounding requires appropriate containment; an ordinary vertical LAFW is not a BSC or CACI.
What Is a Laminar Airflow Workbench?
A laminar airflow workbench (LAFW) is a primary engineering control (PEC) that supplies HEPA-filtered, unidirectional air to maintain an ISO Class 5 compounding work zone. The air classification does not make the entire hood or every item inside it sterile. Personnel must maintain aseptic technique and protect critical sites with uninterrupted first air.
Different Types of Engineering Controls
| Device | Function |
|---|---|
| Horizontal LAFW | HEPA-filtered air flows from the rear toward the operator; used for nonhazardous sterile compounding |
| Vertical LAFW | HEPA-filtered air flows downward; an ordinary vertical LAFW does not provide hazardous-drug containment |
| Biological safety cabinet (BSC) | A different PEC type; an appropriate Class II/III cabinet can provide containment for hazardous compounding |
| Compounding aseptic isolator (CAI) | Enclosed sterile-compounding PEC; a noncontainment CAI does not replace a hazardous-drug containment isolator |
| Compounding aseptic containment isolator (CACI) | An appropriate containment option for hazardous sterile compounding |
Operating and Cleaning Practices
- Follow the manufacturer's instructions, certification findings, and facility SOPs for startup and recovery after shutdown. Do not assume one startup interval fits every PEC.
- Keep critical sites within the qualified work zone and expose them to unobstructed HEPA-filtered first air. Keep hands and supplies from blocking airflow.
- Use the required sterile cleaning, disinfecting, and sporicidal agents inside the PEC. Alcohol disinfection alone does not replace cleaning or required sporicidal treatment.
- Follow the agent's contact time and the facility's wiping sequence; allow surfaces to dry before compounding.
- Apply sterile 70% isopropyl alcohol at the required times during compounding and to gloves as specified by USP 797 and the SOP.
Certification and Room Placement
A PEC and applicable classified areas must be certified before use and at least every six months, with additional certification when changes require it. Testing includes airflow, HEPA integrity, particle counts, and dynamic airflow visualization. ISO Class 5 allows no more than 3,520 particles of 0.5 micrometers or larger per cubic meter.
For Category 1 preparations, an ISO Class 5 PEC may be in an unclassified segregated compounding area with short BUD limits. Category 2/3 generally require a compliant cleanroom suite; qualifying pharmaceutical isolators have separate placement provisions. Hazardous compounding adds the applicable USP 800 containment requirements.
Exam Alert
Distinguish product protection from personnel/environmental containment. A horizontal LAFW is unsuitable for hazardous-drug compounding; a BSC and an isolator are separate device types, not types of LAFW.
Sources: USP 797 FAQs; Indian Health Service sterile-compounding policy.
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Study guide on MometrixRelated Terms
HEPA Filter
A HEPA (High-Efficiency Particulate Air) filter is an air filtration device that removes at least 99.97% of particles 0.3 microns or larger, used in laminar airflow workbenches and cleanrooms to maintain the sterile environment required for compounding sterile preparations.
Aseptic Technique
Aseptic technique is a set of practices and procedures used in sterile compounding to prevent microbial contamination of compounded sterile preparations (CSPs), including proper gowning, hand hygiene, and manipulation within a laminar airflow hood.
USP 795 and USP 797 (Compounding Standards)
USP 795 and USP 797 are United States Pharmacopeia chapters that establish minimum standards for non-sterile compounding (795) and sterile compounding (797), including personnel training, facilities, equipment, and quality assurance requirements.
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