Basic Documentation
Table Of Contents
- Introduction
- Applicable Definitions (Alphabetical Listing)
- Laboratory Safety
- Hazard Assessment
- Chemical Hygiene Plan
- Chemical Hygiene Responsibilities
- Fume Hoods
- When Required & Safe Usage
- Gloveboxes:
- Face Velocity
- Face Velocity Setback
- Size & ADA Compliance
- CAV (Constant Air Volume) Bypass
- CAV (Constant Air Volume) Conventional
- VAV (Variable Air Volume)
- VAV Diversity
- Automatic Sash Closure
- Safe Operation of Sashes
- Accessories, Services and Explosion Protection
- Ductless
- Auxiliary Air
- (Special Purpose) Perchloric Acid
- Room Air Cross Currents
- Minimum Exhaust
- Monitoring
- Selection Criteria and Performance Specifications
- Laboratory Design & Fume Hood Implementation
- Maintenance
- Periodic Testing
- Test Procedures
- Signage and Recordkeeping
- Shutdown Procedures
- Evaluating CAV (Constant Air Volume) Systems
- Evaluating VAV (Variable Air Volume) Systems
- Biological Laboratories
- Biosafety Level 1
- Biosafety Level 2
- Biosafety Level 3
- Biosafety Level 4
- Ventilation for Biosafety Level 1
- Ventilation for Biosafety Level 2
- Ventilation for Biosafety Level 3
- Ventilation for Biosafety Level 4, Cabinet Laboratory
- Ventilation for Biosafety Level 4, Suit Laboratory
- Containment Levels - Canada
- Containment Levels and Ventilation Requirements: Canada
- Biological Safety Cabinets and Classifications
- Biosafety Cabinet Applications
- Biosafety Cabinets – Installation and Safe Usage Recommendations
- Biosafety Cabinets – Certification and Safe Usage - Canada
- Biological Safety Cabinet Design, Construction and Performance Requirements
- Biosafety Cabinet Testing
- Ventilation Systems
- Local Ventilation -When Required
- Ventilation Rates for Animal Rooms
- Ventilation Rates for Animal Rooms
- Ventilation Rates for Biological Labs
- Ventilation Rates for Chemical Laboratories
- Ventilation rates for Storage areas
- Room Supply Air
- Supply Air Quality and Filtration
- Room and Duct Pressurization
- Human Occupancy, Room Temperature and Humidity
- Animal Rooms Room Temperature and Humidity
- Load Calculations
- Room Sound Level and Vibration
- Emergency Control Provisions
- Energy Conservation
- Monitoring
- Maintenance
- Periodic Inspection and Testing
- Periodic Inspection and Testing - Canada
- Test Records
- Management
- Exhaust Systems
- Configuration
- Leakage
- Components
- Manifolded Systems
- Air Velocity
- Stack Height and Discharge Location
- Operational Reliability
- Recirculated Air and Cross Contamination
- Materials and Fire Protection
- Commissioning
- Commissioning - Canada
- Referenced Publications
Biological Laboratories
Siemens Industry, Inc. 77
Topic Requirement(s) Commentary
Biological
Safety Cabinets
and
Classifications:
(Continued)
The Class II, Type A1 BSC: An internal fan draws sufficient room air through the
front grille to maintain a minimum calculated or measured average inflow velocity
of at least 75 lfm at the face opening of the cabinet. The supply air flows through a
HEPA filter and provides particulate-free air to the work surface. Airflow provided in
this manner reduces turbulence in the work zone and minimizes the potential for
cross-contamination. The downward moving air “splits” as it approaches the work
surface; the fan
6 draws part of the air to the front grille and the remainder to the
rear grille. Although there are variations among different cabinets, this split
generally occurs about halfway between the front and rear grilles and two to six
inches above the work surface. The air is drawn through the front and rear grilles
by a fan pushed into the space between the supply and exhaust filters. Due to the
relative size of these two filters, approximately 30% of the air passes through the
exhaust HEPA filter and 70% recirculates through the supply HEPA filter back into
the work zone of the cabinet. Most Class II, Type A1 and A2 cabinets have
dampers to modulate this division of airflow. A Class II Type A1 BSC is not to be
used for work involving volatile toxic chemicals. The buildup of chemical vapors in
the cabinet (by recirculated air) and in the laboratory (from exhaust air) could
create health and safety hazards.
The proper method of connecting a Type A1 or A2 cabinet to the building exhaust
system is through use of a canopy hood,
8,10 which provides a small opening or air
gap (usually 1 inch) around the cabinet exhaust filter housing (Figure 4). The
airflow of the building exhaust must be sufficient to maintain the flow of room air
into the gap between the canopy unit and the filter housing. The canopy must be
removable or be designed to allow for operational testing of the cabinet. Class II
Type A1 or A2 cabinets should never be hard-ducted to the building exhaust
system.
8 Fluctuations in air volume and pressure that are common to all building
exhaust systems sometimes make it difficult to match the airflow requirements of
the cabinet.
The Class II, Type B1 BSC: Some biomedical research requires the use of small
quantities of hazardous chemicals, such as organic solvents or carcinogens.
Carcinogens used in cell culture or microbial systems require both biological and
chemical containment. The Class II, Type B cabinet was designed for
manipulations of minute quantities of hazardous chemicals with in vitro biological
systems.
The cabinet supply blowers draw room air (plus a portion of the cabinet’s
recirculated air) through the front grille and through the supply HEPA filters located
immediately below the work surface. This particulate-free air flows upward through
a plenum at each side of the cabinet and then downward to the work area through
a backpressure plate. In some cabinets, there is an additional supply HEPA filter to
remove particulates that may be generated by the blower-motor system.
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