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The laboratories at KAUST are provided with general ventilation adequate for comfort and sufficient to supply air for chemical fume hoods and other local ventilation devices. Because the general air supply is not adequate for manipulating hazardous materials on an open lab bench, volatile or toxic chemicals shall be handled in a chemical fume hood or other appropriate containment device.
The air pressure in laboratories is maintained at a pressure that is negative with respect to the rest of the building in order to keep airborne substances generated in the laboratory from entering the outside public spaces. In general, doors to labs should remain closed to ensure the
laboratory maintains a proper air balance.
More information can be found in the Lab Ventilation Management Program
Laboratory Ventilation Management Program (LVMP)
Chemical fume hoods are installed in laboratories to protect individuals from airborne substances (gases, vapors, mists, fumes) generated by laboratory experiments. However, simply conducting these experiments in the fume hood does not guarantee adequate protection. The fume hood must be used properly.
Control Banding is a system for assigning generic protection strategies to similar hazards based on a risk assessment of specific instances of those hazards; the hazards are grouped into “bands” that can be managed by the same suite of controls. Factors to consider in making this assignment in the context of laboratory ventilation include chemical hazard, quantity, and the potential for airborne emissions in the laboratories and building. It is important to note that some processes may fall outside a specific control banding system due to unusual hazards or application.
Determination as to whether a specific area, device, or process is appropriate for control banding is the first step in making a control banding assignment.
In the chemical laboratory, general dilution ventilation is a core engineering control of occupant chemical exposures during normal operations. Specification of general ventilation rates should be based on a risk assessment of the hazards associated with the use of volatile chemicals in the laboratory, as outlined in ASHRAE - Classification of Laboratory Ventilation Design Levels (2018). Over-ventilation of laboratory spaces can interfere with the use of the laboratory for specific operations and can make the detection and diagnosis of operational and ventilation problems in the laboratory more difficult.
In this program, ventilation rates are optimized to utilize energy appropriately and contain costs to the university.
Chemical fume hoods are installed in laboratories to protect individuals from airborne substances (gases, vapors, mists, fumes) generated by laboratory experiments. However, simply conducting these experiments in the fume hood does not guarantee adequate protection. The fume hood must be used properly.
Laboratories in which there are significant volatile chemicals or specific process hazards for which employee exposures are expected to be controlled by the general ventilation system. These labs are designated for ventilation at 10 air changes per hour (ACH) when the laboratories are occupied and 8 ACH when the labs are unoccupied. This recommendation relies on the expectation that significant point sources of volatile chemicals are contained by effective local exhaust, in the form of a fume hood, local point exhaust, or an appropriate chemical storage cabinet. For this reason, in these control bands laboratory workers will be trained in best practices for using ventilation systems in the laboratory, specifically in the proper use of the specific fume hood models and control systems provided in their laboratory and the process of deciding which processes should be located in a fume hood based on risk criteria.
In many cases, where use of volatile chemicals are more limited, the specified ventilation rates can be lowered to 6 ACH occupied / 4 ACH unoccupied. Specific chemical classes that require this level of ventilation are those that are used in concentrations and quantities that can create odors and nuisances.
Some specific laboratory uses of chemicals may require higher or lower ventilation rates than those generically described above due to specific hazards or requirements that arise from the processes conducted in the laboratory. Assignment of ventilation requirements for these situations lies outside the scope of the generic control banding process and requires specific analysis to determine ventilation needs. Examples of such situations include animal use areas, semi-conductor processing facilities, and glass-cleaning rooms without local exhaust ventilation, or areas where non-chemical hazards are present.
In the lowest hazard control band are laboratories where the chemicals used are minimal and ventilation requirements can be lowered to those required to support air exhaust from the space, temperature and human occupancy needs for the room to 4 ACH occupied and 2 ACH unoccupied. It should be noted that such rooms may have other hazards, such as lasers, welding fumes or significant heat sources which may drive risk-based ventilation needs. One potential strategy is to manage these occasional or discrete chemical risks with local exhaust ventilation rather than general ventilation.
