Chemical Fume Hoods

Chemical fume hoods are a primary method of exposure control in the laboratory. Fume hoods are ventilated enclosures used to protect laboratory users from toxic fumes and vapors generated by various operations and laboratory procedures.

Fume hoods are engineering controls, meaning that they physically isolate people from hazards. Engineering controls are an effective method of control for work with chemicals where elimination or substitution of the hazardous chemical is unsuitable for the laboratory process or procedure.

Fume hoods provide adequate protection for most laboratory processes using hazardous chemicals when used correctly. The following are considerations for working safely in a chemical fume hood.

Before using a chemical fume hood:

1. Ensure you have received hands-on training on how to use each type of chemical fume hood you will be using in the laboratory. Ensure you know all parts of your fume hood and how they work, how your airflow monitor works and what alarms or alerts mean, and how to conduct your laboratory operations within the fume hood.
2. Review the EHS Annual Fume Hood Inspection sticker on your fume hood to ensure the inspection is up-to-date and the fume hood has passed inspection (green sticker) or is approved for your specific-use (indicated on a yellow sticker).
3. Review the Safety Data Sheets (SDSs) for all chemicals that you will be using prior to use.
4. Review the airflow monitor for the current fume hood condition prior to each use and throughout the work session. Airflow monitors provide continuous monitoring for fume hood conditions. Stay alert of the airflow monitor status and respond to any alarms or alerts. Stop work if conditions are indicated to be unsafe.
5. Ensure the fume hood is turned on.
6. Open the sash to the lowest, safe working height for your operations. Never open the sash above the maximum working height as indicated on the fume hood.
7. Wear personal protective equipment (PPE) as indicated for the hazards you are working with. Safety Data Sheets (SDSs), the laboratory hazard and PPE assessment, laboratory-specific procedures, and the laboratory sign may all be reviewed and considered to select appropriate PPE for the materials you are working with and the processes you are conducting. If you have any questions about PPE selection, please contact EHS prior to conducting work.

Working in a fume hood:

1. Always wear your personal protective equipment (PPE) selected for the materials and processes you are conducting while working in the fume hood. PPE may include eye protection, a lab coat and gloves. Long pants and closed-toe shoes should also be worn.
2. Work at least 6 inches inside the fume hood from the sash opening. This allows for greater personnel protection from hazardous materials.
3. Ensure that you do not block the airfoils or the baffles with materials or equipment.
4. Any large equipment should be elevated off the working surface to allow airflow around and under the equipment.
5. Only store the amount of materials and equipment needed for your current processes inside the fume hood. Excessive storage of materials and equipment may impact fume hood performance.
6. Keep abreast of the fume hood condition when working in it. Check the airflow monitor periodically throughout the work session. If the airflow monitor indicates conditions are unsafe, or if you have any concerns about fume hood performance, close the fume hood sash. Notify any potential users of the fume hood of the fume hood status. Any out-of-order fume hood conditions or concerns should be reported to EHS at safety@ksu.edu or 785-532-5856 so the fume hood can be inspected.
   
   You may perform a visual check of fume hood inward airflow by using a Kimwipe (or other light tissue/paper) and holding it up near the open sash and visualizing if the Kimwipe is pulled into the fume hood. Do not let go of the Kimwipe during this visual verification of airflow.
   
7. After each work session, ensure the fume hood is turned off and the sash is shut. Close all chemical containers and power off any equipment stored in the fume hood. Remove any items that do not require storage in the fume hood. Notify your department safety coordinator of any operations or processes continuing unattended or overnight.

Resources:

• OSHA Quick Card - Chemical Fume Hoods
• Overview of Hoods and Enclosures - Labconco
• Printable Golden Rules Fume Hood Poster from Laboratory Safety Institute
• Video: Fume hood safety DOs and DON'Ts! - Labconco

The Department of Environmental Health and Safety (EHS) Research and Laboratory Safety Program performs annual inspections of all chemical fume hoods at Kansas State University. Inspections verify fume hood performance by qualitatively evaluating the capture and inward pull of smoke by the fume hood, and quantitatively measuring the average face velocity (in feet per minute) of airflow into the fume hood.

Qualitative smoke testing is conducted using a SmokPoint Air Flow Indicator. This indicator provides a continuous stream of “smoke” that allows for visualization of inward airflow and capture efficiency of each chemical fume hood. The smoke is a mixture of glycerin and distilled water.

Quantitative face velocity measurements are taken using a TSI VelociCalc. The TSI VelociCalc is a hot-wire ventilation meter that calculates instantaneous flow velocity from electric voltage measurements. Measurements are taken at the face of the fume hood with the sash open to the designated maximum working height. Individual measurements are taken for each square foot at the face of the fume hood, and then measurements are averaged to result in the final reported face velocity in feet per minute (fpm). The TSI VelociCalc is factory calibrated on an annual basis.

Fume Hood Inspection Schedule

Chemical fume hoods are inspected annually by Department of Environmental Health and Safety staff. Inspections verify fume hood performance by qualitatively evaluating the capture and inward pull of smoke by the fume hood, and quantitatively measuring the average face velocity (in feet per minute) of airflow into the fume hood.

Department leadership, main offices, and safety coordinators will be notified prior to inspections with contact information available to Environmental Health and Safety.

Fume Hood Inspection Criteria and References

References

The following codes and standards inform fume hood performance criteria. These codes and standards guide fume hood inspection criteria on campus.

Fume Hood Inspection Results

EHS has new fume hood inspection labels starting in 2024. The labels are green, yellow, and red/orange corresponding to the fume hood inspection result. The following chart describes the use of the three different colored labels. A fume hood inspection label should be present on each fume hood on campus, and the past inspection date should be within the past year.

EHS Fume Hood Labels

A final report will be sent to department leadership and safety coordinators at the completion of fume hood inspections.

A work order with Facilities Customer Service should be submitted for all failed fume hoods by the responsible laboratory group or department. Facilities customer service can be reached at: 785-532-6389 or faccustomerservice@k-state.edu. The fume hood failure reason will be listed on the final report. Some common failure reasons are detailed in the table below:

Failure Reasons Noted on Report:

Out of Use/ Out of Service Fume Hoods

Fume hoods no longer in use may be removed from the EHS annual inspection schedule. To take a fume hood out of service, please notify EHS. Please share the room number and fume hood ID (listed on the EHS inspection sticker). EHS will post signage on the fume hood indicating that it is out of service, is no longer receiving annual fume hood inspections to verify performance and may not be used until it has passed EHS inspection. Contact EHS prior to use of any out of service fume hoods for inspection.

Airflow monitors are required for fume hoods at Kansas State University on newly purchased fume hoods, remodeled and renovated laboratory spaces, and as part of major repairs.

There are many different airflow monitors that may be used for end users to verify performance of a chemical fume hood prior to each work session. The purpose of this webpage is to introduce the regulatory language surrounding airflow monitors, the function of airflow monitors for chemical fume hoods, the types of airflow monitors you may encounter at Kansas State University, and what to do in the event that your airflow monitor is not working as intended or is presenting with an alarm or language about fume hood performance.

Airflow Monitors at Kansas State University and Troubleshooting

*Section pending to provide the following information for all air flow monitors at Kansas State University. EHS is collaborating with Facilities to provide this information to all fume hood users at the university.*

Name

Picture of Monitor

Description

How to Use

Please contact EHS at safety@ksu.edu or 785-532-5856 for the following conditions:

• If you are working in a chemical fume hood without an airflow monitor

• If you are unsure about the operation of the airflow monitor on your fume hood

• If your airflow monitor is in an alarm status

• If any part of your airflow monitor is not operating as intended

• If you have any concerns about the performance of your fume hood regardless of airflow monitor status
  

Regulatory Language for Chemical Fume Hood Airflow Monitors

Multiple standards reference the use of airflow monitors for chemical fume hoods. The table below summarizes some of these standards and the pertinent language.

If you would like to purchase a chemical fume hood for your laboratory or recycle a fume hood that is no longer in use, please contact EHS at safety@ksu.edu or 785-532-5856. We are happy to help you with these processes.

We referenced the following resources in creation of our webpage: Labconco Corporation, Occupational Safety and Health Administration (OSHA), National Fire Protection Association (NFPA), Laboratory Safety Institute, American Society of Safety Professionals