Engineering controls can help isolate people from hazards and make the lab safer, according to the OSHA/NIOSH “Hierarchy of Controls.” Laboratories require specific engineering controls to address biological, chemical, and physical hazards. Appropriate and mandated engineering controls include ventilation, fume hoods, fire extinguishers, eyewash stations, and safety showers. The following list describes common engineering controls found in academic laboratories.
1. Electrical safety controls
To minimize the risks associated with electrical equipment (e.g., shock, electrocution), all science laboratories, storerooms, and preparation rooms need to have ground fault circuit interrupters (GFCI) electrical receptacles. Note: Do not touch the metal prongs of a plug when plugging it into an electrical receptacle.
In addition, GFCI switches need to be tested at least once a year, because they can corrode. To test the GFCI receptacle, just press the “TEST” button on the outlet. If the GFCI switches are working, the power will be cut off of the two plug receptacles. To make sure the power is off, plug in an electrical device such as a lamp. The light should go out. You could also use a voltage tester, which would indicate no power when the “TEST” button is pushed. Once you confirm that the GFCI is working, press the “RESET” button on the outlet, and the power should be restored.
To neutralize corrosive chemical splash exposure hazards, ANSI/ISEA (ANSI / ISEA Z358.1-2014) requires 10-second access to any eyewash station or safety shower in the laboratory. These devices require exposure to tepid water (60–100°F; 16°–38°C) for 15 minutes minimum.
3. Fire blanket
Flame-retardant wool or similar types of materials can be used to smother small lab fires. Secure fire blankets inside wall-mounted canisters or boxes with appropriate signage.
4. Fire suppression
The National Fire Protection Association (NFPA) requires labs to carry fire suppression equipment such as fire extinguishers and fire sprinkler heads due to the risk of fire or explosions from flammable lab chemicals. Fire extinguishers should be of the A-B-C type. Type D fire extinguishers are for combustible metals such as magnesium, potassium, and sodium. Employers must train science teachers annually for proper use of extinguishers if employee use of the extinguishers is allowed.
Emergency evacuation is critical in the event of an explosion, fire, toxins, shock, and more. Laboratory furniture should be placed to facilitate easy movement and fast egress and ensure that there are no trip/fall hazards. Legal occupancy loads per National Fire Protection Association (NFPA) and the International Code Council (ICC) are approximately 50 sq. ft. per lab occupant. Academic/professional occupancy loads should be addressed based on a maximum of 24 students per laboratory (within legal occupancy load levels).
6. Fume hood
Fume hoods provide local exhaust ventilation for hazardous gases, particulates, vapors, and more, which present a risk to lab occupants. Hoods should be checked and certified operational approximately one to four times a year, depending on frequency of use.
7. Goggle sanitizer
State goggle statutes and OSHA PPE standards require eye protection to be sanitized. Ultraviolet goggle sanitizer cabinets take approximately 15 minutes to sanitize goggles. Alternatives to sanitizers include disinfectants, alcohol, or dish detergent.
8. Master shut-off controls
Master shut-off devices for utilities such as electricity, gas, and water are also a must, given the risks of electrocution, shock, and explosion.
Sensors for smoke, heat, and fire are necessary for a safer laboratory, especially during unoccupied times.
10. Safety shields
When there is risk for projectile motion or splashing of chemicals and springs in demonstrations, legal safety practices require use of safety shields, in addition to chemical splash goggles.
Both OSHA and NFPA (NFPA 45) require forced air ventilation in science laboratories, preparation rooms, and chemical storerooms. NFPA 45-2015 requires that laboratory units and laboratory hoods in which chemicals are present shall be continuously ventilated under normal operating conditions.
Academic science labs must have engineering controls in place and effectively operating. The teacher must report to their employer if these controls are not in place or malfunctioning. They also must not do any demonstrations or other lab work until they are installed and functioning correctly.