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Laboratories utilize various experiment for various purposes to support its operations. From ovens, incubators to gloveboxes, selection of the right type of equipment, training on safe proper operations and adequate maintenance and periodic inspections are critical to effective and efficient laboratory operations.  Some common groups of laboratory equipment and safe work practices and procedures are highlighted below. This list is not comprehensive, consult the equipment manufacturer and EHS for additional questions.


Biological Safety Cabinets


Fume Hoods

Flammable Liquid Storage Cabinets

Glove Boxes

Heating Devices

Refrigerator & Freezers

Stirring & Mixing Devices

Pressure and Vacuum Systems

Safety Cans



Autoclaves are used in research laboratories to sterilize materials using saturated steam under pressure. The process has proven effective and reliable for sterilization and disinfection. The researcher must pay attention to compatible and incompatible materials. In general, do not autoclave flammable, reactive, corrosive toxic or radioactive materials. A listing of common compatible and incompatible materials are normally posted around the autoclave facility.

Compatible materials include: Tissue culture flasks, glassware, pipette tips, media solutions, animal food/bedding, waste, polypropylene 0secondary containers), stainless steel, and gloves.

Incompatible materials include: Acids, bases, organic solvent, chlorides, sulphates, seawater, chlorine, hypochlorite, bleach, non-stainless steel, polystyrene, polyethylene, Low-Density Polyethylene (LDPE) and High-Density Polyethylene (HDPE), Poly Urethane.

  • Follow manufacturer recommended guidelines and facility specific standard operating procedures.
  • Every autoclave and sterilizer should be inspected and serviced on a regular basis to ensure the equipment is functioning properly.
  • Utilize tape indicators (autoclave tape) with heat sensitive, chemical indicators with every autoclave load.

Consult with EHS for questions about the 

Disinfection of biological waste for the purpose of disposal through the sanitary sewer system require the establishment of an EHS-approved standard operating procedure for the disinfection and disposal practice as well as documentation of all waste disposed of by this method. Contact EHS for guidance on disinfection of biological waste for the purpose of disposal through the sanitary sewer.

Biological Safety Cabinets

Biological Safety Cabinets are used to protect laboratory personnel working with biological agents from splashes and aerosols. Contaminated air is filtered through high efficiency particulate (HEPA) filters and vented back into the laboratory room. Typically, BSCs should not be used when working with hazardous chemical concentrations or volumes of vapor-emitting chemicals. When properly maintained a, BSC along with good biosafety practices provide an effective containment system for the safe manipulation of low, moderate, and high-risk microorganisms (Risk Groups 1-3).

  • BSC moves must be coordinated with EHS. They must be decontaminated before they are moved, and certified after they are placed at the new location. 
  • Laboratories are responsible for arranging decontamination services
  • Laboratories are also responsible for arranging the movement of cabinets with University Facilities Services.
  • If the cabinet is destined for surplus or disposal, submit a Laboratory Equipment Clearance Form to EHS.

BSCs require annual certification by trained and certified technicians and must be coordinated by EHS. Please contact EHS for general questions about your biosafety cabinet placement, and annual certification/repairs.

Learn more about Biological Safety Cabinet Installation, Repair and Annual Certification at UH.


Centrifuges are typically utilized in the laboratory to separate fluids of different using rapidly rotating container that applies centrifugal force to its contents. From benchtops to floor models, mini and microcentrifuges, they must be properly installed, operated and maintained for effectiveness. It is critical that the load is balanced each time the centrifuge is used and that the lid be closed while the rotor is in motion.

Other Safety Considerations:

  • Must be operated by trained personnel only
  • Install according to manufacturer specifications
  • Do not overfill the centrifuge tubes and ensure they are inserted properly
  • Maintain a maintenance log
  • Follow manufacturer recommended cleaning instructions.
  • Ensure that the disconnect switch is working properly to shut off the equipment when the top is opened. Follow manufacturer’s instructions for safe operating speed.
  • Flammable and/or hazardous materials use in centrifuges mut be under negative pressure to a suitable exhaust system.

Contact your manufacturer or technical representative for routine maintenance of your centrifuge.
For a safety review of your laboratory centrifuge, contact EHS.

Fume Hood

A chemical fume hood is the primary safety device in a laboratory. When well designed, properly installed and maintained, fume hoods offer substantial degree of protection to the laboratory personnel; but it must be used as designed with full understanding of its limitations. When working properly, fume hoods capture, contain and expel chemical fumes to the exhaust, away from the user. When the sash is don, it provides some protective barrier between the user and the chemical or chemical reactions. Pay attention to the following precautions:

  • Ensure validation sticker is current before use.
  • Check for direction of flow using a Kim wipe prior to use (flow must be into the hood, away from the user).
  • Keep sash at the recommended working height (normally 18 inches).
  • Keep chemicals and equipment at least 6 inches behind the sash during experiments
  • Do not use the hood for permanent storage, remove chemicals and equipment after use.
  • Do not use a hood for unintended functions, e.g. perchloric acid cannot be used in conventional fume hoods
  • Do not use fume hood for waste disposal or accumulation

EHS validates fume hood face velocity after installation and initial certification. If you require a fume hood validation, or are unsure if the chemicals that you are working with are compatible with your hood (perchloric acid, hydrofluoric acid, etc.) please contact EHS for assistance.


Flammable Liquid Storage Cabinets

Hazardous chemicals stored left open in the laboratory/work area shall be kept to the minimum necessary for the work being done. When not in use, all flammable chemicals must be kept in an approved flammable liquid storage cabinet. Flammable liquids must also be stored in appropriate storage cabinets when quantities exceed the Total Allowable Quantities.

A flammable liquid storage cabinet is an approved cabinet that has been designed and constructed to protect the contents from external fires. Storage cabinets are usually equipped with vents, which are plugged by the cabinet manufacturer. Since venting is not required by UH Fire Marshal or NFPA standards, and since venting may prevent the cabinet from protecting its contents, vents should always remain plugged. Storage cabinets must also be conspicuously labeled "FLAMMABLE – KEEP FIRE AWAY"

Safety Considerations:

  • When using flammable liquids, no more than 10 gallons (37.9L) may be kept outside of the cabinet at any time.
  • Flammable and combustible liquid storage cabinets shall meet appropriate NFPA standards and may not be modified in any way (Consult with UH Fire Marshal 713-743-5858)
  • Ensure that all stored containers are in good condition, closed and properly labeled.
  • Avoid placing ignition sources (hot materials, flames, or sparking equipment) in the general vicinity of these liquids. If possible, replace open flames by electrical heating.
  • Do not store flammable chemical in the fumehood.

Glove Boxes

Laboratory glove boxes are securely sealed containers with openings on the same or opposite sides, attached with gloves to allow operators work inside an isolated environment. It is commonly used to protect workers from hazardous materials or to protect hazardous chemicals and materials that may be sensitive to air, moisture, or vapor.

Depending on your laboratory operations and applications, you may use either of a containment glove box or an isolation glove box. Containment glove boxes protect laboratory personnel and the surrounding environment from contamination with hazardous materials. Isolation glove boxes (sometimes referred to as Nitrogen glove box) provide controlled isolated atmosphere e.g. inert gas environment during an experiment or while manipulating certain samples.

Safety Considerations:

  • Perform daily inspections of glove boxes to check the condition, of the gloves. Specifically, look for holes, discoloration. Verify that the connection to the exterior is intact. Inspect the condition of the window especially where the window is connected to the rest of the box.
  • Perform a vacuum pump inspection, ensure all vacuum lines are in good condition. Vacuum oil (if present) must be changed according to recommended frequency.
  • Check the condition of the vacuum line exhaust-mist oil filter.
  • Verify that the scrubber cartridges are meet operational parameters (for glove boxes with solvent scrubber and solvent delivery system)
  • Verify that pressure gauges and pressure indicators function within normal operating ranges.
  • Most importantly, follow manufacturer recommendations regarding operations, service, and maintenance. Service or preventative maintenance contract are highly recommended.
  • Plan for contingencies during power outage or loss of nitrogen.
  • Train all operators prior to working with the glove box; maintain documentation of such training.
  • Use nitrile gloves on the glove box gloves to extend the life of the glove box.
  • Avoid over pressurization, for example, by abruptly extending gloves into the glove box which puts undue stress on the system.
  • Glove boxes must be decontaminated prior to disposal. Submit the Laboratory Equipment Clearance Form to EHS for review.

Contact your manufacturer or technical representative for routine maintenance on the system.
For a safety review of your laboratory glove box, contact EHS.

Heating Devices (Ovens, Hot Plates...)

Heating devices such as ovens, hot plates, heating mantles and tapes, oil, salt and sand baths, hot-tube furnaces, hot-air guns, microwave ovens are commonly used in laboratories.

Use steam-based heating devices when temperatures of 100 degree C are required, and the application does not require shock or spark risks. Another advantage is that they can be left unattended.

Other Safety Considerations:

  • Do not leave the experiment unattended.
  • Enclose the heating element to prevent contact with persons and materials that could easily start a fire.
  • Arrange for repairs of worn out heating devices, especially those with exposed heating elements or discard them properly.
  • Place heating devices away from water, chemicals, or flammable liquids.
  • As much as possible, use fail-safe devices to prevent fires or explosions in laboratories should the temperature increase due to an abrupt change in voltage.
  • Follow safe practices outlined for both electrical safety and pressure and vacuum systems.
  • Never operate microwave ovens with doors open to avoid exposure to microwaves.
  • Do not place metal containers and metal-containing objects in a microwave oven as they may produce an arc that can ignite flammable vapors.
  • Carefully select oven and furnace glassware.
  • Sealed containers, even if loosely sealed, can build pressure upon expansion during heating, creating a risk of container rupture.

Contact your equipment manufacturer or technical representative for routine maintenance on the system. For a safety review of your laboratory glove box, contact EHS.


Refrigerators & Freezers

Laboratory refrigerators and freezers, in contrast to domestic household alternatives can release vapors from the contents. The hazardous contents may spill, creating an ignition hazards and there is also the presence of incompatible chemicals. It is unsafe to store flammable liquids in domestic refrigerators or freezers. Laboratory grade refrigerators and freezers are designed to maintain critical storage temperatures despite frequent door openings.

Consequently, only refrigerators and freezers designated for laboratory use must be used to store hazardous chemicals. Most laboratory fridges are UL listed, manufactured with stringent standards required by health, science and industry with explosion proof and flammable options. 

General Laboratory refrigerators and freezers, while not suitable for the laboratory environment may be used to store aqueous solutions only. Flammable materials must not be stored in these units. To prevent ignition of flammable refrigerators, EHS recommends one of three types of refrigerators:

  • “laboratory-safe” or “flammable material”
  • “explosion-proof”
  • previously modified (“desparked”) domestic models

Flammable solids and liquids must only be stored in flammable material refrigerators and freezers. These units have the compressor and other electrical circuits at the top to reduce the potential for ignition of flammable vapors.

Explosion proof units are designed to be operated in areas were the environment outside of the refrigerator could become explosive.

Older domestic refrigerators that were previously modified or “desparked” by a certified technician. UH Fire Marshal office no longer allows “desparking” of domestic refrigerators.  

Please consult with the UH Fire Marshal at Fire & Life Safety (713-743-5858) if you have need for a “laboratory-safe”, “flammable material” or an “explosion-proof” refrigerator prior to procurement.

Safety Considerations:

  • Food and drinks for human consumption are not allowed in laboratory refrigerators and freezers. Post a label to indicate so.
  • Do not store strong oxidizers or acid with flammable liquids. Compressed gases should not be stored in enclosed spaces like refrigerators. Consult with Chemical Safety in EHS for proper storage guidelines.

Disposal Considerations:

  • All biological, radiological, and chemical hazards must be removed from the refrigerator and decontaminated prior to disposal.
  • If the refrigerator was used to store radioactive isotopes, it should be cleaned and surveyed. Contact Radiation Safety in EHS for assistance to confirm that it is free from radioactive contamination prior to disposal.
  • Submit a Laboratory Equipment Clearance Form to EHS for final review and approval


Stirring & Mixing Devices

Laboratories use various devices fr stirring and mixing, such as magnetic stirrers, stirring motors. Shakers, rotary evaporators for solvent removal. In general, operate stirrers and mixing devices in a manner that will not generate electrical sparks.

Safety Considerations:

  • Stirring or mixing operators must be performed in fume hoods for safety reasons.
  • Use spark-free motors in powered stirring and mixing devices or any other rotating equipment
  • As these devices are operated for longer periods without attention, plan for stirrer failure, electrical overload or blockage of the motion on the stirrer.
  • Do not insert your hands while the stirring or mixing devices are in operation.
  • Glass components of the rotary evaporator should be made of Pyrex or similar glass. Enclose glass vessels in a shield to guard against flying glass fragments or debris should the components implode. Increase in rotation speed and application of vacuum to the flask whose solvent is to be evaporated should be gradual.

Contact your equipment manufacturer or technical representative for routine maintenance of mixing and stirring devices. For a safety review of your laboratory stirring and mixing devices, contact EHS.


Pressure and Vacuum Systems

Working with chemicals under extremes of pressure (high or low pressure) presents risks of implosion and /or explosion. Consequently, procedures must be implemented and thoroughly reviewed to protect against such hazards. Such procedures may include the use of safety shields and proper selection of glassware that can withstand designated pressure extremes.

Safety Considerations:

  • Perform high-pressure operations in appropriately selected pressure vessels that are properly labeled, installed, and protected by pressure-relief and necessary control devices.
  • Inspect and test all pressure equipment at intervals designated by the manufacturer.
  • Hydrostatic testing must be performed before equipment is placed in initial service
  • Utilize Personal protective Equipment such as safety glasses or chemical goggles, face shields and/or explosion shields that protect against the hazards of the vacuum procedures. In addition, vacuum procedure should be carried out inside a fume hood.
  • Use a vacuum trap between the experimental apparatus and vacuum source to protect the laboratory personnel working on the vacuum line or system, prevent vapor and odor back flow into the laboratory and protect the pump an piping from damage.

Contact your equipment manufacturer or technical representative for routine maintenance of high pressure or vacuum devices. For a safety review of your laboratory high pressure operations or vacuum systems, contact EHS.


Safety Cans

A safety can is an approved container of not more than 5 gallons (20L) capacity that has a spring closing lid and spout cover. Safety cans are designed to safely relieve internal pressure when exposed to fire conditions. Safety cans are constructed from metal and come equipped with a flame arrestor and spring-loaded caps on both the filling and pouring spouts to prevent spillage when dropped. The double-perforated metal surface of the flame-arrestor screen prevents flames from entering the container.

Safety cans are utilized for both dispensing products and collecting waste and shall not be modified.

NOTE: Many consumer portable fuel containers available at stores do not meet safety can standards.

Safety Considerations

  • Ensure the safety can is UL or FM listed. Consult EHS prior to procurement if unsure.
  • Do not modify safety cans; dispose of safety cans that have been tempered with.
  • Up to 5.3 gallons (20L) of flammable and combustible liquids may be stored in UL or FM listed safety cans
  • A closed container, one sealed by a lid or other device so that liquid and vapor cannot escape at ordinary temperatures is not the same as a safety container.
  • Safety can is one of OSHA approved material for transferring flammable liquids.

For a safety review of your laboratory safety can, contact EHS.