Autoclaves & Glass Washers

Best practices for these workhorses of the lab

Autoclave Best Practices

Consult the autoclave manual for assistance in choosing the correct cycle parameters depending on the load type. Autoclave manuals should be stored near the autoclave.

Choose the correct cycle

Gravity, Liquid or Vacuum to meet the sterilization requirements of various loads, including red bags, media, glassware, cages, animal bedding, and pipette tips, etc.

With all cycles, the usual operating temperature is 121°C (250°F) and 15 psi pressure.

Key points about each cycle:

Gravity cycle:

Key feature: Typically used for simple, non-porous items such as glassware, biohazardous material (red bag waste), vented containers, and certain types of unwrapped instruments, utensils and waste.

Mechanism: Steam displaces air by gravity, pushing cold air out the bottom. 

Potential drawback: May not be suitable for porous materials as air pockets can remain. 

Liquid cycle:

Key feature: Designed for sterilizing liquids and uses a longer cycle with slower heating and cooling phases to prevent boiling over and splashing.  

Important consideration: Adjust cycle time based on the volume of liquid. 

Vacuum cycle (pre-vacuum):

Key Feature: Used for porous materials or wrapped items where air removal is crucial, such as cages with animal bedding, wrapped goods, or surgical packs.

May require: Multiple vacuum pulses depending on the load.

Choose the right container 

For all cycles, ensure the container you are using can withstand both the temperature and pressure. Glass, metal and HDPE (High Density Polyethylene) plastic are acceptable materials.

Preparation

• Inspect items: Ensure that materials to be autoclaved are autoclavable (e.g., avoid non-heat-resistant plastics).
• Loosen lids: If autoclaving liquids, loosen caps or use vented closures to prevent pressure build-up.
• Use autoclave-safe bags: Place biological waste or contaminated items in appropriate autoclave-safe bags.
• Avoid overloading: Ensure steam can circulate freely by not overloading the autoclave chamber.

Operating Procedure

• Pre-checks: Verify water levels, gasket condition, and overall cleanliness of the autoclave.
• Choose correct settings: Select the appropriate cycle (e.g., gravity, pre-vacuum, or liquid cycle) depending on the materials.
• Add water to liquids: For liquids, ensure sufficient water is in containers to avoid evaporation.
• Run a validation test: Use biological indicators or autoclave tape to confirm effective sterilization.

Post-Cycle Handling

• Cool items properly: Allow hot materials to cool to a safe temperature to avoid burns or explosions from pressurized liquids.
• Check for leaks or spills: Inspect items for integrity post-autoclave, particularly liquid containers.
• Record usage: Maintain a log of autoclave cycles for quality control and compliance.

Maintenance

• Regular servicing: Schedule regular maintenance to ensure the autoclave performs properly.
• Clean periodically: Remove residue, particularly from the drain and chamber, to prevent clogs or contamination.
• Monitor performance: Use thermocouples or biological spore tests periodically to verify proper sterilization.
• Check your water quality: Many problems with autoclaves can be attributed to poor water quality. In areas with water that has high mineral content, use only ROI, distilled or filtered water to avoid problems.

Autoclave Safety

When loading, operating, or unloading an autoclave, laboratory personnel must wear the following:

• Close-toed shoes
• Safety glasses
• Heat-resistant gloves that completely cover the hand and forearm
• Lab coat

This protective gear is designed to protect the wearer from scalds, burns and other injuries caused by residual steam, hot fluids from boiling liquids and spillage. Since laboratory autoclaves use a jacketed construction, laboratory personnel should be aware that metal surfaces can be hot even when the autoclave is not actively in use.

Finally, always be mindful of your hands and arms when closing the autoclave door to prevent injury.

Glasswash best practices

Pre-Washing

• Rinse immediately: Prevent residues from drying on glassware by rinsing immediately after use.
• Segregate glassware: Separate glassware based on contamination type (chemical, biological) to avoid cross-contamination.
• Check for damage: Inspect glassware for cracks or chips to avoid accidents.

Cleaning

• Use appropriate detergents: Select non-corrosive, residue-free detergents designed for laboratory use.
• Soak as needed: Soak stubborn residues to reduce scrubbing effort and avoid scratches.
• Use a glass washer: For large-scale cleaning, use an automated glass washer with deionized or distilled water for rinsing.
• Clean pipettes carefully: Use specialized pipette washers for delicate glass pipettes.

Rinsing and Drying

• Rinse thoroughly: Perform multiple rinses, including a final rinse with deionized water to remove detergent residues.
• Dry in an oven: Use a drying oven set to appropriate temperatures to avoid thermal shock or warping.
• Air-dry when necessary: For sensitive glassware, air-drying in a dust-free environment is recommended.

Post-wash Storage

• Store carefully: Arrange glassware in designated areas to prevent accidental breakage.
• Label clean glassware: Clearly indicate sterilized and ready-to-use glassware to avoid confusion. A separate storage space for dirty glassware is advised.

Quality Control

• Spot checks: Inspect cleaned glassware for residue, cloudiness, or stains.
• Maintain records: Keep logs of cleaning protocols, especially for critical experiments.

Choosing the Right Autoclave and Glass Wash Equipment

When selecting the best autoclaves or glass washers for your lab, remember that sometimes the simpler models can do the job at a lower cost than the fancy ones with multiple options. When you plan your budget, include fees for routine maintenance and extra for emergencies should something malfunction. Talk to your vendors to ensure you understand what the warranty covers and what you may have to pay for out of pocket.

Additional Tips

• Training: Ensure all staff handling autoclaves and glass wash procedures are appropriately trained. The vendor of your equipment should be able to provide training. All VFP lab staff are properly trained in using autoclaves and glass wash equipment.
• Safety Gear: Use appropriate PPE (e.g., heat-resistant gloves for autoclaving, splash goggles for glass washing, etc.).
• Compliance: Follow institutional and regulatory guidelines for sterilization and cleaning. Always follow the manufacturer’s guidelines for your specific equipment.

These best practices ensure safety, efficiency, and compliance in laboratory operations.

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