Laboratory glassware is often subject to repeated use and while many products are designed to withstand this and don't have a specified lifespan as such, they can nevertheless be subject to stresses and general ware and tear, especially if they have been used in certain conditions.

Even damage that is not immediately noticeable can easily lead to a failure that could have a serious impact on the safety of those working in the lab, the substances they are working with and the validity of the processes they are carrying out.

It is therefore important to anticipate any damage at an early stage. This article explores some of the indications that might suggest a product has been damaged, how to carry out an inspection of laboratory glassware and how to dispose of damaged laboratory glassware safely.

Spotting Signs of Stress

Day to day activity places stress on laboratory glassware and minor accidents or incorrect initial usage can lead to wider problems.

Here are some factors that can lead to damaged glassware.

1. Has the product been knocked or dropped?

Many items, especially those made of borosilicate 3.3 glass which is manufactured to specified industry standards, may remain intact if dropped or knocked over. But while some incidents might be harmless, others might introduce points of weakness into a glass product that otherwise looks functional.

It is therefore advisable to take particular care when inspecting glassware that has been knocked over or dropped as even the smallest of cracks could be a major source of weakness. If you are uncertain about the severity of damage after a product has been knocked or dropped, it is always safest to dispose of the product.

2. Has the product been incorrectly heated?

While many items of laboratory glassware are deliberately designed to be heated, doing so in an incorrect manner will place stress on the glass and might lead to future accidents.

For example, all laboratory glassware should be heated and cooled in a gradual manner, to avoid the risk of thermal shock. Heat should also be distributed evenly across the surface of the product to avoid creating hotspots that could cause weakness in the glass. Being aware that an item of glassware has been incorrectly heated is another reason to carry out a proper visual inspection. And potentially dispose of the product.

3. Has the product being incorrectly autoclaved?

Putting products through an autoclave cycle is often essential, especially if they are to be reused. While many items of laboratory glassware are perfectly suitable to autoclave, the cycle must still be carried out correctly to avoid damaging the product.

When sterilising or autoclaving bottles with screw caps for example, the cap must be loosely fitted with a maximum of one turn applied. This will avoid a large pressure difference that will occur in a closed vessel. Such a difference can result in either explosive failure at the point of autoclaving or damage to the glass that might lead to future failure.

4. Has the product been subject to unsuitable pressure or vacuum conditions?

Standard laboratory bottles and other forms of glassware are not recommended for use in pressure or vacuum conditions. Pressure above 1 bar or the presence of a vacuum may lead to stress in the glass. Any glassware that is already showing signs of any damage must not be used subject to pressure or a vacuum. If you are working with positive or negative pressure, only products with the appropriate geometry and wall thickness should be used, such as DURAN® pressure plus+ laboratory bottles.

Carrying out an inspection of laboratory glassware

Regular inspections of laboratory glassware are recommended, especially if the product has been subject to stress or potential damage as described above. Before carrying out an inspection, adequate PPE should be worn, such as gloves, lab coats and safety glasses.

Any inspection of laboratory glassware should be carried out with sufficient lighting and a black and white backdrop to provide adequate contrast and to allow maximum visibility of flaws. A minimum illumination intensity of 1,000 lux is recommended. This is the equivalent light experienced on an overcast day. Light levels should be uniform in nature too, with glares and light flickers avoided where possible as this might lead to damage going unnoticed.

When inspecting glassware, look for any signs of chips, cracks, scratches or bubbles. Any mark in the uniform surface of glassware is also a potential breaking point, especially when the piece is heated or placed through an autoclave cycle.

Disposing of damaged glassware safely

If any damage, or even suspected damage, has occurred glassware should be safely disposed of as soon as possible.

Damaged glassware should be placed in a properly labelled, puncture-resistant box so that all personnel will exercise due caution when handling it.

If the glassware has broken or shattered, avoid handling pieces without proper PPE.

Finally, any broken glass should be free of chemical and biological hazards before disposal. This might mean broken items of laboratory glassware require cleaning - a process that must also be carried out with adequate PPE and care.