Care & Maintenance

Safe use of Glassware

With proper care and correct heating practices, laboratory glassware can provide long, reliable, and efficient service. The following guidelines are designed to help users maximize the lifespan, safety, and performance of their glassware during routine use.

Heating and Cooling

Glass may suffer damage in three ways:

Glass can fail under thermal stress, even when operating under 'steady state' conditions.
Sudden heating or cooling (thermal shock) can cause cracking or breakage.
When glass is heated beyond its recommended temperature and then cooled, it may retain residual (permanent) stress, which can lead to delayed or subsequent failure during use.

The following suggestions will help in avoiding failures during heating and cooling procedures

Proper handling and heating of laboratory glassware are essential for safety, performance, and long service life. Please follow the guidelines below carefully:

During evaporation, never leave the vessel unattended. As the liquid level drops, reduce the temperature gradually to avoid dryness. Overheating a dry vessel can cause cracking or explosion.
Always exercise caution when placing a hot vessel on a cold or damp surface. Sudden temperature changes can lead to thermal shock and breakage.
Allow glassware to cool slowly and naturally. Rapid cooling increases the risk of thermal stress and breakage.
Do not apply heat to glassware that is badly scratched, cracked, or etched, as it significantly increases the chance of failure.
Avoid direct point heating. Always diffuse heat using a metal gauze, air bath, or water bath. Alternatively, ensure uniform heating by gently moving the vessel relative to the heat source.
Uniform heating is critical for many chemical reactions. Use a large, soft Bunsen burner flame and heat slowly to distribute temperature evenly.
Adjust the flame so it contacts the vessel below the liquid level to minimize stress and prevent breakage.
When rapid heating is required, always use anti-bumping devices such as pumice stones or glass wool to prevent sudden boiling and internal abrasion.
Thick-walled glassware should be heated using an electric immersion heater and must not be exposed to direct flame or localized heat sources.
Do not place glassware on electric heaters with exposed heating elements, as this can cause localized stress and increase the risk of breakage.
Ensure the hot plate surface area is larger than the base of the vessel being heated to allow even heat distribution.
When using any electrical equipment, strictly follow the manufacturer’s operating instructions.

Mixing and Stirring

When using a glass vessel with a magnetic stirrer, always use a covered stir bar (follower) to prevent abrasion or scratching of the vessel’s interior surface.
Before operating a glass or metal mechanical stirrer in a glass vessel, carefully set and verify the stirrer height. Ensure the stirrer blades do not come into contact with the bottom or sides of the vessel to avoid damage during operation.

Vacuum and Pressure

Always follow proper safety procedures when working with pressurized or vacuum glassware.
Do not operate scientific glassware beyond its specified pressure or vacuum limits.
Apply and release both positive and negative pressure gradually. Sudden pressure changes must be avoided to prevent damage or failure.

Personal Safety

Always use tongs or heat-resistant (asbestos) gloves to remove glassware from heat sources to avoid burns or breakage.
Strictly follow all recommended safety measures and standard laboratory practices.
Before opening any acid bottle, rinse the exterior thoroughly with water to remove possible residues.
Mercury containers must be kept tightly stoppered at all times. Mercury toxicity is cumulative, and its ability to amalgamate with various metals is well known.
Never taste or smell chemicals for identification, and never drink from laboratory glassware such as beakers.
Label all containers before filling them. Never use unlabeled containers, and safely dispose of the contents of any container without proper identification.
Avoid glass-to-metal contact when clamping glassware. Do not overtighten clamps, as excessive pressure can cause breakage.
If acids, caustic substances, or strong oxidizing solutions splash onto skin or clothing, rinse immediately with large quantities of water.
When working with highly toxic gases such as chlorine, hydrogen sulphide, carbon monoxide, or hydrogen cyanide, always use a protective mask or conduct experiments inside a fume hood in a well-ventilated area.
While handling volatile substances, remember that heat causes expansion. Confined expansion can result in dangerous explosions.
Perchloric acid requires special caution. It can explode on contact with organic materials. Do not use it near wooden benches or tables. Store bottles on glass or ceramic trays with sufficient capacity to contain spills. Always wear appropriate protective clothing when handling perchloric acid.
When using hot plates or electrical equipment, ensure wires and plugs are in good condition. Never touch electrical connections with damp or wet hands.

Cleaning

Accurate and reliable experimental results depend on the use of properly cleaned laboratory apparatus. All laboratory glassware must be physically clean, free from visible residues, and in most applications, chemically clean. In certain sensitive procedures, glassware must also be bacteriologically clean or sterile.

Even trace amounts of grease, contaminants, or residues can compromise results. The most reliable indicator of cleanliness is the uniform wetting of the glass surface when rinsed with distilled water. Any disruption to this uniform wetting may lead to errors such as meniscus distortion and inaccurate volume measurements.

Proper care and maintenance of laboratory glassware ensure precision, repeatability, and safety in every experiment.

General Cleaning

Cleaning of glassware that has contained hazardous materials must be carried out only by experienced and trained personnel.
Most new glassware is slightly alkaline in nature. For accurate and sensitive chemical testing, new glassware should be soaked for several hours in acidified water (1% hydrochloric acid or nitric acid) prior to washing.
Glassware contaminated with blood clots, culture media, or similar biological materials must be properly sterilized before cleaning.
Glassware that is excessively cloudy, heavily soiled, or contains coagulated organic matter should be cleaned using a chromic acid cleaning solution. Dichromates must be handled with extreme caution, as they are highly corrosive.
Glassware should be washed as soon as possible after use. If immediate washing is not possible, items should be soaked in water to prevent residues from drying.
Grease and oily residues can be removed using a weak sodium carbonate solution, acetone, or other suitable fat solvents. Strong alkalis must never be used, as they may damage the glass.
Hot water with recommended laboratory detergents should be used for routine cleaning. For heavily soiled glassware, a mild abrasive cleaning powder may be applied, provided the glass surface is not scratched.
During washing, all parts of the glassware must be thoroughly scrubbed using brushes appropriate to the shape and size of the item. Brushes should be well-maintained and free from damage to prevent abrasion.
When chromic acid cleaning solutions are used, glassware may be rinsed with the solution or filled and allowed to stand. The soaking time depends on the level of contamination.
Certain precipitated materials may require removal using nitric acid, aqua regia, or fuming sulphuric acid. These substances are extremely corrosive and should be used only when absolutely necessary and with proper safety precautions.
It is essential that all soap, detergents, and cleaning agents are completely removed before use. Even trace residues can interfere with serological and culture reactions. After washing, rinse thoroughly with tap water by partially filling, shaking, and emptying the container several times. Perform a final rinse with demineralized or distilled water.
Drying may be carried out in baskets or on pegs, either in air or in an oven at temperatures not exceeding 120°C.
Clean glassware should always be protected from dust by using temporary closures or storing it in a clean, dust-free cabinet.

Apply Now

Vacancy for Senior Process Design Engineer