Class A vs Class B Measuring Cylinders: Which is Right for Your Lab?

Measuring cylinders are essential tools for laboratories, providing a simple and reliable way to measure liquid volumes. But not all cylinders are created equal — accuracy depends on whether the cylinder is Class A or Class B. For Australian schools, universities, and industry labs, understanding this distinction ensures compliance with standards, cost-effectiveness, and reliable results.

What Defines Class A Measuring Cylinders?

Class A measuring cylinders are manufactured to the highest accuracy standards, complying with ISO 4788 and ASTM E1272.

• Tighter tolerances with approximately half the error margin of Class B.
• Often individually calibrated and supplied with certificates for traceability.
• Preferred in analytical chemistry, pharmaceutical labs, and accredited facilities.
• Costlier but essential when precision cannot be compromised.

What Defines Class B Measuring Cylinders?

Class B measuring cylinders meet the same dimensional standards but with wider tolerances.

• Designed for general-purpose use where small variations are acceptable.
• Widely used in teaching labs, industrial settings, and routine tasks.
• More affordable, making them practical for high-volume educational use.
• Provide reliable measurements, though less accurate than Class A.

Why Borosilicate Glass is Preferred

Regardless of class, most high-quality cylinders are made from BORO 3.3 borosilicate glass:

• High resistance to heat, allowing autoclaving and sterilisation.
• Chemical durability against solvents, acids, and alkalis.
• Clarity for accurate reading of graduations.
• Long service life, supporting sustainable laboratory practices.

Comparison Table: Class A vs Class B Measuring Cylinders

FAQs

Q1: Do schools need Class A measuring cylinders?
Not usually. Class B cylinders provide sufficient accuracy for teaching environments at a lower cost.

Q2: Are Class A cylinders worth the investment for research labs?
Yes. Their tighter tolerances ensure reproducibility and compliance with ISO/ASTM standards.

Q3: How can I tell if a cylinder is Class A or B?
It is usually marked on the glass near the graduations. Class A cylinders may also include calibration certificates.

Q4: Are both Class A and Class B cylinders autoclave-safe?
Yes, if made from BORO 3.3 glass, both types can withstand autoclaving.

References

• ISO 4788: Laboratory Glassware — Graduated Measuring Cylinders.
• ASTM E1272: Standard Specification for Laboratory Glass Graduated Cylinders.
• ISO 3585: Borosilicate Glass 3.3 — Properties and Standards.
• University of Melbourne Analytical Chemistry Guidelines.
• NIST Chemistry WebBook, National Institute of Standards and Technology.