Class A vs Class B Measuring Cylinders – What’s the Difference?

Measuring cylinders are essential for volume measurement in any laboratory, but not all cylinders are created equal. The distinction between Class A and Class B accuracy is critical for ensuring reliable results, whether in education, research, or industry.

Accuracy Standards Explained

According to ISO 4788 and ASTM E1272, measuring cylinders are classified into Class A and Class B based on tolerance levels.

• Class A Cylinders – Highest accuracy with tighter tolerances, often ±0.5–1.0 mL depending on capacity.
• Class B Cylinders – Lower accuracy, typically with twice the tolerance of Class A.

This means Class A is preferred for quantitative research, while Class B is sufficient for routine or educational use.

When to Choose Class A Cylinders

• Research and clinical labs where precision matters.
• Quality control (QC) testing in pharmaceutical and industrial settings.
• Calibration work where reproducibility is essential.

Class A cylinders often feature blue graduations for enhanced readability and may come with individual calibration certificates for compliance.

When to Choose Class B Cylinders

• Teaching laboratories where durability and cost-effectiveness are priorities.
• Routine solution preparation where approximate accuracy is acceptable.
• Fieldwork applications where portability outweighs absolute precision.

While less accurate, Class B cylinders still provide reliable measurements for most day-to-day lab applications.

Lab Anecdote

At a Perth-based biotech startup, researchers initially used Class B cylinders for solution prep. During a scale-up phase, they switched to Class A and noticed improved reproducibility in enzyme assays. The slight cost difference was outweighed by the reduction in repeat testing.

Sustainability Insight

Both Class A and B measuring cylinders made from BORO 3.3 borosilicate glass are reusable, recyclable, and long-lasting. Choosing glass over disposable plastics not only reduces environmental impact but also lowers long-term replacement costs for Australian labs.

FAQs

Can Class B cylinders be used for research?
Yes, but they are best suited for non-critical measurements. For research-grade work, Class A is recommended.

Are plastic measuring cylinders as good as glass?
Polypropylene cylinders are durable and acid/alkali resistant, but they lack the heat resistance and clarity of borosilicate glass.

Do all Class A cylinders come with calibration certificates?
Not always. Look for ISO 4788-compliant products if certification is required.

Comparison Table – Class A vs Class B Cylinders

References

• ISO 4788: Laboratory Glassware – Graduated Cylinders
• ASTM E1272: Standard Specification for Cylinders
• University of Queensland – Lab Equipment Selection Guide
• CSIRO – Sustainable Science Practices