ASTM E287 Standard Specification for Laboratory Glass Graduated Burets

Get Certified ASTM E287 Compliance for Accurate Volumetric Measurement

A buret that meets ASTM E287 gives titration results that can be repeated and compared between laboratories. A Class A buret may carry the letter A to show it meets the construction and accuracy requirements, and it may include a serial number. Analysts can check a buret by weighing the water it delivers, which provides a record to support quality systems and audits.

The scope of ASTM E287 includes

• Product type: Glass graduated burets for laboratory use
• Grades: Class A (precision) and Class B (general purpose)
• Capacities: 10, 25, 50, and 100 mL
• Styles: Straight burets with a single-bore or 3-way stopcock, 100 mL burets with a 50 mL intermediate bulb, and self-zeroing burets
• Calibration: To deliver the intended volume at 20 °C, with no after-drainage period
• Accuracy: Class A volumetric tolerances listed in Table 1, with Class B at twice the Class A range
• Stopcock: Permanently attached, handle on the right, plug fitted with a retaining device
• Delivery time: Minimum outflow times for water, listed separately for Class A and Class B

What are the uses of ASTM E287?

ASTM E287 helps laboratories, manufacturers, and buyers specify, buy, and check burets for titration and other volumetric work. Test methods such as ASTM D664 and ASTM D4607 refer to it when they call for a buret. This standard:

• Defines Class A precision burets and Class B general-purpose burets for laboratory use.
• Sets a volumetric tolerance for each buret capacity.
• Requires calibration to deliver the intended volume at 20 °C.
• Supports routine titrations that need the tight tolerances of Class A burets.
• Supports general work and training with Class B burets.
• Gives calibration laboratories pass or fail limits for checking burets.
• Helps glassware makers design, mark, and test their products.
• Helps buyers match the class and capacity of a buret to the method

What burets are covered by ASTM E287?

ASTM E287 covers glass burets in 10, 25, 50, and 100 mL capacities. These include straight burets with a single-bore or 3-way stopcock, 100 mL burets with a 50 mL intermediate bulb, and self-zeroing burets. A self-zeroing buret has an ungraduated, tapered interior extension that ends in an overflow orifice, and some burets include a filling tube. Micro-burets are outside this specification. ASTM E1189 covers Koch-style micro-burets.

Why is ASTM E287 Important?

A titration result depends on the volume of titrant delivered, so any buret error passes straight into the final result. ASTM E287 sets a tolerance for each capacity and requires calibration at one temperature, so users know the largest error to expect. A Class A 25 mL buret, for example, may be off by no more than ±0.03 mL, and a Class B buret of the same size by ±0.06 mL.

ASTM E287 Testing Process and Data Collection

Testing starts with a clean buret and distilled water at a known temperature. Technicians fill the buret, set the zero mark, and deliver water into a weighed vessel at free outflow. The balance records the water mass, and conversion tables convert it to volume at 20 °C. The technician records the nominal volume, delivered volume, water temperature, outflow time, and deviation from the nominal volume.

Common Challenges and Troubleshooting

Air bubbles in the tip or stopcock bore change the delivered volume, so technicians fill the tip and remove bubbles before setting zero. A leaking stopcock lets titrant escape, and the plug needs the retaining device the standard requires to stay seated. Dirty glass makes drops cling to the wall, hiding the meniscus and shifting the reading. View the meniscus at eye level to avoid parallax. Temperature matters because calibration is at 20 °C, so a large departure changes the delivered volume slightly. Delivering the water faster than the minimum outflow time also adds error, because the tolerances assume a controlled delivery.

• The laboratory reports the delivered volume and the deviation from the nominal volume for each check, and states whether the buret meets Class A or Class B limits.
• Technicians record the nominal volume, water mass, water temperature, outflow time, and deviation, so others can repeat and review the check.
• Analysts convert the water mass to volume at 20 °C and compare the deviation to the tolerance for the buret’s class and capacity. Class A tolerances are ±0.02 mL for a 10 mL buret, ±0.03 mL for 25 mL, and ±0.05 mL for 50 mL, and Class B tolerances are twice the Class A range.
• Engineer treats a buret that misses the Class A limits but stays within twice that range as a Class B buret, and treats a buret outside both ranges as not meeting the specification.
• Manufacturers review the results to support acceptance decisions and replace an out-of-tolerance buret, or use it with a documented correction where the method allows it.

Link to ASTM E287 Standard