SOSCLEANROOM | TECHNICAL VAULT | DWK LIFE SCIENCES EDUCATION SERIES | ARTICLE 06
KIMBLE Volumetric Glassware.
Classes, Calibration & TC/TD.
An application-focused guide to KIMBLE® / KIMAX® precision laboratory glassware: volumetric flasks, pipets, graduated cylinders and burets; the meaning of TC and TD markings; calibration certificates; ASTM standards; and responsible selection for analytical and quality-control laboratories.
Article 06 | The essential principle
A graduation mark is not the same thing as a validated measurement.
Every laboratory handles liquids, but not every vessel is intended to measure them with the same accuracy. A beaker's graduations may help with approximate preparation; a calibrated volumetric flask is designed to contain a specified volume within a defined tolerance; a buret is designed to deliver measured increments. For quantitative work, the right question is not merely "What capacity does this hold?" It is "What volume is this instrument calibrated to contain or deliver, with what tolerance and supporting evidence?"
This sixth article in the SOSCleanroom DWK Life Sciences education series focuses on KIMBLE and KIMAX volumetric glassware. It builds on our guides to glass-versus-plastic material selection and DURAN borosilicate glass 3.3, but shifts the discussion from container materials to measurement reliability.
Practical selection rule: Specify the instrument type + nominal volume + accuracy class + TC/TD calibration + applicable ASTM/ISO standard + certificate requirement + method conditions. A manufacturer's glassware brand does not substitute for these details.
Understand the portfolio
What KIMBLE and KIMAX mean—and what they do not.
KIMBLE® is a DWK Life Sciences laboratory glassware brand encompassing volumetric products, tubes, sample containers and specialized laboratory items. KIMAX® appears on numerous KIMBLE volumetric product families. DWK identifies different glass formulations across its assortment: borosilicate glass 3.3, other borosilicate compositions and soda-lime glass occur in different products. Consequently, the word KIMBLE or KIMAX alone does not define glass composition, measurement tolerance or processing limits.
KIMBLE / KIMAX volumetricware
Manufactured and specified for defined measurement tasks, with product-dependent tolerances, calibration designations and standards. Selected versions include individual serialization and certificates.
Check: ASTM/ISO designation, Class A/B, TD/TC, glass type and documentation.
KIMBLE general laboratory glassware
Includes tubes, beakers, vials and specialty apparatus with many different intended uses. A nominal capacity or printed graduation does not establish Class A volumetric performance.
Check: actual use, material, chemical and thermal limitations; do not infer calibrated accuracy.
A useful manufacturer-specific example: DWK describes KIMBLE KIMAX 28014-1 volumetric flasks as borosilicate glass 3.3, while the KIMAX 37006-1 certified volumetric pipet is listed as borosilicate glass 5.1. That difference is why glass composition should be verified at the catalog-number level, rather than inferred from the brand. KIMBLE manufacturer overview →
Choose the correct measuring instrument
Four common volumetric glassware families serve different purposes.
01 | Prepare a fixed volume
Volumetric flasks
Used to prepare solutions to a calibrated volume. A single calibration mark generally represents a specified containment volume at the stated reference temperature. Select the required capacity, accuracy class, stopper or cap design and any certificate requirement.
Selection question: Does the method require accurate containment rather than approximate mixing?
02 | Transfer a defined volume
Volumetric pipets
Bulb pipets transfer a specified nominal volume; graduated pipets support measured aliquots along a scale. The TD/TC designation, delivery and drainage instructions, calibration class and compatible pipet aid influence correct use.
Selection question: Must a known aliquot be delivered under a documented method?
03 | Measure variable volumes
Graduated cylinders
Useful for measuring a range of liquid volumes. Cylinder graduations support intermediate readings, but tolerance and graduation intervals differ by model and class. A cylinder is not automatically interchangeable with a volumetric flask or pipet.
Selection question: How much error can the method tolerate at the actual reading volume?
04 | Dispense during titration
Burets
Deliver a measured changing volume, commonly in titrations. In addition to class and capacity, choose the correct graduation interval, stopcock design, scale visibility and filling arrangement.
Selection question: Does the method require controlled titrant delivery with traceable measurement?
Do not substitute by capacity alone: A 100 mL beaker, 100 mL graduated cylinder and 100 mL Class A flask all hold liquid, but they serve distinct measurement functions and must not be assumed to meet the same tolerance.
Understand measurement accuracy
Class A versus Class B: tighter tolerance is a specification, not a substitute for good technique.
DWK identifies two common volumetric accuracy classes. For applicable volumetric families, Class A or Class AS has tighter permitted volumetric error than Class B; DWK explains that Class B limits are generally twice those of Class A/AS. Class AS is associated with certain delivery instruments designed for faster outflow while retaining Class A-level tolerances. Always interpret the marking against the relevant product standard: the actual tolerance varies with instrument type and nominal volume.
| Attribute | Class A / AS | Class B |
|---|---|---|
| Accuracy tolerance | Tighter allowed volumetric error under the applicable standard. | Typically approximately twice the allowed error of Class A/AS for the corresponding instrument. |
| Common use case | Quantitative analytical preparation, quality control and methods specifying a tight tolerance. | Teaching, general laboratory work and procedures with an appropriately wider error allowance. |
| Documented evidence | Some product families offer serialized, individual or batch certification; confirm each SKU. | Do not assume individual or batch certification is available; DWK states it is not offered for its Class B range. |
| Selection decision | Use when the method's allowable measurement error requires it. | Use only where the total uncertainty/error budget permits it. |
Three different concepts: A graduation interval is the spacing of adjacent marks; a tolerance is the allowed deviation from the stated calibrated volume; measurement uncertainty expresses doubt associated with a measurement result. These values are related but not interchangeable. A buret with 0.1 mL graduation intervals does not automatically have a ±0.1 mL volumetric tolerance or an uncertainty of ±0.1 mL.
Read the markings correctly
TC / IN versus TD / EX: one of the most important labels on volumetric glassware.
TC / IN — To contain
Indicates that the vessel is calibrated for the specified volume held inside when correctly filled and read at its stated conditions. Commonly used for volumetric flasks.
Practical consequence: Pouring the contents out does not necessarily deliver the full stated volume because some liquid remains on the walls.
TD / EX — To deliver
Indicates that the instrument is calibrated for the specified volume delivered using its prescribed drainage or delivery method. Commonly used for pipets and burets.
Practical consequence: Allow the specified drainage and waiting procedure; do not blow out residual liquid unless the instrument and method explicitly instruct it.
DWK notes that ISO usage includes IN for to contain and EX for to deliver, while many ASTM-oriented products use TC and TD. Some KIMBLE items are dual-calibrated: for example, manufacturer catalog 28026-100 identifies distinct marks for TC and TD, with different tolerances at those marks. Never interpret both lines as having identical measurement meaning.
Read the full inscription: Accuracy class, nominal capacity, calibration type, reference temperature, applicable standard and—when provided—individual or batch identification. DWK states that selected volumetric products are marked with a calibration reference temperature, commonly 20 °C, and the appropriate product standard.
Measurement is an operating procedure
Six practical controls that preserve volumetric measurement quality.
- 01Verify the instrument and method.
Check the exact catalog number, intended liquid-handling function, tolerance, calibration designation and current calibration status. - 02Inspect for damage and residue.
Scratched markings, chips, cracks, deposits or a contaminated bore can compromise safe handling or liquid flow. - 03Control the temperature.
Use the reference temperature specified on the instrument and your validated method. Temperature differences affect liquid volume and measurement interpretation. - 04Read the meniscus consistently.
Use the method's prescribed meniscus convention, view the mark at eye level and avoid parallax errors. - 05Follow the delivery procedure.
For TD/EX devices, obey specified drainage, waiting, conditioning and tip-contact steps; do not improvise blow-out or discharge practices. - 06Document the measurement system.
Include operator technique, glassware identification, calibration records, environmental controls and method-specific acceptance criteria.
These are general metrological controls, not universal operating instructions for every instrument. For a validated analytical method, the laboratory's current SOP and the manufacturer instructions govern handling, cleaning and measurement.
Traceability and technical evidence
A Class A label, individual serial number and calibration certificate are three separate specifications.
DWK describes multiple documentation routes across its volumetric portfolio. Product-specific offerings differ by brand, instrument family and catalog number. In particular, Class A accuracy is not itself proof that a particular item includes an individual calibration certificate.
| Evidence type | What it may establish | What to verify before ordering |
|---|---|---|
| Manufacturer Class A specification | Conformance to a defined accuracy class for the specified instrument. | Applicable ASTM/ISO standard, model, nominal volume and tolerance. |
| Batch certificate | Results and identifying information relating to a defined production batch where offered. | Batch identification, certificate scope and whether it meets your laboratory's procedure. |
| Individual/serialized certificate | Instrument-specific identification and calibration data, depending on certificate type. | That the certificate matches the physical serial number, and includes required volume, uncertainty and conditions. |
| Accredited calibration certificate | A reported calibration from a laboratory accredited for the relevant activity, where available. | Accreditation scope, reported results, traceability, uncertainty and your acceptance criteria. |
DWK publishes information about batch-certified, works-certified and accredited calibration products and operates a certificate portal. Check whether the specific KIMBLE item participates in the relevant program; do not assume that every certificate type is available for every DWK product.
Important distinction: Traceability to recognized measurement standards does not mean the U.S. National Institute of Standards and Technology (NIST) directly inspected or certified each individual piece of glassware. In controlled laboratories, the adequacy of the traceability chain must be evaluated against the laboratory's own quality requirements.
Recalibration is risk-based. Do not copy a universal schedule from a generic guide. Consider time in service, glass formulation, cleaning chemistry, heat exposure, abrasive wear, observed damage, drift and the quality-system procedure. DWK's volumetric guidance identifies chemical corrosion and demanding service as reasons to consider recalibration.
Application-to-product decision matrix
Start with the analytical task, then specify the measuring device.
| Laboratory task | Likely instrument family | Key qualification questions |
|---|---|---|
| Prepare a reference or standard solution to a specified final volume | Volumetric flask | Required class, TC marking, reference temperature, stopper/cap, certificate and chemical compatibility. |
| Deliver a fixed aliquot into an analytical preparation | Volumetric pipet | TD/TC designation, volume, tolerance, prescribed drain time and certificate. |
| Measure a variable approximate-to-moderately-precise volume | Graduated cylinder | Class, scale increments, tolerance at use volume and TC/TD basis. |
| Dispense and record titrant volume | Buret | Class, graduation interval, stopcock, fill design, certificate and titrant compatibility. |
| Mix, heat or hold liquids without quantitative volume measurement | General laboratory glassware | Material, temperature, thermal-shock and chemical requirements; do not specify unnecessary volumetric accuracy. |
This matrix is a selection aid. Exact apparatus requirements are determined by the analytical method, product standard and laboratory quality procedures.
Connect technical education with the published catalog
A real SOSCleanroom listing: KIMBLE KIMAX 17054F-50.
Published SOSCleanroom product | Class A buret
KIMBLE KIMAX 17054F-50 — 50 mL Automatic-Zero Buret
This DWK model demonstrates how a complete volumetric specification goes beyond the capacity printed on a piece of glass. DWK lists a 50 mL Class A buret with ±0.05 mL tolerance, 0.1 mL graduation intervals, borosilicate glass 3.3, a three-way PTFE stopcock, an automatic-zero top, individual serialization and a Certificate of Graduation Accuracy.
Nominal capacity
50 mL
Not the same as its graduation interval.
Class A tolerance
±0.05 mL
DWK's listed volumetric accuracy limit for this model.
Graduation interval
0.1 mL
Scale spacing; not a stated uncertainty of the complete analytical result.
Configuration
Automatic-zero
Three-way PTFE stopcock; do not assume that a reservoir bottle or external filling kit is included.
Manufacturer examples, not confirmed SOSCleanroom listings: DWK also publishes KIMBLE KIMAX 28014-1 Class A volumetric flask (borosilicate 3.3, calibrated TC) and 37006-1 Class A certified volumetric pipet (borosilicate 5.1, marked TD). They illustrate different calibrated functions and materials. They are linked as manufacturer documentation examples only; their SOSCleanroom catalog availability has not been established.
Controlled-environment and quality considerations
Accurate glassware is not automatically cleanroom-qualified or sterile.
Precision measurement and contamination control are different qualification topics. A Class A volumetric item may be accurate for its stated purpose while still requiring cleaning, decontamination, transfer controls or additional documentary evidence before use in a controlled environment.
Cleanliness
Verify the receiving condition, cleaning method, residues, particles and compatibility with the analytical method. A listed ISO room class does not certify incoming glassware cleanliness.
Sterility
Do not infer that a volumetric flask, pipet or buret is supplied sterile. Product-specific claims and documentation are required if sterility is a process specification.
Calibration status
Cleaning and thermal exposure may require assessment under site procedures. Material durability is not proof that a calibrated instrument remains acceptable indefinitely.
For pharmaceutical, biotechnology, semiconductor, medical-device or regulated QC work, review the complete procedure and acceptance criteria. A general DWK material or calibration statement does not validate a customer-specific contamination-control process.
Buying and substitution controls
A ten-point specification checklist for volumetric glassware purchasing.
- 07Identify the analytical task.
Preparation, transfer, variable-volume measurement or titration. - 08Record the exact part number.
DWK / KIMBLE / KIMAX catalog reference and product description. - 09Specify nominal capacity.
Confirm the actual volume needed in the method. - 10Specify required tolerance.
Class A, AS or B and the relevant tolerance for the instrument size. - 11Check TC or TD markings.
Do not confuse contained volume with delivered volume. - 12Identify product standards.
Applicable ASTM or ISO specification and edition when required. - 13Check glass and wetted materials.
Glass formulation, stopcock plug, closure and chemical exposure. - 14Define certificate requirements.
Individual, batch, accredited or manufacturer declaration as needed. - 15Confirm included components.
Stoppers, stopcocks, calibration documents, tubing and reservoir kits. - 16Set receiving acceptance criteria.
Damage inspection, markings, serial/certificate match and calibration status.
For substitutions: Match function, calibrated volume, TC/TD designation, tolerance, geometry, contacting materials, certificate scope and method compatibility. The same nominal volume is insufficient to approve a substitute in a controlled analytical method.
Troubleshooting
Common reasons volumetric measurements become unreliable.
| Observed problem | What to investigate | Corrective direction |
|---|---|---|
| Repeated measurements differ | Meniscus/parallax, drainage method, temperature, residual liquid and operator technique. | Recheck SOP, instrument calibration and repeatability before substituting products. |
| Delivered volume is consistently low | Using TC glassware as TD; drainage/waiting procedure; air bubbles in tip or stopcock. | Confirm calibration designation and approved delivery procedure. |
| Graduations are difficult to read | Lighting, scale contrast, damaged markings, meniscus visibility. | Use appropriate viewing conditions and replace damaged glassware. |
| Unexpected titration variability | Stopcock leakage, trapped air, chemical compatibility, titrant standardization. | Inspect full titration system and method controls. |
| Certificate cannot be matched | Missing or incorrect individual serial / production-batch identification. | Resolve traceability before accepting the instrument into controlled service. |
Frequently asked technical questions
KIMBLE volumetric glassware FAQs.
Continue the DWK technical education series
Six connected lessons, one growing DWK knowledge center.
Each guide addresses a different selection decision. Articles 01–05 below have published SOSCleanroom URLs; Article 06 is the current guide.
Browse the complete SOSCleanroom Technical Vault for related product-selection, cleanroom and regulated-environment education.
Primary manufacturer references
DWK Life Sciences technical sources supporting this article.
These manufacturer resources support product-family distinctions, calibration terminology, available certificates and examples. For purchasing or controlled use, give precedence to the most current documentation for the exact part number and your laboratory's method.
- DWK — KIMBLE Laboratory Glassware. Brand, glass families, tubes and volumetric product overview.
- DWK — Volumetric Glassware Technical Guidance. Classes A/AS/B, TC/TD versus IN/EX, inscriptions, calibration, certification and care.
- DWK — Certification. Works, batch and accredited certificate categories and associated limits.
- DWK — Volumetric Glassware Portfolio. Flasks, pipets, cylinders and burets and relevant features.
- DWK — KIMBLE KIMAX 17054F-50. Serialized Class A 50 mL automatic-zero buret specifications.
- DWK — KIMAX 28014-1 Volumetric Flask. Class A TC borosilicate 3.3 product example.
- DWK — KIMAX 37006-1 Volumetric Pipet. Class A TD borosilicate 5.1 product example.
- DWK — Glass Types & Properties. Distinctions between borosilicate and soda-lime compositions and material performance.
Educational and qualification scope: This article is an educational comparison, not a manufacturer certificate or an analytical-method validation. It does not certify that any specific DWK product is sterile, cleanroom-qualified, compatible with every chemical, currently stocked or approved for a particular regulated use. Confirm exact SKU documentation, certificates, current availability and your SOP requirements.
Technical editorial review: November 3, 2026. Product specifications, certificate offerings and catalog availability can change. KIMBLE, KIMAX, DURAN, WHEATON and DWK Life Sciences are trademarks of their respective owners.