Home>ASTM Standards>ASTM E714-94(R2021) pdf free download

ASTM E714-94(R2021) pdf free download

ASTM E714-94(R2021) pdf free download.Standard Specification for Disposable Glass Serological Pipets
1. Scope
1.1 This specification covers disposable glass serological pipets, calibrated “to deliver,” used in measuring volumes of liquids. 1.2 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Terminology
3.1 Definitions ofTerms Specific to This Standard: 3.1.1 accuracy—the expected distribution of mean volumes around the stated volume. 3.1.2 coeffıcient of variation—the expected distribution of individual volumes around the mean volume. 3.1.3 disposable pipets—in accordance with this specifica- tion and the expected product performance expressed in this specification, those serological pipets which are to be used one time only. Any institution or individual who reuses a dispos- able pipet must bear full responsibility for its safety and effectiveness.
4. Materials and Manufacture
4.1 The pipets shall be fabricated from borosilicate glass, Type I, Class A or B; or soda-lime glass, Type II, as defined in Specification E438.
5. Design
5.1 Shape—Pipets shall be straight and of one-piece con- struction. Any cross section of a pipet taken in a plane perpendicular to the longitudinal axis shall be circular. 5.2 Delivery Tips—Delivery tips shall be made with a gradual taper of 10 to 25 mm for capacities up to 2 cm 3 inclusive, and 15 to 30 mm for the 5 cm 3 and 10 cm 3 size(s). The tip end shall be reasonably perpendicular to the longitu- dinal axis of the pipet and shall be firepolished. 5.3 Top End—The 10 cm 3 and 25 cm 3 pipet shall have a top end tooled to a diameter of7 to 9 mm and shall have an overall length of 15 to 25 mm from the top. The top end shall be suitable for plugging with filtering material. All top ends shall be reasonably perpendicular to the longitudinal axis of the pipet, and shall be firepolished. 5.4 Dimensions and Outflow Times—The limiting dimen- sions and outflow times shall be as shown in Table 1. Outflow times shall be determined on unplugged pipets, using distilled water at 25 6 5 °C, and by means of a stopwatch.
6. Markings
6.1 Graduation Markings—Graduation lines shall be be- tween 0.2 and 0.5 mm in width, and in a plane perpendicular to the longitudinal axis of the pipet and parallel to each other. A main graduation line shall extend at least three-fifths ofthe way around the pipet. The values of all main graduation lines shall be in Arabic numerals directly above the line referenced. Intermediate graduation lines shall extend at least one-fifth of the way around the pipet, and least graduation lines shall extend at least one-seventh of the distance around the pipet. The 0 graduation line shall be at least 90 mm below the top of the pipet on all sizes. 6.2 Identification Markings—Each pipet shall be marked with the manufacturer’s or vendor’s name or trademark, its capacity, the symbols “TD” (for “to deliver”) and “20 °C,” and either a wide band or two narrow bands on the mouthpiece end to signify that the last drop must be blown out to achieve full delivery. 6.3 Capacity—The pipet capacity, expressed in cubic centi- metres or millilitres, shall be stated on the package. The expected deviation from the stated capacity shall be based on unplugged pipets and expressed as accuracy and coefficient of variation. Pipets shall be calibrated for delivery at 20 °C (see Section 7).
7. Determination of Accuracy and Coefficient of Variation
7.1 Randomly select a minimum of 30 pipets and test gravimetrically, using distilled water. 7.1.1 Accuracy—The accuracy shall be within the limits of Table 2 and shall be determined as follows:
8.1 Pipets shall be free of defects that may impair their serviceability, such as significant foreign matter or chips that affect the bore.

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