ASTM E934-94(R2021) pdf free download

ASTM E934-94(R2021) pdf free download.Standard Specification for Serological Pipet, Disposable Plastic
5. Design
5.1 Shape—0.5, 1.0, and 2.0-cm 3 pipets shall be straight and of one-piece construction. Any cross section of a pipet taken in a plane perpendicular to the longitudinal axis shall be circular. 5.1.1 Pipets of5.0, 10.0, 25.0, and 50.0 cm 3 shall be straight and may consist ofone, two, or three components, the extruded pipet barrel, the pulled or injection molded tip, and the plain, pulled, or injection molded top end. 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 40 mm. The tip end shall be reasonably perpendicular to the longitudinal axis of the pipet, and shall be free of internal flash. 5.3 Top End—The 5, 10, 25.0, and 50.0-cm 3 sizes shall have a top end with an inside diameter of 2 to 6.5 mm for a minimum distance of20 mm from the open end, and shall have an overall length of24 to 28 mm. On all sizes, the top end shall be suitable for plugging with filtering material. The top may be flat or chamfered and must be without sharp outer edges. All top ends shall be reasonably perpendicular to the longitudinal axis of the pipet. The O.D. of top end should range from 7 to 9 mm. 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 by means of a stopwatch on unplugged pipets when using distilled water at 25 6 5 °C.
6. Markings
6.1 Graduation Markings—Graduation lines shall be be- tween 0.2 mm and 0.5 mm in width, and in a plane perpen- dicular to the longitudinal axis of the pipet parallel to each other. A main graduation line shall extend at least 3 ⁄ 5 ofthe way around the pipet. The values of all main graduation lines shall be in Arabic numbers directly above the lines referenced. Intermediate graduation lines shall extend at least 1 ⁄ 5 ofthe way around the pipet, and least graduation lines shall extend at least 1 ⁄ 8 of the way around the pipet. The zero graduation line shall be at least 90 mm below the top of the pipet on all sides. 6.2 Identification Markings—Each pipet shall be marked with the manufacturer’s or vendor’s name or trademark, its capacity and subdivision, the symbols “TD” (“to deliver”) and “20 °C”, and either a wide band or two narrow bands on the top end to signify that the last drop must be blown out to achieve full delivery.
7. Capacity
7.1 The pipet capacity, expressed as cm 3 (or mL), and the expected deviation from the stated capacity, shall be stated on the product package or published data. The expected deviation from stated capacity is expressed as accuracy and coefficient of variation. Pipets shall be calibrated for delivery at 20 °C. 7.1.1 The accuracy shall be determined as specified in 7.2 and shall be within the limits given in Table 2. 7.1.2 The coefficient of variation shall be determined as specified in 7.2 and shall be within the limits given in Table 2. 7.2 Determination of Accuracy and Coeffıcient of Variation—A minimum number of 30 pipets in accordance with Practice E542, taken at random, shall be tested gravimetrically, using distilled water. Distilled water at 20 6 1 °C is drawn into the pipet and the volume adjusted as in the case of normal use. This is discharged into a tared weighing bottle and the mass, m, is determined using a balance capable of weighing to 60.0001 g. The volume, v x , is computed from the relation: