Standard No.:	GB/T 321-2005
English Name:	Preferred numbers -Series of preferred numbers
Chinese Name:	优先数和优先数系
Chinese Classification:	A20    Comprehensive Technology
Professional Classification:	GB    National Standard
Issued by:	CSBTS
Issued on:	2005-5-16
Implemented on:	2005-12-1
Status:	valid
Superseding:	GB/T 321-1980 Preferred numbers and preferred number series
Language:	English
File Format:	PDF
Word Count:	1000 words
Price(USD):	154.00
Delivery:	via email in 1 business day

1 Scope



This standard specifies the series of preferred numbers.



This standard is applicable to grading of various quantity values, especially in determining product parameters or parameter series, and it shall be selected in accordance with basic series values specified in this standard.



2 Terms and Definitions



2.1

series of preferred numbers

preferred numbers are the conventionally rounded off term values of geometrical series, including the integral powers of 10 and having as ratios the following factors: and , in accordance with Table 1 - Basic Series and Table 2 - Complementary R80 Series set out for the 1 to 10 range, the series of preferred numbers being unlimited in both directions, the values of the terms in other decimal ranges are obtained by multiplying the values in the tables by positive or negative integral powers of 10

Foreword I
1 Scope
2 Terms and Definitions
3 Preferred Numbers