BS ISO 9803-2:2020 pdf free.Vacuum technology一Mounting dimensions of pipeline fittings一Knife-edge flange type.
BS ISO 9803-2 1 Scope This document specifies mounting dimensions for vacuum pipeline fittings (elbows, tees and crosses) of knife-edge flanges for nominal bores from 16 mm to 200 mm.  2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 3669, Vacuum technology一Dimensions of knife-edge flanges 3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 3669 apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses:
-ISO Online browsing platform: available at https://www.iso.org/obp 一IEC Electropedia: available at http://www.electropedia.org/ 4 Requirements 4.1 Mounting dimensions of the vacuum pipeline fittings shall be as specified in Table 1. See Figures 1 to 3. 4.2 Flange dimensions shall be as specified in ISO 3669. One or more flange should be rotatable.4.3 Bolt holes in the flanges specified in ISO 3669 shall be positioned as shown in Figure 4. Angle a is a function of the number of bolt holes.BS ISO 9803-2 pdf download.