A titanium blind flange (BL flange) is a flange which has no bore, and is used to close ends of piping systems. A blind flange also permits easy access to a line once it has been sealed. The blind flanges are sometimes machined to accept a pipe of the nominal size to which reduction is being made. The reduction can be either threaded or welded. One of its functions is to block the end of the pipeline, and the other is to facilitate the removal of debris in the pipeline during maintenance. As far as plugging effect is concerned, it has the same effect as the head and cap. But the head can not be disassembled, and the blind flange is fixed by bolts, which is very convenient to disassemble. Blind flanges are made of carbon steel, alloy steel, stainless steel, plastic, etc.

Size: 1/2″ – 56″ (DN15 to DN1,400)
Pressure:
American standard series: CLASS 150, CLASS 300, CLASS 400, CLASS 600, CLASS 900, CLASS 1500, CLASS 2500
European standard series: PN 2.5, PN 6, PN 10, PN 16, PN 25, PN 40, PN 63, PN 100, PN 160, PN 250, PN 320, PN 400
Flange Facing Types: American series: Flat Face(FF), Raised Face(RF), Groove(G), Male and Female Face(MFM), Ring Type Joint (RTJ)
Material: Gr1 (3.7025), Gr2 (3.7035), Gr7 (3.7235), Gr12 (3.7105)
Standard:
ASME B16.5-2009
EN1092-1-2007 EN1759-1-2004
BS 1560-3 1-1989 BS 4504-3 1-1989
AFNOR NF E29-200-1-2007
ISO 7005-1-1992
AS2219-2000
JIS B2220-2004

Blind flange dimensions are covered in ASME B16.5 – which covers Pipe Flanges and Flanged Fittings for size NPS ½” to 24” for above NPS 26” to 60” it should be as per ASME B16.47.