Intro: 

Spectacle blind flanges are available in all of our stainless steel and chrome-moly grades, from ½” to 24” and beyond, class 150 to 2500. We can also source many of your other grade requirements.

These types of flanges are made from plate, and come in 3 different types.

The first and most widely used type are spec blinds – short for spectacle: these are flanges with two equal outside diameter (OD) parts welded together by way of a ‘bridge’. One of the parts also contains an inside diameter (ID), while the other is a blank, or blind. A whole is put at the halfway mark of the bridge. These are also called spectacles, figure 8’s, and figure 8 blanks, because of their resemblance to reading glasses (spectacles) and figure 8’s. These are referred to as ‘Line Blanks’ in the ASME/ANSI standards.

The second and third types are quite similar: both have longer bridges, referred to as ‘paddles’, which resemble longer handles. One type has only an OD, and so is a blind plate – similar in appearance to a large pizza oven peel. These are referred to as paddle blinds. The other type is exactly the same but comes with an ID as well, enabling flow-through when installed in a piping system. These pieces have holes in the paddle which enables field personnel to determine by sight which piece is installed in a system. These are referred to as paddle spacers, and are often supplied in sets together with the paddle blinds.

All 3 types of these flanges are used in piping systems or pressure vessels where the flow needs to be interrupted from time to time. They are installed between two pipe flanges (as specified above), and by way of a screw inserted into the hole in the bridge or paddle, they are able to rotate or ‘swing’ into and out of position to interrupt or allow the flow, as the user sees fit.

Our spec blind flanges are available with raised, flat, or RTJ faces.