What Is ASME B16.48?
ASME B16.48 is the American National Standard for steel line blanks used to isolate piping for maintenance, from NPS 1/2 through NPS 24, in pressure classes 150 through 2500.
Types of Line Blanks
- Fig. 8 (Spectacle) Blanks — combined blank + spacer in one piece; rotate to switch between open and closed
- Flat Blanks — single blank for permanent or temporary isolation
- Paddles — handled blanks for insertion between flanges
Size & Class Range
| Parameter | Range |
|---|---|
| Size | NPS 1/2 – NPS 24 |
| Pressure class | Class 150 / 300 / 600 / 900 / 1500 / 2500 |
| Materials | A105, A182 F304 / F316 / F321, A350 LF2 |
| Face types | Raised face (RF) and flat face (FF) |
Related Standards
FAQ
What is a Fig. 8 blank used for?
It lets operators switch a line between open and closed without removing the blank — standard practice for maintenance isolation in pipelines and plant piping.
What sizes does B16.48 cover?
NPS 1/2 through NPS 24, classes 150 through 2500.
Blank or paddle — which do I specify?
Specify a Fig. 8 blank when the line needs periodic isolation; a flat blank or paddle for fixed isolation during shutdown.
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