What Are ASME B16.48 Flat Blanks & Paddles?
A flat blank is a solid disc inserted between two flanges to isolate a line. A paddle blank is a flat blank with a plain radial handle (B16.48 para. 2.1.3), usually used together with a paddle spacer (the open equivalent, para. 2.1.4) in larger sizes. ASME B16.48 covers steel line blanks, NPS 1/2 through NPS 24, Classes 150 through 2500.
Dimensions & Tables
- Raised-face flat blanks — dimensions per B16.48 Tables 4.3.1-1 through 4.3.1-6 (Classes 150/300/600/900/1500/2500); the gasket-seating surface and dimensions follow ASME B16.5, and the raised-face height is added to the listed thickness t.
- Paddle blank / paddle spacer — handled versions of the solid/open end of a Fig. 8 blank.
Specific dimensions: consult the referenced B16.48 tables — send us your NPS, class and facing and we will manufacture to standard.
Size & Class Range
| Parameter | Range |
|---|---|
| Size | NPS 1/2 – NPS 24 |
| Pressure class | Class 150 / 300 / 600 / 900 / 1500 / 2500 |
| Typical materials | A105, A182 F304/F316, A350 LF2 |
Related Standards
- ASME B16.48 — Steel Line Blanks (Parent Standard)
- ASME B16.48 Fig. 8 Spectacle Blanks
- ASME B16.5 — Pipe Flanges (NPS 1/2–24)
- Our Flange Range
- ASTM A105 Carbon Steel
FAQ
What is the difference between a flat blank and a paddle blank?
A paddle blank is a flat blank with a radial handle, so it can be pulled out and re-inserted between flanges without sliding it through the pipe bore — typically paired with a paddle spacer.
What dimensions do flat blanks follow?
Raised-face flat blank dimensions per B16.48 Tables 4.3.1-1 through 4.3.1-6, by class; the gasket face follows ASME B16.5.
Fig. 8, flat blank or paddle — which do I specify?
Fig. 8 when the line needs frequent open/close switching; flat blank or paddle for fixed isolation during maintenance shutdowns.
What materials are available?
Carbon steel A105, stainless F304/F316 and low-temperature LF2, in the classes and sizes listed above.
Need This Standard for Your Project?
We manufacture and export flanges, fittings and gaskets to ASME standards. Send your standard, size, material, and quantity — we reply within 24 hours.