# CSA B51 Fitting Category Quick-Reference (A to H)
**Kopfkino India**: orientation only; final classification depends on your product and the current CSA B51 edition.

| Category | Typical basis | Acceptance route |
|---|---|---|
| A | Designed to a recognized standard (e.g. ASME B16 series) | Standard-based |
| B | Designed to a code with calculations | Calculation-based |
| C | Proven by proof test | Proof-test (no ASME certification-mark shortcut) |
| D | Proven by burst test | Burst-test |
| E | Expansion joints / flexible connectors | Specialized review |
| F | Hose assemblies | Assembly-level registration |
| G | Line fittings not otherwise covered | Case-specific |
| H | Manufacturer's quality program / statutory declaration | QMS-based |

**Key rules**
- Registration generally applies to pressure-retaining fittings above 15 psig.
- The category determines the *evidence* the authority needs. Getting it right first time avoids rejection.
- Valves are registered as fittings under CSA B51.

Need help classifying? kopfkinogroup.in/services/fittings-crn/ · india@kopfkino.ca