MSS SP-43 is the standard for wrought and fabricated buttwelding fittings for low-pressure, corrosion-resistant applications. It covers light-wall stainless steel and nickel alloy elbows, tees, reducers, caps and stub ends, mainly in SCH 5S and 10S, for water treatment, food, pharmaceutical, pulp and paper and general chemical piping where pressure is modest but corrosion resistance matters.
Raaj Fittings manufactures MSS SP-43 fittings at our two plants in India in stainless steel, duplex and nickel alloys, for fabricators and stockists across the Middle East, Europe and the Americas.
| MSS SP-43 | ASME B16.9 | |
|---|---|---|
| Intended service | Low pressure, corrosion resistant | Pressure piping |
| Typical walls | SCH 5S and 10S | All schedules |
| Material class (ASTM A403 / A815) | CR | WP |
| Stub ends | Short pattern | Long pattern |
| Pressure rating | Lower; for low-pressure service | Equal to matching seamless pipe |
Some SP-43 fittings have shorter centre-to-end dimensions than their B16.9 equivalents, so the two should not be mixed in a spool without checking the drawing.
The most common SP-43 item is the short-pattern stub end, used with lap joint flanges in stainless and nickel alloy systems. It saves material and length compared with the long-pattern B16.9 stub end, while the backing flange can be carbon steel, which reduces the cost of the joint.
ASTM A403 CR grades (304, 304L, 316, 316L, 321, 347 and others), ASTM A815 duplex CR grades, and nickel alloys to ASTM B366.
Every MSS SP-43 fitting is made from PMI-verified material, dimensionally inspected against the ordered standard and marked with material, size, rating and heat number. Orders are supplied with EN 10204 3.1 certificates; EN 10204 3.2 certification and inspection by the buyer's nominated third-party agency are available on request.
Light-wall stainless steel and nickel alloy buttweld fittings for low-pressure, corrosion-resistant service, such as water treatment, food, pharmaceutical and chemical piping.
CR is the ASTM A403 / A815 class for fittings made to MSS SP-43; WP is the class for fittings to ASME B16.9.
Not always. Some SP-43 fittings are shorter, and SP-43 fittings are intended for lower pressures. Order the standard named in your piping specification.
Yes, short-pattern stub ends to MSS SP-43 and long-pattern stub ends to ASME B16.9, in stainless steel, duplex and nickel alloys.