1. SCOPE………………………………………………….2. REFERENCES
3. GENERAL
4. ADDITIONAL MATERIAL REQUIREMENTS
1. Scope
1.1 This specification is to assist the user in the application and adaption of the check valves described in
PIP PNSMV025. The valves are of stainless steel, with bolted or pressure seal bonnet, flanged (raised
faced) or welding ended (butt or socket), wafer type or swing, and are of dual plate or piston construction.
Nominal pipe sizes NPS 1
/2 to 24 for Classes 150 to 1500 are covered.
1.2 This specification shall be used in conjunction with SES P18-G01.
1.3 This specification is one of a four part series for check valves, each of which represents a group of like
materials, see 3.2.
2. References
Reference is made in this specification to the following documents. The latest issues, amendments, and
supplements to these documents shall apply unless otherwise indicated.
SABIC Engineering Standards (SES)
P02-S01 Piping Materials Standards Specification-Part 1, Group 1
P18-G01 Design Limitations and Applications of Valves
P21-S01 Carbon Steel Check Valves – Materials and Services
P21-S02 Low and Intermediate Alloy Steel Check Valves – Materials and Services
P21-X01 Check Valve Data Sheet
American Society for Testing and Materials (ASTM)
A 193 Alloy-Steel and Stainless Steel Bolting Materials for High Temperature Service
National Association of Corrosion Engineers (NACE)
MR0175 Standard Material Requirements – Sulfide Stress Cracking
Process Industry Practices (PIP)
PNSMV005 Carbon Steel – Check Valve Descriptions
PNSMV015 Low and Intermediate Alloy Steel – Check Valve Descriptions
PNSMV025 Stainless Steel – Check Valve Descriptions
PNSMV035 Bronze and Iron – Check Valve Descriptions
3. General
3.1 The stainless steel check valves described in PIP PNSMV025 and this specification shall be used in
lube oil and other corrosive services, and low temperature and cryogenic services.
3.2 The other specifications in this series are:
a. SES P21-S01, which covers carbon steel check valves described in PIP PNSMV005, and used
in general process services
b. SES P21-S02, which covers low and intermediate alloy steel check valves described in
PIP PNSMV015, and used in general process services
c. Check valves described in PIP PNSMV035, and used in utility services
3.3 Valves in new piping systems shall conform to PIP PNSMV025 and this specification. Valves for
maintaining or tie-in to existing systems may be in accordance with original specifications.
3.4 PIP PNSMV025 describes the valves, their components, and their materials of construction. The trim
for check valves comprises the body and plate seating surfaces, spring, hinge, bearings, and small
internal parts that contact the service fluid.
3.5 The valves have unique valve number designations, for example CH-122, by which they are referred
to in the PIP line classes. See PIP PNSMV025 Section 6 for applicable line classes.
3.6 All design, material, service, inspection, marking, documentation, shipping and other requirements
shall be specified on the data sheet SES P21-X01. This shall be attached to the requisition/purchase order.
4. Additional Material Requirements
For services where the materials specified in PIP PNSMV025 are inadequate, the following requirements
shall be met:
4.1 Materials shall be suitable for continuous exposure at the service conditions and ratings specified.
4.2 Valve components in rubbing or sliding contact shall not gall.
4.3 The corrosion resistance of body-to-cover bolting and gasket material shall be at least equal to the
material of the body and bonnet. However, the bolting material is not required to be more corrosion
resistant than austenitic stainless AISI type 304 (in accordance with ASTM A 193) unless otherwise
specified in the purchase order.
4.4 Halides and wet H2S, or sour service promote sulfide (stress corrosion) cracking. This situation shall
be mitigated by maintaining maximum ductility in the valve parts. Maximum hardness limits shall be as
specified in NACE MR0175. Body-to-cover bolting shall be in accordance with NACE MR0175 Class III.
However, when the valve is to be insulated, or buried, it shall be in accordance with NACE MR0175 Class I
or II. Weldments shall be stress relieved in accordance with NACE sections 3 and 4.
4.5 Check valves in cold service, below -46 °C, shall have special requirements. The body and bonnet
shall be of type 304, or 316 stainless steel, which has sufficient ductility. The trim shall also be stainless
steel, type 304 or 316. Any lubricants shall be designed for the temperature. Bonnet and gland bolting shall
be austenitic stainless steel ASTM A 320. The corresponding nuts shall be ASTM A 194 Grade 8.
4.6 Check valves in service below -73 °C need all of the above specifications, and also the following. The
valves, including trim, shall be made entirely of stainless steel, type 304 or 316. Type 304 shall not be
substituted for type 316 without SABIC approval. Type 316 has better ductility down to -198 °C. Below that
temperature, impact testing is required for either type 304, or type 316. Impact testing shall conform to the
requirements of SES P02-S01.
4.7 The packing material shall be chemically compatible with the fluid, and have sufficient sealing
properties at the temperature of operation. Packing shall be asbestos-free, and corrosion inhibited, to avoid
stem pitting. In hydrocarbon services, packing and stem seals shall not be pure polymer/elastomer unless
the valves have been qualified as fire safe.