NACE International (formerly The National Association of Corrosion Engineers) publishes two standards covering

the use of equipment in environments containingH2S (Hydrogen Sulfide). The standards are: MR0103,Standard

Material Requirements – Materials Resistant toSulfide Stress Cracking in Corrosive Petroleum Refining Environments;

and MR0175/ISO 15156, Petroleum and natural gas industries – Materials for use in H2S-containing Environments in

oil and gas production.

The material requirements of the NACE Standards have resulted in various constructions. Valves constructed

of standard carbon steel (SA21 6 Grade WCB) and 31 6 stainless steel (SA351 Grade CF8M or SA479 Type 31 6) will be

dual certified to NACE MR0103 andNACE MR0175/ISO 15156. 

The customer must decide whether his application requires avalve in compliance with NACE standards. LESER is responsible

for supplying materials in compliance with the applicable NACE specification. As part of the orderrequirement, LESER will

verify that material hardness values are in compliance with the NACE standard on the body, bonnet, nozzle and  disc as

applicable. Additionally, we will offer bolting and springs (for conventional and pilot operated valves only) in compliance

with NACE specifications.