Before delving into the subject of codes, valve standards, and certifications, one must understand the concept of what standardization is, its benefits, and what they bring to the table. Standardization is based on combining procedures, processes, and visual work instruction, to help people perform a task or work to the best of their abilities. Furthermore, using a standardized approach often involves following prescribed standards and certification requirements, e.g., ISO or BSI standards. Standardization often focuses on consistency achieved by applying a clear set of guidelines and best practices. This means that no matter who in an organization performs the task, the results will always be the same, with no loss of productivity or quality.
By João Carlos Vitorino, Director – JCV Industrial
A Summary of Codes, Standards, Specifications
According to the National Fire Protection Association (NFPA), a standard tends be “a more detailed elaboration, the nuts and bolts of meeting a code.” In other words, a code tells you what you need to do, and a standard tells you how to do it. Specifications, unlike codes or standards, outline the requirements of a specific company or product.
For example, in the valve industry, the code requires a block valve to be installed to isolate two different systems. Therefore, the code requires a block valve. This valve can be a gate valve, ball valve or any type of valve, as long as it is a block valve. Then, the standard will dictate that a particular valve should be used based on the application’s service or fluid. The code therefore states that the application requires any block valve, while the standard indicated that a ball valve be used. The standard would also say that to operate the valve one must install it in a certain way.
Now, the specification suggest that, because this project deals with high temperature, it is not possible to use a resilient seat ball valve; a metal seated ball valve must instead be used. Simply put, the specification adds more details to the type of ball valves required, so one would know the materials, and the specification will list all the additional requirements missing from the standard or from the code.
The differences between codes, standards, and specifications are essential to understanding the most common codes and standards that are used for piping and pipe engineering.
What is a Code?
A code is a set of rules that serve as generally accepted guidelines recommended for the industry to follow. They exist for the purpose of safety, quality, or other benefit. Each code specifies the minimum acceptable requirements for a process. Codes may incorporate or refer to existing standards or specifications.
What is a Standard?
A standard is an additional requirement to the code. The code is the minimum requirement, but the standard has higher requirements than the code. The standard also will tell you how to apply the code requirements. The standard can be different from one company to another, but the code is the same, and has to be followed by all companies.
Standards are based on stakeholder consensus that set out specifications for general use, and bring their greatest advantage when they are universal. They can be defined as a set of technical definition and guidelines, or simply a tutorial instruction for designer and manufacturer, where a designer will use the standard to design product and a manufacturer will use it for production. Standards serve as a common language to defining quality and establishing safety criteria for the product. ASTM, API, MSS and ISO are some examples of standards.
What is a Specification?
Unlike a code or standard, which may apply broadly to an industry or region, specifications describe the requirements of a specific company or product. A specification provides requirements for the materials, components, or services used in an application. Sometimes a specification will also dictate a standard installation or design layout of these components. Specification requirements can go beyond code or standard requirements.
An individual company can develop specifications for a particular project or common installation, specifying the materials – potentially even the specific brand desired – for a project. A specification can also be adopted and implemented in many different projects.
Common Codes and Standards Used In Valve Industry
ASME
This is a very critical and very important code that is used in piping and piping engineering.
ASME is split into two main sub-committees; ASME B31 for pressure piping, and ASME B16 committee for the standard of the components, such as fittings, valves, gaskets, and flanges.
The design codes are under B31 committees; ASME B31.1 – Power Piping, and ASME B31.3 – Process Piping. B31.1 mainly is related to the piping in the power generation, and B31.3 is mainly for the process piping in the re-fineries and petrochemical plants.
Pressure Rating Codes:
ASME B16.5 – Pipe Flanges and Flanged Fittings
ASME B16.34 -Valves – Flanged, Threaded, And Welding End
ASME B16.10 – Face-To-Face and End-To-End Dimensions of Valves
ASTM
ASTM is related to materials and material requirements, like the chemical composition and its percentage. It is also related to testing for materials and includes the hardness, and any heat treatment required for the material. Each material has a different ASTM number, creating a wide range.
API
API codes are mainly used in valves, such as gate valves (API600; API602), globe valves (API623; API602), check valves (API594), ball valves (API6D; API608), butterfly valves (API609), and plug valves (API599). There are three API valve/packing emissions standards tests which are prevalent today: API 622 Type Testing of Process Valve Packing for Fugitive Emissions, API 624 Type Testing of Rising Stem Valves Equipped with Graphite Packing for Fugitive Emissions and API 641 Type Testing of Quarter-turn Valve for Fugitive Emissions
NACE
NACE is used when there is a corrosive fluid running inside the pipe. NACE will have additional requirements to the material, including MR 0175/ISO15156: Petroleum and natural gas industries – Materials for use in H2S-containing environments in oil and gas production, and MR0103/ISO17945: Petroleum, petrochemical, and natural gas industries – Metallic materials resistant to sulfide stress cracking in corrosive petroleum refining environments.
MSS
MSS is only used when a valve or a fitting is not covered by ASME. It is divided into two groups, fittings, and valves.
Valve Specifications
When a customer specifies a component a valve, the following information needs to be provided to the procurement team*:
• Valve type (Gate Valve)
• Standard (API 600)
• Construction Type (Bolted Bonnet /Outside Screw & Yoke)
• Material (Casting Carbon Steel ASTM A351 Gr CF8M)
• Size (NPS 4”)
• Standard (API600/ISO10434)
• Obturator Type (Flexible Wedge)
• Obturator Material (AISI 316 + Stellite 6)
• Seat Material: AISI 316 + Stellite 6)
• Bolting/Nuts: ASTM A193 Gr 8M /ASTM A194 Gr 8M
• Sealing Packing (Flexible Graphite + Inconel)
• End Connections (Raised Face Flanges
– ASME B16.5)
• Surface Finish (Concentric Serrated, 125 to 250μin (3.2 to 6.3 μm) Ra\MSS-SP6)
• Face to Face: ASME B16.10
• Pressure Class (ANSI 600)
• Inspection & Test (API 598)
• Additional Requirements (NACE MR0175)
*Example only
Conclusion
Standards are essential for any company to explain to its employees, to its customers, and to its supply chain what it stands for and what it is offering, which today means corporate social responsibility, good governance, resilience, and risk management.
All information above states the importance of all standards involved in practically all phases of a valve fabrication. With embedded standards, the manufacturer knows exactly the product it needs to deliver, and the customer is sure about what they will receive.
Standards have no inherent value; their value lies in the transaction between two parties, such as customer and supplier, regulator and industry, or retailer and consumer. Standards provide a means for one party to provide assurance to another that they are following good industry practice. Innovation becomes less risky as standards provide one of the essential business tools to support new product development and market access.
ABOUT THE AUTHOR
João Vitorino is Mechanical Engineer, MBA in Project Management and in Product and Services Engineering. He also has a post-grad in Industrial Valve Design Engineering. He has more than 15 years of experience in the market focused on equipment for the industrial area, mainly Oil and Gas. He is a valve consultant for Valve World Magazine and Fugitive Emissions Journal. Today he is the Director of JCV Industrial Solutions, which operates in the Brazilian market with equipment and solutions for the industry.