Control valves are a critical part of process manufacturing processes and require great care in selection and specification. But what if the specifications are too stringent impacting both cost and lead times? The costs and delays can have an impact on the overall performance of a capital project.
In a Processing magazine article, How To Avoid Over-Specifying Control Valves, Emerson’s Janelle Prusha shares valuable tips on making sure specifications meet the suitability for the control valve application.
Many end users ask for a review of their technical specifications to identify areas adding unnecessary cost and lead time to their valve, actuator, positioner and related accessory purchases.
They need help evaluating if their requirements were truly needed or were actually more than required for their specific applications. A review of specifications typically reveals instances where cost-saving products and options are overlooked, along with inclusion of unnecessary items and procedures.
She notes the desire by process engineers for a:
…fit-for-purpose approach using industry standards and common designs versus customization that adds cost and development time.
Janelle cites some commonly seen requirements that add costs and time:
- All assembly must occur in North America
- No castings from India or China
- Third-party witness of all welding
She shares an example of a customer waving the assembly requirement and saving $1.2 million in capital costs and 20 weeks in lead time. Janelle notes it’s better to understand the quality standards used by valve manufacturers and how they are enforced with the global foundries used. Finding these standards to be acceptable and waiving these requirements can mean a 25% reduction in project costs can 12 weeks of lead time savings. Similarly, by reviewing and accepting valve manufacturer weld procedures and their compliance with applicable regulations and standards saved one end user $200,000 and 12 weeks of lead time.
Specific to the valve technology and components, some unnecessary specifications include:
- Provide throttling ball valve for pulp mill applications.
- Provide globe valves for hot gas recycle applications.
- Cage-guided valves should not be used with high-viscosity fluids, fluids that contain solids or in slurries.
- Rotary valves shall have splined shafts to limit lost motion.
- Stellite is not acceptable in boiler feedwater due to attack of water-treating chemicals.
Read the article to see why these requirements may be unnecessary as well as ways to eliminate unnecessary options and employ time saving digital processes instead of traditional paper-based ones. Janelle concludes the article:
Working with outdated and unnecessary valve, actuator, positioner and accessory specifications results in increased project costs and lead time by denying access to the latest technology and less expensive solutions. Reviewing valve specifications to identify unnecessary specifications is a necessary first step to cut costs and lead times, and this must be done early in the project.
You can connect and interact with other valve experts in the Valves group in the Emerson Exchange 365 community.