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CONSIDER COSTS AND COST OF OWNERSHIP
The cost of a valve usually means the upfront cost to purchase and install the product. In the most basic of scenarios, a plant engineer might have a choice of two valves, both of which would perform the necessary duty, but with a disparity in pricing.
Cost of ownership, on the other hand, includes long-term and often hidden implications of a product choice. Evaluating cost of ownership requires plant personnel to look past product function and initial pricing. The factors they must consider could include:
Valve quality. Just like with any consumable good, valves built to last longer typically cost more upfront. For example, carbon steel is often less expensive initially than stainless steel. However, while both may perform the needed function, the carbon steel valves may have only a satisfactory chemical resistance rating. This could lead to regular maintenance and replacement costs since their lifespans are typically years shorter than their stainless-steel counterparts. By choosing the costlier option upfront, a plant will need less manpower to maintain the valve over time and can avoid repair and replacement costs.
Factors that increase the quality of a valve, and thus sometimes increase the cost, include:
Valve materials. Besides carbon and stainless steel, valves are made from many other materials such as, ductile iron, cast iron, bronze, plastics and specialty alloys. Each has a different cost point.
Valve technology. Valves are typically offered in two classifications: rotary (gate, globe) or quarter turn (butterfly, plug or ball valves). Each has unique characteristics, and in some cases, several different options are considered by plant engineers before they determine the best valve for the application.
Manufacturer testing. Valve manufacturers test their valves to meet certain specifications. Some manufacturers will meet a wide range of industry specifications while others may be limited to just a few. Manufacturers build their valves and provide detailed instructions and training on how to install, operate and maintain their products. The manufacturers who have invested in the design of their products and quality training to end users may require a premium to recuperate their investments.
Quality assurance. Some valve manufacturers have multiple plants all over the world producing valves. Customers rely on manufacturers to have consistent quality assurance programs in place globally to minimize or avoid receiving defective products from other areas.
Valve applications. Valves have limits for specific pressures and temperatures. Some new packing and seat designs allow for the same valve to be used in many applications while other designs are unique for specific applications. Valves with wider limits may cost more, but since they can be used in different scenarios, they can potentially cut customers’ storeroom carrying costs. One example is Teflon valves. Traditional Teflon can stand up to 400°F (204°C) of heat. However, newer valves that contain Teflon with glass fillers can withstand up to 500°F (260°C). This second type may be slightly more expensive, but they can be used for more applications, potentially reducing the need for multiple valves on the store room shelf.
Standardization. Standardization means committing to one reliable manufacturer for supplying valves plant-wide. This may be costlier upfront, but it also means fewer repair kits or duplicate products in storage. It also can mean better trained plant employees who have had the opportunity to become experts in operating and maintaining the products from their chosen manufacturer.
Repair or replacement costs. At some point, all valves need to be repaired or replaced. The cost to repair or replace a valve is part of the cost of ownership. The timeframe and frequency of such maintenance plays a major role in the longer-term cost. Plant engineers can educate themselves on the proper servicing of their selected valves and add that estimated cost to the upfront cost of the valve. They may determine that a higher-priced valve requires less maintenance and has longer life, ultimately costing less over the course of the expected lifespan.
Valve purchasing is not unlike the process consumers face any time they purchase a common household item. Consumers, like plant engineers, live within a budget, and that sometimes means making a purchase based on function and price. But when the research is done and factors such as quality, reliability, maintenance cost and expected lifespan are taken into account, a different picture of what constitutes the best choice often emerges. VM
Excerpted from hbruidu.com