How Much Do Mechanical Pressure Gauges Cost?
I was recently working on an industrial project for a critical application that required a lot of instrumentation, specifically pressure gauges. The client’s only criteria seemed to be the cost, with very little consideration to the application.
The buyer kept saying, “A gauge is a gauge. What is the cost?” I replied that not all applications are the same, and not all pressure gauges are created equal!
The only honest answer to “how much does a pressure gauge cost” is: “It depends.”
For example, a pressure gauge to measure the air in the tire of your bike is vastly different than a gauge used at a nuclear power plant, an industrial plant, or a processing facility. It all boils down to using the right tool for the job.
Despite aggressive advances in pressure measurement technology, engineers who design new process systems insist on including mechanical pressure gauges. This technology dates back before the Civil War.Why do some pressure gauge designs rely on 160-year-old technology?
Mechanical pressure gauges are reliable indicators powered by the process, they’re impervious to power outages and tend to be more durable than their electronic counterparts.
Keep in mind that many pressure gauge applications can involve serious safety concerns for operators and other end users. In the event of an urgent situation, pressure gauges can tell operators what’s happening inside the pipe. Because pressure gauges are critical to the safety of operators and end-users, it is important to install an adequate configuration.
Top 5 Pressure Gauge Cost Drivers
Figure 1: Categories of Mechanical Pressure Gauges
|Types of Mechanical Pressure Gauges||Commercial Grade
|Critical Process Applications $100-$1,500||Calibration Gauges $300-$1,000|
Process pressure monitoring for:
|Test stands for:
In Figure 1 we’ve separated most pressure gauges into four categories. Although these categories were formed based on the type of application, they each have a tendency to be associated with certain characteristics.
Lighter commercial/residential applications are usually smaller, open front cases with lightweight brass/bronze systems and tend to be on the less expensive side.
Industrial equipment tends to use more expensive pressure gauges that have stainless steel cases and systems and better accuracy. These gauges are also generally smaller, 2.5 or 3.5-inch dial sizes.
Applications with continuous process monitoring are more robust in nature. The dial sizes usually expand to 4.5” or larger. They typically have better accuracy and a stronger focus on safety features such as a solid front style case or safety glass. Some require very specialized capabilities such as inert case fills, diaphragm seals with exotic wetted parts, or have to register extremely low readings with high static/proof pressures requirements.
Test gauges are designed to check the calibration of other instruments. To comply with ASME standards the test gauges have to be four times as accurate as the instrument being checked. Therefore, test gauges have to be extremely accurate, and typically the more accurate the gauge the more it will cost.
2. Accuracy and Dial Size
Depending on the application, accuracy can be very important. Generally, accuracy tolerances vary from ±0.1% to ±5%.
Typically, more accurate pressure gauges are more expensive. In part, this is because it takes longer for a manufacturer to calibrate an instrument to a tighter accuracy, as is the case of a test gauge. But, more commonly, upgrading to a pressure gauge with a better accuracy typically involves an upgrade to a new category of pressure gauges (e.g., moving from a commercial gauge to an industrial-grade gauge). In these instances, the more significant cost impact is upgrading the category versus just tightening up the accuracy.
The same can be said for increasing dial size. For example, going from a smaller 2.5 or 3.5-inch dial to a 4.5-inch or larger dial typically means upgrading to a more expensive category of gauges.
3. Pressure Range
Pressure gauges commonly have ranges from 0-30 psi through 0-600 psi. These ranges do not usually add cost, but if you have vacuum ranges and compound ranges (reading both vacuum and positive pressure) it can increase initial expense.
If you have very high-pressure ranges (1K-15Kpsi), the systems have to be more robust and this will cost. In pressure ranges over 20,000 psi, a material with higher tensile strength like Inconel is usually required.
Conversely, some applications require very low pressure that can’t be registered by the traditional sensing elements found in a 0-15+ psi range. In those instances, different systems, such as bellows or capsule designs, are used. These require more time to calibrate and are costlier to manufacture. In some cases, applications require differential pressure readings with high static pressures but very low differential pressure readings. These can be costlier.
In Figure 2 shows common options that can impact your cost. These are categorized from “$” to “$$$$”: “$” typically being relatively inexpensive options versus “$$$$” typically being more expensive.Pressure gauges can be supplied with a multitude of options for various reasons. Some are designed as safety features to protect the pressure gauge and/or operators. Some are designed for better visibility, or to prolong the lifespan of the pressure gauge.
Critical applications that involve hazardous chemicals often require more expensive options like calibration certificates, material traceability reports, or leak detection applications. In many cases, the more critical the application the more expensive the instrument configuration requirements tend to be.
Again, I say that It all boils down to using the right tool for the job. Once you know your requirements, a good pressure gauge supplier can deliver the product knowledge to help you choose the right options.
Quite commonly pressure gauges are installed in harsh conditions. Under these conditions, pressure gauges can experience pulsation, vibration, extreme temperature, pressure spikes, clogging, and/or corrosion. In these instances, it is important, both for the lifespan of the pressure gauge as well as the safety of those who work with the equipment, that the gauges are adequately protected.
Some accessories, such as flow restrictors, are not necessarily expensive. Others, such as diaphragm seals or pressure limiting valves can sometimes surpass the initial cost of the pressure gauge. In some cases, they can be one, two, or three times the cost of the gauge (or more).
Diaphragm seals with exotic materials and expensive inert system fills can be a significant cost driver. Especially if the diaphragm seal is installed via flange (versus a threaded design).
Isolation rings, which are usually used to protect against heavy slurries, can be moderately expensive for pipe sizes one through ten inches. As the pipe size increased the isolation ring costs proportionately increase. Isolation rings for a 30-inch pipe can jump north of $20K.
Other Cost Considerations
Outside of general options and features, other cost drivers exist. For instance, where is the pressure gauge manufactured? Pressure gauges built in low-cost labor areas tend to be less expensive than those built-in higher-cost labor areas. Selecting a pressure gauge that was imported from a low-cost labor area could save cost, but may also involve longer lead-times, less customization, and/or less access to support.
Brand selection can also impact the cost of a pressure gauge. Some brands are considered to be premium quality and in turn, may cost more in the initial purchase. Yet, most brands that carry a reputation of premium quality have earned that label.
Brands gain the designation for premium quality for a variety of reasons. These reasons can include that they tend to perform better for a longer time, or stand up to harsh conditions more effectively, or perhaps the company provides better resources to ensure the proper installation.
Whatever the reason, this can certainly impact the upfront cost. On the plus side, if the pressure gauges last longer in the application, the initial cost impact will be significantly offset by not having to replace them as often.
These considerations should be included with all the criteria discussed in this article. Utilizing the appropriate configuration for your application will promote product longevity, optimize instrument performance and most importantly protect the equipment operators.
We don’t like to pressure you, but we have more information.
To help explore various options available for pressure gauges, visit a manufacturer’s website. On our website we offer product information pages, white papers, specification sheets, material selection guides, videos, and many other tools. Once you have a configuration, submit for a quote. Buying from a company that is not an authorized distributor could negatively impact your cost. For industry standards/recommendations refer to the ASME B 40.100 standards guide.
Contributors to this article:
John Girard, Territory Manager - Northeast Region
Hope Karimi, Territory Manager - Pacific Region
Austin Haynie, Territory Manager - Southeast Region
Claudette O’Loughlin, E-Commerce Sales Manager
Lou Altieri, Group Product Leader - ASME Process Gauges & Diaphragm Seals
Eric Deoliveira, Product Manager - Temperature, Sanitary & High Purity Gauges
Debbie Harper, Group Product Leader - Industrial & Commercial Gauges
Laura Garofalo, Inside Sales