The Difference Between NIST Traceable Calibrations and ISO-IEC 17025 Accredited Calibrations.

The Difference Between NIST Traceable Calibrations and ISO/IEC 17025 Accredited Calibrations.

by Emmanuel

Customers frequently inquire about the distinction between traceable and certified calibrations when attempting to identify what their goods require. Knowing the significance of each can assist in ensuring that all calibration requirements are completed.

A NIST traceable calibration is one in which a manufacturer or calibration laboratory certifies that the standards used to calibrate a product or device are traceable to the International System of Units (SI) via an unbroken chain of comparable measurements to the National Institute of Standards and Technology (NIST), a U.S. Department of Commerce agency. A broader description of traceability recognizes that metrological traceability to SI may be achieved through any accredited national metrology institution, not just NIST. This sort of calibration does not reflect or determine the degree of expertise of the calibration crew or laboratory. It primarily indicates that the calibration standard is traceable to NIST or another recognized metrology institution (RMI).

 

An ISO/IEC 17025 approved calibration is globally recognized. The ISO 17025 accreditation certifies the calibration laboratory’s competency. According to ISO 17025, any number of national metrology institutions, such as the NIST, must be internationally approved for acceptable measurement traceability. A third-party organization, such as A2LA, NAVLAP, or any number of other ILAC-MRA signatory organizations, is one way to show metrological traceability. These organizations evaluate the laboratory and its operations in order to determine the laboratory’s competence to perform calibrations and provide accredited calibration results. The certificate is linked with the scope of work for which the laboratory has been accredited. The laboratory is audited on a regular basis to verify that it is still in accordance with the ISO/IEC 17025 standard.

 

Because the discipline of calibration is assessed in addition to the traceability of the standards, ISO/IEC 17025 approved calibration may be regarded a step above NIST calibration. Furthermore, the ISO/IEC 17025 calibration comprises not only the measurement traceability, but also the measurement uncertainties of the calibration findings.

What is the difference between NIST traceable (or comparable) calibration and ISO/IEC 17025 calibration?

The decision is frequently made by a company’s quality manual or the quality department. The selection might also be influenced by how the equipment requiring frequent calibration will be utilized. For example, if the equipment is utilized in a vital application and the firm faces responsibility if something goes wrong, ISO/IEC 17025 calibration may be worth considering. If the device is used primarily for reference purposes in a low-risk environment where the measurement must be “close enough,” a NIST traceable calibration is most likely all that is necessary.

Critical measurements include altimeters in airplanes, nuclear plant temperature, flow measurements in which flow or volume is connected with a monetary value, and medical equipment that monitors air pressure.

Tire gauges, process gauges that indicate good or bad (usually with green and red areas on the dial face), pressure switches and pressure dial gauges used in air compressors, or torque wrenches used in auto repair shops are examples of non-critical, low risk measurement devices that may be suitable for NIST calibration.

It is ultimately the duty of the device’s owner to decide the proper form of calibration necessary – NIST or ISO/IEC 17025 approved – to guarantee the calibration fulfills the criteria of their industry.

More information about the ISO/IEC 17025 standard may be obtained on the International Organization for Standardization (ISO) website and the International Laboratory Accreditation Cooperation (ILAC) website.

 

Let Gulf Coast Manage Your Calibration Schedule.

Are you looking for calibration services, or is your equipment producing out-of-the-ordinary results? If so, you’ve come to the right place. Gulf Coast Calibration has over 40 years of expertise and has developed to become one of the Gulf Coast region finest weighing equipment and calibration firms. Our calibration services, which encompass equipment in a variety of sectors, are provided through our in-house laboratory or on-site at our clients’ facilities.

Call us to discuss your calibration, test or repair needs at:
713.944.3139.

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A2LA Certification - Gulf Coast Calibration

A2LA Certification: All the Information You Need

by Emmanuel

A2LA certification is a prestigious accreditation that validates an organization’s expertise in specific testing and calibration fields. Accreditation by the American Association for Laboratory Accreditation (A2LA) is recognized in the industry as a mark of excellence and dependability.

In today’s competitive market, standing out from the crowd is critical. Obtaining A2LA certification is one way to accomplish this. A2LA certification is an internationally recognized accreditation that confirms a company’s expertise in specific testing and calibration fields.

In this blog post, we’ll look at why A2LA certification is important and how it can help your company.

What is A2LA Certification?

A2LA certification is a globally recognized accreditation body that offers services such as testing, calibration, and laboratory accreditation. It is a non-profit organization that has accredited over 3,100 organizations worldwide in its 40-year history.

A2LA certification ensures that a company meets stringent technical and management requirements, and that its employees are competent and qualified to perform testing and calibration activities. A2LA’s accreditation scope includes medical, aerospace, automotive, and environmental industries.

Why is A2LA Certification Important?

Both organizations and their clients benefit from A2LA certification. A2LA accreditation gives organizations a competitive advantage in the industry, improves their reputation, and boosts their credibility. A2LA accreditation also demonstrates an organization’s dedication to quality and continuous improvement.

For clients, A2LA accreditation ensures that an organization’s testing and calibration services are dependable, accurate, and up to the highest standards. Clients can rest assured that their products and services will meet regulatory and industry standards.

Importance of A2LA Certification

  • Exhibit Competence and Credibility

A2LA certification provides an objective and unbiased assessment of a company’s technical and management capabilities. It shows clients, regulators, and stakeholders that your company has met the highest standards and is capable of providing reliable and accurate testing and calibration services.

You can distinguish your company from competitors who do not have the same level of accreditation by obtaining A2LA certification.

  • Improves Reputation and Marketability

A2LA certification is a mark of quality and dependability in the industry. It improves your company’s reputation and credibility with clients, regulators, and stakeholders.

A2LA accreditation can also help your organization’s marketability. Clients are more likely to select an accredited organization because they are confident that their products and services will meet regulatory and industry standards.

  • Ensures Compliance with Regulations and Standards

A2LA certification ensures that your organization meets the highest testing and calibration standards. It shows your dedication to quality and continuous improvement.

A2LA accreditation also ensures that your organization complies with all regulations and standards. This lowers the likelihood of noncompliance and the associated penalties and fines.

  • Increases Efficiency and Effectiveness

A2LA certification necessitates the implementation of a strong quality management system (QMS). By streamlining processes and reducing errors and rework, this improves efficiency and effectiveness.

A2LA certification allows your organization to identify and address areas for improvement in your QMS. This can result in increased efficiency, lower costs, and higher customer satisfaction.

  • Provides Access to New Markets

A2LA certification is recognized globally. This gives your company access to new markets and opportunities for growth.

A2LA accreditation also demonstrates your organization’s dedication to quality and compliance. This can be a major factor in gaining new clients and expanding into new markets.

Conclusion

A2LA certification is a valuable accreditation that demonstrates a our expertise and dependability in the testing and calibration industry. Accreditation by A2LA provides benefits to both us and our clients, such as increased credibility, reputation, and quality assurance. Accreditation by A2LA entails a rigorous evaluation and assessment process, but the benefits are well worth the effort.

Call us to discuss your calibration, test or repair needs at:
713.944.3139.

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External Factors and Corrections in Pressure Calibration

External Factors and Corrections in Pressure Calibration

by Emmanuel

Pressure calibrations entail more than simply recording the pressure number and comparing it to a recognized standard. Because pressure measurements are affected by several factors such as temperature, local gravity, pressure medium characteristics, and local adjustments, it is critical to account for these external factors and corrections when performing high precision pressure calibrations.

There is a wide range of calibration software on the market that automatically adds these corrections to the recorded pressure values from the reference and DUT. However, understanding the sources of deviation and errors in the calibration setup can be aided by being aware of these adjustments.

Site specific adjustments

Specific modifications are made to the recorded value to account for characteristics that impact the pressure output in respect to the location of the site and the ambient environment. These modifications may include sea level adjustments, local gravity adjustments, and temperature variations in the surroundings.

Typically, sea level adjustments are done to account for variations in height and barometric pressure. To compensate for gravitational forces on masses, local gravity corrections are utilized. Temperature compensation is used to capture the correct reference device output as the ambient temperature changes.

  • Sea Level

This adjustment is critical for absolute ranges, especially barometric pressure ranges. Regardless of height, this adjustment gives a common barometric reference. Because all of the barometers are calibrated to sea level, this makes it easy for meteorologists to track weather fronts.

As the altitude of an absolute sensor increases, it approaches absolute zero. However, this might cause issues with a barometric range sensor because the reading will no longer be 14.5 psi when vented to atmosphere. The local barometric pressure may instead be 12.0 psi. This is not the case when a sea level adjustment is applied. The present barometric pressure in Denver, Colorado, for example, will be closer to 14.5 psi than 12.0 psi. This is due to the sea level adjustment done to the barometer sensor.

  • Local Gravity

A correction for local gravity is the final site-specific adjustment and perhaps the biggest contribution to inaccuracies, particularly in piston-gauge systems. Gravity is the acceleration that allows mass sets to exert force on the piston area, resulting in pressure. The gravity of the Earth varies over its whole surface, with the lowest gravity acceleration being around 9.7639 m/s2 and the maximum gravity acceleration being roughly 9.8337 m/s2.

The local gravity may be used during the pressure calculation for a piston gauge, and a gravity adjustment may not be required. Many industrial deadweight tests, on the other hand, are calibrated to standard gravity (9.80665 m/s2) and must be rectified.

  • Temperature

Temperature fluctuations are another source of mistake in pressure calibrations. While pressure transducers, such as the CPT9000 Premium Pressure Transducer, are temperature adjusted during production, not all transducers are. Manufacturers of such transducers establish the connection of the pressure output’s accuracy to temperature rise or drop through applicable temperature standards.

Temperature adjustment is especially necessary for reference standards requiring temperature monitoring, such as piston gauges. Piston-cylinder systems, regardless of composition (steel, tungsten carbide, etc.), must be temperature corrected during operation since all materials expand or contract in response to temperature changes based on their thermal expansion coefficient.

As the temperature of the piston cylinder rises, the piston-cylinder system expands, increasing the area and decreasing the pressure generated. As the temperature drops, the piston-cylinder system contracts, causing the area to shrink. As a result, the pressure created rises. This modification will be delivered immediately to the piston’s region.

Media related adjustments

Media-related changes may be irrelevant to regular users of pressure controllers or gauges. However, media-related changes are required for primary standards since they affect the desired target specification and associated uncertainty.

  • Air Buoyancy

Air buoyancy is one of the most critical modifications that must be made to piston-cylinder systems.

The pressure generated by the air surrounding us acts as a column of air. It also exerts an upward pull on things at the same time. If this modification is not made, the displayed value may be incorrect. Any mass, including the piston, will require what is known as an air buoyancy adjustment.

This adjustment is only required for gauge calibrations in which the reference is exposed to ambient air (atmospheric reference). It is insignificant for absolute since the ambient air is effectively eliminated by using vacuum as a reference.

  • Surface Tension

When using oil-lubricated piston-cylinder systems, the surface tension of the fluid must be overcome in order to “free” the piston. Essentially, depending on the diameter of the piston, this results in an extra “phantom” mass load. As the piston’s diameter rises, so does the effect.

This adjustment is more critical at lower pressures and becomes less relevant as pressure increases.

Device specific adjustments

Device-specific modifications, such as head height and distortion correction (piston-cylinders only), are required for precision devices where slight changes in measurement might contribute to inaccuracies that effect the calibration’s total uncertainty.

  • Distortion

A distortion adjustment is a comparable correction that must be performed to piston-cylinder systems. As the pressure on the piston-cylinder system grows, the piston area increases, forcing it to create less pressure.

As the pressure grows, the piston area expands, resulting in less pressure than intended. The distortion coefficient is normally supplied by the manufacturer, although it may also be measured experimentally.

  • Head Height

If the reference standard is a pressure controller, the only correction that may be required is a head height correction. This adjustment cancels out the discrepancies in height / placement of the sensing elements in the reference relative to the DUT. If the DUT is below the reference level, the value will be positive; if the DUT is above the reference level, the value will be negative. A head height correction must be determined regardless of the pressure medium and dependent on the precision and resolution of the DUT.

Mensor pressure controllers, such as the CPC6050, Modular Pressure Controller, allow the operator to enter a head height and the instrument will compute the corrective head height.

Conclusion

Being aware of and compensating for the elements that influence the output of your pressure calibration may make a substantial difference in the total uncertainty of a calibration. While some of these adjustments, such as local gravity and sea level, will remain constant between calibrations, others will change dramatically depending on the reference device, pressure range, and even the equipment under test.

Let Gulf Coast Manage Your Calibration Schedule.

Are you looking for calibration services, or is your equipment producing out-of-the-ordinary results? If so, you’ve come to the right place. Gulf Coast Calibration has over 40 years of expertise and has developed to become one of the Gulf Coast region finest weighing equipment and calibration firms. Our calibration services, which encompass equipment in a variety of sectors, are provided through our in-house laboratory or on-site at our clients’ facilities.

Call us to discuss your calibration, test or repair needs at:
713.944.3139.

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Hydraulic vs. Pneumatic Pressure in Calibration | Gulfcoastcalibratio.com

Hydraulic vs. Pneumatic Pressure in Calibration

by Emmanuel

When considering how to build or enhance a calibration program, there is a lot to consider. Especially when dealing with a wide range of pressure ranges – both high and low – when gas and liquid are employed in the process and as the calibration medium. The fundamental issue is always safety. The pressure range and media that are planned or present in your calibration scope are intimately connected to safety. Fortunately, there are several factors that impact the use of one media over another.


Hydraulic oil being poured into an instrument

What Pressure – What Media??

The distinction between high and low pressure is purely arbitrary. High pressure often refers to pressure ranges exceeding 10,000 psi for pressure calibration components, however this is a matter of opinion and the unique operating environment. Everything is dependent on the extent of the action. If your highest range is 3,000 psi, it is your “high pressure.”

In general, pneumatic medium is utilized to calibrate the majority of pressure sensors with pressure ranges less than 1,500 psi. Some specialized applications need pneumatic media at pressures of up to 10,000 psi. As pressure rises, hydraulic fluids, most typically water or oil, become the dominating medium. It is safer to utilize hydraulic media at these higher pressure levels for the reasons explained below. The capacity to do pneumatic calibrations at pressures more than 10,000 psi exists, although it is an exception and is normally discouraged for safety concerns.

Safety

The amount of energy stored in a container filled with air or a non-volatile gas depends on the pressure and volume of the system. Because of its compressibility, pneumatic medium can store far more energy than hydraulic media. The greater the volume or pressure, the more energy is stored and potentially released in the event of a breach. A abrupt release of pressure into the environment in a high-energy pneumatic system is best defined as an explosion, and it may inflict significant harm to life and property.

Fortunately, most calibrating systems have modest volumes and hence reduced energy, but they can still inflict harm when in close proximity to a breach. The biggest worry in safety is the possibility of a high energy system containment failure. Because the volume of a typical calibration system is small, the major variable of interest is pressure. As a result, hydraulic media is often employed at pressures more than 10,000 psi. When using pneumatic media at pressures more than 10,000 psi, correctly rated fittings and tubing must be used to keep the gas contained inside the system.

Fittings

The standard industrial connectors used for connecting calibrating components containing both hydraulic and pneumatic media have a maximum pressure range of 10,000 to 15,000 psi. Fittings designed for higher pressure systems can also be utilized in low pressure systems. Elastomeric seal fittings must be compatible with the fluids utilized. Fittings developed specifically for greater pressure generally have a maximum pressure of at least 60,000 psi. Most of these are compatible with hydraulic or pneumatic fluids at their rated pressures; however, careful pressure and media selection is required.

Tubing

Depending on the wall thickness, pressure ratings for 1/4 inch OD (outside diameter) seamless stainless steel tube range from 4,000 to 10,300 psi. Fittings and tubing components often used in industrial applications or calibration labs to hold pressure and transmit fluids (both gas and liquid) have pressure ratings of up to and around 10,000 psi. Hardened stainless steel tubing can bear pressures of up to 60,000 pounds per square inch. These tube types are suitable for both gases and liquids.

Flexible nylon tubing with a working pressure rating of roughly 300 psi is often utilized in calibrating applications. Synthetic fiber reinforced flexible tubing with a value of roughly 5,800 psi is also employed. Flexible tubing is often used for pneumatic media, whereas stainless steel tubing is utilized for hydraulic media.

Compatibility

When a device is used in a process that contains hydraulic media, it is usually better to calibrate it using hydraulic fluid. If it is calibrated with air or nitrogen, it must be carefully cleaned to avoid contaminating the pressure calibrator. Alternatively, if a device under test is utilized with a gas and calibrated with a liquid, it must be cleaned before being returned to service to avoid process contamination. These factors must be considered before using a pneumatic or hydraulic medium as the calibration medium.

Pneumatic Media Types

In calibrating applications, pneumatic media are often clean, dry air or nitrogen. Other media, especially inert gasses, can be employed but are often more costly. Because of the significant danger of leakage, some inert gases, such as helium, may need to be avoided. Outside of specialist equipment and optimum calibration settings, flammable gases, such as oxygen, should be avoided, since they can induce spontaneous burning of residual oil at high pressures. The majority of other gases are rarely utilized in calibration.

Hydraulic Media Types

Hydraulic media can be deionized water or oil, depending on the equipment being tested and the calibrator used to generate the pressure. Many fluids can be utilized, but they must be compatible with the equipment under test and the calibrator. Distilled water, sebacate oil, HFE-7500, Shell Tellus-22, and other fluids are commonly used. Fluid recommendations should be provided by the calibration device’s manufacturer.

Conclusion

Many factors influence whether pneumatic or hydraulic media should be used in a calibrating application. Safety, both in terms of equipment and staff, is frequently the first priority. High-pressure pneumatic systems are more dangerous than high-pressure hydraulic systems. When calibrating devices that utilize a different medium, verified compatibility or rigorous cleaning instructions must be followed. To guarantee that all safety hazards are addressed, tubing, fittings, and seals must all be suitable with the medium being utilized.

Let Gulf Coast Manage Your Calibration Schedule.

Are you looking for calibration services, or is your equipment producing out-of-the-ordinary results? If so, you’ve come to the right place. Gulf Coast Calibration has over 40 years of expertise and has developed to become one of the Gulf Coast region finest weighing equipment and calibration firms. Our calibration services, which encompass equipment in a variety of sectors, are provided through our in-house laboratory or on-site at our clients’ facilities.

Call us to discuss your calibration, test or repair needs at:
713.944.3139.

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What are Trade-offs Among Speed, Stability and Volume for Calibration

What are Trade-offs Among Speed, Stability and Volume for Calibration?

by Emmanuel

There are inherent trade-offs between the rate at which a pressure setpoint is reached, the stability of that setpoint once reached, and the volume of the system where the pressure is being introduced when controlling pressure using a precision pressure controller in a calibration laboratory or in a production environment. This is crucial to comprehend for a production line when throughput is key. The correlations between these three factors still exist in calibration labs, where slower speeds and longer stay times are more common, but they have less impact on workflow.

For the sake of this discussion, we will concentrate on a system that includes a device that is being tested or calibrated and a precision pressure calibrating controller, such as the CPC4000. Precision pressure controllers control pressure in a volume made up of tubing, a manifold, and the transducer or transducers under test. An algorithm that reads the controller’s internal reference sensor and adjusts the regulator to add or exhaust gas to and from the system to create a steady pressure controls the stability of the pressure output.

Photo Credit: mensor

In this case, the speed, stability, and volume trade-offs can have a substantial impact on the effectiveness of the entire system.

Speed Vs. Stability

Let’s start by looking at a system with a constant volume’s speed and stability. The predicted maximum pressure variation around a given point over time is the definition of the control stability parameter of a precision pressure controller. A stable situation will be shown, for instance, if the pressure stays within the CPC6050 stability window for a user-defined stable dwell duration, typically 3 or 4 seconds. This stability window is 0.003% of the active transducer range.

The time it takes to arrive at a setpoint while meeting the stability window requirements and dwell time is referred to as the speed.

Pressure calibration devices must quickly achieve a setpoint in a high-speed production testing environment in order to maximize the throughput of the component being tested. More goods can be generated the faster this is done. Testing tire pressure sensors, which are a standard feature in all new cars, is an illustration of this.

Sensors may be linked via a manifold or chamber with a constant volume and checked in groups often. In general, it is more difficult to reach a steady pressure within a short dwell time the faster a volume is filled. Momentum and thermodynamics are involved. When abruptly stopped, a large volume of gas flowing into a system will behave like a spring, causing the pressure to fluctuate about a point until the oscillation is eventually muted. Additionally, as gas moves from a low to a high pressure, it will heat up and then cool down over time, resulting in a reduction in pressure from the starting point.

By reducing the gas flow when the setpoint is reached and then adjusting the gas’s entrance and exhaust to maintain stability at that setpoint, the oscillation as previously mentioned may be managed. To prevent overshoot, the controller’s algorithm must be calibrated to recognize when to begin the throttle-down process and how to respond to slight variations in pressure near the setpoint. Every system will have a perfect set of parameters that regulate the gas’s entry and exit to operate at its fastest and most stable.

However, the faster the setpoint is attained, the more difficult it is to regulate the variation around the setpoint. The volume and geometry of the pipe and valve system, the pressure change, the temperature of the gas, and the temperature of the surrounding environment are all system variables. The operator must balance the need for speed with the need for steadiness. When the dwell period is short, the reading of the pressure standard and the reading of the equipment being tested may disagree somewhat. Given the device’s speed, stability, and precision, the operator will evaluate if the measurements are acceptable.

Speed Vs. Volume

A sensor testing system comprises a fixed volume into which pressure must be regulated. The more volume there is, the more gas is required to attain any particular setpoint. The conclusion is that larger quantities are slower to regulate than smaller volumes, which makes sense. However, bigger volumes may house a greater number of sensors, thus the slower pace may be offset by the greater number of sensors that can be evaluated simultaneously.

Volume Vs. Stability

limited variations in the amount of gas entering or departing the system create a comparatively big change in pressure in a limited volume. Small changes in the amount of gas entering or departing the system, on the other hand, will create minimal change in the system pressure in a big volume. Keeping this in mind, many applications choose a greater capacity to improve system stability.

Conclusion

It is vital to understand how speed, stability, and volume impact overall system performance. Once the aim for these variables has been set, the following step is to select the best pressure controller for the intended output. 

Let Gulf Coast Manage Your Calibration Schedule.

Are you looking for calibration services, or is your equipment producing out-of-the-ordinary results? If so, you’ve come to the right place. Gulf Coast Calibration has over 40 years of expertise and has developed to become one of the Gulf Coast region finest weighing equipment and calibration firms. Our calibration services, which encompass equipment in a variety of sectors, are provided through our in-house laboratory or on-site at our clients’ facilities.

Call us to discuss your calibration, test or repair needs at:
713.944.3139.

Request for Calibration Quote
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