Setra Blog


May 01, 2017

What is absolute pressure?

Absolute pressure is the pressure measured relative to a perfect vacuum, which is considered absolute zero pressure. This means it includes the atmospheric pressure in addition to the pressure of the system being measured. 

An incredibly diverse array of applications require the measurement of air pressure. Depending on the application, users need to be able to interpret pressure readings in different ways and use appropriate units to reflect those readings accurately.

Absolute Pressure Defined

Absolute pressure is measured relative to a full vacuum. In contrast, the pressure that is measured against atmospheric pressure (also known as barometric pressure) is called gauge pressure. A full vacuum has an absolute pressure reading of 0 PSIA and the average barometric pressure at sea level is ~14.7 PSIA.

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April 27, 2017

What are the different methods of low pressure calibration?

Ensuring the accuracy of transducers used in the measurement of room pressure in critical environments is extremely important in order to maintain patient safety. Because the differences in measured pressure are so small (only fractions of an inch of water column) calibrating these devices can be very tedious and usually difficult to perform without the right tools and processes.

In general, there are two industry standard methods of low pressure calibration: hand pump calibration and automated calibration.

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April 17, 2017

Why does The Joint Commission care about room pressurization?

The Joint Commission (TJC) is a non-profit organization that evaluates and accredits healthcare organizations in the United States, ensuring that hospitals and other medical facilities are providing safe and high-quality care to their patients. Inspections occur every three years and take between 2 to 3 days. In most jurisdictions, Medicare and Medicaid funding is contingent on accreditation by TJC.

One of the most important standards scored in a Joint Commission evaluation is room pressurization (EC.02.05.01). According to ASHRAE Standard 170 (used specifically by TJC as its standard), over 60 different areas of concern within a facility need to be either positively or negatively pressured. Pressurization in these spaces is tested simply by holding a tissue at the bottom of a door and determining whether the tissue is blown back away or sucked towards the gap.

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April 03, 2017

What Are The Different Types of Pressure Tests for Engine Test Stands?

Did you know that companies spend hundreds of millions of dollars on research and development for off-highway vehicle engines? A portion of the R&D goes into developing specialized engine test stands to ensure that the engines are functioning properly.

Engine test stands are complex, engineered systems designed to measure, control and record parameters during the different engine manufacturing stages.
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March 31, 2017

What is a Hydrogen Fuel Cell?

Although hydrogen is in its infancy as a fuel source, its future is incredibly bright. The technology behind hydrogen fuel cells is improving daily and its viability as a replacement to the internal combustion engine seems likely. Hydrogen is already being used in specialty vehicles such as forklifts and buses, and it’s only a matter of time before infrastructure is in place to serve the consumer automotive market. Why do hydrogen fuel cells have such great appeal? Because their only byproducts are heat and water vapor, making hydrogen fuel cells a truly zero-emission locomotive technology.

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March 31, 2017

What is the difference between NEMA and IP ratings?

In manufacturing, there are two standards used to measure the different grades of electrical enclosures and how resistant they are to the ingress of certain materials. NEMA ratings and IP ratings both define degrees of protection against substances such as water and dust, but use different test methods and parameters to define their enclosure types (NEMA 250 and IEC standard 60529).

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March 31, 2017

What is Capacitance?

 

 

 

 

 

 

 

 

 

 

 

 

 

Capacitance is the ability of an object to hold an electrical charge. Capacitors are components in an electrical circuit that can store a charge and are considered one of the three fundamental electronic components along with inductors and resistors.

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March 27, 2017

What is Barometric Pressure?

Simply put, barometric pressure is the measurement of air pressure in the atmosphere, specifically the measurement of the weight exerted by air molecules at a given point on Earth. Barometric pressure changes constantly and is always different depending on where the reading takes place.

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March 23, 2017

What is peak demand?

Looking at your electric bill can be a daunting task. There are many factors that can affect your bill’s total — factors that are only amplified in large commercial and industrial sites.

One such consideration is peak demand. Peak demand is the largest instance of power usage in a given time frame, typically a rolling fifteen minute window. Measured in kilowatts (kW), peak demand is different than consumption. Total consumption  is measured in kilowatt hours (kWh) over a given period of time (e.g. monthly, quarterly, etc.). 

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March 20, 2017

What is the difference between 17-4 and 316L stainless steel?

When selecting stainless steel for various applications, understanding the differences between 17-4 and 316L stainless steel is crucial. Both alloys offer unique properties tailored to specific needs.

Stainless steel (SS) comes in all shapes, sizes, and compositions. It’s an alloy comprised of several different elements such as iron, nickel, and chromium with superior corrosion resistance compared to its constituent parts. Different applications require different material properties. In fact, there are dozens of individual grades of stainless steel alone, each with a unique proportion of ingredients and application benefits. This article will focus on two types in particular: 17-4 and 316L stainless steel.

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