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Emissions, often referred to as Greenhouse gases (GHG) have been identified as a contributing factor in climate change. Climate change is one of the worlds more pressing challenges.
*Approximately 1-3% of methane leakage is the result of leaks in equipment intentional pressure release practices, or accidental releases during normal transportation, storage, and distribution activities.
Emissions is defined as the production and discharge of something, especially gas or radiation. In this instance we are talking about the production of unwanted gases often referred to as Greenhouse gases (GHG) that have been identified as a contributing factor in climate change. Climate change is one of the world’s more pressing challenges. Manmade carbon gas emissions total over 29 GT(gigatons) annually. To meet a 2° target according to the Paris Agreement, 15 GT of CO2 must be eliminated.
Fugitive emissions (unintentional production and discharge) account for 5.2% of all Greenhouse Gas Emissions according to the World Resources Institute, 2017. Sealing products that are extremely tight sealing are necessary to assist in the reduction of Greenhouse Gas Emissions globally.
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Emissions are the constant loss of product from within a pipe through and/or around a sealing element. Emissions are directly correlated to the sealability of a gasket or sealing product. It has been stated that “all gaskets leak”, but what is acceptable and unacceptable? Many companies are creating mandates to reduce GreenHouse Gas Emissions (GHG Emissions) to reduce the footprint for greenhouse gases and the EPA has strict standards when it comes to emissions for the oil and gas process. The creation of these requirements can now make a gasket that was once acceptable for emissions no longer acceptable.
Emissions today may not have been emissions in the past. As sensing technology has gotten better and the world has become more environmentally conscious, stricter and stricter requirements have been put in place. Chemicals that are injurious to the environment are often labelled as VOCs and HAPs.
"Volatile organic compounds (VOC) means any compound of carbon, excluding carbon monoxide, carbon dioxide, carbonic acid, metallic carbides or carbonates, and ammonium carbonate, which participates in atmospheric photochemical reactions. Source EPA.
HAPS are Hazardous Air Pollutants, also known as toxic air pollutants or air toxics, are those pollutants that are known or suspected to cause cancer or other serious health effects, such as reproductive effects or birth defects, or adverse environmental effects. EPA is working with state, local, and tribal governments to reduce air emissions of 187 toxic air pollutants to the environment.
Emissions can be measured in many different ways. Emissions measurement is the process of measuring the amount of pollutants, in a gaseous or particulate form, being emitted to the air from a specific source, such as an industrial process.
Measurements of emissions can be used to understand the relative importance of a given source compared to other sources and in developing emissions inventories.
Government or industry personnel use emissions measurements to assess the performance of control strategies. The gas stream can be measured before and after a pollution control device to determine how efficiently it captures pollutants. Emission measurements also are used to determine compliance with regulations limiting the amount of pollution that a source may emit.
Measurements can be taken over a short time period (e.g., hours), often referred to as a source test, or with methods that measure on a continuous basis, often called continuous emissions monitoring. Either way, it is important obtain data from samples that are representative of the emission stream using methods that are reliable.
Air Emission Measurement Center - The EPA hub for stationary source air emissions test methods and procedures.
Monitoring emissions under EPA's market-based (e.g., cap and trade) programs, more here.
Also, click here to learn more about vehicle and fuel emissions testing.
There is something else that is an unwanted type of emission and it is called Greenhouse Gas Emissions. Greenhouse gases trap heat and make the planet warmer. Human activities are responsible for almost all of the increase in greenhouse gases in the atmosphere over the last 150 years.1 The largest source of greenhouse gas emissions from human activities in the United States is from burning fossil fuels for electricity, heat, and transportation.
There are many methods such as FID, FTIR, NDIR, airplane LIDAR, optical gas imaging, Aerostat Aloft Platforms, Radial Plume Mapping and Eddy Covariance Methods.
For more information we recommend viewing the EPA official website.
Through research, we have found that one of the items that is supposed to keep product within the piping systems can actually allow material to escape into the atmosphere...the isolation gasket or insulating gasket! Most isolation gaskets are produced of some time of Glass Reinforced Epoxy (GRE). The glass in the epoxy matrix is a straight rod (similar to a straw) and media (especially gases) can follow that straight path and escape into the atmosphere.
This is 300psig Nitrogen at ambient temperature. Similar examples have been witnessed with hydrocarbon gases. The thing to note here is that the example in the picture was in a test lab with ideal flange conditions and proper bolt load. With less than ideal flange conditions and improperly torqued bolts, the permeation and emissions can be much, much worse!
Another cause of emissions or poor sealability can be poor installation. Over 80% of gasket failures are due to improper installation practices or improper equipment conditions.
One of the answers lies in a patented solution from GPT….The VCS-ID gasket (hyperlink - https://www.gptindustries.com/en/products/pikotek-vcs-id-isolating-gaske...). The VCS-ID gasket is constructed of GRE and a 316SS core, but a PTFE inside diameter (ID) seal prevents any media from ever getting to the GRE. The PTFE immediately seals the pipe bore and is extremely chemically compatible.
Emissions can worsen as flanges get larger due to flange rotation. The VCS-ID reduces this issue by instituting a dual seal design for isolation gaskets 6” NPS (nominal pipe size) and larger. The Secondary seal is in an outboard location.
Note: Testing Performed at ambient temperature/500psig He /5hrs / 7,500psi gasket stress VCS-ID™ was single design only
Another major improvement to emissions and sealing is to participate in GPT’s GFIT program, GPT Flange Isolation Training. This program certifies participants in the proper alignment of flanges, the correct method of evaluating flange faces, tried and true torquing techniques, inspection procedures and provides “hands on” elements for both installation and isolation gasket testing.
According to the clean air act, all new oil storage tanks that come into service after April 12, 2013, must have VOC controls within 60 days of service or by April 15, 2014 (whichever is later). Tanks that were in service as of April 12, 2013, must have VOC controls no later than April 15, 2015. Tanks subject to existing federal or state CAA permits are exempt if they emit less than 6 tons of VOC per year with controls. Owners/Operators have the option of either reducing the VOC emissions at a tank by 95% or meeting an alternative emissions limit if the owner or operator can make a demonstration that the tank emits less than 4 tons of VOC per year without controls.
Proper compression of the gasket is extremely important, but can be usurped by poor flange conditions or installation practices. We recommend using an installation procedure like this and making sure that flanges are aligned.
There are two training programs that GPT offers. One is the GFIT (GPT Flange Installation Training) program and the other is a Level I, II and III training program that teaches more about product selection, design and use.
The common issue that we see is the use of homogeneous GRE products in gaseous applications and then concern when they initiate some type of leak detection. It is quite common for these types of products to permeate (especially under higher pressure), so for gaseous applications, we recommend the use of a PTFE ID sealed isolation product.
Surprisingly, the answer is yes. With high pressure and time, the media can permeate through the GRE. Another reason we recommend a PTFE ID seal to prevent any media contact with the GRE.
Sealing capability is typically reliant upon two seemingly simple factors: gasket permeability and gasket load. Gasket permeability can be deceiving because many gaseous mediums are invisible and unless a person can acoustically hear the leakage or see a colored gas emitting from the gasket, the gasket has often been deemed “sealing”. As technology and requirements have become more strict, we now know the above not to be true. A gasket can still be leaking if a person is unable to see or hear leakage. Many companies now use a soapy water mixture to place on the gasket surface and gases leaking through the gasket or around the gasket will be displayed as bubbles.
Also, many companies now use much more sophisticated methods to assess leakage. The companies will use infrared technology to see temperature changes in the air caused by leaking gases. Companies will also use gas analyzers, helicopters, unmanned aerial vehicles, solar powered sensors (SPods) and chromatographs as well as other means.
There are also methods used to estimate fugitive methane emissions in transmission pipelines.
Gasket load can be as complex as emission monitoring. Gaskets typically have a psi (pounds per square inch) or a kPa (1 kPa is approximately the pressure exerted by a 10-g mass resting on a 1-cm2 area. 101.3 kPa = 1 atm.) minimum requirement and a maximum allowable limit (note the maximum can change if the gasket is subjected to exposure in a liquid). Let’s say a gasket has a minimum gasket load (or stress) of 3,000 psi or 20,684 kPa and a maximum gasket load (or stress) of 15,000 psi or 103,421 kPa. This means the gasket will start to effect an acceptable seal at the minimum stress and can begin to break down at the maximum stress.
A “good” load on this gasket might be around 10,000psi or 68,948 kPa. This allows for some bolt stress relaxation and gasket relaxation to occur before leakage or gasket failure. Now how does one achieve the proper gasket stress? The answer is in torquing the bolts to the proper level to achieve the required gasket stress. This is where it can begin to get “complex”. The proper gasket stress will depend on many variables (reused nuts/bolts, rusty nuts/bolts, calibrated torque wrench, aligned flanges, proper flange face RMS (root mean square) finish (should be concentric or spiral grooves), type of lubricant used (if any), type and number of washers used (should be two washers).
Even the orientation of the nuts can be a factor (printed side of the nut should face away from the washers). There are other factors that should be taken into account, but these are the primary factors. Much has been written on this subject and a good book to read is John Bickford’s book on “Gaskets and Gaskets Joints.'
Here is a video that will help with the installation of an isolated kit in a flange. Installing an isolation kit is different than installing a standard gasket in even the same flange.