Ready for Low-E Valve Technology?

Definition

The terms we have become familiar with are “Certified Low-Leaking Valves” and “Certified Low-Leaking Valve Packing Technology” as defined by the EPA in consent decrees. In more current consent decrees, new valves entering will be required to be certified as “Low E Technology”. A “Low-E Valve “is defined as:

“A valve (including its specific packing assembly) or valve packing for which the manufacturer has issued a written warranty that it will not emit fugitives at greater than 100 ppm, and that, if it does so emit at any time in the first five years, the manufacturer will replace the valve; provided however, that no valve shall qualify as "Low-E" by reason of written warranty unless

(i) the valve (including its specific packing assembly) either:

(a) first was tested by the manufacturer or a qualified testing firm pursuant to generally-accepted good engineering practices for testing fugitive emissions and the results of the testing reasonably support the warranty; or

(b) is as an Extension of another valve that qualified as "Low-E";

(ii) A valve (including its specific packing assembly) that:

(a) Has been tested by the manufacturer or a qualified testing firm pursuant to generally-accepted good engineering practices for testing fugitive emissions and that, during the test, at no time leaked at greater than 500 ppm, and on Average, leaked at less than 100 ppm; or

(b) Is an Extension of another valve that qualified as ‘Low-E’.”

This current definition of Low E Valve Technology adds test documentation to this requirement. Manufacturers have offered this warranty without supporting test data. Today there are reputable packing and valve manufacturers that can meet these low emission level requirements and documentation to assist valve manufacturers in achieving Low E requirements.

Test Protocols

Many existing test protocols are designed to measure the performance of valves and packing products. The two most commonly used protocols are API standards and ISO 15848-1. The API standards utilize methane as the media and Method 21 to measure emissions while the ISO test typically uses helium as the media with vacuum as the leak detection method. It is important to note the EPA only recognizes emission testing conducted utilizing Method 21.

API 622 fugitive emissions test protocol evaluates the performance of a valve packing in a specified test fixture, number of strokes and temperature cycles while monitoring emissions in ppm. This protocol allows for average leakage measurements up to 500 ppm and one retorque throughout the test. The test is not a pass or fail, but determines if a packing completed the test without exceeding these limits.

The API 624 valve fugitive emissions test protocol is soon to be published. This standard sets the limit of 100 ppm emissions from the valve and no retorques are allowed. The standard also requires valve manufacturers to use an API 622 tested and qualified packing in this test. Not all API 622 qualified packings will be able to meet the API 624 requirements.

Starting with a valve packing qualified to API 622 with a maximum leakage of below 50 ppm and no retorques is important. Factors such as surface finish, tolerances and valve design will affect packing performance. When selecting a packing that has a maximum leakage of below 50 ppm allows for these factors and gives the valve manufacturer a better chance of meeting the API 624 requirements.

Converting to Low E Technology

As a valve manufacturer, adapting the Low E Technology as a standard for your equipment puts you in the position to provide the latest in valve packing sealing. Since Low E packings seal to such a tight standard, using them for all services allows you to offer the latest in sealing technology to all your users. A few forward thinking valve manufacturers have taken the lead to convert all their valves to Low E Technology. This is a benefit to their customers with a variety of valves ( some requiring Low E technology, while others are exempt as they are not in VOC and VHAP services). This standardization minimizes confusion and the need for the customer to keep two sets of valves (one for Low E services and one for all others). It also prevents installing the wrong valve in a Low E Technology required process.

Valve and packing manufacturers have the opportunity to be proactive in supplying Low E Technology to their customers. The EPA is knowledgeable of the current state of Low E technology and will no longer accept the argument that low emission valve technology is unavailable. Incorporating Low E Packing in your valves addresses the growing need in the emissions valve market as more consent decrees are issued and EPA enforcement is stepped up.

Walter S. Moquin is currently Manager of Business Development for Mechanical Packings and Gaskets with the A. W. Chesterton Company where he oversees the business for pump and valve packings. Moquin has conducted technical equipment reliability seminars and training regarding process systems and components. He was also responsible for field testing of new products, failure analysis, and application engineering. He currently is involved with Chesterton’s Valve Emissions Program and working with the EPA, end users and valve OEMs to better understand Low E packing technology. He can be contacted at moquinws@chesterton.com