Creating practical, unified standards for qualifying and testing valves has been a constant struggle for the industry as it seeks to meet the fugitive emission requirements established by the U.S. Environmental Protection Agency (EPA).
The initial response by industry came from the American Petroleum Institute (API) when it added better defined and more stringent requirements as part of the 2011 edition of API 622 (Type Testing of Process Valve Packing for Fugitive Emissions.) At that time, a major change to the standard removed an allowance for performing the emissions test with packing installed into a valve.
This change, along with provisions addressing API 622 packing tests for fugitive emissions to be performed only in a fixture, created the need and opportunity for API to develop the API 624 valve type testing standard (Type Testing of Rising Stem Valves Equipped with Graphite Packing for Fugitive Emissions). API 624 was published in 2014 and became a mandatory requirement within API 600 (Steel Gate Valves—Flanged and Butt-welding Ends, Bolted Bonnets) and API 602 (Gate, Globe, and Check Valves for Sizes DN 100 [NPS 4] and Smaller for the Petroleum and Natural Gas Industries).
In addition to API 600 and API 602, industry expects that API 623 (Steel Globe Valves—Flanged and Butt-welding Ends, Bolted Bonnets) and API 603 (Corrosion-resistant, Bolted Bonnet Gate Valves—Flanged and Butt-welding Ends) also will have to comply with API 624 when the documents are republished by the API in the near future.
API 624 and API 622 are connected because valves tested and certified to API 624 must have packing that meets the requirements of API 622. Currently, an API task group is working on updating and better defining changes so that the two standards align more closely.
Because API 624 compliance will be mandatory as part of API 600 and API 602, creating products to meet the requirement, as well as to meet other global emission standards, means packing and valve manufacturers should work closely together on reviews of their respective products. This collaboration will facilitate meeting low-emission (Low-E) performance and complying with changes in industry design codes for valves.
THE REVIEW PROCESS
Reviews for all components of a valve intended for Low-E applications should include required testing, effective tolerances and cost-effective packing installation procedures.
The review process also should study stem finish, bushing material choice, packing style, torque processes and proper lubrication of the gland flange bolting as well as the potential need to make valve design changes. Valve designs must be reviewed to better understand how potential changes might affect valve performance and effectiveness once the valve is in the hands of the end user.
All of these variables differ from manufacturer to manufacturer. In considering them, the industry needs to look beyond the basics of product design to more intricate details such as assembly procedures performed within the manufacturing process to achieve the API 624 Low-E compliance. Even more importantly, these details may need consideration under EPA consent decrees for end users with enhanced leak detection and repair programs (leakage no greater than 100 ppm for five years).
In addition to valve design considerations, packing installation processes must be reviewed and defined so that the installations are correct, efficient and effective. Valve manufacturers’ and packing manufacturers’ engineering groups can work closely together to define the installation process and create step-by-step written instructions to be followed. Once this has been done, valve manufacturing personnel must receive hands-on training to ensure effective sealing and Low-E warranty compliance. Moreover, the development effort does not end with training the manufacturing staff. End-user personnel and valve repair/replacement shop personnel must also receive hands-on instruction to create best practices for required maintenance procedures.
Once a joint effort is made to properly define and certify what packing should be used and what changes must be made to valve designs or manufacturing practices, the packing and valve manufacturers must monitor each other for consistency in the production of their respective products. This continual sharing of information between the two bodies will ensure any new technologies in valve or packing manufacturing that are implemented are up to date with end-user requirements. These requirements might include:
- A valve capable of achieving low emission (leakage less than 100 ppm) should be easy to operate manually (350N).
- On/off valves should require minimal maintenance over the course of a plant’s life cycle.
- The equipment should meet both current and future EPA compliance requirements but not be cost prohibitive.
- It should meet global testing initiatives such as those for the International Organization for Standards or TA-Luft (Germany’s air pollution requirements).
The ultimate goal is to be able to provide exactly what the industries we serve require and need. With regard to valves, that means:
- Valves capable of passing the required testing protocol
- to be certified as a Low-E valve
- Valves capable of achieving Low-E with minimal maintenance between unit turnarounds
- Five-year warranties as defined by currently active consent decrees, consent decrees now under negotiation or those being issued by the EPA
- Valves capable of handling variability in service conditions (such as mechanical cycles and thermal cycles)
- Multiple valve types that are capable of meeting Low-E compliance
With a strong working relationship in place between packing manufacturers and valve manufacturers, Low-E compliance can be achieved whether the valves are new, used or modified. This is best achieved when the two parties have the capability and willingness to transfer and share pertinent information (including new technologies) via constant and open communication.