The specification mark will be valid beginning in January as originally planned, despite the challenges of the COVID-19 pandemic, said Chuck Coe of Grease Technology Solutions, an independent consultant who has been closely involved in its development.

However, the HPM specification is expected to make its debut with provisional certification for the high load subcategory until ASTM can address precision problems with its D4170 fretting wear test, Coe noted.

NLGI will begin filing trademark applications for the HPM mark this month in North America, followed by China, Japan, Thailand, India, the European Union, Australia and Brazil.

While the price of certification has not yet been set, O’Halloran promised a “reasonable flat fee” that will include testing. She acknowledged that the cost will be higher than that of GC-LB certification because of the additional testing involved.

The Center for Quality Assurance will administer the specification and conduct qualification testing, which will take four to six weeks, according to CQA’s Mike Kunselman. This timeline may shorten to three to four weeks, he said.

HPM is not intended to replace NLGI’s legacy GC-LB certification mark, which has been the mark of basic grease quality since 1966. GC-LB is “good grease with a lot of utility in the market today,” said Coe. Instead, HPM will provide higher performance and broader utility for the market.

In addition to the core performance requirements, four subcategories will certify enhanced performance in particular areas: water resistance (WR), high load carrying capacity (HL), salt water corrosion resistance (CR) and low-temperature performance (LT). A grease may qualify for HPM only or HPM plus any combination of subcategories.

A fifth subcategory, high temperature/long life (LL), is under development but may take another two to five years, he estimated. Additional categories, such as electric motor greases, may also be added in the future, Coe said, and he encouraged feedback from industry stakeholders.

Proposed test limits for the specification were based on ASTM D4950, Standard Classification and Specification for Automotive Service Greases, along with data available from public sources, industry marketing specifications and claims, Coe reported. Some limits were revised following interviews with end users, GC-LB certification holders and original equipment manufacturers, as well as a virtual workshop held in March.

For limits lacking consensus, the steering committee relied on internal data from committee members’ individual companies. For limits with insufficient supporting data, the committee is conducting validation testing on greases deemed likely to meet specification requirements.

“Our philosophy is that the limits should be challenging but achievable,” Coe explained.

The specification is not meant to satisfy all requirements for specialized industries, which often have their own specifications, he noted. Instead, HPM could be a good platform on which to build such specialized specifications.

Coe also emphasized that HPM, like GC-LB, is “chemistry neutral,” and qualification is based solely on performance. “There is no limit to raw materials chemistry or manufacturing process,” he said. While there is a possibility for different HPM greases to be incompatible, Coe acknowledged that the risk of end users applying incompatible greases exists regardless of the specification. “If NLGI included a compatibility requirement, it would likely exclude some types of grease,” he said. (See the October 2019 issue of Lubes’n’Greases for more information on grease compatibility.)

“If you look at GC-LB today, the majority of greases are lithium complex,” Coe observed. “My expectation is that will be similar for HPM.” Other thickeners can qualify, though, such as calcium sulfonate, aluminum complex and polyurea, he noted.

The HPM specification is meant to be a “living document” that can evolve to meet the industry’s needs, said NLGI President Joe Kaperick of Afton Chemical. But it is not expected to change every year, and any changes will be made with good reason, thoughtfulness and input from NLGI members, he said.

Kunselman assured attendees that there will be a transition period after any changes to the specification. “This is not intended to push products out by making changes too quickly,” he said.

O’Halloran said NLGI will soon host a webinar series highlighting HPM tests. The organization will also give a presentation on HPM during the Society of Tribologists and Lubrication Engineers’ Commercial Marketing Forum on Sept. 30 at 10:30am Central Standard Time.

The most recent details on the specification were presented at a June webinar and are available at https://www.nlgi.org/about-us/high-performance-multiuse-grease/