March 21, 2020

ASME NM.2 Implications for FRP Manufacturers and Purchasers

D. Bruce Hebb, P.Eng. is the V.P. Engineering at RPS Composites, and is a member of the Committee responsible for NM.2. We asked him to answer a few questions about this new standard.

What is ASME NM.2?

“NM.2 Glass-Fiber-Reinforced Thermosetting-Resin Piping Systems” is one of three Standards for Nonmetallic Pressure Piping Systems (NPPS) published by ASME, the American Society of Mechanical Engineers.


Why was it created?

The Standard was created by an ASME Committee of end users, manufacturers, and other subject matter experts to specify construction requirements for nonmetallic pressure piping and components. Up until now there had been no single definitive source and there was a need for a more clearly understood, uniform, and complete set of rules specifically applicable to FRP piping systems.


How will NM.2 impact the FRP pressure piping marketplace?

This new standard should give owners a greater sense of ease when they’re ready to source their FRP piping systems, especially systems with higher levels of complexity and criticality. Compliance with NM.2 will differentiate not only manufacturers from each other, but probably even brands within the same company.

“This Standard provides requirements for the design, materials, manufacture, fabrication, installation, examination, and testing of glass-fiber-reinforced thermosetting-resin (FRP) piping systems.”

It’s the owner’s responsibility to select the piping standard that best applies to the proposed piping installation, but as NM.2 becomes the gold standard, the bar will be raised and I expect some manufacturers will have difficulty complying with many of the rigorous requirements. Owners may well start to see claims of NM.2 compliance but with exceptions, which really isn’t compliance.

The ASME NPPS Standards specify engineering requirements deemed necessary for safe design and construction of nonmetallic pressure piping. These Standards contain mandatory requirements, specific prohibitions, and nonmandatory guidance for construction activities.


Does the standard address more than pipe and fittings?

Ultimately, the Committee was concerned about the safe and reliable operation of FRP piping systems, and to that end, yes, we looked beyond the pipe itself. For example, there is a section on Piping Support. Next to installation errors, improper piping support is one of the most common reasons that FRP piping does not perform as it should.


Does it apply to dual laminate piping?

No, not yet, but the intention is to include this some time in the near future. Nor does it include mortar piping, products with fibers other than glass, thermoset resins other than PE, VE and epoxy, high pressure pipe, ducting, and a few other exclusions.


Are there implications regarding repair of NM.2-compliant piping systems? For example, does a compliant manufacturer have to perform service?

No, NM.2 does not address operation or maintenance.


Will there be an official stamp on NM.2- compliant products like the RTP-1 stamp for compliant vessels and tanks?

Like the B31 piping codes, manufacturers do not have to be certified by ASME to produce piping in compliance with the standard, so piping will not bear an ASME stamp.


Is RPS Composites NM.2 compliant?

Yes, we have several piping systems that are NM.2 compliant including our HPPE P-150 corrosion resistant FRP piping, our HPPE A-150 corrosion/abrasion resistant FRP piping, and our HPPE H-150 and HPPE H-150-200 high temperature corrosion resistant FRP piping.


Where can readers go to receive more information?

NM.2 is now available in print from ASME. Readers can also receive advice from their NM.2 compliant manufacturer.

“These Standards prohibit designs and practices known to be unsafe and contain warnings where caution, but not prohibition, is warranted.”