INOX-a four-letter word for change
The stainless steel option and its influence on the design and installation of potable water systems.
Over the course of time, many changes to the National Plumbing Code (NPC) were related to the first-time inclusion of new technology. In Europe, INOX or stainless steel has been used for decades in piping interior building systems including potable water, even in the single-family residential context. That has not been the case here in Canada, where this is a fairly recent phenomenon.
While there are some first time changes for 2015, one of the most notable changes ushered in with the publication of this new version is the inclusion of stainless steel pipe and fittings for interior building service use, specifically in potable water systems without the requirement for a Variance or “alternative solution.”
Why is there an interest and enthusiasm in having stainless pipe OK’d for use in plumbing systems? One reason would be pipe sizing versus copper. Like most polymer piping systems, the design flow in feet per second (FPS) or metres per second (MPS) allows for higher flow rates in stainless pipe than does copper. As an example, in BC the flow rate limitation for copper is three FPS on hot water lines and four FPS on cold water lines. By contrast, the City of Vancouver allows flow rates of up to eight FPS in stainless piping, allowing smaller diameter stainless to be utilized in equivalent systems.
This change to the NPC has been discussed for some time and recognizes a material, which has an extensive history in our industry. In Canada, stainless steel has been specified and installed as part of our infrastructure in water treatment facilities for many years. Recognizing this, many authorities having jurisdiction (AHJs) at the civic and provincial levels, have moved to streamline or eliminate the need for alternative solution submissions by issuing regulations to permit the use of stainless in potable systems.
A partial list of AHJs moving to adjust or eliminate requirements
1. The City of Saskatoon
2. The City of Vancouver
3. The Province of Alberta
4 The Province of Quebec
These bulletins all contain some reference to the material requirements of the products suitable for use, listing alternatively either or both of:
Pipe or tubing- Type 304/304L or 316/316L
• A269, A312 or A312m, A778
Pipe or tubing
• B36.19m, B16.19
While some have required an NSF/ANSI 61 listing on pipe, not all have required this on the fittings. The City of Vancouver has called this out specifically, requiring NSF/ANSI 61 markings on both the pipe and the fittings. It is unclear if this requirement will change over time.
On the NSF International web site there is a great Q&A, which addresses the issue of the suitability of stainless for potable water systems.
Q: “Are all stainless steel products compliant with NSF/ANSI 61?”
A: “No. Only products that are certified to NSF/ANSI 61 can be assumed to meet the requirements of the standard. Certification to NSF/ANSI 61 includes product testing and production location auditing to ensure ongoing compliance with the health based requirements of NSF/ANSI 61. This includes testing products on an annual basis, by exposing them to different formulated waters (typically at pH 5, pH 8 and pH 10) and testing for regulated metals such as antimony, arsenic, barium, cadmium, chromium (including chromium VI), copper, lead, mercury, selenium, thallium, and nickel, as well as any other inorganic and organic leachate concerns that may derive from cutting oils, lubricants, process aids, welding, machining, and other forming by-products. The certification process also includes annual unannounced inspections of the manufacturing facility to verify that the manufacturer is making the product using the same raw materials, material suppliers and production process as the products that are tested.”
Go to www.nsf.org/q-and-a-all/qa-detail/nsf-ansi-standard-61 for further information, including how to search for companies who have listed (compliant) products.
The Canadian Institute of Plumbing & Heating (CIPH) recently hosted What’s going on in Canada: A Codes and Standards Webinar, where the question of the pending changes related to the inclusion of stainless pipe systems was addressed. See 2015 NPC Presentation for some background on why this change has developed in the market.
An important issue addressed in the webinar was that of implementation. Not all provinces operate concurrently with their amended version of the National Plumbing Code. Thus, even though the 2015 National Plumbing Code has now been published, the changes therein, including this change making stainless pipe systems permissible may not come into effect in your area for some time. See Figure 1, an adoption timeline by province.
While Canada has not adopted universal lead-free requirements for all plumbing system components, stainless steel pipe and fitting systems do present another piping system option that can be compliant.
A visit to the NSF website also provides information on understanding plumbing products marking at www.nsf.org/consumer-resources/health-and-safety-tips/water-quality-treatment-tips/plumbing-product-markings. “Since January 4, 2014, manufacturers wanting to sell plumbing products in the U.S. must demonstrate that those products do not contain more than 0.25 percent lead if the product is intended for contact with drinking water. The weighted average lead content of a product is determined by multiplying the lead content of each component that is in contact with water by the surface area of that component, then dividing this number by the entire water contact surface area of the product. Products produced prior to 2014 that met this requirement may be marked with NSF/ANSI 61G, NSF® pw-G, NSF/ANSI 372 or NSF® 372, while products produced after January 4, 2014 may display an NSF/ANSI 61, NSF® pw, NSF/ANSI 372 or NSF® 372 marking.”
An earlier webinar presented by CIPH, titled Update on Low Leaded Plumbing Products in Canada, also addressed some pending changes related to Low Lead requirements in Canada, specifically:
2010 interim changes for Low Lead in plumbing
Reference to the 2012 editions of:
• CSA B125.3 “Plumbing Fittings”
• ASME A112.18.1/B125 “Plumbing Supply Fittings”
The ill effects of exposure to lead on human health have been well known for decades. Due to the more stringent requirements for lead content in American jurisdictions, limiting the lead content for fittings in the NPC has been recognized. CSA B125.3 Plumbing Fittings and ASME A112.18.1/B125.1 Plumbing Supply Fittings, which are referenced in the 2010 NPC for the performance of plumbing fittings and supply fittings, respectively, have been updated to include requirements and definitions for low-lead content fittings.
In an effort to harmonize requirements across North American jurisdictions (with reference to the 2012 editions of CSA B125.3 and ASME A112.18.1/B125.1) changes have been made to the 2010 NPC. As other standards are updated to reference the NSF 372 low lead requirements, code change requests will be forwarded to the NRC to update the reference materials in the NPC.
At this point, it remains to be seen how much the stainless option will influence design and installation given the choices in PE-x, PP-RT, PE-RT, CPVC and other non-ferrous materials available for use in plumbing systems. As is the case with other piping choices, corrosion resistance, flushing and cleaning, expected service life, warranty and flow rates remain as factors to be considered when designing and installing potable and process piping systems in buildings.
Mark Evans has held positions of increasing responsibility at the regional and national level of the wholesale supply, rep agency and manufacturing sectors of the plumbing and heating industry.
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May 11, 2022