This is a common field procedure where internal surfaces are washed with an alkaline solution to neutralize any acids that might form. The standard notes that field experience has demonstrated austenitic stainless steels are effectively protected when alkaline wash solutions are properly applied to all wetted surfaces.
As of 2025, the official NACE SP0170 PDF 2021 costs approximately $150–$250 for members (less if you join AMPP). For a piece of equipment that costs millions, this is a trivial investment.
: The relative humidity inside the vessel must be kept below 20% to 30% , ensuring that the internal metal surface temperature always remains safely above the ambient dew point to prevent condensation. Material Selection Considerations nace sp0170 pdf 2021
Keeping the equipment dry prevents the reaction needed to form the acid.
Oxygen levels must be strictly monitored via continuous testing if any connected lines are broken. 2. Alkaline Washing (Neutralizing Acids) This is a common field procedure where internal
The standard solution typically consists of soda ash (sodium carbonate, Na2CO3cap N a sub 2 cap C cap O sub 3
While users frequently search for a version, the active, governing edition of this standard remains NACE SP0170-2018 . The 2018 edition remains fully current as it has been systematically reaffirmed by AMPP downstream committees. Official, authorized digital copies can be acquired in PDF format directly from AMPP Standards Store or the ANSI Webstore . For a piece of equipment that costs millions,
When process equipment—such as hydrotreaters, desulfurizers, and fluidized catalytic cracking units (FCCUs)—operates at high temperatures (
This method involves keeping the system free of moisture and oxygen.
No. This is a common point of confusion. deals with "Control of External Corrosion on Underground or Submerged Metallic Piping Systems," focusing on cathodic protection for buried pipelines. NACE SP0170 is entirely different, focusing on internal cracking of refinery equipment (stainless steel alloys) during shutdowns.