Assessing the internals

by Vincent Powers

The NFPA 25 five year internal assessment has finally become a routine task within the fire protection industry.  Though some think this is a new requirement, it is in fact not new.  It has been a requirement of NFPA 25 since its inception in 1992, it actually goes back to NFPA 13A, which was the recommended practice for inspection, testing, and maintenance before NFPA 25 was a thing.

An NFPA 25 Internal Assessment or an NFPA 25 Internal Inspection?

First things first, why is it an NFPA 25 internal assessment and not an internal inspection?  The 2011 edition of NFPA 25 chapter 14 was labeled obstruction investigation and Section 14.2 was the internal inspection of piping section.  In the 2014 edition Chapter 14 changed to Internal piping condition and obstruction investigations with Section 14.2 becoming the Internal Assessment Section and has not changed since.

The reason that it is called an assessment and not an inspection is that the technician is discerning or assessing if there is stuff (foreign organic or inorganic) in the pipe and is it enough to block sprinklers or piping.  An inspection would simply imply looking inside the pipe and say yes there is or is not stuff in the pipe.

If enough stuff is found inside the pipe to obstruct sprinklers or piping, then an obstruction investigation shall be conducted.  An obstruction investigation is a deeper dive into the system to determine how far back into the system does the stuff go? This will determine the course of action, such as replacing the pipe or implementing a flushing program.

All of this information can be obtained in chapter 14 of NFPA 25.  There is also an abundance of information in Annex A as well as Annex D for both obstruction investigations and internal assessments of the piping.

If your company and its technicians perform these tasks it would be a great idea to read these.  Also understand that chapter 14 is related to the internal requirements for piping, this does not include check valves, orifices, or strainers, this information is found in other chapters of the standard.  It does however include ice obstruction investigations, which is required annually when piping passes into a freezer.

Let us talk just a little about corrosion.  Corrosion can start in a sprinkler system as soon as a few weeks after the in-service date and is one of the biggest issues we fight within the fire protection industry.

There are 9 forms of corrosion, they can be found in annex section D.2.6. When MIC (microbiologically influenced corrosion) hit our industry we thought every corrosion issue was related to      MIC, since we have discovered that it is an issue but not as big as we once thought it to be. Many times, the corrosion we see can simply be trapped water from roll grooving pipe, again not ruling out other reasons but just providing one example. The intent here is to determine what type of corrosion you are dealing with when determining how to prevent it from continuing to happen.

One of the questions we get regularly in regard to the pipe thickness, is when should piping be replaced? There is no real guidance on this subject from manufacturers or NFPA.  The only documentation that I could find is FM Global data sheet 2-1 where on page 4 a table is provided to assist in determining this information.

This blog was only to draw some attention to the internal issues with piping and knowing that there is an abundance of information to assist in determining the cause of the corrosion and mitigating it moving forward.