Obstruction Investigation

An Informal Interpretation by the AFSA:

Obstruction Investigation

 “Is an obstruction investigation required every 5 years or whenever one of the 14 conditions exist?”

We have reviewed NFPA 25, 2011 edition as the applicable standard. Our informal interpretation is that an obstruction investigation is conducted when any of the 14 conditions in Section 14.3.1 exists.

The internal pipe inspections and obstruction investigations are two separate tasks. The internal inspection of piping has a frequency of every 5 years in Section 14.2. The obstruction investigation has no time limit and is initiated when any of the listed 14 conditions are present. For example, there were some systems installed for only a few months that have experienced pinhole leaks. This is a condition listed to initiate an obstruction investigation and obstruction prevention program. These 14 conditions can show up at any time. A system that does not exhibit any of the 14 conditions listed under Section 14.3.1, an internal inspection of piping or “visual” inspection shall be completed every 5 years by opening a flushing connection at the end of one main and by removing a sprinkler toward the end of one branch line. This would include each system if drained for another inspection procedure. The Handbook commentary clarifies that the inspection required by 14.2.1 should be coordinated with the internal inspection requirement of system control valves, such as required by 13.4.1.2 for alarm valves. Subsection 14.2.1, is not intended to place an additional burden on the property owner by requiring an additional inspection every five years. If the system is drained for another 5-year inspection, then the internal inspection of that particular system can be completed.