Sample Size for Testing Sprinklers Return to Blog
An Informal Interpretation from the American Fire Sprinkler Association
“I have six apartment buildings that were constructed in 2002 that have dry sidewall sprinklers protecting the breezeways. The dry sprinklers require testing since they are over 10 years old. NFPA requires a minimum of 1 percent of the total sprinklers but not less than four sprinklers to be tested. To meet this requirement would this be for each building individually or could it be based on the entire six buildings since they were all constructed in the same year with the same make, model and temperature of sprinklers?”
We have reviewed NFPA 25, 2014 edition that you indicated as the applicable standard. Our informal interpretation is testing all six breezeways as one sample is appropriate.
The installation standards are easy because they are generally written to address single systems, but even then there are exceptions such as water supplies and FDC connections. NFPA 25 is not written in a per system format (although our inspection forms typically are per system to better communicate what has been performed). You’re right that we generally look at individual buildings, but in the case where it’s an open breezeway between buildings, treating it as one area would be no different than treating a warehouse with three systems as a single area. Let’s now look at the actual text on this issue. The scope (Section 1.1) indicates it applies to fire protection systems (plural). This could be interpreted either way. More importantly, Section 5.3 on Testing tells us that a representative sample from one or more areas shall be tested. The representative sample is intended to cover the all the sprinklers within a given environment (since the potential for corrosion, loading, painting, etc. varies based on the function and exposure of where the sprinklers are placed. The sample can come from different areas within a system or different floors (that are typically different systems).
This is clarified in the NFPA 25 Handbook where the commentary on Section 18.104.22.168 states:
“The sample should be somewhat random and should be representative of the sprinklers installed in the system. For example, sprinklers should be selected from different floors or areas of the building and not selected simply because they are more accessible than other sprinklers. In addition, the selection should take into consideration the age and types of sprinklers as well as the environmental conditions to which they are subjected.”
The sample is also not required to be every type installed as long as one of the types from the same manufacture is tested as dictated by A.22.214.171.124.
Considering all the breezeways are the same environment with the same manufacturer, pulling a single sample of four sprinklers or 1percent of the total sprinklers from the combined areas meets the intent of the standard. There is a downside when defining a larger area as the representative sample. That is, if there is a failure from any one of the different areas, you have to replace the sprinklers in all of the areas.