sprinklernotes
Mixing of Sprinklers with Different Temperature Ratings in The Same Compartment
You asked the following questions: “I have an AHJ questioning the placement of a 165-degree concealed pendent in the same area as a 155-degree recessed pendent. I have tried to explain to him that they are both of ordinary temperature rating, but he is concerned about skipping.” In response to your question, we have reviewed NFPA 13, 2016 edition as the applicable standard. Our informal interpretation is a 165-degree sprinkler can be installed in the same compartment as a 155-degree sprinkler. First, 165-degree sprinklers and 155-degree sprinklers are both rated as ordinary temperature per Table 6.2.5.1. NFPA 13, Chapter 8 provides multiple scenarios where high temperature rated sprinklers are required to be installed within the same compartment as ordinary temperature rated sprinklers, including near heat-producing sources. While NFPA 13 does provide a restriction on mixing sprinklers with different response-time indexes (RTI) (ie: standard response and quick response) there is no restriction on mixing sprinklers of mixed temperature ratings within a system or within a compartment. I would also note there is also no restriction on mixing sprinklers with differing orientations within a compartments (ie., upright, pendent, and/or sidewall sprinklers) or even standard spray adjacent to extended coverage, provided they are all of the same RTI.
