CODE & STANDARD REFERENCES
How Do You Inspect for Sprinkler Temperature?
BULB SPRINKLER COLORS
We’re continuing on our series of site walkthroughs from the perspective of an insurance carrier. Here we’re talking about checking the temperature of sprinklers as we walk through the site.
The temperature rating of the sprinkler is easy information to collect - in particular with bulb sprinklers. All you have to do is check the color.
Sprinkler temperatures are defined and governed by NFPA 13. There’s a table specific to Temperature Ratings, Classifications, and Color Coding in Table 220.127.116.11 from the 2002 through the 2016 editions, and Table 18.104.22.168 in the 2019 and 2022 Edition of NFPA 13.
Red bulbs indicate ordinary temperature. These bulb colors could also be orange, or a sprinkler with a non-colored or black frame and still be considered ordinary temperature. This is the most common temperature used, and can accommodate a maximum temperature rating of 100 degrees Fahrenheit, or 38 degrees Celsius. The sprinkler itself, when considered Ordinary Temperature, must have a rating of 135-170 degrees Fahrenheit, or 57-77 degrees Celsius.
Intermediate-Temperature sprinklers are next. They are identified by a yellow or green glass bulb, or a white frame. They can accommodate maximum ceiling temperatures of 150 degrees Fahrenheit, and have a rating of 175-225 degrees. In Celsius, they can accommodate 66 degrees with a rating of 79-107 degrees.
A popular point of contention today is the use of intermediate-temperature sprinklers throughout a project. Sometimes inspectors and plan reviewers take exception to the use of intermediate temperature sprinklers throughout a project, because it’s a little less common. However, NFPA 13 actually explicitly allows the use of both ordinary and intermediate-temperature sprinklers throughout a project. This comes from Section 22.214.171.124 in the 2002-2016 Editions, and Section 126.96.36.199 in the 2019 and 2022 Editions.
One advantage to the use of Intermediate-Temperature sprinklers is that they can accommodate warm air coming from HVAC diffusers. If diffusers have the ability to emit air temperatures greater than 100-degrees Fahrenheit (or 38 degrees Celsius), then an Ordinary-Temperature sprinkler would need to be spaced further away from the diffuser, or an Intermediate-Temperature sprinkler would have to be used.
Using an Intermediate-temperature sprinkler throughout a project allows more flexibility in the sprinkler layout, and avoids the concern of being too close to a diffuser that emits warm air. This flexibility can sometimes mean less sprinklers on a job, or less of a need to meticulously design and inspect each space based around the air diffuser locations.
The next temperature sprinkler is high-temperature, which becomes more common for storage applications. These have blue glass bulbs, or blue colored frames. These can accommodate a maximum ceiling temperature of 225 degrees Fahrenheit, with a temperature ranting from 250 to 300 degrees. For Celsius, that’s a ceiling temperature of 107 degrees Celsius and a rated range for the sprinkler itself of 121-149 degrees.
HIGH TEMP ADVANTAGES
For storage arrangements, high-temperature sprinklers can offer an advantage by activating less sprinklers during a fire overall, yet still activate in a reasonable amount of time since the heat release for storage applications can be significant.
Because of this, there are some design benefits to using high temperature sprinklers for storage applications. One common benefit is the allowance for a reduced design density with high-temperature sprinklers for miscellaneous storage. We’ll get into those terms and a lot more detail on that down the road, but that’s one example that comes into play with high temperature sprinklers.
High temperature sprinklers may also come into play with higher-ambient temperature areas. Think about areas right next to unit heaters or inside commercial kitchen cooking vents. High temperature sprinklers might be used in either of these areas.
GREEN & BLUE CONFUSION
One note here during an inspection – green and blue colors can easily be confused from the ground level, depending on the height of the sprinkler and the overall luminosity inside the room. It sometimes takes getting closer to the sprinkler to check the actual temperature rating.
LESS COMMON RATINGS
Beyond high-temperature, we have some less commonly used ratings. These include extra high, which is purple bulb or red frame; very extra high, which is black bulb or green frame, and ultra high, which is a black bulb or orange frame.
These categories range from 400 to 600 degrees Fahrenheit, and accommodate ceiling temperatures of 375 to 625 degrees Fahrenheit. These become 204-343 degrees Celsius, with a maximum ceiling temperature of 191 to 329 degrees Celsius.
All of these references can be found in the table from NFPA 13.
CORROSION-RESISTANT & CONCEALED SPRINKLERS
For sprinklers that are corrosion-resistant, the color identification might be a dot on the top of the deflector. This is also allowed by NFPA 13.
For factory-painted or concealed sprinklers, color identification might not be present. To see the temperature, the deflector itself will usually identify the temperature rating.
SPRINKLER RATINGS OVER TIME
Could these temperature rating change over time? No, not unless the sprinklers have been swapped or replaced. Could some temperature ratings be inappropriate for the environment they are in? Yes, especially near heat sources.
The intent of looking at temperature ratings during an inspection is to be sure that the sprinkler temperature matches its installed environment. If a new heat source was brought in or removed, it might be time to reevaluate the existing sprinkler temperature.
IMPORTANCE OF TEMP CHECKS
If a temperature looks out of place, then the rabbit hole to explore is NFPA 13 Section 8.3.2 in the 2002-2016 Editions, or Section 9.4.2 in the 2019-2022 Editions. There is some specific guidance on where to use the different sprinkler temperature classifications based on the expected ambient temperature in the space and the proximity to nearby heat sources.
Not everyone has the temperature ratings & their requirements memorized, but by taking notes and looking for sprinkler temperatures that appear out-of-place, it is possible to find and verify that the correct sprinkler is in the correct setting.
For Franck Orset I’m Jeff Kelm, this is MeyerFire University.
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