Sprinklers shall be inspected from the floor level annually for these signs
By Grant Lobdell, General Manager and as seen in the November 2021 edition of - FPC - Fire Protection Contractor Magazine
According to the current, 2020 edition of NFPA 25 Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems, “sprinklers shall be inspected from the floor level annually.” (188.8.131.52) Any sprinkler that shows signs of any of the following shall be replaced according to 184.108.40.206.1:
- Corrosion detrimental to sprinkler performance
- Physical damage
- Loss of fluid in the glass bulb heat-responsive element
- Loading detrimental to sprinkler performance
- Paint other than that applied by the sprinkler manufacturer
Beyond water damage, leakage can also accelerate corrosion of various sprinkler components. If the corrosion occurs around the water seal, potentially binding it to the frame with its deposits, it may not release when the sprinkler activates. If the corrosion occurs on a soldered link release mechanism, the metal links may bind together, and the sprinkler may not activate. If the corrosion occurs on the deflector, the distribution pattern could be affected by the buildup of corrosion deposits. Identifying leakage may not be as easy as spotting a water puddle, however. Often times, the leak is slow enough such that the water evaporates before the puddle appears. In this case, it may only be identified by isolated corrosion deposits where the water collects before evaporation.
Corrosion detrimental to sprinkler performance
Corrosion can bind metal components of a sprinkler together, delaying or preventing sprinkler activation and/or water seal release. Corrosion deposit build up can affect the water distribution pattern if located on the deflector. Corrosion can be identified by its colorful deposits. If there is ever any doubt whether or not the corrosion identified is detrimental to sprinkler activation and/or water seal release, Dyne Fire Protection Labs can perform the field service test as described in 220.127.116.11 to make this determination. Note the sampling requirements in that section only apply to the routine testing at intervals described. If the testing occurs outside those intervals, it is considered non-routine according to the annex of the standard and is not subject to those sampling requirements of that section. In other words, a certain number of random samples do not need to be pulled for non-routine testing – you can certainly pull the worst-case scenario for examination. Also note, however, that Dyne Fire Protection Labs does not evaluate the water distribution pattern during this testing. Only the release mechanism and water seal performance are evaluated.
Physical damage can obviously come in many different forms. A bent deflector can affect the water distribution pattern. A cracked frame or damaged release mechanism could lead to premature activation. A damaged water seal or the frame around the water seal could lead to leakage. Identifying damage is easy enough if you compare the sprinkler to others in the area and/or new sprinklers of the same model. Anything out of the ordinary could indicate damage.
Loss of fluid in the glass bulb heat-responsive element
The amount of fluid in the glass bulb is directly related to the activation temperature. As temperatures increase, the fluid expands putting pressure on the glass until its hot enough where that expansion produces enough force to break the glass. Therefore, a loss of fluid in the glass bulb can lead to a higher activation temperature. If enough fluid is missing, the sprinkler will not activate until the glass of the bulb melts! When identifying the loss of fluid in a glass bulb, be careful to not mistake a discoloration of the fluid for the loss of fluid. According to A.18.104.22.168.1, “glass bulbs in sprinklers exposed to sunlight or installed in cold environments such as walk-in coolers and freezers might lose or change their temperature classification color due to the environment.” This section goes on to state that tests have been done to show that the loss of color does not impact performance. In fact, for sprinklers that lost their color due to cold temperatures, often the color will return if the sprinkler is brought back to room temperature. To verify whether a glass bulb has lost its fluid or if it has just lost its color, look for the air bubble inside the fluid. If the air bubble is there and it appears to be the appropriate size compared to others in the area/new sprinklers of the same make, there hasn’t been a loss of fluid in the glass bulb. If, on the other hand, the bubble is much larger than expected or can’t be found (i.e. there is no liquid for a bubble to appear in), there may have been a loss of fluid in the glass bulb.
Loading detrimental to sprinkler performance
In most cases, detrimental loading insulates a sprinkler’s activation mechanism, delaying release. However, depending on the type and severity of loading, it could prevent sprinkler activation entirely, hold the water seal in place preventing full release, and/or block portions of the deflector, changing the distribution pattern of the water after activation. Loading can be considered any material on the sprinkler that was not put there by the manufacturer. As mentioned before, if there is ever any doubt whether or not the loading identified is detrimental to sprinkler activation and/or water seal release, Dyne Fire Protection Labs can perform the field service test as described in 22.214.171.124 to make this determination. Also consider the following according to A.126.96.36.199.1, “in lieu of replacing sprinklers that are loaded with a coating of dust, it is permitted to clean sprinklers with compressed air or a vacuum, provide that the equipment does not touch the sprinkler.”
Paint other than that applied by the sprinkler manufacturer
Paint applied after the sprinkler was assembled by the manufacture can hold various sprinkler components together. If the paint is across the water seal and frame, it could hold the water seal in place after activation. If the paint is on the release mechanism, it could insulate and delay release or, in the worst case, hold the release mechanism together preventing release entirely. If the paint is on the deflector, it could affect the water distribution pattern. For these reasons, only paint applied by the sprinkler manufacturer is allowed. Paint applied by someone other than the manufacturer can be identified based on where it located (i.e. on the release mechanism and/or water seal) and how uniform it is. Note the floor level inspection mentioned in 188.8.131.52 of NFPA 25 and the replacement of any sprinklers that show the signs mentioned above and in 184.108.40.206.1 should occur before sampling for the routine field service test. Failure to do so could lead to a failure(s) in the sample group and result in the replacement of all sprinklers in the sample area.
If you have any questions regarding this article, please contact Dyne Fire Protection Labs at email@example.com or (800) 632-2304.