Bed bugs have been around for thousands of years and were thought to have been eradicated in the developed world around 1940. However, since about 1995, there has been a resurgence, most likely due to a number of reasons such as the banning of certain pesticides and an increase in international travel.
So, what does this have to do with sprinklers, you may ask? Well, one of the treatment strategies recommended by the National Pest Management Association (NPMA) to rid an area or room of a bed bug infestation is the use of heat. As a matter of fact, a temperature of 113°F (45°C) is needed to kill most bugs in a living area, however that temperature would have to be maintained for several hours and might not take care of the problem entirely. A temperature of 122°F (50°C) is necessary to eradicate all life stages (bugs, nymphs and eggs) and only needs to be maintained for about one minute, which seems to be the more cost effective approach. Some companies are even suggesting a temperature range of 130°F to 160°F (54°C to 71°C).
Why is this a problem? As you may already know, sprinklers are heat sensitive devices that, when exposed to certain temperatures, are designed to activate and discharge water to control or extinguish a fire. Even when exposed to heat from sources other than a fire, sprinklers can and will activate and discharge water. The typical discharge from a single sprinkler can range from as little as 15 gallons per minute (gpm) [57 liters per minute (lpm)] to as much as 60 gpm (230 lpm)! This flow rate might be desired if your building is on fire, but for an unintended activation, that’s a lot of water!
So, regarding temperature, how much is too much? NFPA 13-2016 “Standard for the Installation of Sprinkler Systems” tells us in Table 18.104.22.168.
As you can see in the Table, when ceiling temperatures exceed 100°F (38°C), ordinary temperature sprinklers (the type typically found in most buildings) are susceptible to activation. Even if the sprinklers do not activate immediately, the glass bulb or fusible link could be stressed, causing the sprinkler to activate at a later time.
There are a few methods that can be employed to avoid exposing sprinklers to heat. The pest management industry is addressing this problem with the development of sprinkler covers that either shield the sprinklers from excessive heat or contain a small amount of water that is frozen and placed over the sprinkler to keep it cool during the heat treatment process. Another manufacturer suggests using ice packs in their cover to keep the sprinkler cool during the treatment process. It is unclear how these covers and coolants will affect sprinklers, since these methods have not been evaluated by the usual testing labs. None of these devices presently indicate any type of listing or approval.
A more traditional method for dealing with the heat treatment process involves an impairment program as required by NFPA 25-2017 Standard for the Inspection, Testing and Maintenance of Water Based Fire Protection Systems. A system impairment involves closing the water supply valve to the sprinkler system, draining the water from the system and either leaving the system impaired for a short period of time or removing the sprinklers in the affected area and plugging the outlets temporarily so that the sprinkler system can be turned on while the heat treatment process is completed. The latter method will maintain protection in areas not being treated for bed bugs, although the impairment program will require either some form of temporary protection such as a fire watch with an extinguisher or some other method for providing temporary fire protection (a charged hose line from a standpipe perhaps) when using either method. For detailed information on system impairments, see NFPA 25, Chapter 15.
Keep in mind that once sprinklers are removed from a system, they must be replaced with new sprinklers; the old sprinklers cannot be reused (see Section 22.214.171.124 of NPFA 25). The traditional method of system impairment can be costly and will most likely involve a licensed sprinkler contractor to complete the work in addition to the pest removal contractor, but this will ensure that the bed bug infestation problem has been solved without compromising fire protection. The new covers that are recommended by pest control contractors are a nice idea, but testing should be done to verify that they work as advertised and will not compromise the operating element of the sprinkler. Regardless of the method used, this is not a (Do-it-Yourself) DIY type of project!
Be safe, sleep tight, and don’t let the bed bugs bite!