Protecting Fire Sprinkler Systems

The National Fire Sprinkler Association provides insights into how fire sprinklers work and some best practices for protecting the devices when using heat treatment for bed bug mitigation.

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Consider the following: If a preferred method of controlling bed bugs is heating an infested room to a temperature of 122°F for as little as a minute, then raising the temperature this high is a safe and effective method with no other repercussions. Correct? Not exactly. There’s a bit more to the scenario for PCOs that Bob Upson, former fire fighter and fire marshal, and now manager of engineering services, National Fire Sprinkler Association (NFSA) shared with NPMA PestWorld 2017 attendees in Baltimore.

Ultimately, increasing the room temperature to 122°F generally causes the ambient room temperature to increase to 155°F to 160°F, which then causes damage to any fire sprinklers in the room. To review the fire sprinkler damage issue in conjunction with the pest management industry to see what guidelines could be established, Upson wrote a white paper for NFSA titled “Heat Treatment for Bedbug Mitigation in Fire Sprinklered Properties.” (To read, visit the “online extras” section of

FIRE SPRINKLER 101. Upson began his presentation by offering a “101 crash course” in the basics of fire sprinkler operation. Although there are three types of sprinkler orientation — pendent, upright and sidewall — the most common type is pendent (unless the sprinklers are located in an industrial environment). And, all essential sprinkler components are the same despite the type. The most essential part to this particular topic, though, is the activating link, or the heat sensitive component to the sprinkler system, which will either be in the form of a glass bulb or solder link.

As Upson explains, when a fire occurs, heat and hot gases rise, hitting and spreading out across the ceiling, and eventually coming into contact with the sprinkler. The activation speed of the sprinkler depends on three elements:

  1. Plume characteristics — the heat and velocity of the fire
  2. Response time index (RTI) — how fast the sprinkler heats up (usually very quickly)
  3. Operating temperature — the temperature at which the sprinkler is designed to open

Essentially, the National Fire Protection Association (NFPA) has defined rules related to sprinkler system installation, and as a result, temperature ratings have been established in the industry. In relation to the operating temperature and temperature ratings, Upson explains that, “Given the normal day-to-day temperature in the room” there is a tendency “to use the lower temperature sprinklers in residential and life-hazard” environments where high heat is not expected, noting that in a typical residential fire, ceiling temperatures can reach higher than 1,400°F in just four minutes.

Color codes have been established to identify which rating of sprinkler (or the operating temperature) is installed, and the colors indicate the following operating temperatures and classifications:

  • Orange 135°F — Ordinary
  • Red 155°F — Ordinary
  • Yellow 175°F — Intermediate
  • Green 200°F — Intermediate
  • Blue 286°F — High
  • Purple 360°F — Extra High

With a glass bulb sprinkler, the color of the liquid in the bulb gives an indication as to what temperature that sprinkler is designed to operate. With a solder link sprinkler, the color is indicated on the frame. Lower ratings would apply to residential applications, while higher ratings would apply to industries expecting to regularly use high heat, like an environment that would utilize an industrial oven.

For PMPs, the two sprinklers most likely to be encountered will be ordinary or intermediate (where maximum ambient temperatures are not supposed to exceed 100°F or 150°F), respectively, both of which are used in residential and life-hazard occupancies, explains Upson. There needs to be “a buffer between the ambient temperature — the area around the sprinkler — and the actual operating temperature because things begin to go bad when you intrude into that space.” Even if maximum temperatures are not reached, the heating element could experience long-term damage.

SPRINKLER PROTECTION. “Four typical strategies for safeguarding sprinklers during heat-based bed bug mitigation have been identified in the pest management industry,” explains Upson. The first option is to monitor temperatures at the sprinkler locations. Here, a temperature probe or sensor would be placed by each sprinkler, and if the sprinkler operates or if the critical temperature is exceeded (based on ambient temperature, not operating temperature), the sprinkler would need to be replaced.

Second, protect the sprinklers from elevated temperatures with some sort of casing. The unfortunate complexity in this option, though, is that nothing can be attached to a sprinkler without violating code. So, no clippings or hangings. And, dry ice used in an attempt to alter the temperature could cause damage to the sprinkler. Third, disable the sprinkler system during the heat treatment. Strict procedures involving applicable professionals need to be followed in this scenario that could cause a potential life safety issue, so this is not a generally recommended option. And, fourth, remove and replace the sprinkler systems.

This fourth option, to remove and replace the sprinklers, has been identified as a viable strategy in several scenarios. In any of the scenarios, the sprinkler system would need to be shut down and drained, impairment procedures need to be followed, and the involvement of a licensed sprinkler contractor is recommended or required, depending on jurisdiction and local regulations. Remove and replace scenarios need to be identified and evaluated based on the situation, building management, contract, insurance, and jurisdiction.

The general recommendation from Upson is that if the sprinkler is “not an intermediate, then get it changed over in the first treatment.” Upson explains that if pest control operators are performing these bed bug heat treatments in hotels and apartments, there are likely to be return visits. “So, you want to get to the situation where you have intermediate (temperature),” he continues, so start “encouraging contractors now.”

SPRINKLER IMPAIRMENTS. In general, NFPA has governed that an impairment is a condition where a fire protection system in full or in part is out of order and could cause the system to fail in a fire event. And, when an impairment occurs, impairment procedures must be followed; and, when the system is restored, testing must occur to ensure that the system works properly. Impairment is caused by the attachment of foreign material, sprinkler blockage or obstruction, or the water supply being turned off.

Included in the impairment procedure process is a series of notifications that must be made, including making notifications to the following individuals and organizations:

  • Building owner or property manager
  • Fire department
  • Insurance carrier
  • Alarm company
  • Authorities Having Jurisdiction (AHJ), which could be the building department, fire marshal, etc., depending on local jurisdiction and regulation

SUMMING IT UP. To conclude and summarize the information presented, Upson provides the following takeaway points for the pest management industry:

  • “The most conservative option is to plug pipe outlets during heat treatments, so that there are no sprinklers in the room at all.”
  • When circumstances are desirable to keep systems in service during heat treatments, replace “ordinary temperature” sprinklers with “intermediate temperature” sprinklers.
  • “The one I like the best,” shares Upson, is that if “intermediate temperature” sprinklers are installed and monitored individually, they may be left in place as long as they are not exposed to excess temperatures. “As long as you have intermediate sprinklers in place, it’s a lot easier to make sure that you don’t go over temperature. If you have ordinaries, you’ve got to protect them somehow.”
  • “Ideally, decisions about the best strategy for protecting fire sprinkler systems during heat-based bed bug mitigation should involve input from a variety of stakeholders.” Get the stakeholders together to strategize and develop the best bed bug mitigation plan.

The author is a Cleveland-area freelancer.

June 2018
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