April 29, 2019
UL has recently issued the first certification for trace heating equipment for use with a fire sprinkler system including the installation on sprinkler branch lines. This new certification complements the requirements in the NFPA 13, Standard for Installation of Sprinkler Systems, and provides an additional option for protecting fire sprinkler piping from freezing in cold environments.
NFPA 13 Requirements
To prevent damage and facilitate the effective discharge of water from a fire sprinkler system, NFPA 13 generally references the use of a dry pipe system, pre-action system or a listed (certified) antifreeze solution in areas subject to freezing. As an alternative, NFPA 13 also allows for trace heating systems – or heat tracing, as referenced in NFPA 13 – to be used on a wet pipe sprinkler system in certain locations, provided the heat tracing system is listed (certified) for this purpose. Furthermore, to address the unique concerns associated with the use of trace heating systems on sprinkler branch lines, NFPA 13 requires that trace heating be specifically certified for this type of installation.
Product Certification for Fire Sprinkler Applications
Trace heating equipment has been used for decades in a broad range of applications such as building plumbing systems, fuel lines, deicing of roofs and gutters, frost heave protection and similar applications. UL has a long history and experience in certifying trace heating equipment for many of these applications. However, these certifications do not address the unique concerns associated with use on a sprinkler system providing fire safety. With this in mind, it is important to verify that that the trace heating equipment used on a fire sprinkler system is listed (certified) for this specific use. Otherwise, the level of safety provided by the fire sprinkler system may be adversely impacted.
A trace heating system intended for fire sprinkler applications is typically composed of several elements including the trace heating cable elements and associated controls. UL’s certification of trace heating for fire sprinkler systems includes the application of requirements from the 2012 edition of IEEE 515.1 that are relevant to sprinkler systems along with additional requirements described in UL 515A, Outline of Investigation for Electrical Resistance Trace Heating and Associated Controls for Use In Sprinkler and Standpipe Systems. Several of the key requirements include:
- Performance tests using a section of sprinkler branch line piping with a sprinkler installed to evaluate the ability of the trace heating system to prevent (1) the sprinkler system water from freezing at low ambient temperatures and (2) the sprinkler’s heat responsive element from reaching excessive temperatures during high ambient temperature conditions.
- Provisions for permanent connection to a power supply.
- Provisions for connection to a fire alarm system.
- Tests to confirm the ability of the trace heating system to provide important alarms and signals such as low water temperature, high water temperature, failure of the primary controller, ground faults, loss of continuity and loss of incoming supply voltage.
- Tests of the trace heating system controls to confirm compliance with relevant requirements of UL 864, Control Units and Accessories for Fire Alarm Systems.
- Confirmation that instructions are available from the manufacturer to properly design and install the trace heating system so that it will provide the necessary freeze protection without obstructing the water discharge pattern from a sprinkler head. The information included in the manufacturer’s instructions requires the use of a non-combustible insulation and protective cover that will maintain its integrity when exposed to water discharged from a sprinkler system.
The requirements associated with the UL certification of trace heating systems are comprehensive and intended to address the needs of the fire protection community relative to maintaining effective fire sprinkler protection even in cold environments.
Recent UL Certification of Trace Heating Equipment for Fire Sprinkler Use
It is important to understand that only trace heating systems UL listed (certified) for use in fire sprinkler systems are included in the category code number (CCN) VGNJ, Heating-Cable Systems for Use on Fire Protection System Piping. Trace heating equipment UL certified for several other end-use applications are covered by different CCNs.
When sprinkler systems are installed in locations subject to freezing, NFPA 13 generally references the use of a dry pipe system, pre-action system or a listed antifreeze solution. However, UL 515A allows other approaches to be used to prevent the freezing of water in the system. While NFPA 13 does not permit trace heating systems to be used in lieu of heated valve enclosure rooms, these systems provide an option for protecting portions of fire sprinkler piping from freezing in cold environments. As highlighted in NFPA 13, it is important for trace heating equipment to not only be listed (certified), but certified specifically for the fire sprinkler system application including use on sprinkler branch lines.
UL’s certification of trace heating equipment for fire sprinkler use includes comprehensive requirements that evaluate the ability of the equipment to maintain the integrity and effectiveness of a fire sprinkler system.
For more information related to these products or their listing, please contact Kerry Bell at [email protected].
Author: Kerry M. Bell, UL Corporate Fellow, Principal Engineer, Fire Sprinkler and Pump Equipment