The hanging and bracing of a sprinkler system is a key consideration in every sprinkler design and installation. Assuring that the hanging and bracing products used to install sprinkler systems are effective is imperative for proper performance and stability of the system. One method for achieving such assurance is through the third party UL Listing of the hanging and bracing products.
Chapter 9 of NFPA 13 – Standard for the Installation of Sprinkler Systems states that “…the components of hanger assemblies that directly attach to the pipe or to the building structure shall be listed.” There are some exceptions, as permitted by other sections of NFPA 13. To demonstrate compliance with this section, UL offers a Listing service that lets end users and Code Officials know that the manufacturer has submitted a product through the evaluation process with successful results and is manufacturing the product in accordance with the UL Certification Program requirements.
An example of this is a product Listed to Standard ANSI/UL 203 – Pipe Hanger Equipment for Fire Protection Service. The scope of UL 203 covers the performance of pipe hanger equipment for use in supporting pipe employed in sprinkler systems, water-spray systems, and other piping systems used in fire protection. This includes products, such as various hanger types (band, clevis, ring, etc.), brackets, flange clamps and C clamps, ceiling flanges, clips, concrete inserts, couplings, expansion anchors, powder driven fasteners, and retaining straps. The load evaluation requirements for such pipe hanger equipment within UL 203 are consistent with the NFPA 13 requirements. Similarly UL 203A – Sway Brace Devices for Sprinkler System Piping contains requirements for sway brace devices.
UL 203 Testing
Products submitted for evaluation are installed and evaluated in a manner to simulate field installations. For example, hangers are installed in a test assembly with the test load applied to a pipe in the hanger, and anchors are installed in concrete blocks for testing. For hangers and other equipment used to support pipe covered by UL 203, testing may consist of the following depending on the product type:
- Metallic Coating Thickness Test – applicable for coatings where corrosion resistance is required based on product design
- Pull Test – applicable to load bearing hanging equipment to evaluate the product strength to withstand the test loads, without rupture, pull out or release of load.
- Equipment for metallic pipe – tested with load equivalent to 5X the weight of 15 ft span of schedule 40 steel water filled pipe plus 250 lbs, or minimum load of 750 lbs for 2” and smaller pipe.
- Equipment for thermoplastic pipe – tested with load equivalent to 5X the weight of 15 ft span of thermoplastic water filled pipe plus 250 lbs, or minimum load of 340 lbs for 2” and smaller pipe.
- Threaded parts are installed and tightened to specific torques for testing.
- Concrete inserts, expansion shells/anchors, and fasteners are installed into concrete blocks for testing.
- Vibration Test – applicable to expansion anchors, powder driven fasteners, welded studs, C-clamps without locking nut or retaining strap, and other hangers subject to performance under vibration. This test consists of 100 hrs vibration with a test load applied.
- Upward Thrust Test – applicable to products intended to restrain the vertical movement of pipe and shall withstand 340 lbs without displacement of more than 1/8 inch.
UL Listing Process
There are multiple elements of UL’s Listing process for a product. For example, the steps in the table below are part of an evaluation for a new manufacturer of hanging equipment:
Proper system support is a critical aspect of an installation to achieve the desired level of protection expected of a sprinkler system. Manufacturers find value in having a UL Listing for a product, knowing that an independent third party has evaluated representative samples of the product against the requirements of the standard. Authorities having jurisdiction, end users, and product installers look for the UL Listing Mark as an indication that the product has been manufactured in accordance with the UL requirements. The evaluation process identifies those products that do not meet the standard requirements. The UL Surveillance Program is a key component of the Listing as it provides a counter-check that products are continuing to be manufactured in accordance the specifications of the originally evaluated product. These aspects combined make UL Listing of a product an important element in the design and installation
of effective fire sprinkler systems.
For further information, go to www.ul.com