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BlazeMaster® Fire Sprinkler Systems UL Listed for Open-Web Joists in Residential Basements

By: Lainey Liotta on August 2nd, 2023

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BlazeMaster® Fire Sprinkler Systems UL Listed for Open-Web Joists in Residential Basements

Listings and Innovations

Our team at BlazeMaster® Fire Protection Systems is committed to creating innovative solutions in response to our customers’ needs. For instance, in working with a major national homebuilder we learned they wanted to use BlazeMaster pipe and fittings in unfinished basements with open-web joists – but there was not a listing for this application.

Our customer wanted to adopt open-web construction, which uses less wood, to save money as timber costs spiked. BlazeMaster pipe and fittings have been used for many years with open-joist systems for multi-family and hospitality projects under NFPA 13R – but not for residential exposed basements under NFPA 13D.

To address the customer’s need, our team of experts went to work to create a proposed approach, set installation guidelines, and complete an arduous testing process required by Underwriter Laboratories (UL). The fire source used in UL 1821 is a 1 megawatt fire producing a peak temperature of about 1600o F (871o C) – hot enough to leave scorch marks on the wall (see photo above). The open-web fire sprinkler system was then pressurized to 175 psi without leaking.  

After successful tests, we received an enhancement to BlazeMaster’s UL listings for exposed basements. The listing enhancement applies only to BlazeMaster pipe and fittings from Johnson Controls (Tyco) and Viking – it does not cover competing brands. The listing does not allow for mixing and matching different brands of materials – the system must be completely built with BlazeMaster pipe and fittings as well as BlazeMaster solvent cement. This requirement ensures a quality and compliant installation.

Key Steps for Open-Web Installation

It is critical that you follow the manufacturer guidelines for installation (Viking and JCI have already updated their guides to include open-web installation). Here are several key things to know:

  • Install with wood or steel joists with a nominal depth of 16 inches (406 mm) or less, and a maximum spacing of 24 inches (610 mm) on center.
  • Use listed quick-response horizontal sidewall sprinklers – no pendants -- with a maximum temperature rating of 155o F (68o C) and a minimum K-factor of 4.2, installed below the joists.
  • Install with sprinkler deflectors a maximum of 4.5 inches (115 mm) below the bottom of the joists in anticipation of future installation of a finished ceiling.
  • Locate horizontal sidewall sprinkler deflectors within the maximum distance from the wall as specified in their listing, but in no case more than 7 inches (178 mm) from the face of the wall or soffit on which they are mounted. The maximum distance between sprinklers must not exceed 14 feet (4.26 m). Locate sprinklers no more than 5 feet (1.5 m) from all corners. Lesser spacings are permitted based on limitations of the sprinklers.
  • Ensure the flow for a single sprinkler or for multiple sprinklers flowing is not less than 14 gpm (53 lpm) per sprinkler with a discharge density not less than .07 gpm per square foot (.12 lpm per square meter).
  • Limit the protected area to less than 1,792 sq. ft (127.5 sq. m), with a maximum width of 32 ft (7.5 m) and a maximum length of 56 ft (17 m).
  • Mount piping directly to the wall using listed support devices or other listed support devices either below the joist bay to a maximum of 4.5 inches (115 mm), below the bottom of the joist, or in the joist bay with drops to the sidewall sprinkler.

Review the manufacturers’ installation guides to get all the details.

Ongoing Innovations that Benefit BlazeMaster CPVC Customers

The new listing enhancement is the latest in a series of updated listings for unfinished basements we have secured to help builders and contractors. In 2021, we secured an updated UL listing allowing installation of mains and branch lines perpendicular and/or parallel to the joists. The listing update also:

  • Allowed use of BlazeMaster pipe and fittings with 16-inch joists (the first CPVC fire sprinkler system granted this listing)
  • Expanded the blocking requirement to 44 feet
  • Removed the 1,000-square-foot protected area requirement

Increased the asymmetrical head layout to 16 inches x 16 inches

These updates reflect BlazeMaster’s deep commitment to science, service and safety as we innovate to support our customers’ needs. It’s an ongoing process for our team, and we will continue to keep you informed as we develop new applications for BlazeMaster fire sprinkler systems.

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