When installing a fire sprinkler system, it’s common practice to use hard pipe for armovers and drops to connect branch lines to the sprinkler head – a time-consuming process that is prone to errors causing costly rework and delays.
Flexible drops are a popular alternative first introduced in Japan in 1980 to avoid compromising fire protection systems in seismic events. In the 1990s, flexible sprinkler hoses started to be used in cleanrooms and duct systems in the United States, and their use grew from there into applications like schools and hospitals.
What many designers and contractors don’t know is that flexible sprinkler drops can be used with BlazeMaster® Fire Protection Systems. Using flexible drops with BlazeMaster pipe and fittings offers:
Designing a BlazeMaster fire sprinkler system with flexible drops is a straightforward process using ready-made screw-on adapters or mechanical couplings to attach the drop to the branch line and sprinkler head. There are a variety of couplings that meet the requirements of ASTM, UL, and FM. Our BlazeMaster CPVC manufacturing partners, Tyco and Viking, offer couplings that make the attachments easy and affordable.
To install a flexible drop, connect the line to the outlet in the branch line. The sprinkler head is connected to the other end of the flexible drop. Once the ceiling grid is installed, an installer can go to the job site and locate the drops in their final location. The fitter installs a bracket to support the flexible drop, puts the flexible drop into the bracket, and cuts the ceiling tile. This takes about 10 minutes or less on average per sprinkler head.
That’s much simpler than installing hard pipe armovers. Installers must wait until the acoustic ceiling tile is put in to know the lengths of the armover and drop. Unless the design and pre-fabrication of armovers was 100% accurate, the work must be done on-site. It’s a challenging process – trying to plan the installation from drawings is almost impossible. It’s typically a two-person job, with one installer on a ladder making measurements and calling down to a partner with a power machine who cuts the pipe for the armover. This process could take an estimated 15 - 30 minutes for each sprinkler head, depending on the complexity of the ceiling installation.
This time could be extended dramatically for more complex situations where the installer needs to install drops around duct work, cable boxes, plumbing lines, and other mechanical and structural members located within the interstitial space. It may also take more time if the armover is greater in length and may require an additional hanger as required by NFPA 13.
Flexible drops eliminate all that complexity. They are available in a wide range of lengths, up to six feet, so installers can work around anything that’s above the ceiling.
Flexible drops also streamline system testing as per Section 29.1.1.1 of NFPA 13 (2022): “Unless permitted by 29.2.1.3 through 29.2.1.6, all piping and attached appurtenances subjected to system working pressure shall be hydrostatically tested at 200 psi (14 bar) and shall maintain that pressure without loss for 2 hours.” With hard-pipe sprinkler drops, the installer may need to hydrostatically test of the system again after the sprinkler heads have been installed. With the use of flexible drops, the installer can complete the hydrostatic test as per NFPA 13 during the rough-in stage.
Flexible drops are a smart option for installing BlazeMaster fire sprinkler systems, especially when it comes to saving time and avoiding corrosion. For more information, contact our expert technical support team.