Sprinkler Pipe Frequently Asked Questions

  • How do I go about specifying the right products in my specification?
    Since most new products are not "scheduled", some care must be taken to designate the product of choice for the intended use. Stating the brand name of the "original" product or listing "approved equals" simplifies the task versus composing a long description of the products spec's and features. Performance spec's can be in the form of UL/FM approvals, ASTM Stds, CRR minimums,-NFPA-13 or the form of origin.-See Sample Specification section of each product type for more details.
  • Is it OK to use Schedule-40 A-120 pipe for sprinkler pipe specifications?
    A-120 was officially dropped from the ASTM Std. as of December 1987.
  • What ASTM pipe standards are acceptable for fire sprinklers?
    NFPA recognizes three steel pipe standards: A-795, A-53, and A-135.
  • I'm not familiar with all of those, please explain the differences.
    All three have similar requirements regarding steel type, physical test, and acceptable tolerances for production. One difference is that A-53 requires each piece of pipe to be "hydro" tested where as A- 795 and A-135 allow a Non-Destructive Electric test (eddy current) to check the weld seam integrity for any defects. Also, NFPA-13 requires the entire sprinkler system to be hydro-tested after installation and final approval is given.
  • If they're all acceptable, which is the best for my needs?
    As with any product, one looks at three variables: Price, Quality, and Availability. Steel pipe is very competitively priced. The "listed" pipes offer price advantages from 5 - 15% over traditional pipe. In general, domestic manufactures produce a higher quality product: cleaner, true-to-length, and more consistent steel. Most domestic manufacturers produce A-135 or A-795 pipe, including Schedule-10/ Schedule-40 pipe and all perform better and are less expensive to use. Availability is across town, for your convenience.
  • What do I need to know about these special fire sprinkler pipes?
    Most innovations involve increasing the hydraulics flow characteristics by changing the amount and/or quality of the steel without changing the type of fittings normally used. For example, Dyna-Flow pipe, (Sch-10 alternate) has a thinner wall but uses higher strength steel resulting in better hydraulics, lower material, and labor cost. Another type known as "light-wall threadable" offers exceptional hydraulics in a threadable branch line pipe (ie: BLT/XL). Most light-wall threadable pipe (except Dyna-Thread are required by UL-to have threads checked with a ring gauge for conformity with ANSI B1.20.1, and hanger spacing is limited to 12'. Consult NFPA-13 or manufacturer for details.
  • What is the meaning of corrosion resistance ratios, (CRR)?
    CRR is a factoring system developed by UL to compare the thinnest point of Threaded Schedule-40 to that of other types of pipe/joint combinations. The wall thickness ratio implies relative life-span of the pipes at the joints. Typically, any roll grooved or weld joint has a better CRR factor than the same size joint of threaded Schedule-40 pipe.