Hanging, Bracing and Restraint Requirements for Fire Sprinkler System Piping

This article is about Hanging, Bracing and Restraint Requirements for Fire Sprinkler System Piping and Technical Requirement in commercial buildings, plants and refinery projects related to Plumbing Engineering System as per international codes and standards.

Hanging, Bracing and Restraint Requirements for Fire Sprinkler System Piping

General

1. Hangers and their components shall be ferrous. (NFPA 13 Para 2-6.1.2)
2. The components of hanger assemblies that directly attach to the pipe or to the building structure shall be listed. (NFPA 13 Para 2-6.1.1)
3. Sprinkler piping or hangers shall not be used to support non-system components. (NFPA 13 Para 2-6.1.7)
4. The use of listed inserts set in concrete to support hangers shall be permitted. (NFPA Para 2-6.2.1)
5. Listed expansion shields for supporting pipes under concrete construction shall be permitted to be used in a horizontal position in the sides of beams. (NFPA13 Para 2-6.2.2)
6. In concrete having gravel or crushed stone aggregate , expansion shields shall be permitted to be used in the vertical position to suppoprt pipes 4″” (102 mm) or less in diameter. (NFPA 13 Para 2-6.2.2)
7. For the support of pipes 5″ (127 mm) and larger, expansion shields, if used in the vertical position, shall alternate with hangers connected directly to the structural members, such as trusses and girders, or to the sides of concrete beams. (NFPA 13 Para 2-6.2.3)
8. In the absence of convenient structural members, pipes 5″” (127 mm) and larger shall be permitted to be supported entirely by expansion shields in the vertical position, but spaced not over 10′ (3m) apart. (NFPA 13 Para 2-6.2.3)
9. Expansion shields shall not be used in ceilings of gypsum or other similar soft material. (NFPA 13 Para 2-6.2.4)
10. In cinder concrete, expansion shields shall not be used except on branch lines where they shall alternate with through bolts or hangers attached to the beams (NFPA 13 Para 2-6.2.4).
11. Holes for expansion shields in the side of concrete beams shall be above the centre line of the beam or above the bottom reinforcement steel rods. (NFPA 13 Para 2-6.2.6)
12. Where expansion shields are used in the vertical position, the holes shall be drilled to provide uniform contact with the shield over its entire circumference. Depth of the hole shall not be less than specified for the type of shield used.(NFPA 13 Para 2-6.2.5).
13. Powder driven studs, welding studs, and the tools used for installing these devices shall be listed. (NFPA 13 Para 2-6.3.1)
14. Representative samples of concrete into which studs are to be driven shall be tested to determine that the studs will hold a minimum load of 750 lbs (341 kg) for 2″ (51 mm) or smaller pipe, 1000 lbs (454 kg) for 2½”, 3″ or 3½” (64 mm, 76 mm, or 89 mm) pipe and 1200 lbs (545 kg) for 4″ or 5″ (102 mm or 127 mm). (NFPA 13 Para 2-6.3.3)
15. Hanger rod size shall be the same as that approved (acceptable to the Authority Having Jurisdiction) for use with the hanger assembly and the size of rods shall not be less than that given in Table 2-6.4.1.
    Exception: Rods of smaller diameters than indicated in Table 2-6.4.1 shall be permitted where the hanger assembly has been tested and listed by a testing laboratory and installed within the limits of pipe (NFPA 13 Para 2-6.4.1)
16. Table 2-6.4.1 Hanger Rod Sizes

Pipe Size

Diameter of Rod

in.

mm.

Up to and Including 4 in.

3/8

9.5

5, 6, and 8 in.

1/2

12.7

10 and 12 in.

5/8

15.9

• The size of the rod material for eye rods shall not be less than that specified in Table 2-6.4.3 ê Where eye rods are fastened to wood structural members, the eye rod shall be backed with a large flat washer bearing directly against the structural member, in addition to the lock washer. (NFPA Para 2-6.4.3)

• The size of the rod material for U-hooks shall not be less than that given in Table 2-6.4.2 ê Drive screws shall be used only in a horizontal position as in the side of a beam in conjunction with “U” hangers only. (NFPA 13 Para 2-6.4.2)
• Table 2-6.4.2 U-Hook Rod Size

• “Threaded sections of the rod shall not be formed or bent. (NFPA 13 Para 2-6.4.4) “

Sprinkler

1. The maximum distance between hangers shall not exceed that in Table 4-14.2.2.1. See Attachment No.1 in this SAIC
   Exception No. I: The maximum distance between hanger for steel Pipe and copper tube shall be modified as specified in items B2, B3, and B4 as specified in this SAIC
   Exception No. 2: The maximum distance between hangers for CPVC pipe and polybutylene pipe shall be modified as specified in the individual product listings.
   Exception No. 3: Holes through concrete beams shall be acceptable for the support of steel pipe as a substitute for hangers. (NFPA 13 Para 4-14.2.2.1)
   Note: The above applies to the support of steel pipe or copper tube.
2. There shall be not less than one hanger for each section of pipe.
   Exception No. I : Where sprinklers are spaced less than 6 ft ( I .8 m) apart, hangers spaced up to a maximum of 12 ft (3.7 m) shall be permitted.
   Exception No. 2: Starter lengths less than 6 f t ( I .8 m) shall not require a hanger, unless on the end line of a side feed system or where an intermediate cross main hanger has been omitted. (NFPA 13 Para 4-14.2.3.1)
   Note: The above applies to the support of steel pipe or copper tube.
3. The distance between a hanger and the centerline of an upright sprinkler shall not be less than 3 in. (76 mm). (NFPA 13 Para 4-14.2.3.2)
4. Note: The above applies to the support of steel pipe or copper tube.
5. The unsupported length between the end sprinkler and the last hanger on the line shall not be greater than 36 in. (914 mm) for 1-in. (2.5-cm) pipe or 48 in. (1219 mm) for 1-1/4-in. (3.2-cm) pipe, and 60 in. (15.2 cm) for 1-1/2 in. (3.8-cm) or larger pipe. Where any of these limits is exceeded, the pipe shall be extended beyond the end sprinkler and shall be supported by an additional hanger.  Exception No. 1 : When the maximum pressure at the sprinkler exceeds I00psi (6.9 bars), and a branch line above a ceiling supplies sprinklers in a pendent position below the ceiling, the hanger assembly supporting the pipe supplying an end sprinkler in a pendent position shall be of a type that prevents upward movement of the pipe.

Exception No. 2:

When the maximum pressure at the sprinkler exceeds 100 psi (6.9 bars), the unsupported length between the end sprinkler in a pendent position or drop nipple and the last hunger on the branch line shall not be greater than 12 in. (305 mm) for steel pipe or 6 in. (152 mm) for copper pipe. When this limit is exceeded, the pipe shall be extended beyond the end sprinkler and supported by an additional hanger. The hanger closest to the sprinkler shall be of a type that prevents upward movement of the piping (NFPA 13 Para 4-14.2.3.3)
Note: The above applies to the support of steel pipe or copper tube”

Standpipe

“Standpipes shall be supported by attachments connected directly to the standpipe. (NFPA 14 Para 4-4.1.1)
“Standpipe supports shall be provided at the lowest level, at each alternate level above, and at the top of the standpipe. (NFPA 14 Para 4-4.1.2)
“Supports above the lowest level shall restrain the pipe to prevent movement by an upward thrust where flexible fittings are used. (NFPA 14 Para 4-4.1.2)
“Clamps supporting pipe by means of set screws shall not be used. (NFPA 14 Para 4-4.1.3)
“Horizontal piping from the standpipe to hose connections that are more than 18″” (457 mm) in length shall be provided with hangers. (NFPA 14 Para 4-4.2.1)”
“Horizontal piping hangers shall be spaced at a maximum separation distance of 15′ (4.6 m). The piping shall be restrained to prevent movement by an upward thrust where flexible fittings are used. (NFPA 14 Para 4-4.2.2).

International Codes and Standard References for Hanging, Bracing and Restraint Requirements

Location and Spacing of Sprinkler Technical Requirements

Hangers and Supports Selection & Material Inspection Checklist

1-SAES-S-050 Sprinkler & Standpipe System Components in Buildings.
2-NFPA 14 – Installation of Standpipe and Hose.
3-NFPA 13 – Installation of sprinkler Systems.

Attachment 1 – Maximum Distance Between Hangers