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Informal Interpretations Answer Questions on Residential Installations


by , from the 1/2001 issue of Sprinkler Age, page 28

The following informal interpretations were prepared by the Technical Services Department of the American Fire Sprinkler Association (AFSA) in answer to specific questions from contractors and/or AHJs. AFSA's informal interpretations are provided by AFSA Director of Technical Services Roland Huggins, a P.E. registered in fire protection engineering; Phill Brown, S.E.T., CFPS, a NICET IV certified automatic sprinkler technician; and Kenneth Saks, degreed fire protection engineer. These opinions are provided for the benefit of the requesting party and are provided with the understanding that the AFSA assumes no liability for the opinions or actions taken on them.



Subject: Insulating Exposed CPVC Pipe

Question: Can CPVC Blazemaster Pipe be protected by Micro-Lokª Fiber Glass Pipe Insulation be installed "exposed" and still meet all listing and code requirements of UL & NFPA 13D? The CPVC pipe is being installed in the attic of single family dwellings. The AHJ is requiring two sprinklers to be installed in the attic to provide early detection, water flow & possible steam generation in a fire situation."



Answer: Our informal interpretation is the installation of two sprinklers installed in the attic does not constitute a sprinklered attic space and the pipe insulation will not be required.



NFPA 13D does not require sprinkler protection of the attic space in a single-family residence. The UL listing for CPVC pipe allows for the pipe to be installed in combustible spaces not required to be protected in accordance with NFPA 13D. The addition of two sprinkler heads to provide an alarm exceeds the requirements of NFPA 13D but not to the level of making the attic a fully sprinklered space. This additional local requirement will not change the listing of a product. The insulation of the pipe should not be required.



The use of the Micro-Lokª Fiber Glass Pipe Insulation to meet the requirement of protection CPVC pipe in a fully sprinklered attic space will rest with the AHJ. The UL listing requires the minimum protection of 3/8-inch gypsum wallboard, 1/2-inch plywood soffits or suspended membrane ceiling with lay-in panels. The AHJ could consider Micro-Lokª Fiber Glass Pipe Insulation if it provides an equal level of protection to one of the three acceptable methods, especially the lay-in ceiling.



Subject: CPVC Pipe Exposed

Question: Can CPVC Blazemaster Pipe be installed "exposed" under 2x10 joist construction when the joist spaces are filled with non-combustible insulation forming a flat, smooth ceiling?



Answer: Our informal interpretation is yes, the listing for "Blazemaster" allows it to be used exposed if installed in light hazard occupancies and installed under "smooth flat ceilings."



The listing, as identified in Underwriters Laboratories Inc. Directory (UL) and the manufacturer installation guidelines, BlazeMaster is approved for both concealed and exposed installations. The Blazemaster CPVC pipe and fittings may be installed "exposed" subject to the following additional limitations:

- exposed piping to be installed below a smooth, flat, horizontal ceiling construction

- listed quick-response sprinklers with deflectors installed no more than 8" below the ceiling or residential sprinklers are to be installed on the pipe.





This is a gray area due to insulation not being included in the examples of smooth ceilings in the appendix of NFPA 13. Use of insulation, as the ceiling is a new classification that was added to the 1999 edition of NFPA 13. It currently is discussed in NFPA 13: A-5-5.4.1 which states that batt insulation installed in each joist pocket forms an effective thermal barrier and can be considered the ceiling. Without any doubt, the ceiling boundary line is the insulation. This arrangement also satisfies the heat flow characteristics of a smooth ceiling.

The 2x10 joist with the joist channels completely filled with insulation effectively forms a flat smooth ceiling. As such the listing requirement is met and the CPVC pipe can be exposed.



Subject: Hydrostatic Test of 13R Underground

Question: Is the underground fire service for a 13R system required to be hydrostatically pressure tested to 200 psi?



Answer: In response to your question, we have reviewed NFPA 13R, 1999 edition as the applicable standard. Our informal interpretation is that it does not need to be tested up to 200 psi.



The acceptance tests for an NFPA 13R system includes flushing the underground and the ambiguous requirement to perform hydrostatic tests in accordance with NFPA 13. With the inclusion of NFPA 24, NFPA 13 now contains requirements for aboveground and underground hydrostatic tests. Since 13R simply says to test according to NFPA 13, it could be argued that this includes the underground. However, this is not the intent of 13R. One piece of evidence is Figure 2-1.2.1, Certificate for Aboveground Pipe. It requires a hydrostatic test for the aboveground pipe and flushing of the underground, but does not contain any requirements for pressure testing the underground. This is because this certificate didn't change from the previous edition of NFPA 13R when it was clear there was no requirement for the underground. Further, 13R does not refer to the underground as a fire service main (because it could come off a domestic line). The 1996 edition of 13R also contained the requirement to hydrostatically test according to NFPA 13, but at that time there were no requirements in NFPA 13 to pressure test the underground. It was simply an oversight by the NFPA 13R technical committee in not updating the reference to NFPA 13 limiting it to aboveground only.



It should be noted that the above is my opinion as a member of the NFPA Committee on Automatic Sprinklers. It has not been processed as a formal interpretation in accordance with the NFPA Regulations Governing Committee Projects and should therefore not be considered, nor relied upon, as the official position of the NFPA.



Subject: Protection Area in Garages

Question: What is the protection area of heads in garages in a three-story residential apartment building?



Answer: In response to your question, we have reviewed NFPA 13 and NFPA 13R, 1996 edition as the applicable standards. Our informal interpretation is that the protection area of a head will be in accordance with its listing and section 4-5.2.2.



The protection area per head is independent of the hydraulic design method utilized. Section 4-5.2.2 of NFPA 13 limits the area to 400 sq. ft. It is further refined for standard pendent and upright heads and is 130 sq. ft. for an ordinary hazard group 1 occupancy like a garage. Additionally, the listing of the sprinkler may limit the area of coverage. If you are inquiring about the hydraulic design method to be used, please see section 5-3.2.3. It says that areas outside the dwelling unit but within the same structure are to be protected in accordance with the design criteria of 5-2.3 (Area/Density Curves).



If NFPA 13R is the standard being used for the apartment, section 2-5.2 covers this application. It says that design criteria (sprinkler protection areas, design discharge) for areas outside the dwelling unit is to be based on NFPA 13 standards. Sprinkler coverage areas and hydraulic design criterions can be found in chapters 4 and 5 of NFPA 13.



Subject: Sprinklers and Overhead Garage Doors

Question: Are sprinklers required under the overhead door in a garage for a system using NFPA 13R?



Answer: In response to your question, we have reviewed NFPA 13R, 1999 Edition as the applicable standard. Our informal interpretation is that sprinklers are not required below overhead doors.



Section 2-5.2 Exception 2 reads: "Garage doors shall not be considered obstructions and shall be ignored for placement and calculation of sprinklers." The handbook adds that the reason for this exception is because garage doors are usually left in the closed position, and the associated hazard is within the level of protection provided by NFPA 13R. If using an older version of 13R, it can be assumed that this was the intent of the standard since previous editions made no reference either way to garage doors and the committee recognized the issue for inclusion in the 1999 edition.



editor's note:

As noted in the opening of this article, these informal interpretations were prepared by the Technical Services Department of the American Fire Sprinkler Association. AFSA informal interpretations are provided by AFSA Director of Technical Services Roland Huggins, a PE registered in fire protection engineering, Phill Brown, a NICET IV certified automatic sprinkler technician, and Kenneth Saks, degreed fire protection engineer.



These opinions are provided for the benefit of the requesting parties and are provided with the understanding that the AFSA assumes no liability for the opinion or actions taken on them.



When appropriate and time permits, informal input from the AFSA representative on the applicable NFPA committee will be included.



These opinions have not been processed as "formal interpretations" by NFPA and should not be considered, nor relied upon, as the official position of the NFPA or its committees.



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