Informal Interpretations Help Douse Disagreements
The informal interpretations featured in this issue of Sprinkler Age address NFPA 30, Flammable and Combustible Liquids Code. AFSA’s informal interpretations are provided to AFSA members by Senior Vice President of Engineering & Technical Services Roland Huggins, P.E. and Senior Manager of Fire Protection Engineering Tom Wellen, P.E. These opinions are provided for the benefit of the requesting party, and are provided with the understanding that AFSA assumes no liability for the opinions or actions taken on them.
SUBJECT: Spill Containment Sizing
QUESTION: “When using a foam-water system to protect a flammable liquid and spill containment that is required, is the total duration of flow the foam supply duration or the water supply duration?”
ANSWER: In response to your question we have reviewed NFPA 30, Flammable and Combustible Liquids Code, 2015 edition that you indicated as the applicable code as well as the International Fire Code (IFC). Our informal interpretation is that the demand of the foam solution is used for the duration of 20 minutes. NFPA 30 does not specify the time for sizing of the containment area of the indoor system demand. If the containment area is sized for the system demand for the total duration specified by NFPA 30, the containment area could be rather large. As such, other references such as the IFC was used for guidance. The IFC states in 5004.2.2.3 for indoor design, “Secondary containment for indoor storage areas shall be designed to contain a spill from the largest vessel plus the design flow volume of fire protection water calculated to discharge from the fire-extinguishing system over the minimum required system design area or area of the room or area in which the storage is located, whichever is smaller. The containment capacity shall be designed to contain the flow for a period of 20 minutes.”
Secondary containment is only part of the other requirements of NFPA 30. The design approach should be coordinated with the engineer of record on the project including approval of the Authority Having Jurisdiction (AHJ).
SUBJECT: Bourbon or Whiskey Barrel Storage
QUESTION: “I need assistance on determining the design criteria for a very old warehouse built in 1900. It’s a typical wood framed building with brick exterior walls and concrete floors. The roof is pitch 4 in 12 where the peak is approximately 28 ft and the eave is approximately 22 ft. The storage is white oak barrels filled with bourbon stacked four high having a top elevation of 9 ft-6 in. What NFPA standard would apply?”
ANSWER: In response to your question we have reviewed NFPA 13, Standard for the Installation of Sprinkler Systems, 2016 edition that you indicated as the applicable standard as well as the 2015 edition of NFPA 30. Our informal interpretation is that design criteria for this application are outside the scope of NFPA standards. The issue is the wooden barrels containing distilled spirits. Section 22.2.1 indicates that sprinkler system discharge criteria for the protection of flammable and combustible liquids shall comply with NFPA 30. NFPA 30 in Section 1.3.2 refers to Chapters 9 through 12 for the storage of flammable or combustible liquids in containers, portable tanks, and intermediate bulk containers in the occupancies covered by the scope of each chapter. Chapter 9 indicates this chapter does not apply to parenthesis (7) Distilled spirits and wines in wooden barrels or casks. The NFPA 30 Handbook commentary under this section states, “This exemption from the provisions of Chapter 9 acknowledges that even though distilled spirits and wines might be considered flammable liquids, the wooden barrels do not present the same rupture hazard as metal containers or the same spill hazards as plastic containers. When wooden barrels or casks are exposed to fire, they do not fail violently. Rather, the metal hoops on the barrels that secure the staves expand and allow loosening of the staves, which results in leaking distilled spirits adding fuel to the fire. However, sprinkler systems often control the fire before the metal hoops on the barrels are affected. Also, note that the distilled spirits industry and The Distilled Spirits Council of the United States, Inc. maintain their own guideline document entitled Recommended Fire Protection Practices for Distilled Spirits Beverage Facilities.”
Since the application is outside the scope of NFPA 30, the industry document may have discharge protection criteria for storage of bourbon or whiskey in white oak barrels. The contents of the document above are not known but may allow sloped ceilings. If that document does not address sloped ceilings and references NFPA 13 criteria, Section 12.1.2 regarding ceiling slope would apply. The sprinkler system criteria specified in Chapter 12 and Chapters 14 through 20 is intended to apply to buildings with ceiling slopes not exceeding 2 in 12 (16.7 percent) unless modified by a specific section in Chapter 12 and Chapters 14 through 20. The exception would be if the storage were qualified to fall within Chapter 13 for Miscellaneous Storage.
SUBJECT: Palletized Class IIIB Liquids in Containers
QUESTION: “Class IIIB liquids (flash point of 485.6°F) are stored in 21/2-gallon plastic jugs in cardboard boxes stacked two high. Each pallet contains approximately 272 gallons. What criteria do I apply?”
ANSWER: In response to your question we have reviewed NFPA 30, 2015 edition as the applicable code. Our informal interpretation is that NFPA 30 does not provide criteria for palletized storage of Class IIIB liquids in plastic containers. Section 18.104.22.168 indicates to use Figure 16.4.1(b) for miscible and nonmiscible flammable and combustible liquids in nonmetallic containers and in nonmetallic intermediate bulk containers. The decision tree in this figure says to use Tables 22.214.171.124, 126.96.36.199 or 188.8.131.52, if applicable. Table 184.108.40.206 is applicable for rack storage that does not apply for this application. Tables 220.127.116.11 and 18.104.22.168 apply for intermediate bulk containers (IBCs). As such, it appears that NFPA 30 is not allowing this material to be stored palletized. The FM Global Data Sheet 7-29 dated April 2012 (Interim Revision July 2014) was referenced that does provide criteria for palletized storage of Class IIIB liquids in plastic containers. Section 22.214.171.124 addresses storage of liquids with flash points at or above 200°F per Tables 15 or 17, as applicable, based on storage arrangement, roof/ceiling height, and storage height. Table 17 is for palletized/solid pile storage of liquids with closed-cup flash points at or above 200°F in plastic containers. This table provides the number of design sprinklers at pressures in psi for various K-factors. The use of this standard as an alternative to NFPA 30 should be approved by the AHJ.
SUBJECT: NFPA 30 for Flammable Liquid Storage Warehouse
QUESTION: “We have a flammable liquid storage warehouse that is requiring protection for Class IB and IC flammable liquids in plastic containers ranging from under 1 gallon up to 53 gallons in size. These will be stored on single- or double-row racks up to 16 feet and 20 feet in height. What protection criteria should be used?”
ANSWER: In response to your question we have reviewed NFPA 30, 2015 edition as the applicable standard. Our informal interpretation is that protection will require an engineered design. Section 126.96.36.199 refers to figure 16.4.1(b) for miscible and nonmiscible flammable and combustible liquids in nonmetallic containers and in nonmetallic intermediate bulk containers. The referenced figure is a decision tree to lead to the appropriate table for protection criteria where the decisions lead to the storage as unprotected and to see Table 188.8.131.52. The table limits the quantity per pile or rack and specifies maximum storage heights per the liquid class. The handbook commentary under Section 184.108.40.206 says that the table applies to unprotected storage areas that might not survive a fire. Thus no protection criteria are available from NFPA 30 for this liquid class in nonmetallic containers. There are many fire protection issues that must be addressed such as containment, electrical, fire suppression. As such, a registered professional engineer may be needed to determine the criteria for the storage located indoors. FM Global may address some of this storage in Data Sheet 7-29 dated April 2012 (Interim Revision July 2014) in Section 220.127.116.11 as an alternative. The limitation of this section are containers less than or equal to 1 gallon. The other source that should be considered is the local fire code. For instance, the 2015 edition of the IFC has considerations to be addressed in Chapters 50 and 57.
SUBJECT: Flammable Liquids
QUESTIONS: “We have a project with a storage room identified as S-1 storage inside a building with B and M occupancies. The architectural plans and Owners Information Certificate have called out the use of NFPA 30; 12.8.1 and 12.8.2 for the general storage of Class IB and IIIB liquids not exceeding the Maximum Allowable Quantities (MAQ) allowing for shelf storage to 8 ft. The information has not been provided for the container type, size, and if its cartoned or uncartoned. They have also referenced NFPA 13 for the design criteria of Class IV commodities up to 20 ft. Does NFPA 30 in 12.8.2 (2) and (5), which has no option for storage of Class IB or IIIB liquids on solid shelves and limits Class IB to 5 ft storage, apply to 12.8.1(1), or does 12.8.1 (1) divert directly to NFPA 13 for 20 ft high storage of Class IV commodities based on storage configuration of the liquids? For example, Class IB and IIIB liquids can be stored on back-to-back shelves to 8 ft, and the remainder of NFPA 30 Chapter 12 no longer applies? Does NFPA 30 in 12.8.2 still apply to the storage arrangement for the liquids being stored? In reference to NFPA 30 in 12.8.1, the annex indicates that the provisions of sprinklers designed to protect Class IV commodities to a height of 20 ft for the liquid storage quantities and arrangements allowed in a general-purpose warehouse should not be construed as providing adequate protection. Is utilizing NFPA 30 in 12.8.1 (1) still applicable, and if a fire sprinkler contractor utilizes this section have they now assumed some legal liability for this building and the occupants after a fire event?”
ANSWER: In response to your questions, we have reviewed NFPA 13, 2016 edition and NFPA 30, 2015 edition as the applicable standard and code. Our informal interpretations for your questions are below. It’s interesting that although you have a mixed occupancy building (B and M occupancies), they are assigning a storage room (assume it is a normal-sized room) as an S-1 occupancy. Even more interesting is that they are applying criteria for a normal everyday warehouse (general purpose) to the one room. Having said that, they are responsible for determining these factors. They have also defined the sprinkler criteria (mostly) so they are also liable for that decision. Having said that, as a team member, if something appears wrong, you should raise a red flag so they can decide how to proceed. You are not designing this project, but simply laying out the sprinklers in accordance with their design.
How to properly address flammable liquids is not an easy task. In looking at the referenced NFPA 30 criteria, it’s a bit ambiguous. I talked with the NFPA liaison assigned to this committee to shed a little light on it. The annex text was added because the technical committee defined these criteria based on engineering judgment. The same is true for most of the density/area curves for storage but NFPA 13 annex didn’t add a similar statement. The criteria is applicable and since it has been in place for over 20 years we can be confident their judgment was pretty solid. In applying their criteria, NFPA 30 in 12.8.1 does three things: 1) It tells you that this criteria can be used for general warehouses, 2) It identifies the maximum allowed size of the container for each flammable liquid class, and 3) It identifies the sprinkler design basis is to follow NFPA 13 for a 20-ft high Class IV commodities based on the storage configuration of the liquids. Thus, the Class IB can be in containers no larger than 1.3 gallon and the Class IIIB no larger than 275 gallon. The actual allowed storage heights are lower than 20 ft (as dictated by 12.8.2), but the density and area is that from the curves for 20 ft. The reference to base on storage configuration just means to use NFPA 13, Chapter 14 if the liquids are stored as a solid pile and Chapter 16 if stored on racks.
Moving on to NFPA 30 in 12.8.2, it also tells us: 1) the maximum combined amount of liquids (by class) that are allowed in the entire warehouse (or in your case, the room) and 2) the maximum height of storage of Class III by the allowed storage configuration. Thus, there can be no more than 660 gallons of Class IB, it can be stored no higher than 5 ft, and can only be high piled stored on floor. To me the latter portion is also the most ambiguous item. The easy part is that it excludes storage on racks. The tough part is whether or not it applies to solid shelf storage. This is old text that came about when NFPA 231, Standard for General Storage, and NFPA 231C, Standard for Rack Storage of Material, still existed. The reference to high pile was casually meant to be storage greater than 12 ft. The real purpose was to drive you to one of those two documents. NFPA 13 now covers this in Chapters 14 and 16. The appropriate interpretation of on the floor is that you use Chapter 14. This chapter addresses palletized, solid piled, bin box, and shelf storage. All of these are treated the same (with some differences in allowed storage heights) whereby the same density is applied for the same storage height. If anything, solid shelving presents less of a hazard than solid piled but they are treated the same. There is no need to raise a red flag on that part of the owner’s certificate. I would raise a red flag regarding exceeding 5 ft on the Class IB liquids. As you know, if an exchange of questions and answers is not in writing, it never happened.
EDITOR’S NOTE: These interpretations were prepared by AFSA’s Technical Services Department in answer to specific questions from contractors and/or AHJs. These opinions are provided for the benefit of the requesting party, and are provided with the understanding that AFSA assumes no liability for the opinions or actions taken on them. AFSA members can access over 4,400 informal interpretations online. Visit firesprinkler.org.