The NFSA’s Codes, Standards, and Public Fire Protection personnel provided the following answers to 12 questions related to sprinklers near fabric canopy, flushing of the system, Two-Car Stacked Parking  and many other questions and Answers. 


Question #1 – Intermediate Sprinklers Throughout a Building

An office building with drop ceilings with horizontal diffusers in the ceilings is to be equipped with a sprinkler system installed in accordance with the 2010 edition of NFPA 13. Section states that ordinary- and intermediate-rated sprinklers must be used throughout. Intermediate sprinklers throughout the building are preferred because if ordinary temperature sprinklers are installed, they may need to be replace after the duct work goes in creating greater cost.  

Can intermediate temp sprinklers be used in place of ordinary sprinkler heads without any reason or justification for a needed temperature increase?  

ANSWER: There is no requirement to justify the necessity for a needed temperature rise in order to utilise intermediate-temperature sprinklers instead of ordinary-temperature sprinklers throughout a structure. Section, which expressly mandates the deployment of ordinary- and intermediate-temperature sprinklers across all structures, makes this apparent. 

 Section,,, or may call for a sprinkler with a higher temperature rating (higher than intermediate), according to this section. 

 People commonly misinterpret this provision, thinking that regular temperature sprinklers must be utilised unless there is a compelling cause to employ a higher temperature spray.

This is not the case, and in an effort to make this notion more explicit, the committee inserted an annexe note (A. to the 2019 version of NFPA 13, which states in detail that it is permitted to install the following across a building: 

  1. Sprinklers at room temperature
  2. Sprinklers for medium temperatures 
  3. or a combination of sprinklers for normal and intermediate temperatures

Question #2 – Combustible Canopy

Can sprinklers be omitted below a combustible fabric canopy that extends 3-ft from the building in accordance with the 2016 edition of NFPA 13?  

If there is no flammable storage beneath a 3-foot wide combustible canopy, then sprinklers are not necessary. Sprinkler protection beneath outside projections, such as canopies, is only necessary when the canopy extends more than 4 feet from the structure, as indicated in Section 8.15.7. In the event that there is flammable storage below, this criterion is modified. In this instance, Section mandates the installation of sprinklers in areas where combustible storage is present beneath canopies that extend more than 2 feet.  

As stated in Section, if the outer canopy is made of noncombustible, restricted combustible, or fire-retardant treated wood products and is wider than 4 feet, sprinklers may be skipped. In addition, this part permits the exclusion of sprinklers from beneath projections that have a wood frame that is noncombustible, limited-combustible, or fire retardant-treated and covered in flame-resistant fabric (satisfying test method 2 of NFPA 701).

Question #3 – Obstruction Investigation

During recent 5-year obstruction investigations, scale and/or slime was found in 20% to 30% of the pipe.  

At what percentage of scale and/or slime does the 2020 edition of NFPA 25 require flushing of the system?

If sufficient debris is discovered to impede pipes or sprinklers, a full flushing programme must be carried out in line with NFPA 25, Section 14.3.3.  

The standard does not mention what that quantity is, however according to annexe Section D.3.2, more than 1/2 cup of scale is sufficient to justify a flushing programme. Noting that it just offers clarification and extra information, the annexe is not binding. Additionally, Annex D offers excellent guidance on how to carry out an obstruction inquiry and how to put a flushing programme in place.  

Question #4 – Combination Standpipe – Minimum Size

Section 7.6.2 of the 2016 edition of NFPA 14 states that the minimum size for a standpipe that is part of a combined system in a partially sprinklered building is 6-inches.  

Does this mean that a 4-inch standpipe is acceptable for a hydraulically designed combination sprinkler/standpipe system in a fully sprinklered building?  

In completely protected structures, a 4-in. minimum standpipe pipe is permissible. Buildings with an automated fire sprinkler system installed throughout would not be covered by Section 7.6.2. According to Section 7.6.1, the smallest standpipe pipe size is 4 inches, and all standpipes that are a component of a combined system in partly sprinklered buildings must have a minimum 6 inch pipe size.  

Additionally, Section permits systems hydraulically constructed in accordance with 7.8.1 to have a minimum standpipe size of 4 inches for buildings covered throughout by an authorised automatic sprinkler system in accordance with NFPA 13 or NFPA 13R.  

In order to better address this in the 2016 edition, the technical committee added “where only a portion of the building has sprinkler protection” to Section 7.6.2 and clarified the exception in Section, allowing the 4 in. pipe for systems hydraulically designed in accordance with Section 7.8.1. This public remark was justified on the grounds that it clarifies the circumstances under which a riser must be 6 inches tall as well as the connections between Sections 7.6.2 and 7.6.3.  

The technical committee tried to further explain this matter in the 2019 edition of the standard by making Sub-Section a stand-alone requirement in Section 7.6.3 once more. The committee said that “AHJs still don’t believe that a standpipe can be 4 in. when the building is sprinklered throughout,” which was used to justify the adjustment. AHJs are not permitting the standpipe to be 4 in. despite the building being sprinklered all throughout since this is a subset under The committee decided on this modification with unanimity.  

In addition, the standard permits the standpipe demand or the sprinkler demand, whichever is larger, to be used to determine how much water is supplied to combined systems in buildings that are fully protected by NFPA 13 and NFPA 13R

(Section However, in structures with combined systems and only partial sprinkler protection, the flow rates required by Section 7.10.1 must be raised by the lesser of the sprinkler demand, 150 gpm for light hazard occupancies, or 500 gpm for ordinary hazard occupancies.  

Question #5 - Drain Sizes

Do the drain sizes shown in Table of the 2019 edition of NFPA 13 apply to just system riser and supply mains, or do they apply to feed mains, cross mains, and gridded mains that are not controlled by a sectional valve?  

We have always assumed drains for trapped feed, cross and gridded mains shall be sized in accordance with 16.10.5 (auxiliary drains).

The minimum necessary drain size for sprinkler system main drains or sectional connections connected to sprinkler system control valves must comply with NFPA 13, 2019 edition, Section 16.10.4, yes.Drain connections for system supply risers and mains must be the size specified in Table, as stated in Section In accordance with Section, interior sectional or floor control valves must have a drain connection with a minimum size as stated in Table to drain the system component that is under their control.  

In line with Section 16.10.5, drains for trapped pipe portions that cannot be drained by the main drain specified in Section 16.10.4 must be sized.This applies to all varieties of trapped plumbing, such as feed mains, cross mains, and/or branch lines, that cannot be drained back to the main drain.Only the minimum drain size for auxiliary drains is addressed in Section 16.10.5. Auxiliary drains are supplied, according to Section, in cases when a change in pipe direction prohibits system piping from draining through the main drain valve.

Question #6 – Corridor with Single Line of Sprinklers

A project includes a corridor with 10 standard spray sprinklers on a single branch line. It appears that the 2016 edition of NFPA 13 includes two differing sections that may apply to this situation. Section states that the calculation

must include “up to five sprinklers” and Section states that the calculation must include “up to seven sprinklers.”  

 What is the difference between these sections?  

Because Section is a subset of the room design approach and Section is a subset of a specific design area, they differ from one another.  

Before discussing the intricacies of these two procedures, it is necessary to go over Section The designer has the choice to compute the system using one of three design methods in this section:  

  •  As per, Density Area Method  
  •  Method for Room Design as per  
  •  According to, Special Design Method  

The designer is free to make this choice, but it must take into consideration site-specific requirements and the approach must be suitable for the system being created.  

As previously mentioned, Section describes a room design strategy for hallways that are covered by a single sprinkler line. The corridor in issue must fulfil the conditions for using the room design approach in order to use this system. The corridor in question shall be the chamber which generates the most demand, as defined in Section The room that would put more strain on the system than other rooms in the building must be the one that is estimated. In some circumstances, using the density/area technique rather than the room design method might be preferable since the room that generates the largest demand is so big.  

Additionally, the walls must have a fire resistance rating equivalent to the necessary water supply time in order to employ the room design technique (see Section Additionally, protection for the apertures must follow Section If the aforementioned requirements are satisfied, 5 sprinklers can be computed in accordance with  

A particular design technique known as Section is frequently applied to spaces like exterior loading docks and certain internal corridors. A maximum of seven sprinklers must be estimated if these sorts of surfaces are protected by a single line of sprinklers but do not match the standards of the room design technique.

Question #7 – Two-Car Stacked Parking

The 2016 edition of NFPA 13 in Section A.5.3.1 includes automobile parking as an Ordinary Hazard Group 1 category. Section A.5.4.2 clearly identifies stacked parking (two car high) as an Extra Hazard Group 2 occupancy.  

Does this mean that it is not permitted to install sidewall sprinklers under each car in the car stacker and use an Ordinary Hazard Group 1 density for the ceiling level sprinklers?  

The 2016 edition of NFPA 13 is ambiguous about this, thus it is not necessary. Due to the obstruction caused by the car in the stacker and as stated in Section 5.4.2, Extra Hazard Group 2 criteria is appropriate where “shielding of combustibles is extensive,” it is suggested that parking garages with car stackers should be considered an Extra Hazard Group 2 (EH2) occupancy. Sprinklers can be installed underneath the vehicles in the stacker to prevent blockages from the ceiling-level sprinklers. Based on this, it would be permissible to utilise sprinklers at the ceiling level that are in the Ordinary Hazard Group 1.  

The latest edition of NFPA 13 (2022) has defined this idea, despite the fact that the 2016 edition of the standard does not explicitly express it. 

 The proposed occupancy categorization for parking garages was modified from Ordinary Hazard Group 1 to Ordinary Hazard Group 2 in the 2022 edition, it should be mentioned. This was due to the fact that modern automobiles differ significantly from older models. There are a lot more plastics in them, as well as plastic fuel tanks and occasionally lithium-ion batteries. Based on this, the committee increased the indicated hazard grade since modern automobiles provide a higher fire load than cars from the past.  

The 2022 edition confirmed in Section 10.3.2(9) that sidewall sprinklers are allowed beneath each level of vehicles while maintaining the EH2 rating for car stackers (Section A.4.3.5(9)). This clause permits the installation of sidewall sprinklers “under cars in car stackers…under each level of cars.” The annexe note to this Section (A.10.3.2(9)) contains the major change in this instance. If sidewall sprinklers are put beneath the vehicles, it permits either an Ordinary Group 2 (OH2) ceiling system or an EH2 ceiling system without coverage under the cars.

Question #8 – Cloud Ceiling and Residential Sprinklers

In a residential high-rise condominium, the architect is proposing to install a cloud ceiling in a dwelling unit. This cloud ceiling meets the requirements of Section 8.15.24 which allows the sprinklers to be omitted above the cloud ceiling.  

Can residential sprinklers be used below the cloud ceiling while omitting sprinklers above the cloud?  

No, there is no protection above and household sprinklers cannot be installed below a cloud ceiling. The usage of home sprinklers is not covered by NFPA 13, 2016 edition, Section 8.15.24 for exceptional circumstances and cloud ceilings, which is solely meant for rapid response standard spray or extended coverage sprinklers.  

This is specified in Section, which stipulates that when applying the special scenario cloud ceiling rules of Section 8.15.24, all sprinklers must be rapid response standard spray, extended coverage pendent, or upright sprinklers. Please be aware that this criterion will still apply to the 2019 and 2022 editions.  

Since rapid response sprinklers may be utilised in line with Section 8.15.24 to allow sprinklers to be omitted above these clouds, NFPA 13 does not mandate the deployment of residential sprinklers in dwelling units.

Question #9 – Seismic Separations for Drain Piping

Section states that sprinkler piping crossing a seismic separation is required to have an approved assembly.  

 Do drain lines require a seismic separation assembly?  

No, provided that the pipe used for the drain is located after the drain valve.  

 According to NFPA 13, 2016 edition, Section, sprinkler pipe of any size that crosses building seismic separation joints at ground level and above must have an authorised seismic separation assembly installed. In this section, sprinkler piping—not all piping—is expressly mentioned. Drainpipe crossing a seismic separation assembly would not be covered by this provision.  

 Sprinkler pipework is referred to as pipe that provides a sprinkler in all of the standard’s references to it. Drain pipe is thus not regarded as sprinkler piping.  

The phrase “all piping” is used in Section in contrast. This rule states that any plumbing, including drains, fire department connections, and other auxiliary piping, that extends through walls, floors, platforms, and foundations must have space around it. As a result, the drain pipe for would need to comply with the specification for clearance.  

It should be noted that drain pipe downstream of the drain valve is explicitly excluded under Section for sway bracing.  

Question #10 – Roof Above Balcony

Section 903. from IBC 2012 requires sprinkler protection above balconies where the building is Type V construction, provided there is a roof or deck above. Since a “roof” is not defined with specific dimensions in IBC, would it be appropriate to apply Section from NFPA 13R 2022 that specifies a roof dimension as greater than 4 ft?  

Yes. A balcony and roof size (more than 4 feet) was included for the outside sprinkler application in the NFPA 13R 2022 version. The International Building Code (IBC) originally included the criterion in 2003 with the intention and support of testing of having a full roof or balcony above.  

 The phrase “roof or deck above” from the 2009 IBC aimed to make this clearer. However, the placement of balcony sprinklers is not regular since there is no size and no definition of a roof. Section 9.3.20 of the 2022 NFPA 13R and NFPA 13 were updated and connected for uniform application.  

Question #11 – ESFR obstruction rules for Ordinary Hazard Occupancies

An ESFR system installed in an existing warehouse. A new tenant is taking over the building and the new occupancy will be considered to be an ordinary hazard occupancy. We are trying to determine if sprinklers are required beneath a 3 ft. wide solid conveyor installed more than 10 ft. below the overhead sprinklers.  

Do the ESFR obstruction rules apply or the obstruction rules for standard systems?  

If the AHJ agrees to allow the current version of NFPA 13 to apply, then the usual spray obstruction rules would be in effect. 

The NFPA 13 edition for 2022 particularly addressed this idea. This edition’s Section indicates that ESFR sprinklers are allowed to “…meet the obstruction discharge requirements of” in light and ordinary hazard occupancies. 

The guidelines for conventional spray sprinkler obstacles are found in Section According to this portion of the NFPA 13’s 2022 version, the 3 ft. wide conveyor you mentioned would not require sprinklers. 

The committee approved this revision to NFPA 13 as Second Revision No. 1129, which was based on the NFSA’s Public Comment No. 197. 

Despite the absence of a comparable part in the 2016 edition, it is advised that you speak with the AHJ since this new section is regarded as the agreement of the technical committee in charge of NFPA 13.

Question #12 – Standpipe - Stairs vs. Ladder

The 2007 edition states in Section 7.3.2 that hose connections are required to be installed on the roof “where stairways do not access the roof.” In cases where there is stairway access to the roof, this section states that the hose connection may be located on the highest landing of the stairwell instead of the roof.  

 Can a reasonable argument be made that a permanent ladder constitutes “stair access.”?

The answer is that a permanent ladder qualifies as roof “access” stairs. 

 Where stairways do not have “access” to the roof, NFPA 14 Standard for the Installation of Standpipes and Hose Systems, Section 7.3.2 (5) mandates hose connections on the roof. 

 In the 2013 version annexe, the standard made this clarification, stating that the only permissible methods of ‘access’ to a roof are via a stairway, a fixed ladder, a permanent ladder rung or a pull-down stair with a roof hatch. (A. Section) 

 In addition, buildings without an inhabited roof are exempt from the need for roof top hose connections stated in Section 1011.12 of the International Building Code, which allows access via an alternative tread device, a ships ladder or a permanent ladder.  

Courtesy: Roland ASP, CET NFSA Technotes (Best of Oct 2021)