Sidewall Sprinklers Allowed for Water Curtain?

12/29/2022

Can sidewall heads be used for water curtain application?

While typically pendent are used to provide a water curtain around a vertical opening, I am working on a project where the arrangement led to sidewall heads being preferred by the architect.

NFPA 13 is not explicit about water curtain needing to be a specific type of sprinkler, it just says it should be a standard spray with 3gpm /lineal ft applied.

Thanks in advance.

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10 Comments

Pete H

12/29/2022 08:04:49 am

I see no code reason why not as long as you don't have any gaps in coverage or have any sprinklers too close without baffles.

It still seems wrong though.

Jesse

12/29/2022 08:12:10 am

Architects....

What most architects don't know about what we do can fill a book. And that book is NFPA 13...

I often answer questions in this forum by referring to the listing. If there is a sidewall sprinkler listed for that application, I'd go for it. But I'm not sure there is. There are sprinklers that are listed for that application. If it were my project I'd have the architect come up with a sidewall sprinkler listed for that use. And when he or she couldn't do that I'd use a product that is specifically listed for that.

Glenn Berger

12/29/2022 08:16:28 am

IMO, it depends on your specific application. Your application is a curtain system around a floor opening, I would use pendent sprinklers in this application. There are published limitations where vertical sidewall sprinklers can be used.

Also, do not let the architects dictate type of sprinkler to be used.

Todd E Wyatt

12/29/2022 09:27:08 am

SUMMARY
The use of an “Approved Alternate Method” (e.g. deluge sprinkler system) for determining the “fire resistance of building elements, components or assemblies” shall be approved by the AHJ.

Protection of “Vertical Openings” (VO) shall meet the requirements of (1) of the (16) prescribed solutions per 2021 IBC Section 712 Vertical Openings :
712.1 Each vertical opening shall comply in accordance with one of the protection methods in Sections 712.1.1 through 712.1.16.

An automatic sprinkler system (ASPS) is NOT an approved protection method for VOs.

EXPLANATION
The adopted Building/Fire Codes (e.g. 2021 IBC/IFC) are the scoping Codes as to WHERE an automatic sprinkler system (ASPS) is required to be installed based on the building’s Occupancy Classifications (OC) and/or “specific buildings and hazards” per 2021 IBC Section 903 Automatic Sprinkler Systems. The scoping Codes reference the applicable standard (e.g. NFPA 13) as HOW automatic sprinkler systems are to be “designed and installed.” Per 903.3.1.1.1 Exempt Locations, the IBC lists exempt locations for ASPS.

The only scoping Code reference to a “deluge ASPS” is per “404.6 Enclosure of Atriums” as an alternative to protection by 1-hour fire barrier and/or 1-hour horizontal assembly.

“Alternative Materials, Design and Methods of Construction and Equipment” can be submitted to the AHJ for consideration. As a former AHJ, I would not accept an active system (e.g. ASPS) in lieu of a passive system (e.g. fire-resistance rated shaft enclosure for a VO) for this condition but the AHJ may have a different take on this.

REFERENCES
2021 IBC
Chapter 7 Fire and Smoke Protection Features
Section 702 Multiple-Use Fire Assemblies
703.2 Fire Resistance
The fire-resistance rating of building elements, components or assemblies shall be determined in accordance with Section 703.2.1 or 703.2.2 without the use of automatic sprinklers or any other fire suppression system being incorporated, or in accordance with Section 703.2.3.
703.2.1 Tested Assemblies
703.2.2 Analytical Methods
703.2.3 Approved Alternate Method
The fire resistance of building elements, components or assemblies not complying with Section 703.2.1 or 703.2.2 shall be permitted to be established by an alternative protection method in accordance with Section 104.11.

104.11 Alternative Materials, Design and Methods of Construction and Equipment
The provisions of this code are not intended to prevent the installation of any material or to prohibit any design or method of construction not specifically prescribed by this code, provided that any such alternative has been approved. An alternative material, design or method of construction shall be approved where the building official finds that the proposed alternative meets all of the following:
The alternative material, design or method of construction is satisfactory and complies with the intent of the provisions of this code,
The material, method or work offered is, for the purpose intended, not less than the equivalent of that prescribed in this code as it pertains to the following:
1. Quality.
2. Strength.
3. Effectiveness.
4. Fire resistance.
5. Durability.
6. Safety.
Where the alternative material, design or method of construction is not approved, the building official shall respond in writing, stating the reasons why the alternative was not approved.

404.6 Enclosure of Atriums
Atrium spaces shall be separated from adjacent spaces by a 1-hour fire barrier constructed in accordance with Section 707 or a horizontal assembly constructed in accordance with Section 711, or both.
Exceptions:
1. A fire barrier is not required where a glass wall forming a smoke partition is provided. The glass wall shall comply with all of the following:
a. Automatic sprinklers are provided along both sides of the separation wall and doors, or on the room side only if there is not a walkway on the atrium side. The sprinklers shall be located between 4 inches and 12 inches (102 mm and 305 mm) away from the glass and at intervals along the glass not greater than 6 feet (1829 mm). The sprinkler system shall be designed so that the entire surface of the glass is wet upon activation of the sprinkler system without obstruction;
b. The glass wall shall be installed in a gasketed frame in a manner that the framing system deflects without breaking (loading) the glass before the sprinkler system operates; and
c. Where glass doors are provided in the glass wall, they shall be either self-closing or automatic-closing.

Section 903 Automatic Sprinkler Systems
903.1 General
Automatic sprinkler systems shall comply with this section.
903.1.1 Alternative Protection
Alternative automatic fire-extinguishing systems complying with Section 904 shall be permitted instead of automatic sprinkler system protection where recognized by the applicable standard and approved by the fire code officia

Todd E Wyatt

12/29/2022 09:28:19 am

REFERENCES (Part 2)
Section 903 Automatic Sprinkler Systems
903.1 General
Automatic sprinkler systems shall comply with this section.
903.1.1 Alternative Protection
Alternative automatic fire-extinguishing systems complying with Section 904 shall be permitted instead of automatic sprinkler system protection where recognized by the applicable standard and approved by the fire code official.
903.2 Where Required
Approved automatic sprinkler systems in new buildings and structures shall be provided in the locations described in Sections 903.2.1 through 903.2.12.

Exception: Spaces or areas in telecommunications buildings used exclusively for telecommunications equipment, associated electrical power distribution equipment, batteries and standby engines, provided that those spaces or areas are equipped throughout with an automatic smoke detection system in accordance with Section 907.2 and are separated from the remainder of the building by not less than 1-hour fire barriers constructed in accordance with Section 707 or not less than 2-hour horizontal assemblies constructed in accordance with Section 711, or both.

Section 712 Vertical Openings
712.1 General
Each vertical opening shall comply in accordance with one of the protection methods in Sections 712.1.1 through 712.1.16.
712.1.1 Shaft Enclosures
712.1.2 Individual Dwelling Unit
712.1.3 Escalator Openings
712.1.3.1 Opening Size
712.1.3.2 Automatic Shutters
712.1.4 Penetrations
712.1.5 Joints
712.1.6 Ducts and Air Transfer Openings
712.1.7 Atriums
712.1.8 Masonry Chimney
712.1.9 Two-Story Openings
712.1.10 Parking Garages
712.1.10.1 Automobile Ramps
712.1.10.2 Elevators
712.1.10.3 Duct Systems
712.1.11 Mezzanine
712.1.12 Exit Access Stairways and Ramps
712.1.13 Openings
712.1.13.1 Horizontal Fire Door Assemblies
712.1.13.2 Access Doors
712.1.14 Group I-3
712.1.15 Skylights
712.1.16 Openings Otherwise Permitted

Jay

12/29/2022 03:52:05 pm

Todd, please see the section you referenced above, 712.1.3 Escalator Openings for the requirement of closely spaced sprinklers with draft stops, aka water curtain sprinklers.

Jay

12/29/2022 05:07:51 pm

Also, the code does not require the "window" sprinklers used for atrium enclosure, in lieu of 1-hr fire resistant glazing, to be a deluge sprinkler system.

Todd E Wyatt

12/30/2022 07:10:21 am

The commentor did not state that the Vertical Opening (VO) was an esculator opening. If it is, it would be required to meet the prescriptive requirements of 712.1.3 Escalator Openings :

712.1.3 Escalator Openings
Where a building is equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1, vertical openings for escalators shall be permitted where protected in accordance with Section 712.1.3.1 or 712.1.3.2.

712.1.3.1 Opening Size
Protection by a draft curtain and closely spaced sprinklers in accordance with NFPA 13 shall be permitted where the area of the vertical opening between stories does not exceed twice the horizontal projected area of the escalator. In other than Groups B and M, this application is limited to openings that do not connect more than four stories.

712.1.3.2 Automatic Shutters
Protection of the vertical opening by approved shutters at every penetrated floor shall be permitted in accordance with this section. The shutters shall be of noncombustible construction and have a fire-resistance rating of not less than 1.5 hours. The shutter shall be so constructed as to close immediately upon the actuation of a smoke detector installed in accordance with Section 907.3.1 and shall completely shut off the well opening. Escalators shall cease operation when the shutter begins to close. The shutter shall operate at a speed of not more than 30 feet per minute (152.4 mm/s) and shall be equipped with a sensitive leading edge to arrest its progress where in contact with any obstacle, and to continue its progress on release therefrom.

"Draft curtain and closely spaced sprinklers" does not necessarily equate to "water curtain around a vertical opening."

2019 NFPA 13
3.3.57* Draft Curtain.
A continuous material protruding downward from the ceiling to create a reservoir for collecting smoke and heat.

ENHANCED CONTENT
The definition of draft curtain clarifies that, for sprinkler system purposes, the intent or function is to bank heat or smoke. The definition correlates with NFPA 204, Standard for Smoke and Heat Venting. Although not explicitly addressed within NFPA 13, NFPA 204 requires the curtain to be constructed of rigid materials.

The term "water curtain" does not occur in 2019 NFPA 13.

"Deluge Sprinkler System" is defined as follow :

3.3.206.3 Deluge Sprinkler System.
A sprinkler system employing open sprinklers or nozzles that are attached to a piping system that is connected to a water supply through a valve that is opened by the operation of a detection system installed in the same areas as the sprinklers or the nozzles. When this valve opens, water flows into the piping system and discharges from all sprinklers or nozzles attached thereto.

ENHANCED
A deluge system’s mode of activation is similar to that for a preaction system. With the exception of the non-interlock preaction system, the activation of these two types of systems depends on the operation of a supplemental detection system. The difference between the two types of systems is that preaction systems employ automatic sprinklers that respond to heat, and deluge systems use open (nonautomatic) sprinklers or open nozzles. Operation of the detection system in a preaction system fills the system piping with water once certain interlocks are triggered. Water is not discharged from the system until a sprinkler operates. For a deluge system, operation of the detection system results in flow from all system sprinklers or nozzles. Deluge systems are normally used for high hazard areas requiring an immediate application of water over the entire hazard. An aircraft hangar is an example of a facility that is likely to use deluge systems. The exhibit below illustrates an example of a deluge system using a supplemental electronic heat or smoke detection system.

Todd E Wyatt

12/30/2022 07:15:23 am

"Also, the code does not require the "window" sprinklers used for atrium enclosure, in lieu of 1-hr fire resistant glazing, to be a deluge sprinkler system."

I stated that the 2021 IBC permits (not requires) the substitution of an atrium's Fire Barrier with a prescriptively complying automatic sprinkler system (ASPS) :

404.6 Enclosure of Atriums
Exceptions:
1. A fire barrier is not required where a glass wall forming a smoke partition is provided. The glass wall shall comply with all of the following:
a. Automatic sprinklers are provided along both sides of the separation wall and doors, or on the room side only if there is not a walkway on the atrium side. The sprinklers shall be located between 4 inches and 12 inches (102 mm and 305 mm) away from the glass and at intervals along the glass not greater than 6 feet (1829 mm). The sprinkler system shall be designed so that the entire surface of the glass is wet upon activation of the sprinkler system without obstruction;
b. The glass wall shall be installed in a gasketed frame in a manner that the framing system deflects without breaking (loading) the glass before the sprinkler system operates; and ...

Anthony

1/2/2023 11:26:04 am

First off you can only use closely spaced sprinklers for: atrium protection or if you have a letter from the AHJ saying that sprinklers that are closely spaced are an approved alternative.

in such a cases I do not believe that side wall heads would be appropriate as the goal of the "curtain" is to create a cooling area around the vertical opening reducing the heat transferred between floors.

In architect speak: "Sprinklers do not create wall/hr ratings they reduce the requirements of wall ratings."

That sentence has stopped a lot of long e-mail exchanges in my life.

Sidewall Sprinklers Allowed for Water Curtain?

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