Difference of "Spray Room" vs "Spray Area?"

2/7/2025

Our facility is exploring constructing two large (7,200 ft²) facilities for media blasting and coating large steel structures.

The facilities have a ceiling height of approximately 40' and are enclosed via a large roll-up door on one end. The coating systems are categorized as flammable liquids.

There has been some internal debate on how to categorize these per the IFC - as "spray rooms," which would require fire suppression, or "spraying spaces," which the IFC does not have a prescriptive requirement for fire suppression.

The commentary in the IFC notes that spraying spaces are typically "unenclosed", leading us to lean towards considering these spray rooms, even though they make up the entirety of the building versus a portion of it.

We've reached out to some of the local AHJs, who all seem to agree with the spray room determination. However, the builder of the structures has indicated that most of their installations have not required suppression, even when reviewed by the local AHJ.

Is categorizing these structures as "spray rooms" the wrong application of the term?

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5 Comments

Chad

2/7/2025 08:15:24 am

Those are spray rooms, IMHO as an AHJ.

Unless the builder has an written interpretation showing why its not from others you would accept, I would imagine it was an overly nice interpretation due to the building being not near anything else, (perceived low hazard), lack of water supply/not thinking about dry chem or, a misapplication of area vs. room.

I also acknowledge that many AHJ's do not work with these often and unless you do, it can be confusing as to what is needed.

Connor R

2/7/2025 08:39:04 am

Looking at the IBC and IFC commentary, in spraying spaces the requirement for a fire suppression system comes down to the occupancy classification of the space. If the MAQ is exceeded (most likely considering these are for coating large steel structures) then the area is classified as an H occupancy and must be sprinklered.

From IFC 2021 commentary:

-
2404.3.4 Spraying spaces.
Spraying spaces shall be designed and constructed in accordance with the International Building Code, and Section 2404.3.4.1 and Sections 2404.4 through 2404.8 of this code.

Commentary:
❖ Because spraying spaces are not enclosed, the occupancy classification of the room in which the spraying space is located depends on whether the MAQs of hazardous materials per control area are exceeded. The occupancy of buildings or portions of buildings housing these coating operations is typically classified as Group H-2 [because flammable liquids are typically in open system use or under pressure greater than 15 pounds per square inch (psi) (103 kPa)] where the aggregate quantity of flammable/combustible liquids or dusts stored or used in a single control area exceeds the MAQ per control area listed in Table 5003.1.1(1). However, the occupancy is to be classified as Group F-1 or as a mixed use (such as Group F-1/S-1) for processes where the quantities do not exceed the MAQ per control area.
-

From IBC 2021:

-
415.4 Automatic sprinkler system.
Group H occupancies shall be equipped throughout with an automatic sprinkler system in accordance with Section 903.2.5.
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IFC 2021 defines Spray Booth, Spray Room, and Spraying Space as follows:

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SPRAY BOOTH. A mechanically ventilated appliance of varying dimensions and construction provided to enclose or accommodate a spraying operation and to confine and limit the escape of spray vapor and residue and to exhaust it safely.

SPRAY ROOM. A room designed to accommodate spraying operations, constructed in accordance with the International Building Code.

SPRAYING SPACE. An area in which dangerous quantities of flammable vapors or combustible residues, dusts or deposits are present due to the operation of spraying processes. The fire code official is authorized to define the limits of the spraying space in any specific case.

Commentary:
❖ Spraying spaces generally occur in one or a combination of three forms. The least desirable form is open floor area spraying, where the spraying area consists of an entire floor of a building without isolating the spraying operation. A better form is the spray room, which isolates the spray operation by construction to less than an entire floor of the facility. The optimum form is a specially designed spray booth that isolates the operational hazards of spraying to an appropriately regulated space. Regardless of the form, all require special safeguards to address hazards, including adequate ventilation, fire suppression and management of overspray.
-

Notice that the Code recognizes that a spraying space may not necessarily be in a spray room or a spray booth. The commentary does suggest that spraying spaces require fire suppression, but that requirements is driven by the occupancy, not the form factor.

2/7/2025 08:41:50 am

Also notice that "The fire code official is authorized to define the limits of the spraying space in any specific case."

Conceivably, the fire code official could use that to define the spraying space as the entire area and push for the classification as a Spray Room. Then, fire suppression would be required (though not necessarily sprinkler, as an alternative fire suppression system could be used).

Pete H

2/7/2025 11:09:04 am

I agree, I'd go towards spray rooms. Especially if the local AHJ's agreed for spray rooms. Cause then it no longer matters if other AHJ's in other jurisdictions let it be considered a spray area, the one that has jurisdiction where relevant said spray rooms.

If this was a large 7200 sq ft warehouse with a couple of 100 sq ft open areas for painting, I'd say spray area. This seems to be a 7200 sq ft enclosed area that is capable of spraying the flammable liquid throughout the entirety of the 7200 square feet.

Todd E Wyatt

2/7/2025 11:11:00 am

If the Hazardous Materials (HM) can be managed with Control Areas (CA) to meet the Maximum Allowable Quantities (MAQ) to meet an Occupancy Classification (OC) of Group F Factory instead of Group H Hazardous, the requirement for an Automatic Sprinkler System (ASPS) will be determined by the scoping Code (e.g. IBC-2021) per 903.2.4 Group F-1 #1-#3 (see REFERENCES below).

REFERENCES
IBC-2021
Chapter 9 Fire Protection and Life Safety Systems
Section 903 Automatic Sprinkler Systems
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.
903.2.4 Group F-1
An automatic sprinkler system shall be provided throughout all buildings containing a Group F-1 occupancy where one of the following conditions exists:
1. A Group F-1 fire area exceeds 12,000 square feet (1115 m2).
2. A Group F-1 fire area is located more than three stories above grade plane.
3. The combined area of all Group F-1 fire areas on all floors, including any mezzanines, exceeds 24,000 square feet (2230 m2).

Difference of "Spray Room" vs "Spray Area?"

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