Waterflow, ITD Req'd for Powder Coating Booth?

3/16/2023

We have an internal discussion agreeing to disagree, regarding protection of a non-flammable powder coating booth in a tenant building with existing sprinkler system.

We are installing a dedicated auxiliary wet system dropping down with a loop to pick up a valve for an OHII system per NFPA 33 (2016) 9.4.2 (2). Protection Automatic Systems - Powder coating operations.

First Question - Section 9.2.1 and 9.7.1 indicates there must be a means to accomplish all of the following:

(1) Activate a local alarm in the vicinity of the of the spraying operation
(2) Transmit an alarm signal to the facility fire alarm system if such is provided. "In this case yes existing alarm, with existing overhead sprinkler system"
(3) Shut down the coating material delivery system
(4) Shut down all spray application operations
(5) Stop any conveyors into and out of the spray area.

To accomplish the above one side of the office believes a flow switch is needed to accomplish this requirement with double set of contacts.

The other side of the office contends the existing alarm system is adequate enough and if activated the main flow switch will accomplish this. The argument is if this is a dedicated auxiliary system with potential multiple tenants and requires the water flow switch for the Aux Booth System to activate per 9.2.1 and 9.7.1 as noted.

Is this correct?

Question 2 - if a flow switch is required to accomplish 9.2.1 there shall be a means to test with inspector's test connection or a riser manifold with a combination inspector's test & drain at the new dedicated auxiliary riser. Is that correct?

There needs to be an indicating control valve per 9.4.5 operable from floor level for the Aux. Booth System.

Question 3 - can the valve be chained and locked open or does this control valve need electrically supervised open.?

Does there need to be a main drain for this auxiliary system?

I think everyone can follow the arguments so would appreciate some responses. Much appreciated.

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5 Comments

Anthony

3/16/2023 08:13:02 am

Question 1) you can't use the riser flow switch because of the requirement for a 'local alarm.' The flow switch will provide a 'general' alarm.

Question 2) Means of testing does not a full test and drain (see below)

Question 3) I don't see why not.
Question 3a) not a main drain per se but a means of fully draining the system via an aux valve/Drian. would depend on total volume of the system for proper sizing. I wouldn't think it would have to be hard piped to the exterior.

This sounds similar to elevator (or any small monitored 'sub system') requirements for a flow switch and a tamper switch on a control valve. Generally I'll design in a tee with a capped/plugged ball valve in a continent location so a tester can come by and attach a garden hose or just put a bucket on a ladder and trip the flow switch. I would think this is the easiest and cleanest instillation. Also you have no idea how long the powered coating room will be used, 5 years? 10 years? after the booth life cycle is over with a control valve in place you can remove or alter the piping servicing the booth without removing the primary system from service.

Todd E Wyatt

3/16/2023 08:48:46 am

The scoping Code (e.g. 2021 IBC) includes the following reference to “PAINT SPRAY BOOTHS” and associated “WATERFLOW SWITCHES” :

2021 Code
Chapter 9 Fire Protection and Life Safety Systems
Section 903 Automatic Sprinkler Systems
903.1 General
Automatic sprinkler systems shall comply with this section.
903.4 Sprinkler System Supervision and Alarms
Valves controlling the water supply for automatic sprinkler systems, pumps, tanks, water levels and temperatures, critical air pressures and WATERFLOW SWITCHES on all sprinkler systems shall be electrically supervised by a listed fire alarm control unit.
5. Control valves to commercial kitchen hoods, PAINT SPRAY BOOTHS or dip tanks that are sealed or locked in the open position.

NFPA 33 is not a “Referenced Standard” per 2021 IBC Chapter 35 Referenced Standards but it is a “Referenced Publication“ per 2019 NFPA 13 (which is the referenced standard edition per 2021 IBC) :

2019 NFPA 13
Chapter 2 Referenced Publications
2.1 General.
The documents or portions thereof listed in this chapter are referenced within this standard and shall be considered part of the requirements of this document.
2.2 NFPA Publications.
NFPA 33, Standard for Spray Application Using Flammable or Combustible Materials, 2018 edition.

NFPA 33 is referenced (2) times in 2019 NFPA 13 in Chapter 26 Special Occupancy Requirements :

Chapter 26 Special Occupancy Requirements
ENHANCED CONTENT
Sprinkler criteria from other NFPA codes and standards are consolidated in Chapter 26 of NFPA 13 so that sprinkler design and installation criteria for special occupancies can be found in a single location. These other NFPA standards specify certain design requirements for automatic sprinkler systems, and this chapter extracts those requirements and makes reference to the remaining chapters of this standard. In the extracted material, no method for implementing the design information, such as density/area, is given without referencing the remainder of NFPA 13.
To fully understand the criteria in Chapter 26, the user should consult the referenced NFPA standards. The referenced standards provide options for standard sprinkler protection, such as water spray sprinklers, foam-water sprinklers, and other special extinguishing systems, for the protection of the specified hazards.
REORGANIZATION NOTE
This chapter was Chapter 22 in the 2016 edition of NFPA 13. The entire chapter was carried over and sections renumbered to replace the Chapter 22 prefix with the Chapter 24 prefix.

26.4 Spray Application Using Flammable or Combustible Materials.
26.4.1 Design Requirements.
26.4.1.1*
The automatic sprinkler system shall be a wet pipe system, a dry pipe system, a preaction system, or an open-head deluge system, whichever is most appropriate for the portion of the spray operation being protected. [33:9.6.1]
A.26.4.1.1
Subsection 9.6.1 of NFPA 33 lists four types of automatic sprinkler systems and requires that the one “most appropriate for the portion of the spray area being protected” be used. Generally, an open-head deluge system provides the highest level of protection, given that all sprinklers in the protected area flow simultaneously. This type of system is most appropriate for large, downdraft, water-wash spray booths when protecting automatic electrostatic spray application zones. [33:A.‍9.6.1]
Wet pipe automatic sprinkler systems are appropriate for protecting spray booths that utilize nonelectrostatic application processes or operations using listed electrostatic application processes. Wet pipe systems are also generally used to protect exhaust plenums (eliminator or scrubber sections), exhaust ducts, and air recirculation filter houses. [33:A.‍9.6.1]
Dry pipe systems have been included because some exhaust duct designs include sections that are subject to freezing. [33:A.‍9.6.1]
Preaction systems have been included because some spray application processes and equipment can be damaged by unwanted water discharge. This damage can be disruptive and costly. Powder spray booths and solvent concentrator (air pollution abatement) systems are examples of systems where it is appropriate to use a preaction system. [33:A.‍9.6.1]

ENHANCED CONTENT
NFPA 33, Standard for Spray Application Using Flammable or Combustible Materials, requires that a spray area be protected by an automatic fire protection system but not necessarily by a sprinkler system. Other types of systems, such as a dry chemical extinguishing system or a carbon dioxide system, can be used if the building itself is not protected by sprinklers. The usual situation is protection of an individual spray booth in a nonsprinklered building, such as an auto body shop. Such alternative systems might be more effective and more compatible, depending on the material being sprayed. The intent, however, is that a spray application process located in a sprinklered building should also be protected

Dan Wilder

3/16/2023 09:06:32 am

Not a FA Guy...but we have done several booths, enclosed equip (tire carousels and the like) and small modular mezzanines with aux systems due to the temporary or potential for relocation of the unit so IMO...

A local flow switch with double contacts would seem to be the best way to approach. This provides a local and limited area of impact specific to the booth and associated delivery/application/and material movement systems instead of running into shutting down an entire operational area from a single flow switch in a remote location (pretty much every time a new ITM person/company comes in). This would also potentially provide a contact for a local alarm vs running new wire (possibly conduit) from a remote location.

A commercial riser assembly (or similar fabbed assembly) would be the best when the flow switch is required, nice plug and play. Best practice would be to provide a hard pipes solution for testing discharge, but I've seen these setups with 50-gallon barrels or gondolas to catch water for the test and subsequent draining (not the best but sometimes needed, nearest janitorial sink is also helpful if not the exterior of the building.

This is AHJ dependent. I have one AHJ that has written into their IFC amendments that ANY valve controlling fire sprinklers needs to be electronically monitored and supervised, the AHJ right next to it allows for a chain/lock for control valves.

NFPA 22' - 16.11.6.2 (Indicating Control Valves)
Such valves shall be sealed, locked, or electrically supervised in the open position.

franck

3/16/2023 10:26:10 am

Dan summarized it well.
No strong requirement for electrical supervision of the valve. It is up to the AHJ. A locked valve is most of the time sufficient (if regular checks are performed) as the valve is normally not located in an easily accessible location (should be close to the ceiling).

Alarm from the main system is not desirable to interlock the stop of operation in the spray booth as a fire (or even a test of the system) may stop the operations and have quite huge consequences on the process.
I did it once on a rolling mill producing very thin metal sheet for razor blades. Activation of the sprinkler alarm stopped the process and cut the steel plate… Not my best souvenir…

And of course, if you have a system with a dedicated flow switch, you need an ITC to test it (how would you know it works ?) and to drain it properly (future modifications /maintenance operations would be difficult otherwise)

Jesse

3/16/2023 10:46:20 am

I think Dan and Franck summarized it very well. I like the idea of a localized flow switch.

Waterflow, ITD Req'd for Powder Coating Booth?

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