Applicable Code for Sprinklers in Dust Collection?

10/11/2023

A client of ours operates a printing press facility and has installed a machine to collect and form dust into "bricks" to avoid venting them to atmosphere.

The machine is fed by ducts that tap into an existing dust collection system.

The client asked for a quote to adjust the overhead sprinkler system because of the new ducts but I think the new ductwork and machine might require suppression of some form, as well as interacting with the existing sprinkler system at the roof.

(1) Does NFPA 13 (2016 Edition) Section 11.2.3.2.2.2 indicate that the existing roof system cannot have quick response sprinklers?

"Quick-response sprinklers shall not be permitted for use in extra hazard occupancies or other occupancies where there are substantial amounts of flammable liquids or combustible dusts."

It's hard to tell from the floor but I believe at least some of the systems have quick response.

(2) Is the dust collector ductwork governed by NFPA 13 at all?

Section 22.33 Exhaust Systems for Air Conveying of Vapors, Gases, Mists, and Noncombustible Particulate Solids would not seem to apply since the particulate dust is a paper product and inherently combustible.

(3) Are dust collector machines like paint booths in that manufacturers pre-coordinate requirements and access for sprinklers into the filter media?

Thanks for all the guidance; I haven't seen this application before.

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3 Comments

Dan Wilder

10/11/2023 08:54:22 am

My thoughts...but without a review of the building and it's classification.

Printing & Publishing is classified as an F-1 occupancy

There are some sprinklers that carry a standard response listing while utilizing a quick response element....verify the type of sprinkler if at all possible.

1) No, the ductwork/equipment is the high hazard issue not the space as most spray operations occur within equipment or enclosures (again, really need the occupancy defined). The collection system likely allows the lesser design basis by removal of the high hazard combustibles. As 13 does not allow quick & standard response sprinklers within the same compartment without some sort of separation, again, verify the QR/SR type.

2) There is a long list but NFPA 13 (Section 22.4 has some guidance and references NFPA 33) isn't the guiding standard on combustible vapors with ducts...some recent notes
--NFPA 91 Standard for Exhaust Systems for Air Conveying of Vapors, Gases, Mists, and Particulate Solids - Section 9.1 just says provide protection...Section 1.1 says it's not within scope for exhaust systems for conveying particulate solids.
--NFPA 34 - Standard for Dipping, Coating, and Printing Processes Using Flammable or Combustible Liquids (applicable but no FP criteria for ductwork)
--NFPA 33 - Standard for Spray Application Using Flammable or Combustible Materials - Section 9.5.1.6

3) Sometimes....There may or may not be ports already for collector machine (heavily dependent on MFG) that occur at the intake collar, within the filter media bed if any, plenum prior to the filters and the plenum after the filters (clean air) but not always. The ductwork, including hood capture systems, the associated collar connections, wye fitting increasers, and bulk duct runs back to the collector rarely have precoordinated ports so that is on the installer (Check out the Victaulic AQD or Flexhead 1000, 1100, 1200, 1300 Series for possibly avoiding the access panel requirement)

A good writeup - https://risklogic.com/fire-protection-at-printing-plants/

10/11/2023 08:56:25 am

Looking back, I know the intent was combustible dust, but vapors generated by the spray application will also play a part.

Anthony

10/11/2023 12:10:05 pm

1) Can't use QR sprinklers if you're in extra hazard. So, your new routing should take that into account. Even if it's still ordinary hazard you can use std response sprinklers and be in compliance. the only reason QR sprinklers would be a good idea in a setting like this is for area reduction in the hydraulic area which I would guess isn't used.

2) Not really. NFPA 13 is about open floor plan sprinkler coverage not internal duct or machinery sprinklers.

3) Generally if FP is required for the use case the duct or dust collector is designed for then, yes, there will be ports for sprinklers and the like. However there are plenty of cases where a dust collector or otherwise has no FP and that is determined by the final instillation.

FYI:

NFPA 61, NFPA 484, NFPA 652, NFPA 654, NFPA 655, and NFPA 664 are all being rolled into NFPA 660 dealing with dust control

Applicable Code for Sprinklers in Dust Collection?

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