First Revision No. 15-NFPA 91-2013 [ Chapter 2 ] Page 1 of 28

First Revision No. 15-NFPA 91-2013 [ Chapter 2 ]

Chapter 2 Referenced Publications2.1 General.The documents or portions thereof listed in this chapter are referenced within thisstandard and shall be considered part of the requirements of this document.2.2 NFPA Publications.National Fire Protection Association, 1 Batterymarch Park, Quincy, MA 02169-7471.

NFPA 25, Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems, 2008 2014 edition.

NFPA 51B, Standard for Fire Prevention During Welding, Cutting, and Other Hot Work, 2009 2014 edition.

NFPA 68, Standard on Explosion Protection by Deflagration Venting, 2007 2013edition.

NFPA 69, Standard on Explosion Prevention Systems, 2014 2008 edition.

NFPA 70®, National Electrical Code®, 2008 2014 edition.

NFPA 86, Standard for Ovens and Furnaces, 2007 2015 edition. NFPA 221, Standard for High Challenge Fire Walls, Fire Walls, and Fire Barrier Walls, 2009 2015 edition.

NFPA 259, Standard Test Method for Potential Heat of Building Materials,2013 2008 edition.

NFPA 780, Standard for the Installation of Lightning Protection Systems,2014 2008 edition.

2.3 Other Publications.2.3.1 SMACNA Publications.Sheet Metal and Air Conditioning Contractors' National Association, 4201 Lafayette Center Drive, Chantilly, VA 20151-1209.

Accepted Industry Practice for Industrial Duct Construction,2008. 1975.

Rectangular Industrial Duct Construction Standard, 2004.

Round Industrial Duct Construction Standard, 1999.

Thermoplastic Duct (PVC) Construction Manual, 2nd edition, 1995.

Thermoset FRP Duct Construction Manual, 1997.2.3.2 Other Publications.Merriam-Webster's Collegiate Dictionary, 11th edition, Merriam-Webster, Inc.,Springfield, MA, 2003.2.4 References for Extracts in Mandatory Sections.NFPA 33, Standard for Spray Application Using Flammable or Combustible Materials, 2015 2007 edition.

NFPA 329, Recommended Practice for Handling Releases of Flammable andCombustible Liquids and Gases, 2015 2010 edition.

Page 1 of 28National Fire Protection Association Report

4/2/2013http://submittals.nfpa.org/TerraViewWeb/ContentFetcher?commentParams=%28Comment...

NFPA 654, Standard for the Prevention of Fire and Dust Explosions from theManufacturing, Processing, and Handling of Combustible Particulate Solids,2013 2006 edition.

Submitter Information Verification

Submitter Full Name: [ Not Specified ]Organization: [ Not Specified ]Submittal Date: Fri Mar 01 09:06:19 EST 2013

Committee Statement and Meeting Notes

Committee Statement: References Update.Response Message:



First Revision No. 19-NFPA 91-2013 [ New Section after 3.3.2 ]

3.3.3* Centralized Vacuum Cleaning System.A fixed-pipe system utilizing variable-volume negative-pressure (i.e., vacuum) airflows from remotely located hose connection stations to allow the removal of dust accumulations from surfaces and conveying those dusts to an air-materialseparator (AMS). [ 654 , 2013]




CommitteeStatement:

These terms are used in this document and the committee wanted to be consistent with the current edition of NFPA 654, see FR-20-NFPA 91-2013 for the added annex.

Response Message:



First Revision No. 5-NFPA 91-2013 [ Section No. 3.3.2 ]

3.3.2* Air-Moving Device.A power-driven fan, blower, or other device that establishes an airflow by moving a given volume of air per unit time. [ 654 , 2013]


Submitter Full Name: [ Not Specified ]Organization: [ Not Specified ]Submittal Date: Thu Feb 28 14:43:16 EST 2013


CommitteeStatement:

To be consistent with NFPA 654, 2013 edition as these documents are used together often.

Response Message:Committee Notes:

Date Submitted By

Feb 28, 2013

Duval Extract this Definition from NFPA 654.




3.3.4* Dust Collection System.A combination of equipment designed to capture, contain, pneumatically convey,collect, and remove airborne dusts from the airstream. [ 654 , 2013]




CommitteeStatement:

These terms are used in this document and the committee wanted to be consistent with the current edition of NFPA 654, see FR-22-NFPA 91-2013 for associated annex material.

Response Message:




3.3.14* Pneumatic Conveying System.An equipment system that comprises a material feeding device; an enclosed ductwork, piping, or tubing network; an air-material separator; and an air-moving device and that is used to transfer a controlled flow of solid particulate materialfrom one location to another using air or other gases as the conveying medium.[ 654 , 2013]




CommitteeStatement:

These terms are used in this document and the committee wanted to be consistent with the current edition of NFPA 654, see FR-24-NFPA 91-2013 for associated annex material.

Response Message:




4.1.2.1Where more than one type of material is to be handled by a system, compatibility shall be verified by literature review or test.4.1.2.2Where incompatibility is found, provisions shall be made for cleaning the system prior to transporting a new material.


Submitter Full Name: [ Not Specified ]Organization: [ Not Specified ]Submittal Date: Tue Feb 26 12:21:44 EST 2013


CommitteeStatement:

This change is in response to CSB Recommendation 2003-RI-I-RI-R5. This change is similar to what was accepted in NFPA 654.

ResponseMessage:




4.1.12Exhaust ducts passing through a fire barrier having a fire resistance rating of 2 hours or greater shall meet one either of the following specifications:

(1) Wrapped or encased with listed or approved materials having a fire resistance rating equal to the fire barrier for 3 m (10 ft) 10 ft (3 m) of theduct on each side of the fire barrier including duct supports within thisspan

(2) Constructed of materials and supports having a minimum fireresistance rating equal to the fire barrier

(3) Enclosed with a shaft that is constructed of material having a fire resistance rating equal to the fire barrier for 10 ft (3 m) of the duct on each side of the fire barrier with no inlets to the duct within this distance, and the duct entry into and exit from the shaft is protected in accordance with 4.1.13




CommitteeStatement:

This provides a third option for when those situations where it is not feasible to change the material of the exhaust duct or insulate the duct. Based on information provided in FM Global Data sheet 7-78.

ResponseMessage:Committee Notes:

Date Submitted By

Mar 1, 2013

Duval Original wording of the third requirement:

3) Enclosed with a shaft around the duct for 3 m (10 ft) on each side of the fire barrier and all of the following:a) The shaft shall have a fire resistance rating equal to the fire barrierb) Inlets to the duct shall not be permitted within the shaft enclosurec) Duct entry into and exit from the shaft shall be protected in accordance with 4.1.13




4.2.4If sprinkler protection is provided inside the duct system, then the duct supportsshall also be designed to carry the anticipated weight of any accumulation ofsprinkler discharge.4.2.4.1*As an alternative to 4.2.4, it shall be permitted to provide low-point drains in the ducts in accordance with 4.2.4.1.1 4.2.4.1 through 4.2.4.1.4 4.2.4.2 .4.2.4.1.1Where drainage would not cause water damage , friction-retained caps or equivalent drainage arrangements shall be used .4.2.4.1.2*Where drainage would cause water damage, drainage discharge shall be consistent with requirements of the state and local building codes.4.2.4.1.3Where hazardous residue is present in the duct, drains shall be arranged for proper disposal of wastes in the drain water.4.2.4.1.4Drains shall be designed to minimize air leakage into the ducts.4.2.4.2B ranch-duct inlets to the main horizontal ducts near the top of the mainduct shall be located to lessen the possibility of sprinkler discharge flowing back through the branches and into critical processes.




CommitteeStatement:

The Committee wanted to provide an alternate to strengthening duct support when providing sprinkler protection. The information is based on FM Global Data Sheet 7-78. See FR-25 for associated annex material.


Date Submitted By

Mar 18, 2013

M, Beady 4.2.4.1.1 - Deleted 'use'

Mar 18, 2013

M. Beady 4.2.4.2 - Deleted 'Locate'




4.4.2*The design of the system shall be documented, and the documentation shall include the following information:

(1) Data on the range of particulate size(2) Concentration of particulate or dust in the conveyance air stream(3) Potential for reaction between the transported particulates and the

extinguishing media used to protect process equipment(4) Conductivity of the particulates(5) Concentration of flammable vapors or gases in the conveyance air

stream(6) Other physical and chemical properties that could affect the fire

protection of the process

4.4.3Existing systems shall not be modified without considering the effects of those changes on the system performance, including the redesign of the system to incorporate the proposed changes.




CommitteeStatement:

These requirements are taken from NFPA 654 that are not only applicable to the design of ducts for dust but also applicable to vapor and gases. See FR-27-NFPA 91-2013 for annex material.

ResponseMessage:




4.4.8The rate of airflow at each hood or other pickup point shall be designed so as to capture, convey, and control the material. [ 654: 7.3.2.3]




CommitteeStatement:

This section was revised relocated in the 2013 edition of NFPA 654 to the dust collection section. This section in NFPA 91 is applicable to more than just dust collection, as such the extract was removed, but the content of the section remained.

Response Message:




4.4.9*All ductwork shall be sized to provide the air volume and air velocity necessary to keep the duct interior clean and free of residual material. [654:7.3.2.4] 7.3.2.6.6]




CommitteeStatement:

The extracted section numbering has changed in NFPA 654 and is updated here.

Response Message:



First Revision No. 28-NFPA 91-2013 [ Section No. 4.6.5.2 ]

4.6.5.2The minimum allowable clearance with protection provided, shown as dimension B in Figure 4.6.5.1, shall be calculated by using the following equation:

(4.6.5.2)

where: B = minimum allowable clearance with protectionA = required clearance with no protectionR = maximum allowable clearance reduction in %




CommitteeStatement:

Added equation numbers to cross-referenced equations to conform to the NFPA Manual of Style.

Response Message:




7.1.9 Manifolding of Ducts.Where an explosion hazard exists, the requirements in 7.1.9.1 through 7.1.9.4 7.1.10 shall apply.7.1.9.1Manifolding of ducts to air–material separators shall not be permitted.7.1.9.2Ducts from a single piece of equipment or from multiple pieces of equipment interconnected on the same process stream shall be permitted to be manifolded.7.1.9.3Ducts from nonassociated pieces of equipment shall be permitted to bemanifolded, provided that each duct is equipped with an isolation deviceprior to manifolding in accordance with NFPA 69, Standard on Explosion Prevention Systems.7.1.9.4Ducts for centralized vacuum cleaning systems shall be permitted to bemanifolded.




CommitteeStatement:

Section 7.1.10 does not apply to just situations where manifolding exists, but to all AMS where lightning protection is provided. This is an editorial correction.

Response Message:



First Revision No. 9-NFPA 91-2013 [ Section No. 8.4 ]

8.4 Open Flames and Sparks.The requirements of 8.4.1 through 8.4.3 8.4.4 8.4.4 shall be applied retroactively.8.4.1Prior to the start of any hot work on a duct, the duct shall be investigated for the presence of combustible residue or flammable vapors.8.4.2Cutting and welding shall comply with the applicable requirements of NFPA 51B , Standard for Fire Prevention During Welding, Cutting, and Other Hot Work .8.4.3Grinding, chipping, and other operations that produce either sparks or open flame ignition sources shall be controlled by a hot work permit system in accordance with NFPA 51B , Standard for Fire Prevention During Welding, Cutting, and Other Hot Work .8.4.4Smoking shall be permitted only in designated areas.




CommitteeStatement:

The revision was to clarify that there is a hazard with hot work on ducts and to ensure that the hot work operator is checking for all associated hazards.

Response Message:



First Revision No. 10-NFPA 91-2013 [ Section No. 9.1 ]

9.1* General.Any portion of an exhaust system utilizing combustible components or having the potential for combustible residue buildup on the inside, where the duct cross-sectional area is greater than or equal to 75 in.2 (480 cm2), shall be provided with an automatic extinguishing system within the duct and at the duct intake, hood, enclosure, or canopy. , or shall be constructed of material listed for use without sprinkler protection.

Global FR-10 Hide Deleted

9.1.1Unless combustible residue buildup is present, an automatic extinguishing system shall not be required where ductwork is fabricated from listed limited combustible material.




CommitteeStatement:

This revision clarifies the statement extinguishing systems is needed where ever there is combustible residue regardless of duct construction.

Response Message:



First Revision No. 20-NFPA 91-2013 [ New Section after A.3.3.2 ]

A.3.3.3 Centralized Vacuum Cleaning System.This system normally consists of multiple hose connection stations hard-piped to an AMS located out of the hazardous area. Positive displacement or centrifugal AMDs can be used to provide the negative pressure air flow. The hoses and vacuum cleaning tools utilized with the system should be designed to be conductive or static-dissipative in order to minimize any risk of generating an ignition source. Low MIE materials should be given special consideration in the system design and use. A primary and secondary AMS separator combination (e.g., cyclone and filter receiver) can be used if large quantities of materials are involved. However, most filter receivers are capable of handling the high material loadings without the use of a cyclone. [ 654 , 2013]




Committee Statement: Annex to FR-19-NFPA 91-2013.Response Message:




A.3.3.4 Dust Collection System.A typical dust collection system consists of the following:

(1) Hoods — devices designed to contain, capture, and control the airborne dusts by using an induced air flow in close proximity to the point of dust generation (local exhaust zone) to entrain fugitive airborne dusts.

(2) Ducting — piping, tubing, fabricated duct, etc., used to provide the controlled pathway from the hoods to the dust collector (AMS). Maintaining adequate duct velocity (usually 4000 fpm or higher) is a key factor in the proper functioning of the system.

(3) Dust collector — an AMS designed to filter the conveyed dusts from the conveying air stream. Usually these devices have automatic methods for cleaning the filter media to allow extended use without blinding. In some systems, a scrubber or similar device is used in place of the filter unit.

(4) Fan package — an AMD designed to induce the air flow through the entire system.

The system is designed to collect only suspended dusts at the point of generation and not dusts at rest on surfaces. The system is also not designed to convey large amounts of dusts as the system design does not include friction loss due to solids loading in the pressure drop calculation. Thus, material loading must be minimal compared to the volume or mass of air flow. [ 654 , 2013]




Committee Statement: Annex material for FR-21-NFPA 91-2013.Response Message:



First Revision No. 12-NFPA 91-2013 [ Section No. A.3.3.2 ]

A.3.3.2 Air-Moving Device.Air-moving devices include fans, centrifugal fans, or mixed-flow fans. These devices have previously been called blowers or exhausters. Air-moving devices also include steam ejectors and similar devices.

An air-moving device is a fan or blower. A general description of each follows:

(1) Fans:

(a) A wide range of devices that utilize an impeller, contained within a housing, that when rotated create air/gas flow by negative (vacuum) or positive differential pressure.

(b) These devices are commonly used to create comparatively high air/gas volume flows at relatively low differential pressures.

(c) These devices are typically used with ventilation and/or dust collectionsystems.

(d) Examples are centrifugal fans, industrial fans, mixed or axial flow fans, and inline fans.

(2) Blowers:

(a) A wide range of devices that utilize various-shaped rotating configurations, contained within a housing, that when rotated create air/gas flow by negative (vacuum) or positive differential pressure.

(b) These devices are commonly used to create comparatively high differential pressures at comparatively low air/gas flows.

(c) The most common uses of these devices are with pneumatic transfer, high-velocity, low volume (HVLV) dust collection, and vacuum cleaning systems.

(d) Examples are positive displacement (PD) blowers, screw compressors, multi-stage centrifugal compressors/blowers, andregenerative blowers.




CommitteeStatement:

Revised the definition to extract it from NFPA 654, 2013 edition to be consistent since these documents are used together often.

ResponseMessage:




A.3.3.14 Pneumatic Conveying Sytem.Pneumatic conveying systems include a wide range of equipment systems utilizing air or other gases to transport solid particles from one point to another. A typical system comprises the following:

(1) A device used to meter the material into the conveying air stream

(2) Piping, tubing, hose, etc., used to provide the closed pathway from the metering device to the AMS

(3) An AMS designed for the separation of comparatively large amounts of material from the conveying air/gas stream

(4) An additional metering device (typically a rotary airlock valve or similar device) that might be used to allow discharge of the separated material from the conveying air stream without affecting the differential pressure of the system

(5) An AMD designed to produce the necessary pressure differential and air/gas flow in the system (positive or negative)

A pneumatic conveying system requires the amount of material conveyed by the system to be considered as a major factor in the system pressure drop calculations. Both positive and negative (i.e., vacuum) differential pressure are used for pneumatic conveying. The decision of which is the best for a specific application should be based on a risk analysis, equipment layout, and other system operational and cost factors. Dense phase conveying can also be considered for the application, especially with more hazardous materials (e.g., low MIE). The inherent design and operational features of this approach can provide significant safety and operational advantages over other types of pneumatic conveying systems. [ 654 , 2013]








A.4.1.2Materials, when mixed, should not create a fire, explosion, or health hazard. For additional information, see ASTM E 2012, Standard Guide for the Preparation of a Binary Chemical Compatibility Chart .




CommitteeStatement:

This change is in response to CSB Recommendation 2003-RI-I-RI-R5. This change is similar to what was accepted in NFPA 654.

ResponseMessage:




A.4.2.4.1A 4 in. (102 mm) drain with a capacity of approximately 150 gpm (565 l/min) istypically used. Other sizes are acceptable when designed by knowledgeablecontractors.A.4.2.4.1.2The preferred location for discharging the drain is outdoors or to an existing waste drainage system.




CommitteeStatement:

Annex material for FR-26-NFPA 91-2013. This information is based on the FM Global Data Sheet 7-78.

Response Message:




A.4.4.2The design of the pneumatic conveying, dust collection, or centralized vacuumcleaning system should be coordinated with the architectural and structuraldesigns. The plans and specifications should include a list of all equipment,specifying the manufacturer and type number, and the following information:

(1) Name of owner and occupant

(2) Location, including street address

(3) Point of compass

(4) Ceiling construction

(5) Full-height cross section

(6) Location of fire walls

(7) Location of partitions(8) Materials of construction

Plans should be drawn to an indicated scale and show all essential details such as location, construction, ventilation ductwork, volume of outside air at standard temperature and pressure that is introduced for safety ventilation, and control wiring diagrams.








A.4.4.9Dust collection systems and centralized vacuum cleaning systems handling combustible dusts usually use branched duct networks with multiple pickup points and variable material loading. In contrast, dilute phase and dense phase pneumatic conveying systems are typically linear systems with controlled infeed and consistent material loading. Dust collection systems for combustible dusts represent a significant increase in deflagration risk compared with most pneumatic conveying systems. A properly designed system is critical to minimizing that risk.For guidance on determining air volume and air velocity, refer to IndustrialVentilation — A Manual of Recommended Practice, published by the American Conference of Governmental Industrial Hygienists (ACGIH). [654: A.7.3.2.4]A.7.3. 2. 6.6]




Committee Statement: Extracted reference material from NFPA 654 has been updated.Response Message:



First Revision No. 29-NFPA 91-2013 [ Section No. B.1.1 ]

B.1.1 NFPA Publications.National Fire Protection Association, 1 Batterymarch Park, Quincy, MA 02169-7471.

NFPA 1, Fire Code, 2015 2009 edition.

NFPA 11, Standard for Low-, Medium-, and High-Expansion Foam, 2015 2010edition.

NFPA 12, Standard on Carbon Dioxide Extinguishing Systems, 2012 2008 edition.

NFPA 12A, Standard on Halon 1301 Fire Extinguishing Systems, 2015 2009edition.NFPA 13, Standard for the Installation of Sprinkler Systems, 2013 2010 edition.

NFPA 15, Standard for Water Spray Fixed Systems for Fire Protection, 2012 2007edition.

NFPA 17, Standard for Dry Chemical Extinguishing Systems, 2013 2009 edition.

NFPA 17A, Standard for Wet Chemical Extinguishing Systems, 2013 2009 edition.

NFPA 30, Flammable and Combustible Liquids Code, 2015 2008 edition.

NFPA 30B, Code for the Manufacture and Storage of Aerosol Products, 2015 2007 edition.

NFPA 32, Standard for Drycleaning Plants, 2011 2007 edition.NFPA 33, Standard for Spray Application Using Flammable or CombustibleMaterials, 2015 2007 edition.

NFPA 34, Standard for Dipping and Coating Processes Using Flammable orCombustible Liquids, 2015 2007 edition.

NFPA 35, Standard for the Manufacture of Organic Coatings, 2011 2005 edition.

NFPA 36, Standard for Solvent Extraction Plants, 2013 2009 edition.

NFPA 45, Standard on Fire Protection for Laboratories Using Chemicals, 2015 2004 edition.

NFPA 61, Standard for the Prevention of Fires and Dust Explosions in Agricultural and Food Processing Facilities, 2013 2008 edition.

NFPA 68, Standard on Explosion Protection by Deflagration Venting, 2013 2007edition.

NFPA 77, Recommended Practice on Static Electricity, 2014 2007 edition.

NFPA 85, Boiler and Combustion Systems Hazards Code, 2015 2007 edition.

NFPA 86, Standard for Ovens and Furnaces, 2015 2007 edition.

NFPA 92 92A , Standard for Smoke-Control Systems Utilizing Barriers and Pressure Differences , 2012 2009 edition.

NFPA 92B , Standard for Smoke Management Systems in Malls, Atria, and Large Spaces , 2009 edition.NFPA 96, Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations, 2014 2008 edition.



NFPA 120, Standard for Fire Prevention and Control in Coal Mines, 2015 2010edition.

NFPA 204, Standard for Smoke and Heat Venting, 2015 2007 edition.

NFPA 211, Standard for Chimneys, Fireplaces, Vents, and Solid Fuel–BurningAppliances, 2013 2010 edition.

NFPA 303, Fire Protection Standard for Marinas and Boatyards, 2011 2006edition.

NFPA 318, Standard for the Protection of Semiconductor Fabrication Facilities, 2015 2009 edition.

NFPA 409, Standard on Aircraft Hangars, 2011 2004 edition.

NFPA 484, Standard for Combustible Metals, 2015 2009 edition.

NFPA 654, Standard for the Prevention of Fire and Dust Explosions from theManufacturing, Processing, and Handling of Combustible Particulate Solids, 2013 2006 edition.

NFPA 655, Standard for Prevention of Sulfur Fires and Explosions, 2012 2007edition.

NFPA 664, Standard for the Prevention of Fires and Explosions in WoodProcessing and Woodworking Facilities, 2012 2007 edition.

NFPA 750, Standard on Water Mist Fire Protection Systems, 2014 2010 edition.

NFPA 801, Standard for Fire Protection for Facilities Handling RadioactiveMaterials, 2014 2008 edition.

NFPA 2001, Standard on Clean Agent Fire Extinguishing Systems, 2015 2008edition.




CommitteeStatement:

Updated references to current editions. NFPA 92a and 92b were withdrawn and incorporated into NFPA 92.


Date Submitted By

Mar 1, 2013

Duval Double check in Second Draft Stage that none of these risk not being returned.



First Revision No. 30-NFPA 91-2013 [ Section No. B.1.2.4 ]

B.1.2.4 ASTM Publications.ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959.

ASTM E 136, Standard Test Method for Behavior of Materials in a Vertical Tube Furnace at 750°C,2012. 2004.




Committee Statement: Current edition of this test standard is 2012.Response Message:



First Revision No. 31-NFPA 91-2013 [ Section No. B.3 ]

B.3 References for Extracts in Informational Sections.NFPA 68, Standard on Explosion Protection by Deflagration Venting, 2013 2007edition.

NFPA 329, Recommended Practice for Handling Releases of Flammable andCombustible Liquids and Gases, 2015 2010 edition.

NFPA 654, Standard for the Prevention of Fire and Dust Explosions from theManufacturing, Processing, and Handling of Combustible Particulate Solids, 2013 2006 edition.




Committee Statement: Updated editions of extracted references.Response Message:



Documents

First Revision No. 15-NFPA 91-2013 [ Chapter 2 ] Page 1 of 28