Technical Committee on Heat Recovery Steam Generators ......Technical Committee on Heat Recovery...

Technical Committee on Heat Recovery Steam Generators and Other Combustion Turbine Exhaust

Systems

AGENDA

Entergy Corporation 639 Loyola Avenue

New Orleans, LA 70113 February 28 – March 1, 2013

1. Chair’s welcome, call to order, and opening remarks at 8:30 a.m. 2. Self-Introduction of Committee Members and Guests 3. Approval of Minutes from the May 23-25, 2013 Pre-First Draft Meeting in Birmingham,

AL. See www.nfpa.org/85next to review. 4. Staff Liaison Report A. Committee membership update (For the period March 5, 2010 – Feb. 5, 2013)

Name Category Change Date Michael Mulherin M (Alt. to G. Gaetke) Resign 5/25/2010 John Stevens M (Alt. to S. Graf) Resign 4/25/2011 Steven Graf M (Principal) Change from Alt to P 8/10/2010 Philip Souers M (Alt. to M. Cancelado) Change from P to Alt 10/22/2010 Miguel Cancelado M (Principal) Change from Alt to P 10/22/2011 Todd Young U (Principal) Resign 7/18/2011 Joshua Kelly M (Alt to A. Beaty) Resign 12/12/2012 Harley Ross M (Alt to R. Kleen) Appoint 8/2/2010 David Paul Cannon SE (Principal) Appoint 3/1/2011 George Pyros M (Principal) Appoint 3/1/2011 Dwight Hyche I (Principal) Appoint 3/1/2011 David Dexter M (Alt to G. Gaetke) Appoint 8/9/2011 Roy Reeves M (Principal) Appoint 8/9/2011 John Burney U (Principal) Appoint 10/18/2011 Fedja Drndarevic E (Principal) Appoint 10/18/2011 Bruce Wertz SE (Principal) Appoint 8/9/2012 Adam Kuentzler M (Alt to S. Meierotto) Appoint 8/9/2012 David King U (Principal) Appoint 8/9/2012

(Total Voting Members – 27; M=30%, SE=33%, U=22%; I=11%; E = 4%) B. Revision Cycle Review and timeline (Attachment A) 5. Old Business (Also See Pre-FD Meeting Actions, Attachment D) A. Fresh Air Firing. The committee established a task group in the Pre-FD meeting

to further develop coverage on fresh air firing. The task group members are: M. Polagye (chair); M. Fry, S. Meierotto, I. Yarinovsky, and J. Walawender.

1

http://www.nfpa.org/85next�

B. Consistency with Fundamentals. A task group was established in the Pre-FD meeting to identify issues in chapter 8 that may be redundant, inconsistent, or incompatible with chapter 4. The task group members are: J. Burney; G. Gaetke; D. Hinshaw; and R. Reeves.

C. Vent Line Sizing for Triple Block/Double Bleed Systems. The committee established a task group in the pre-FD meeting to review relevant standards regarding sizing the downstream vent valve in a triple block/double bleed system to determine if coverage can be added to chapter 8 that would permit alternate sizing from the requirement of chapter 4. The task group members are: R. Kleen (chair); P. Cannon; D. Hyche; J. Walawender.

D. Purging of HRSG/Bypass Stack. The committee briefly discussed ambiguity in the coverage on purging of the HRSG where a bypass stack is also present. Mr. Kleen volunteered to develop specific public input to clarify.

E. Pressurizing Air in Double Block and Bleed Systems. The committee will continue to review this issue for the First Draft meeting.

6. New Business A. Review BCS-FUN actions. The committee members are asked to review the

actions of the Fundamentals committee (sent under separate cover) and bring forward any items warranting further dicussion.

B. Create First Revision of Chapter 6. The committee should review the Public Input (Attachment B) and revise chapter 6 of NFPA 85 as appropriate.

C. Request from I. Yarinovsky. (Attachment C) 7. Other Items? 8. Date/Location of Next Meeting. The Second Draft meeting must take place between

Nov. 15, 2013 and January 24, 2014. The BCS-FUN meeting is tentatively scheduled for Dec 4-5, 2013 in Atlanta, GA.

9. Adjournment.

2

Attachment A: Fall 2014 Revision Cycle

3

Process Stage Process Step

Dates for TCDates for TC with CC

Public Input Closing Date* 1/4/2013 1/4/2013Final date for TC First Draft Meeting 6/14/2013 3/15/2013Posting of First Draft and TC Ballot 8/2/2013 4/26/2013Final date for Receipt of TC First Draft ballot 8/23/2013 5/17/2013Final date for Receipt of TC First Draft ballot ‐ recirc 8/30/2013 5/24/2013Posting of First Draft for CC Meeting 5/31/2013Final date for CC First Draft Meeting 7/12/2013Posting of First Draft and CC Ballot 8/2/2013Final date for Receipt of CC First Draft ballot 8/23/2013Final date for Receipt of CC First Draft ballot ‐ recirc 8/30/2013Post Final First Draft for Public Comment 9/6/2013 9/6/2013

Public Comment closing date 11/15/2013 11/15/2013Final Date to Publish Notice of Consent Documents (Documents That Received No Comments)

11/22/2013 11/22/2013

Appeal Closing Date for Consent Documents (15 Days) (Documents That Received No Comments)

12/7/2013 12/7/2013

Final date for TC Second Draft Meeting 5/2/2014 1/24/2014Posting of Second Draft and TC Ballot 6/13/2014 3/7/2014Final date for Receipt of TC Second Draft Ballot 7/7/2014 3/28/2014Final date for receipt of TC Second Draft ballot ‐ recirc 7/14/2014 4/4/2014Posting of Second Draft for CC Mtg 4/11/2014Final date for CC Second Draft Meeting 5/23/2014Posting of Second Draft for CC Ballot 6/13/2014Final date for Receipt of CC Second Draft ballot 7/7/2014Final date for Receipt of CC Second Draft ballot ‐ recirc 7/14/2014Post Final Second Draft for NITMAM Review 7/18/2014 7/18/2014

Notice of Intent to Make a Motion (NITMAM) Closing Date 8/22/2014 8/22/2014Posting of Certified Amending Motions and Consent Documents 10/17/2014 10/17/2014Appeal Closing Date for Consent Documents (15 Days) 11/1/2014 11/1/2014SC Issuance Date for Consent Documents (25 Days) 11/11/2014 11/11/2014

Tech Session Association Meeting for Documents with CAMs 6/22‐25/2015 6/22‐25/2015

Appeal Closing Date for Documents with CAMs (20 Days) 7/15/2015 7/15/2015SC Issuance Dates for Documents with CAMs 8/27/2015 8/27/2015

Comment Stage (Second Draft)

Tech Session Preparation (& Issuance)

Appeals and Issuance

2014 FALL REVISION CYCLE

Public Input Stage

(First Draft)

*Public Input Dates may vary according to documents and schedules for Revision Cycles may change. Please check the NFPA Website for the most up‐to‐date information on Public Input Closing Dates and schedules at www.nfpa.org/document # (i.e. www.nfpa.org/101) and click on the Next Edition tab

4

Attachment B: Public Input

5

Public Input No. 196-NFPA 85-2013 [ Section No. 8.4.3.2.1.8 ]

8.4.3.2.1.8 The fuel piping materials and system design shall be in accordance with ASME B31.1, Power Piping , or ASME B31.3, Process Piping .

Statement of Problem and Substantiation for Public Input

This requirement is redundant with 4.10.1 and does not offer anything unique to chapter 8.

This comment is the result of work by a Task Group created by the HRSG Technical Committee to review chapters 3 & 4 for inconsistencies or non-essential material relative to chapter 8.

Submitter Information Verification

Submitter Full Name: Gordon GaetkeOrganization: The Dow Chemical CompanyAffilliation: NFPA 85 HRSG Technical CommitteeSubmittal Date: Thu Jan 03 11:58:39 EST 2013

Copyright Assignment

I, Gordon Gaetke, hereby irrevocably grant and assign to the National Fire Protection Association (NFPA) all and full rights in copyright in this Public Input (including both the Proposed Change and the Statement ofProblem and Substantiation). I understand and intend that I acquire no rights, including rights as a joint author, in any publication of the NFPA in which this Public Input in this or another similar or derivative form is used. I hereby warrant that I am the author of this Public Input and that I have full power and authority to enter into this copyright assignment.

By checking this box I affirm that I am Gordon Gaetke, and I agree to be legally bound by the above Copyright Assignment and the terms and conditions contained therein. I understand and intend that, by checking this box, I am creating an electronic signature that will, upon my submission of this form, have the same legal force and effect as a handwritten signature

Page 27 of 78National Fire Protection Association Report

2/6/2013http://submittals.nfpa.org/TerraViewWeb/ContentFetcher?commentParams=%28Comment...

6


8.4.3.2.3.5 Relief valve outlets, vents, drains, and telltales shall be provided with piping to allow safe discharge allow for the discharge of liquids or vapors to a location meeting the requirements of 4.9.1 and shall be designed for the expected range of external temperatures and protected against mechanical damage.


The objective of this suggested change is to replace "safe discharge" as it may be unenforceable language.

Related Public Inputs for This Document

Related Input RelationshipPublic Input No. 216-NFPA 85-2013 [Section No. 6.7.3.1.2.2]


Submitter Full Name: Ted JablkowskiOrganization: Fives North American CombustioSubmittal Date: Thu Jan 03 16:31:42 EST 2013


I, Ted Jablkowski, hereby irrevocably grant and assign to the National Fire Protection Association (NFPA) all and full rights in copyright in this Public Input (including both the Proposed Change and the Statement ofProblem and Substantiation). I understand and intend that I acquire no rights, including rights as a joint author, in any publication of the NFPA in which this Public Input in this or another similar or derivative form is used. I hereby warrant that I am the author of this Public Input and that I have full power and authority to enter into this copyright assignment.

By checking this box I affirm that I am Ted Jablkowski, and I agree to be legally bound by the above Copyright Assignment and the terms and conditions contained therein. I understand and intend that, by checking this box, I am creating an electronic signature that will, upon my submission of this form, have the same legal force and effect as a handwritten signature



7

Public Input No. 197-NFPA 85-2013 [ Section No. 8.4.3.4.5 ]

8.4.3.4.5 The ignition transformer shall not be energized before the HRSG enclosure Duct Burner purge is completed, and shall be de-energized at the end of the igniter trial for the ignition period.


HRSG enclosure purge is not a defined term. There are defined terms for “HRSG Enclosure”, “HRSG Purge”, “Duct Burner Purge” and “Combustion Turbine Purge”. The definition for HRSG Purge is a reference to other definitions and not a definition in itself; therefore not a clear requirement for 8.4.3.4.5. Since this requirement is part of 8.4.3 HRSG Fuel-Burning System, Duct Burner Purge seems to be appropriate requirement instead of Combustion Turbine Purge. [Note to editors: change “Aflow” to “A flow” in 3.3.118.3.]









8

Public Input No. 198-NFPA 85-2013 [ Section No. 8.5.4.1 ]

8.5.4.1 Expansion provision shall be made for the movement of the duct betweenthe combustion turbine exhaust duct and the HRSG, and HRSG enclosure and other combustion turbine exhaust systems.


By definition the combustion turbine exhaust duct is part of the HRSG enclosure, so it is unclear of intent of original wording in treating them as separate entities. Because the transition duct from the combustion turbine exhaust to the HRSG is prone to thermal expansion due to the very high thermal temperatures and is an interface location, the original requirement may have been trying to specifically identify this transition duct in the requirement. The recommended wording may better define this piece in addition to referring the user to the entire HRSG enclosure.









9

Public Input No. 200-NFPA 85-2013 [ Sections 8.6.2, 8.6.3, 8.6.4 ]

Sections 8.6.2, 8.6.3, 8.6.48.6.2 All wiring electrical equipment and wiring shall comply with the requirements of NFPA 70, National Electrical Code.8.6.3 All high voltage equipment shall be marked in accordance with the requirements of NFPA 70 , National Electrical Code .8.6.4 *Where an area is identified as a hazardous location as defined by Article 500 of NFPA 70 , National Electrical Code , the equipment design, the types of enclosures, and the wiring methods shall be as specified by that code.


The original paragraphs require following NFPA 70 for wiring compliance, marking high voltage equipment, and design of hazardous locations. There could be other electrical equipment requirements which are not addressed. The recommended wording provides a more encompassing requirement that includes the original intent. It also is consistent with other chapters addressing electrical design (see 5.3.8.1 and 9.4.6.7.1). Lastly, it avoids creating a definition for “high voltage” which is a term used, but not defined, in 8.6.3. NFPA 70 may define “high voltage”, but HRSG TC’s application of high voltage could be different than NFPA 70.

It may be prudent for Fundamentals TC to contain these Electrical requirements in chapter 4 since multiple chapters are showing redundancy. Paragraphs 8.6.2 – 8.6.4 do not appear to contain any unique requirements for HRSGs or other combustion turbine exhaust systems. Paragraphs 8.6.1.1, 8.6.1.2, 8.6.5 and 8.6.6 all seem to be fundamental requirements which could be of value to all TC’s.








10


8.7.3.2.2.2 The pressure at the gas flowmeter shall be monitored at the upstream tap if the gaseous fuel flowmeter is part of the combustion HRSG control system and is not pressure compensated.


“Combustion Control System” is a defined term which contains phrases or concepts not applicable to Chapter 8 such as “furnace fuel”, “air inputs”, “air-fuel ratio”. The phrase “HRSG Control System” is a defined term that seems more applicable here. “Combustion Control System” was used only one time in chapter 8 - at 8.7.3.2.2.2.









11


8.7.4.3 Duct Burner Master Fuel Trip. For an operating duct burner, including the start-up or shutdown sequences, a duct burner master fuel trip shall be initiated by the following conditions:

Low fuel pressure

Combustion turbine exhaust or fresh air (if provided) flow across the duct burner that drops below the minimum required for operation of the duct burner as specified by the burner manufacturer or as proven by trial; it is permitted to infer this flow from the operating status of the combustionturbine, fresh air fan (if provided), and damper(s) (if provided) position(s)Combustion turbine trip except for systems operating as defined in 8.10.2.4

Loss of all burner flame other than during a normal duct burner shutdown sequence

Partial loss of flame determined to create a hazardous accumulation of unburned fuel at any burner element or zone

Loss of duct burner element(s) resulting in incorrect element firing configuration, in accordance with 8.8.5.8.3.2

Light-off failure of first burner in multiple burner operationFailure to prove a safety shutoff valve closed on command to close

Closing of last individual burner safety shutoff valve other than during a normal duct burner shutdown sequence

High fuel pressure

Low water level on high pressure section of HRSG

Loss of energy supply for boiler HRSG control, burner management, or interlock system

Low atomizing media (if provided) supply pressure

Detection of burner management system malfunctionManual trip [See 4.11.6 (8).]

Loss of augmented air supply where the operation of the duct burner requires augmented air

Fresh air (if provided) transfer failure (See 8.10.2.4.)

Logic controller failure [See 4.11.6 (10) and 4.11.6 (11).]




12

Change from “boiler control” to “HRSG control” in 8.7.4.3 (12) as shown. Definition of boiler refers to furnace which is not representative of HRSGs. HRSG is a defined term and more fitting than boiler. Term “boiler” used one time in chapter 8 at 8.7.4.3(12) so eliminating term in this paragraph will eliminate “boiler” from chapter 8.









13

Public Input No. 203-NFPA 85-2013 [ Section No. 8.7.5 ]

8.7.5 Burner management system logic shall be maintained either in nonvolatile storage or in other memory that retains information on the loss of system power.


This paragraph is redundant with 4.11.6 (12).









14

Public Input No. 160-NFPA 85-2013 [ Section No. 8.8.3 ]

8.8.3 Cold Start Preparation. Preparation for starting shall require an inspection by the owner/operator thatincludes the following:

A unit free of foreign material and not in need of repair

A unit inspected for accumulated liquid fuel, and draining and cleaning performed if such accumulation is present

All personnel evacuated from the unit and associated equipment and all access and inspection doors closed

All combustion turbine fuel stop valves (or equivalent) and duct burner and igniter safety shutoff valves proved closed by valve position and all ignition sources de-energized Exception : Where the igniter capacity is 1.5 MWt (5 million Btu/hr) or less, proof of closure of igniter safety shutoff valves by means other than valve position shall be permitted.

Gaseous fuel system vents open and venting to an outside location that does not present a hazard; fuel lines drained of condensate

Circulating valves open to provide and maintain liquid fuel flow in the burner headers

Prescribed drum water levels established in natural and forced circulation HRSGs and prescribed flow established in forced circulationand once-through HRSGs

Burner elements and igniters positioned in accordance with manufacturer's specification

Energy supplied to control systems and to interlocks

Meters or gauges indicating fuel header pressure to the unit

Instrumentation tested and functional

A complete functional check of the interlocks performed after an overhaul or other interlock-related maintenance

Verification of an open flow path through the HRSG system


As written, this paragraph is open to misinterpretation as to who should do the inspection.

Jurisdictional authorities (AHJ) have for many years been inappropriately interpreting NFPA 85 as containing in-service inspection responsibilities for the National Board Commissioned Boiler Inspectors employed by Authorized Inspection Agencies as defined by the National Board document NB-369 Qualifications and Duties for Authorized Inspection Agencies (AIAs) Performing Inservice Inspection Activities and Qualifications for Inspectors of Boilers and Pressure Vessels. This has caused significant legal issues for Authorized Inspection Agencies. The proposed change is intended to make it clear that NFPA 85 does not contain any requirements.for in-service inspections for these agencies.




15

Related Input RelationshipPublic Input No. 132-NFPA 85-2013 [Section No. 3.2.2]


Submitter Full Name: Brian MooreOrganization: Hartford Steam Boiler InspectiSubmittal Date: Wed Jan 02 14:38:33 EST 2013


I, Brian Moore, hereby irrevocably grant and assign to the National Fire Protection Association (NFPA) all and full rights in copyright in this Public Input (including both the Proposed Change and the Statement of Problem and Substantiation). I understand and intend that I acquire no rights, including rights as a joint author, in any publication of the NFPA in which this Public Input in this or another similar or derivative form is used. I hereby warrant that I am the author of this Public Input and that I have full power and authority to enter into this copyright assignment.

By checking this box I affirm that I am Brian Moore, and I agree to be legally bound by the above Copyright Assignment and the terms and conditions contained therein. I understand and intend that, by checking this box, I am creating an electronic signature that will, upon my submission of this form, have the same legal force and effect as a handwritten signature



16


8.8.4.6.1* System 1 Gaseous Fuels. Triple block and double vent valve arrangement in accordance with thefollowing requirements:

Fuel gas block and vent valve positions shall be continuously monitored. If continuous monitoring is lost or any valve deviates from its assigned position, purge credit is lost, and subsequent start of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with 8.8.4.2.Pressures in the two double block and vent pipe sections shall be continuously monitored. If continuous monitoring is lost or eitherpressure indicates leakage, purge credit is lost, and subsequent start of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with 8.8.4.2.

The combustion turbine purge credit period shall not exceed 8 days (192 hours). If a combustion turbine purge in accordance with 8.8.4.2 is performed during the 8-day period, the combustion turbine purge credit is reinitiated for an 8-day period.

If the 8-day period has been exceeded and 1) to 4) requirements are still valid, the combustion turbine can be purged in accordance to 8.8.4.2.1.1 and provided the CEMS (Continuous Emissions Monitoring System) registers 0% LEL UHC at the exhaust stack outlet during the purge, combustion turbine purge credit is reinitiated for an 8-day period.


Operators may not pay attention to the 8-day period count down timer. If the 8-day period has been exceeded this does not necessarily indicate that UHC has bled into the combustion turbine combined cycle exhaust system, as the triple block and double vent would typically provide the isolation needed. If UHC bleed through does occur the CEMS system would indicate as such during the combustion turbine purge process and so the combustion turbine control system would close loop on LEL to determine if above 0%. CEMS systems are standard equipment supplied and installed on all combustion turbine plant exhaust systems. Here are URL links to CEMS systems for reference: http://www.americanecotech.com/Air_Monitoring_Equipment/Air_monitor_gas/CEMS.aspxhttp://www.ge-mcs.com/en/bently-nevada-software/performance/system-1-pems.html?tmpl=component&page=


* Combustion turbine normal shutdown.

* Prior to each start-up and following each normal shutdown, block valves shall be validated for gas leak tightness via a valve-proving system. As a minimum, the most downstream block valve shall be valve proved during the start-up sequence, and the middle block valve shall be valve proved during the shutdown sequence. The most downstream block valve shall be tested only when airflow is passing through the combustion turbine.



17


8.8.4.6.2. 3* System 3 Liquid Fuels with Pressurized Pipe Section. Triple block and double drain valve arrangement filled with an inert gas or air and maintained at a pressure that prevents liquid fuel from entering the combustion turbine or duct burner in accordance with the following requirements:

Air or inert gas shall be introduced to create and maintain a pressurized pipe section between the middle and most downstream block valves.

The liquid fuel block and drain valve positions shall be continuously monitored. If continuous monitoring is lost or any valve deviates from its assigned position, purge credit is lost and subsequent start of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with 8.8.4.2.

Pressures in the two double block and drain pipe sections shall be continuously monitored. If the continuous monitoring is lost or thepressure downstream of the middle block valve decreases to less than 20.7 kPa (3 psid) above the upstream pressure, purge credit is lost and subsequent start-up of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with 8.8.4.2.

The combustion turbine purge credit period is maintained as long as the conditions in 8.8.4.6.3 (2), (3), and (4) are met.

Provisions shall be made to ensure that fuel cannot enter the air or inert gas supply line at any time.

8.8.4.6.3.1 An inert liquid shall be permitted to be used in lieu of inert gas if acceptable to the original equipment manufacturer.

Additional Proposed Changes

File Name Description ApprovedHold_NFPA85BCS-HRS_8.8.4.6.2.3.pdf Held Comment 85-32


NOTE: This public input appeared as Comment 85-32 (Log #CC504) which was held from the F10 ROC on Proposal 85-109.The committee modified the wording to clarify ambiguities in the text.


Submitter Full Name: TC on BCS-HRSOrganization: TC on Heat Recovery Steam GeneratorsSubmittal Date: Thu Jan 03 09:59:05 EST 2013


* Combustion turbine normal shutdown shall be completed .



18

Public Input No. 129-NFPA 85-2012 [ New Section after 8.8.4.6.3.1 ]

8.8.4.6.4* System 4 Liquid Fuels with Liquid Level Sensing.

Triple block and double drain valve arrangement with a pipe section that includes a vertical rise above the liquid supply level and below the lowest combustor / duct burner nozzle in which the liquid level is monitored so as to prevent liquid fuel from entering the combustion turbine or duct burner in accordance with the followingrequirements:(1)*Combustion turbine normal shutdown.(2) A section of piping at an elevation lower than the lowest fuel nozzle for the combustion turbine or duct burner shall exist between the middle and most downstream block valves.(3) The liquid fuel upstream and middle block valves, drain valves and the vent valve positions shall be continuously monitored. If continuous monitoring is lost or any valve deviates from its assigned position, purge credit is lost and subsequent start of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with 8.8.4.2.(4)* The limit liquid fuel level in the piping between the fuel supply and the combustor / duct burner shall be continuously monitored. If the continuous monitoring is lost or the liquid fuel level rises above the limit level, purge credit is lost and subsequent start-up of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with 8.8.4.2.(5) The combustion turbine purge credit period is maintained as long as the conditions in 8.8.4.6.4 (3), and (4) are met.The associated Annex A text is:A.8.8.4.6.4 See Figure A.8.8.4.6.4. The intent of this section is to assure the liquid fuel level in the piping between the fuel supply and the combustor / duct burner nozzles never rises to a height that would allow the fuel to enter the combustionturbine or HRSG.A.8.8.4.6.4(1) The combustion turbine normal shutdown includes sufficient postpurge airflow to satisfy the requirements of the combustion turbine purge.A.8.8.4.6.4(4) The liquid level monitoring required by this paragraph may be accomplished by means of a level switch, level transmitter, pressure sensor or any other device that provides a positive indication of liquid level within the piping between the block valves and the fuel nozzles.



19

Figure A.8.8.4.6.4 System 4 Liquid Fuels with Liquid Level Sensing


The current Purge Credit requirements for liquid fuel systems are specific and do not offer significant flexibility in design. The proposed alternative provides a simplified approach that assures liquid fuel cannot reach with the GT combustion nozzles or (if used) Duct Burner nozzles by virtue of having the stop valves at a lower elevation than the nozzles and monitoring the liquid level between the valves and the nozzles. The level monitoring, which can take any of several approaches, serves the same function as providing a pressure plug - a positive method of assuring fuel cannot flow to the nozzles - allowing an unlimited purge credit period. Additionally, the level monitoring approach is very robust and not dependent on valve tightness to assure the safety of the system.

Additionally; some GT liquid fuel designs include separate fuel valves (V3 in the drawing) for each fuel nozzle. In these designs, the requirement to monitor valve position places a monitoring device (possibly redundant for reliability purposes) for each valve. For a unit with 14 separate nozzles where reliability requirements drive a redundant signal with voting (e.g. 2oo3 logic) the system will end up with 42 separate position signals that must be monitored and any faults resolved. The proposed approach avoids this cost and complexity while assuring fuel cannot enter the GT of HRSG during the Purge Credit period.


Submitter Full Name: Lawrence DannerOrganization: General Electric, EnergySubmittal Date: Thu Dec 27 12:03:42 EST 2012


I, Lawrence Danner, hereby irrevocably grant and assign to the National Fire Protection Association (NFPA) all and full rights in copyright in this Public Input (including both the Proposed Change and the Statement of Problem and Substantiation). I understand and intend that I acquire no rights, including rights as a joint author, in any publication of the NFPA in which this Public Input in this or another similar or derivative form is used. I hereby warrant that I am the author of this Public Input and that I have full power and authority to enter into this copyright assignment.



20

Public Input No. 183-NFPA 85-2013 [ New Section after 8.8.7.2 ]

8.8.7.2 All duct burner fuel supply vent valves shall be opened. Renumber subsequent sections.


File Name Description ApprovedHold_NFPA85BCS-HRS_8.8.7.2_New_.pdf Held Comment 85-35


NOTE: This public input appeared as Comment 85-35 (Log #CC503) which was held from the F10 ROC on Proposal 85-109.The committee recognizes that there is no specific requirement to open the vent valves on

a normal duct burner shutdown. The committee believes that this is good engineering practice.




I, TC on BCS-HRS, hereby irrevocably grant and assign to the National Fire Protection Association (NFPA) all and full rights in copyright in this Public Input (including both the Proposed Change and the Statement ofProblem and Substantiation). I understand and intend that I acquire no rights, including rights as a joint author, in any publication of the NFPA in which this Public Input in this or another similar or derivative form is used. I hereby warrant that I am the author of this Public Input and that I have full power and authority to enter into this copyright assignment.

By checking this box I affirm that I am TC on BCS-HRS, and I agree to be legally bound by the above Copyright Assignment and the terms and conditions contained therein. I understand and intend that, by checking this box, I am creating an electronic signature that will, upon my submission of this form, have the same legal force and effect as a handwritten signature



21


8.10.2.2 Each system's operating mode shall be evaluated to ensure safe operation ensure the design operation during transfer from combustion turbine operation to fresh air firing mode and from fresh air firing mode to combustion turbine mode.


The objective of this suggested change is to replace "safe operation" as it may not be unenforceable language.


Related Input RelationshipPublic Input No. 223-NFPA 85-2013 [Section No. 7.2]


Submitter Full Name: Ted JablkowskiOrganization: Fives North American CombustionSubmittal Date: Thu Jan 03 16:53:08 EST 2013


I, Ted Jablkowski, hereby irrevocably grant and assign to the National Fire Protection Association (NFPA) all and full rights in copyright in this Public Input (including both the Proposed Change and the Statement ofProblem and Substantiation). I understand and intend that I acquire no rights, including rights as a joint author, in any publication of the NFPA in which this Public Input in this or another similar or derivative form is used. I hereby warrant that I am the author of this Public Input and that I have full power and authority to enter into this copyright assignment.




22

Public Input No. 172-NFPA 85-2013 [ Section No. A.8.3.3.1 ]

A.8.3.3.1 The following factors, at minimum, should be considered during the design evaluation:

Single versus multiple steam pressure levels

Allowable combustion turbine exhaust backpressure

Supplementary, auxiliary, or augmented firing

Combustion turbine exhaust bypass system

Corrosiveness and fouling of by-products of combustion (e.g., fin tube versus bare tube, metallurgy, cold-end metal temperature)Single or multiple fuels

SCR or other environmental control systems

Heat transfer surface cleaning (during operation and shutdowns) and inspection by the owner/operator

Freeze protection

Rapid start, operating and transients, and thermal shock

Dry operation

Protective systems

Degree of automation and complexity of control systemsOperator interface

Overall system performance evaluation, feedback, and iteration (expert system database consideration)

Description of start-up validation test program (reference test cases and simulator data library where available)

Combustion turbine (purge exhaust)

Bypass stack and damper

HRSG and interconnecting ducts

Forced draft fan, induced draft fan, or discharge stack, in any combination

Burner management system logic

Flame monitoring and tripping systems

Combustion control system

Power supplies configuration and codes

Piping system configuration and codes

Operating information

Input/output selection

Information displayed

Data transmission (noise accuracy considerations)



23

Logic controller software and hardware considerations

Requirements for operation from a remote location

Initial control tuning


As written, this paragraph is open to misinterpretation as to who should do the inspection.

Jurisdictional authorities (AHJ) have for many years been inappropriately interpreting NFPA 85 as containing in-service inspection responsibilities for the National Board Commissioned Boiler Inspectors employed by Authorized Inspection Agencies as defined by the National Board document NB-369 Qualifications and Duties for Authorized Inspection Agencies (AIAs) Performing Inservice Inspection Activities and Qualifications for Inspectors of Boilers and Pressure Vessels. This has caused significant legal issues for Authorized Inspection Agencies. The proposed change is intended to make it clear that NFPA 85 does not contain any requirements.for in-service inspections for these agencies.


Related Input RelationshipPublic Input No. 132-NFPA 85-2013 [Section No. 3.2.2]


Submitter Full Name: Brian MooreOrganization: Hartford Steam Boiler InspectiSubmittal Date: Wed Jan 02 15:35:41 EST 2013


I, Brian Moore, hereby irrevocably grant and assign to the National Fire Protection Association (NFPA) all and full rights in copyright in this Public Input (including both the Proposed Change and the Statement of Problem and Substantiation). I understand and intend that I acquire no rights, including rights as a joint author, in any publication of the NFPA in which this Public Input in this or another similar or derivative form is used. I hereby warrant that I am the author of this Public Input and that I have full power and authority to enter into this copyright assignment.

By checking this box I affirm that I am Brian Moore, and I agree to be legally bound by the above Copyright Assignment and the terms and conditions contained therein. I understand and intend that, by checking this box, I am creating an electronic signature that will, upon my submission of this form, have the same legal force and effect as a handwritten signature



24

Public Input No. 215-NFPA 85-2013 [ Section No. A.8.4.3.2.2.1 ]

A.8.4.3.2.2.1 Usually this can be accomplished by providing full relieving capacity vented to a safe location. a location meeting the requirements of 4.9.1.


The objective of this suggested change is to replace "safe location" as it is unenforceable language.


Related Input RelationshipPublic Input No. 214-NFPA 85-2013 [Section No. 6.6.3.1.2.2]


Submitter Full Name: Ted JablkowskiOrganization: Fives North American CombustioAffilliation: October 2012 email consensus of several NFPA 85 TC members.Submittal Date: Thu Jan 03 16:17:57 EST 2013


I, Ted Jablkowski, hereby irrevocably grant and assign to the National Fire Protection Association (NFPA) all and full rights in copyright in this Public Input (including both the Proposed Change and the Statement of Problem and Substantiation). I understand and intend that I acquire no rights, including rights as a joint author, in any publication of the NFPA in which this Public Input in this or another similar or derivative form is used. I hereby warrant that I am the author of this Public Input and that I have full power and authority to enter into this copyright assignment.




25

Public Input No. 63-NFPA 85-2012 [ Section No. A.8.4.3.2.2.1 ]

A.8.4.3.2.2.1 Usually this can be accomplished by providing full relieving capacity vented to a safe location. Refer to the information included in Section 4.9.1 as guidance regarding what might constitute a safe location.


The phrase “safe location” may not be specific enough guidance for some individuals who might refer to this Annex material. This change would utilize language already included in NFPA 85 to provide more specifics related to the intent of this phrase. Related public inputs are being submitted against sections 4.9.1, 6.6.2, 6.6.3.1.2.2, 6.6.3.1.12 and A.8.4.3.2.2.1.


Submitter Full Name: Dale EvelyOrganization: Southern Company Services, IncSubmittal Date: Thu Nov 29 07:28:39 EST 2012


I, Dale Evely, hereby irrevocably grant and assign to the National Fire Protection Association (NFPA) all and full rights in copyright in this Public Input (including both the Proposed Change and the Statement of Problem and Substantiation). I understand and intend that I acquire no rights, including rights as a joint author, in any publication of the NFPA in which this Public Input in this or another similar or derivative form is used. I herebywarrant that I am the author of this Public Input and that I have full power and authority to enter into this copyright assignment.

By checking this box I affirm that I am Dale Evely, and I agree to be legally bound by the above Copyright Assignment and the terms and conditions contained therein. I understand and intend that, by checking this box, I am creating an electronic signature that will, upon my submission of this form, have the same legal force and effect as a handwritten signature



26

Public Input No. 199-NFPA 85-2013 [ Section No. A.8.6.4 ]

A.8.6.4 3.3.3 For guidance in determining area classification, see NFPA 497, Recommended Practice for the Classification of Flammable Liquids, Gases, or Vapors and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas; NFPA 499, Recommended Practice for theClassification of Combustible Dusts and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas; NFPA 70, National Electrical Code, Article 500; and either API RP 500, Recommended Practice for Classification of Locations for Electrical Installations at Petroleum Facilities Classified as Class I, Division 1 and Division 2, or API RP 505, Recommended Practice for Classification of Locations for Electrical Installations at Petroleum Facilities Classified as Class I, Zone 0, Zone 1, and Zone 2.


Change the Electrical Area Classification appendix reference from A.8.6.4 to A.8.3.3.3. Paragraph 8.3.3.3 is the only requirement for defining Electrical area classification in chapter 8. The appendix provides references for determining that classification which seems better suited to 8.3.3.3 than 8.6.4. Paragraph 8.6.4 addresses electrical design requirements for hazardous locations.









27

Public Input No. 179-NFPA 85-2013 [ Section No. A.8.8.4.6.2 ]

A.8.8.4.6.2 2.2 See Figure A.8.8.4.6.2. 2 . The intent of this section is to maintain an air or inert gas plug in the fuel piping to prevent fuel from entering the combustion turbine or HRSG, and not to prove valve leak tightness. The Combustion Turbine Purge Credit can be maintained as long as the conditions in 8.8.4.6.2.2 are met.Figure A.8.8.4.6.2 System 2.2 System 2 Gaseous Fuels with Pressurized Pipe Section.


File Name Description ApprovedHold_NFPA85BCS-HRS_8.8.4.6.pdf Held Comment 85-30


NOTE: This public input appeared as Comment 85-30 (Log #CC502) which was held from the F10 ROC on Proposal 85-109.The committee modified and reorganized the paragraphs to prioritize the actions and

clarify some ambiguities in the text.




I, TC on BCS-HRS, hereby irrevocably grant and assign to the National Fire Protection Association (NFPA) all and full rights in copyright in this Public Input (including both the Proposed Change and the Statement ofProblem and Substantiation). I understand and intend that I acquire no rights, including rights as a joint author, in any publication of the NFPA in which this Public Input in this or another similar or derivative form is used. I hereby warrant that I am the author of this Public Input and that I have full power and authority to enter into this copyright assignment.



28

Public Input No. 181-NFPA 85-2013 [ Section No. A.8.8.4.6.3 ]

A.8.8.4.6.2. 3 See Figure A.8.8.4.6.2. 3. The intent of this section is to maintain an air or inert gas plug in the fuel piping to prevent fuel from entering the combustion turbine or HRSG and not to prove valve leak tightness. The Combustion Turbine Purge Credit can be maintained as long as the conditions in 8.8.4.6.2.2 are met.Figure A.8.8.4.6.2. 3 System 3 Liquid Fuels with Pressurized Pipe Section.


File Name Description ApprovedHold_NFPA85BCS-HRS_8.8.4.6.2.3.pdf Held Comment 85-32


NOTE: This public input appeared as Comment 85-32 (Log #CC504) which was held from the F10 ROC on Proposal 85-109.The committee modified the wording to clarify ambiguities in the text.





29

Attachment C: Request from I. Yarinovsky

30

NOTE: New text is shown in RED. 8.9.2.1.4.3 In the event that HRSG isolation is disabled and the combustion turbine can continue to be operated with an exhaust temperature at least 56°C (100°F) lower than the lowest autoignition temperature of the constituents comprising the fuels designed for use in the specific combustion turbine, the combustion turbine exhaust gas at this lower temperature shall be permitted to be used to purge the HRSG. 8.9.2.2.2.2 In the event that the HRSG isolation is disabled and the combustion turbine can continue to be operated with an exhaust temperature at least 56°C (100°F) lower than the lowest autoignition temperature of the constituents comprising the fuels designed for use in the specific combustion turbine and duct burner, the combustion turbine exhaust gas at this lower temperature shall be permitted to be used to purge the HRSG.

31

Attachment D: Pre-FD Meeting Actions

32

First Revision No. 9-NFPA 85-2013 [ Global Input ]

Chapter 8 change - replace "stop valve or equivalent valve" with "safety shutoff valve" everywhere it appears.


Submitter Full Name: Jenny DepewOrganization: NFPASubmittal Date: Fri Jan 11 11:11:29 EST 2013

Committee Statement and Meeting Notes

Committee Statement:

The committee replaced the term "stop valve" with "safety shutoff valve" for consistency with the rest of the document and NFPA 37. The committee removed the reference to "equivalent valves" because, for a duct burner system, only safety shutoff valves are used to stop fuel flow. It is the intent of the committee to enable designers and/or operators to use the individual burner safety shutoff valve, where provided in accordance with 8.4.3.2.1.11, as the most downstream safety shutoff valve when it is not practical to install the third shutoff valve in the main fuel supply line. The previous text wasworded to require the individual burner safety shutoff valves to be used as the "third valve".

ResponseMessage:

FR-9-NFPA 85-2013



33

First Revision No. 11-NFPA 85-2013 [ Section No. 8.4.2.2.1 ]

8.4.2.2.1 The HRSG system's required interlocks shall prevent starting of the combustion turbine unless the HRSG starting conditions are satisfied, which shall include but not be limited to the following:

The water levels in drum(s), if provided, are within the defined start-uprange.

The feedwater supply system is available to respond to demand.

The pressure in steam or water spaces is not high.

The exit temperature of duct burner(s), if provided, is not high.The position of stack closure, if provided, is correct.

The pressure in the HRSG enclosure is not high.

The augmented air supply, if provided, is in operation. (See 8.8.4.2.4 .)

Where a combustion turbine purge credit is being used, all fuel systems connected to the HRSG are satisfactorily isolated.




CommitteeStatement:

The committee deleted subparagraph (7) because the starting sequence requires flow to be established through the combustion turbine prior to starting augmented air systems.

Response Message:

FR-11-NFPA 85-2013



34


8.4.2.2.4 The combustion turbine exhaust system's required interlocks shall preventWhere a HRSG is not provided, an interlock shall prohibit starting the combustion turbine unless the following starting conditions are satisfied: The pressure in the if the combustion turbine exhaust ductwork system pressure is not high.

The tempering air supply, if provided, is in operation.•




CommitteeStatement:

The committee modified paragraph 8.4.2.2.4 because the starting sequence requires flow to be established through the combustion turbine prior to starting tempering air systems.

Response Message:

FR-12-NFPA 85-2013



35

First Revision No. 14-NFPA 85-2013 [ Section No. 8.4.3.2.2.3 ]

8.4.3.2.2.3 Triple Block and Double Vent Valve Arrangement. Three stop safety shutoff valves or equivalent valves in series, with proof of closure, shall be provided in each the fuel line to the duct burner for units with combustion turbine purge credit provisions in accordance with 8.8.4.6. Automatic An automatic vent valves valve shall be provided between each of these valves. The most downstream valve for a duct burner installation shall be located in each burner line (runner) in

8.4.3.2.2.4* Where individual burner safety shutoff valves are installed in accordance with 8.4.3.2.1.11 , the individual burner safety shutoff valve shall be permitted to be the most downstream safety shutoff valve required in 8 . 4.3.2.2.3.




CommitteeStatement:

The committee replaced the term "stop valve" with "safety shutoff valve" for consistency with the rest of the document and NFPA 37. The committee removed the reference to "equivalent valves" because, for a duct burner system, only safety shutoff valves are used to stop fuel flow. It is the intent of the committee to enable designers and/or operators to use the individual burner safety shutoff valve, where provided in accordance with 8.4.3.2.1.11, as the most downstream safety shutoff valve when it is not practical to install the third shutoff valve in the main fuel supply line. The previous text was worded to require the individual burner safety shutoff valves to be used as the "third valve".

ResponseMessage:

FR-14-NFPA 85-2013



36


8.7.4.1.6 Interlock functions shall be initiated by one or more of the following:

A switch or transmitter independent of control functions and signals

Two analog signals with a divergence alarm

Three analog signals employing an auctioneering system and a divergence alarm or other fault diagnostic alarm

, including those functions outside the burner management system, shall meet the functional requirements of 4.11.3.




CommitteeStatement:

The committee deleted the requirement and referenced the chapter 4 material to eliminate redundancy in the code.

ResponseMessage:

FR-17-NFPA 85-2013

Public Input No. 154-NFPA 85-2013 [Section No. 8.7.4.1.6]



37

First Revision No. 20-NFPA 85-2013 [ Section No. 8.8.4.1 ]

8.8.4.1* Combustion Turbine Purge Process. The purge of the combustion turbine shall be in accordance with the manufacturer's instructions and with the requirements of 8.8.4.2 or 8.8.4.6 and 8 .8.4.7, as applicable.

8.8.4.1.1 Where a combustion turbine or HRSG is provided with fuelsystems for multiple fuels, the purge requirements for each type of fuel shallbe met.




CommitteeStatement:

The paragraph is revised to be consistent with changes made in FR37 to separate purge credit requirements for liquid fuel systems.

ResponseMessage:

FR-20-NFPA 85-2013



38


8.8.4.2.4 4*Where augmented air firing or tempering air is provided, a means shall be supplied for interlocking and purging the augmented or tempering air system prior to initiating and shall be purged during the combustion turbine purge in accordance with the combustion turbine and HRSG manufacturers' operatinginstructions .




CommitteeStatement:

The committee recognized that 8.8.4.2.4 did not clearly prevent operators from running the augmenting or tempering air fans while the combustion turbine is not in operation or purge. It is not good practice to have air flowing in the reverse direction into the combustion turbine and this reverse flow can come from the augmenting or tempering air system. Tempering air was added to the section because it was reported to the committee that there are tempering air systems other than those associated with SCRs.

Response Message:

FR-23-NFPA 85-2013



39


8.8.4.6* Combustion Turbine Purge Credit for Gaseous Fuel Systems .

Following a combustion turbine normal shutdown, combustion turbine purge credit shall be allowed permitted to be established for the next start-up event provided that one of the systems described in the following requirements aremet for each combustion turbine and duct burner fuel system.8.8.4.6.1

through*

Combustion turbine and duct burner manufacturer's valve-proving requirements, fuel supply system requirements, and safety control system requirements shall be met.8.8.4.6.

3 is incorporated for each combustion turbine and duct burner fuel system. In addition, a

2 A positive means to prevent leakage of ammonia into the idle HRSG or other combustion turbine exhaust system shall be provided in accordance with 4.10.3 .8.8.4.6.

1 * System 1 Gaseous Fuels. Triple3 A triple block and double vent valve arrangement is installed on the combustion turbine in accordance with 8.4.2.1.2.2 and is installed on the

following requirements:HRSG fuel burning system (if provided) in accordance with 8.4.3.2.2.3

8.8.4.6.4 One of the following shall be used to establish the purge credit.(A)* Valve-proving Method (Note: Renumber A.8.8.4.6.1 here.)

(1) * Combustion turbine normal shutdown and duct burner normal shutdown, where provided, shall be accomplished . (2) Fuel gas block and vent valve positions shall be continuously monitored. If continuous monitoring is lost or any valve deviates from its assigned position, purge credit is lost, and subsequent start of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with 8.8.4.2 . (3) Pressures in the two double block and vent pipe sections shall be continuously monitored. If continuous monitoring is lost or either pressure indicates leakage, purge credit is lost, and subsequent start of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with 8.8.4.2 . (4) * Prior to each start-up and following each normal shutdown, block valves shall be validated for gas leak tightness via a valve-proving system. As a minimum, the most downstream block valve shall be valve proved during the start-up sequence, and the middle block valve shall be valve proved during the shutdown sequence. The most downstream block valve shall be tested only when airflow is passing through the combustion turbine.



40

(5) The combustion turbine purge credit period shall not exceed 8 days (192 hours). If a combustion turbine purge in accordance with 8.8.4.2 isperformed during the 8-day period, the combustion turbine purge credit isreinitiated for an 8-day period.(B)* Pressurized Pipe Section Method. (Renumber A. 8.8.4.6.2

* System 2 Gaseous Fuels with Pressurized Pipe Section. Triple block and double vent valve arrangement filled with an inert gas or air and maintained at a pressure that prevents gaseous fuel from entering the combustion turbine or duct burner in accordance with the following requirements:

here)(1) * Combustion turbine normal shutdown and duct burner normal

shutdown, if provided, shall be accomplished . (2) Air or inert gas shall be introduced to create and maintain a pressurized pipe section between the middle and most downstream blockvalves. (3) Fuel gas block and vent valve positions shall be continuously monitored. If continuous monitoring is lost or any valve deviates from its assigned position, purge credit is lost and subsequent start-up of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with 8.8.4.2 . (4) Pressures in the two double block and vent pipe sections shall be continuously monitored. If the continuous monitoring is lost or the pressure downstream of the middle block valve decreases to less than 20.7 kPa (3 psid) above the upstream pressure, purge credit is lost and subsequent start-up of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with 8.8.4.2 . (5) Combustion turbine purge credit period is shall be considered to be maintained as long as the conditions in 8.8.4.6.2 (2), (3), and (4) are met.


•

8.8.4.6.3 * System 3 Liquid Fuels with Pressurized Pipe Section.

Triple block and double drain valve arrangement filled with an inert gas or air and maintained at a pressure that prevents liquid fuel from entering the combustion turbine or duct burner in accordance with the following requirements:

•


•

The liquid fuel block and drain valve positions shall be continuously monitored. If continuous monitoring is lost or any valve deviates from its assigned position, purge credit is lost and subsequent start of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with 8.8.4.2 .

•

Pressures in the two double block and drain pipe sections shall be continuously monitored. If the continuous monitoring is lost or the pressure downstream of the middle block valve decreases to less than 20.7 kPa

(




41

3 psid) above the upstream pressure, purge credit is lost and subsequent start-up of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with 8.8.4.2 . The combustion turbine purge credit period is maintained as long as the conditions in 8.8.4.

6

.3(2)

, (3), and (4) are met.


8.8.4.6.3.1 An inert liquid shall be permitted to be used in lieu of inert gas if acceptable to the original equipment manufacturer.




CommitteeStatement:

The committee restructured the paragraphs to be consistent with the NFPA Manual of Style. The introductory paragraph referred to systems being installed, but the subsequent subparagraphs described operational sequences. The committee separated the requirements from the sequences and renumbered accordingly. The committee added the requirement for a normal duct burner shutdown to make it clear that all systems must be in a "normal" condition in order for the combustion turbine purge credit to be established. The committee added the requirement for meeting the requirements of OEM of the combustion turbine to ensure that the integrity of the combustion turbine fuel systems and safety controls are maintained. This is particularly important for any retrofit installed to meet the combustion turbine purge credit requirements.

ResponseMessage:

FR-30-NFPA 85-2013

Public Input No. 178-NFPA 85-2013 [Section No. 8.8.4.6]



42


8.8.4.6 7 * Combustion Turbine Purge Credit for Liquid Fuel Systems .

Following a combustion turbine normal shutdown, combustion turbine purge credit shall be allowed permitted to be established for the next start-up event provided that one of the systems described in the following requirements aremet for each combustion turbine and duct burner fuel system. 8.8.4.

6.1 through 7.1 *

Combustion turbine and duct burner manufacturer's fuel supply valve monitoring system requirements and safety control systemrequirements shall be met.

8.8.4.6.3 is incorporated for each combustion turbine and duct burner fuel system. In addition, a

7.2 A positive means to prevent leakage of ammonia into the idle HRSG or other combustion turbine exhaust system shall be provided in accordance with 4.10.3 .8.8.4.

6.1 * System 1 Gaseous Fuels. Triple7.3 A triple block and double

ventdrain valve arrangement is install on the combustion turbine in accordance with 8.4.2.1.1.2 and is installed on the

following requirements:HRSG fuel burning system (if provided) in accordance with 8.4.3.2.2.4.

8.8.4.7.4

One of the following shall be used to establish the purge credit:

(A) Proof-of-Closure Method (1) * Combustion turbine normal shutdown

. Fuel gas block and vent and duct burner normal shutdown, where provided, shall be accomplished.(2) Liquid fuel block and drain valve positions shall be continuously

monitored. If continuous monitoring is lost or any valve deviates from its assigned position, purge credit is lost, and subsequent start of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with 8.8.4.2 . (3) Pressures in the two double block and

vent



43

drain pipe sections shall be continuously monitored. If continuous monitoring is lost or either pressure indicates leakage, purge credit is lost, and subsequent start of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with 8.8.4.2 .

•

The combustion turbine following requirements:

•

(4) The combustion turbine purge credit period shall not exceed 8 days (192 hours). If a combustion turbine purge in accordance with 8.8.4.2 isperformed during the 8-day period, the combustion turbine purge credit isreinitiated for an 8-day period.8.8.4.6.2 * System 2 Gaseous Fuels with Pressurized Pipe Section. Triple block and double vent valve arrangement filled with an inert gas or air and maintained at a pressure that prevents gaseous fuel from entering the combustion turbine or duct burner in accordance with the following requirements:


Fuel gas block and vent valve positions shall be continuously monitored. If continuous monitoring is lost or any valve deviates from its assigned position, purge credit is lost and subsequent start-up ofthe combustion turbine requires a combustion turbine purge prior to light-off, in accordance with 8.8.4.2 .

Pressures in the two double block and vent pipe sections shall be continuously monitored. If the continuous monitoring is lost or the pressure downstream of the middle block valve decreases to less than20.7 kPa (3 psid) above the upstream pressure, purge credit is lost and subsequent start-up of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with 8.8.4.2 .Combustion turbine purge credit period is maintained as long as the conditions in 8.8.4.6.2 (2), (3), and (4) are met.


8.8.4.6.3 * System 3 Liquid Fuels with Pressurized Pipe Section. Triple block and double drain valve arrangement filled with an inert gas or air and maintained at a pressure that prevents liquid fuel from entering the combustion turbine or duct burner in accordance with the

(B)* Pressurized Pipe Section Method (Renumber A.8.8.4.6.3 here) (1)*Combustion turbine normal shutdown and duct burner normal shutdown, where provided, shall be accomplished.

* Prior to each start-up and following each normal shutdown, block valves shall be validated for gas leak tightness via a valve-proving system. As a minimum, the most downstream block valve shall be valve proved during the start-up sequence, and the middle block valve shall be valve proved during the shutdown sequence. The most downstream block valve shall be tested only when airflow is passing through the combustion turbine.





44

(2) Air or inert gas shall be introduced to create and maintain a pressurized pipe section between the middle and most downstream blockvalves. (3) The liquid fuel block and drain valve positions shall be continuously monitored. If continuous monitoring is lost or any valve deviates from its assigned position,

purge credit purge credit is lost and subsequent start of the combustion turbine requires a combustion turbine purge prior to

light-offlightoff , in accordance with 8.8.4.2 . (4) Pressures in the two double block and drain pipe sections shall be continuously monitored. If the continuous monitoring is lost or the pressure downstream of the

middle block middle block valve decreases to less than 20.7 kPa (3 psid) above the upstream pressure, purge credit is lost and subsequent start-up of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with 8.8.4.2 . (5) The combustion turbine purge credit period is maintained as long as the conditions in 8.8.4.

67 .

34 ( B)( 2), (3), and (4) are met. (6) Provisions shall be made to ensure that fuel cannot enter the air or inert gas supply line at any time.8.8.4.6.3.1 7.5 An inert liquid shall be permitted to be used in lieu of inert gas if acceptable to the original equipment manufacturer.






45

CommitteeStatement:

The committee separated the purge credit requirements for liquid fuels from the requirements for gaseous fuels. The introductory paragraphs are repeated for completeness. The committee added the proof-of-closure method to enable operators of liquid-fuel fired units to establish purge credit without the use of an inert gas or air plug. Realizing that the plug provides an infinite time for purge credit, the proof-of-closure method only provides an 8 day limit. With multiple drains in the system between the safety shutoff valves that are gravity-fed to safe areas, and no pressure on the middle or downstream safety shutoff valves, there is minimal opportunity for fuel to leak into the combustionturbine or duct burner. The committee added the requirement for a normalduct burner shutdown to make it clear that all systems must be in a "normal" condition in order for the combustion turbine purge credit to be established. The committee added the requirement for meeting the requirements of OEM of the combustion turbine to ensure that the integrity of the combustion turbine fuel systems and safety controls are maintained. This is particularly important for any retrofit installed to meet the combustion turbine purge credit requirements.

Response Message:

FR-37-NFPA 85-2013

Public Input No. 182-NFPA 85-2013 [Section No. 8.8.4.6]



46

First Revision No. 41-NFPA 85-2013 [ Section No. 8.8.7.3 [Excluding

any Sub-Sections] ]

8.8.7.3 The automated vent or drain valve associated with the main safety shutoff valves shall be opened.8.8.7.4* The duct burners shall be taken out of service in a manner that relieves fuel pressure in the pipe section between the two most downstream safety shutoff valves.8.8.7.5 When the unit (combustion turbine and duct burner) is being taken out of service, the combustion turbine load shall be reduced in accordance with the manufacturer's shutdown procedures.


Submitter Full Name: Kimberly SheaOrganization: National Fire Protection AssocSubmittal Date: Mon Jan 14 10:51:58 EST 2013


Committee Statement:

The committee recognizes that there is no specific requirement to open the vent or drain valves on a normal duct burner shutdown. Pressure should be relieved in the pipe section immediately upstream of the safety shutoff valve(s) closest to the duct burner during a shutdown to prevent the possibility of leakage into the HRSG.

ResponseMessage:

FR-41-NFPA 85-2013



47


8.8.7.4 When establishing a combustion turbine purge credit in accordance with 8.8.4.6.2 4(B) , the following procedure shall be implemented prior to combustion turbine shutdown for duct burners utilizing gaseous fuels (System2 Pressurized Pipe Section Method ):

Open both vent valves of the duct burner fuel supply.

Admit the blocking medium to purge any remaining fuel until the fuel level is less than 25 percent of the LEL.

Close the downstream (header) vent valve.Establish and maintain the required blocking pressure




CommitteeStatement:

The paragraph is revised to be consistent with changes made in FR30.

Response Message: FR-40-NFPA 85-2013



48


8.8.7.5 When establishing a combustio

Date post:	03-Feb-2021
Category:	Documents
Upload:	others
View:	1 times
Download:	0 times