DAQ-2024-011121

DAQE-GN159410009-24

{{$d1 }}

Jeff Monson
Mortenson Construction
1499 N Pony Express Pkwy
Eagle Mountain, Utah 84005

Re: Temporary Boiler Approval for the Stadion LLC, Eagle Mountain Data Center

Dear Mr. Monson,

The Division of Air Quality (DAQ) has received your letter dated October 1, 2024, concerning the
temporary boiler usage at the Eagle Mountain Data Center. The DAQ has determined that the use of the
temporary boilers is allowed under the following conditions:

1. Mortenson Construction can operate up to six, 5 MMBtu/hr, natural gas-fired boilers with a 9ppm
NOx emissions rate (each).
2. The temporary boilers shall only be used for closed-loop testing, closed-loop cleaning, and
commissioning operations.
3. The operator shall maintain daily operating records of each temporary boiler.
4. Using the temporary boilers shall not exceed 16 months.
5. Weekly opacity observations shall be conducted to ensure visible emissions do not exceed 10%
opacity.

Please direct any technical questions regarding this letter to Mr. Tad Anderson, who may be reached at
[phone].

{{$s }}

Jon L. Black, Manager
New Source Review Section

JLB:TA:jg
{{#d1=date1_es_:signer1:date:format(date, "mmmm d, yyyy")}} {{#s=Sig_es_:signer1:signature}}
195 North 1950 West • Salt Lake City, UT
Mailing Address: P.O. Box 144820 • Salt Lake City, UT 84114-4820
Telephone [phone] • Fax [phone] • T.D.D. [phone]
www.deq.utah.gov
Printed on 100% recycled paper
State of Utah

SPENCER J. COX
Governor
DEIDRE HENDERSON
Lieutenant Governor

Department of
Environmental Quality

Kimberly D. Shelley
Executive Director

DIVISION OF AIR QUALITY
Bryce C. Bird
Director

* ) ' & — / F v A ? A C A A w C G ˜
October 7, 2024
October 1, 2024

Mr. Tad D. Anderson
Major New Source Review
Utah Division of Air Quality
195 North 1950 West
Salt Lake City, UT 84116

Subject: Temporary Boiler Approval Request
Mortenson Construction

Dear Mr. Anderson:
Mortenson Construction requests approval from the Department of Air Quality (DAQ) to operate
three temporary boiler skids that will be fueled by natural gas. This operation is necessary while
the hydronic piping systems at Meta’s Eagle Mountain Data Center undergo closed-loop testing
and cleaning (fill/flush) and commissioning operations. Once operational, these hydronic
systems will cool the servers installed in the building and the temporary boilers will no longer be
needed.
On October 24, 2024, we are scheduled to begin the fill/flush for our hydronic piping. During
this process, the boilers will provide freeze protection for the piping. Once we enter the
commissioning phase at the end of November 2024, the boilers will simulate the full production
heat load on the system. This will heat the water to the temperature it will reach when the servers
are in operation, allowing us to thoroughly test the building's cooling system.
Mortenson will be utilizing six 5 MBTU AERCO Benchmark Water Boiler 5000N units (two per
skid). These temporary boilers are natural gas-powered and equipped with low NOx burners to
meet stringent NOx and CO emissions requirements. They feature an oxygen level monitoring
system, AERCO Edge built-in Boiler Sequencing Technology (BST), and can achieve NOx
emissions of 9 ppm or less, with an efficiency range of 87% to 98%. Please reference the
attached product data for additional information regarding these boilers.
Mortenson expects these temporary boilers to be on site for 16 months. During this time, they
will be utilized at four separate locations, with no single location being used for more than 10
months. Records can be maintained as needed based on UDEQ’s recommendation.
If you have any questions, require additional information, or would like to discuss it further,
please contact Jeff Monson of Mortenson Construction at 385-522-4983 or
[e-mail].

Sincerely,

Jeff Monson
Mortenson Construction
Sr. MEP Project Manager

Attachments:
1. Schedule
2. Product Data for AERCO Benchmark Water Boiler 5000N

100 Oritani Drive • Blauvelt, NY 10913 • Phone [phone] • Fax [phone]
BILL OF MATERIALS
Date: 01/25/24
Project: 33391
Company/Purchaser: Taft Engineering Inc.
Location: Albuquerque, NM
Engineer: NA
Quote Number: SQDZ002152_1
Name: Meta KND 1-2
Proposed Equipment:.
Qty (6) Model: BMK5000N-NFGCG-US-E0SS Benchmark 5000N Boiler which will include the following:
439 Stainless steel heat exchanger with Single inlet
Fault Mode Diagnostic Panel with Digital Readout
Gas Train is in accordance with CSD-1
Normally Open Fault Relay
Adjustable Automatic Reset High Limit
Manual Reset High Limit with max 210°F Setpoint
20:1 Modulating Air/Fuel Valve
Electric Probe Low Water Cut-Off
Combination Temperature and Pressure Gauge
Insulated Heat Exchanger
Pressure Relief Valve (shipped loose)
Condensate Trap (shipped loose)
3” External Manual Gas Cock (shipped loose)
- Pressure Vessel/Heat Exchanger: 15 Year Non-Prorated From Shipment
- “EDGE[ii]” Control Panel: 3 Years From Shipment
- Other Components: 2 Years From Shipment
- Please Review the Warranty online for additional information.
* If additional warranties are purchased, the extended warranties will either be in addition to or
supersede the standard warranty.
Accessories per Model:
Qty Part#Description
1 25099-4 4000/5000N BMK OUTDOOR ENCLOSURE
1 58187-8 SPARE PARTS KIT, 125 psi
1 EDGE2 Edge[ii] - (BMK)
Gas Supply: Up to 14”WC
1 A2 HIGH ALTITUDE CALIBRATION is required.
Ducted Combustion: Yes
Instruction Package: INSTRUCTION PACKAGE (O&M)
Control Type: Edge
Fuel Type: Natural Gas
Gas Train: FM
Electrical: 460/3/60
Inlet: Single
Qty (1) Model: BST Controls and Management Systems which will include the following:
Accessories per Model:
Qty Part#Description
1 61058 Onboard BST header temperature Sensor (Dual Bead PT1000) – Direct
Connect
1 BST Onboard Boiler Sequencing Technology
1 EDGE Edge
1 EDGE2 Edge[ii] - (BMK)
Additional Items:
Qty Part#Description
REFERNCE SHEET NO.
SHEET NO.
DWN BY:
SCALE:
DATE:
JOB NO.:
NO
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:
DA
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KEYNOTES
KEY PLAN
NOT FOR CONSTRUCTIONFOR REVIEW ONLY
"These Drawings, and any Specifications or other documents
prepared by Yearout Mechanical, Inc. and its consultants are
instruments of Yearout Mechanical's service and Yearout
Mechanical, Inc. retains all common law, statutory and other
reserved rights, including copyright. Any construction based on
these documents, or the submittal of these documents to any
governmental entity for approval without the consent and
approval of Yearout Mechanical LLC shall be a violation of
Yearout Mechanical, Inc.'s reserved rights herein."
M-401
YMI 2/6/24
NTS
SO
U
T
H
L
A
N
D

B
O
I
L
E
R

S
K
I
D
1
01
/
0
5
/
2
0
2
4
IS
S
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F
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R
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V
I
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W
1/2"=1'-0"
Boiler Skid Details
2
.25x6"x3"
3
Regtangular Tube Steel
6
6x13x2.1571 Channel
4
5
Size#Item
1
1
6"x13x2.157"Channel
2
2
3
3
6x13x2.157 Channel
7'-11 1/2"x16'x.25"Diamond Plate
5
6
6
6
6
6
6
3
4
4
4
4
10"x4"x.5"Steel Plate W/2" Hole (Lifting Eye)
1/2"=1'-0"
Boiler Skid Frame Dimensions
NTS
Boiler Skid Frame Parts ID
1/2"=1'-0"
Boiler Skid Left View
1/2"=1'-0"
Boiler Skid Right View
1/2"=1'-0"
Boiler Skid Left View
NTS
Boiler Skid ISO View
NTS
Boiler Skid ISO View
1/2"=1'-0"
Boiler Skid Frame Left View
Co
n
t
r
o
l

P
a
n
e
l
Electrical Panel
Gas Regulator
2" NG
3"

N
G
Flow Meter
Gas Regulator
2" NG
10" H
W
S
6" HW
S
6" HW
S
HWR
10"

H
W
S
10
"

H
W
R
3" NG
FRAME PARTS LIST
Enclosure Not Shown For Clarity Enclosure Not Shown For ClarityEnclosure Not Shown For Clarity
Boiler Enclosure
Pump
Total Weight - 9950 lbs
3"
N
G
2" NG
2" NG
Technical Data Sheet
Benchmark 750-6000 with Edge Controller
High Efficiency Boilers
The AERCO Benchmark® (BMK) Water Boiler is designed for condensing
application in any closed loop hydronic system. It delivers unmatched
burner modulation to match energy input directly to fluctuating system.
No other product packs as much capacity into such a small footprint that
fits through a standard door and can be transported in a freight elevator.
Energy Efficient
To minimize emissions, the BMK Series is fitted with a low NOx burner
whose emissions will meet the most stringent NOx and CO requirements.
The fully modulating burner also maintains AERCO standards for energy
efficiency, longevity, reliability and construction quality.
The BMK Series comes standard with AERCO’s designed and patented,
Oxygen Level (O2) monitoring system. This monitoring system, designed
to display the O2 level directly on the unit in real time, can also be
remotely monitored via Modbus giving the customer the ability to measure
the emissions level and fuel economy of the boiler without traditional
combustion calibration devices. This system, combined with AERCO’s
TComp™ O2/air temperature compensation (a standard combustion
control feature available with BMK boilers for 15+ years) provides precise
combustion and maintains O2 levels throughout the year for best
combustion efficiency. Application and Plant Design
The BMK boilers can be used as an individual unit or in modular
arrangements and offers selectable modes of operation. In addition to
controlling the boiler according to a constant set point, indoor/outdoor
reset schedule or 4-20mA signal, one or more units can be integrated via
Modbus communications protocol. For boiler plants ranging from 2-16
boilers, the AERCO Edge® built-in Boiler Sequencing Technology (BST)*
can be utilized. The Benchmark can be easily integrated with a
facility-wide Energy Management or Building Automation System.
Features
• Natural gas, propane, or dual fuel
• 20:1 turndown ratio (5%) depending on capacity
• Integrated O2 monitoring and alert for critical conditions
• 439 stainless steel fire tube heat exchanger
• Capable of variable primary flow Installations
• NOx emissions capable of 9PPM or less @ all firing rates
*depending on capacity
• Compact footprint, light weight, freight elevator friendly
• Ducted combustion air capable
• Easy open access for service
• Reliable quiet operation
• Acceptable vent materials AL29-4C,
Polypropylene, PVC, cPVC (model dependent)
• Optional gas train with VPS (Value Proving
System) for BMK Platinum 4000/5000/6000
• Outdoor solution available
Edge [i]
• Precise temperature vontrol
• On-board Boiler Sequencing Technology (BST)
• Controls options: constant setpoint, indoor/
outdoor reset, remote setpoint, 4-20mA
signal or ModBus
*See BST System technical data sheet for
additional system details and capabilities
Manager On On On Off Off Off
Specifications
1. Values are for natural gas FM compliant gas trains only. See Benchmark Gas Components & Supply Design Guide GF-2030 for propane,
DBB & dual fuel gas train minimum gas pressure requirements.
2. See Benchmark Electrical Power Guide GF-2060 for Service Disconnect Switch amperage requirements.
3. BMK5000/6000 operating at standard gas pressure (>14” W.C.) can achieve 9 ppm NOx.
4. BMK5000/6000 low gas pressure option is available as a different style number. It operates between 4” and 10” of gas pressure.
BMK
750 1000 1500 2000 2500 3000 4000 5000N 50004 60004
Boiler Category ASME Sect.IV
Gas Connections (NPT)1’’2’’3”2 / 3’’
Max. Gas Pressure 14’’2psi/10”4
Min. Gas Pressure 1 4’’14 / 4”4
Max. Allowed Working Pressure 160 PSIG 80PSIG/150 PSIG Optional
Electrical Req.
120V/1PH/60Hz 2 13 FLA 16 FLA N/A
Electrical Req.
208V/3PH/60Hz 2 N/A 10 FLA 23 FLA 19 FLA
Electrical Req.
460V/3PH/60Hz 2 N/A 5 FLA 12 FLA 9 FLA
Electrical Req.
575V/3PH/60Hz 2 N/A N/A N/A 7 FLA
Water Connect.
(Flanged)3’’4’’6”6’’
Min. Water Flow (GPM)12 25 35 75
Max. Water Flow (GPM)175 250 350 500 600
Water Volume Gallons 28 26 44 40 60 55 77 110
Water Pressure Drop 3.0 PSIG @100 GPM 3.0 PSIG @170 GPM 3.2 PSIG @ 250 GPM 5.0 PSIG @475 GPM 4.0 PSIG @500 GPM
Turndown Ratio 15:1 (7%)20:1 (5%)20:1 (5%)15:1 (7%)15:1 (7%)15:1 (7%)20:1 (7%)12:1 (8%)15:1 (7%)
Vent/Air Intake Connections 6 Inch 8 Inch 12 Inch Vent/10 Inch Air Intake 14 Inch Optional/ 12 Inch Flue Venting
Vent Materials AL29-4C Polypro, CPVC,
PVC AL29-4C Polypro
Type of Gas Natural Gas, Propane, Dual Fuel
NOx Emissions <9ppm
Capability4 ✓✓<13 ppm ✓✓
Temp. Control Range 50ºF to 190ºF
Ambient Temp. Range 0ºF to 130ºF
Standard Listings & Approvals UL, CUL, CSD-1, ASME
Gas Train Operations FM Compliant or Factory Installed DBB (IRI)
FM Compliant or Factory
Installed DBB (IRI), VPS
(Value Proving System)
FM Compliant, VPS (Val-
ue Proving System)
Sound Rating dbA 65 65 70 70 72 72 75 79
Weight (dry) Ibs.669 700 1406 1500 2,000 2,170 2200 3,000
Shipping Weight Ibs.862 900 1606 1700 2,200 2,300 2350 3,800
Ratings
1Max output dependent upon application – see efficiency curves
Dimensions
750-4000
Dim: Inches
BMK Min Input
MBH
Max Input
MBH
Max Output1
MBH Efficiency Range Thermal Efficiency
80º to 180ºF
750 50 750 653-720 87%-98%95.6%
1000 50 1000 870-960 87%-98%96.8%
1500 75 1500 1305-1440 87%-98%94.6%
2000 100 2000 1740-1920 87%-98%94.6%
2500 167 2500 2175-2400 87%-98%93.5%
3000 200 3000 2610-2880 87%-98%94.6%
4000 267 4000 3480-3840 87%-98%94.1%
5000N 250 4990 4341-4790 87%-98%93.8%
5000 400 5000 4350-4800 87%-98%94.8%
6000 400 6000 5220-5760 87%-98%94.5%
BMK Models (Width) A (Depth)
B (Height) C D E F G H I J K L
750 28’’24.5’’78’’34’’10.2’’9.6’’53’’21’’17.1’’4.5’5.1’’51.5’’
1000 28’’25’’78’’34’’10.2’’9.6’’53’’21’’17.1’’4.5’’5.1’’51.5’’
1500 28’’43.6’’78’’58.4’’6.6’’11.5’’57.8’’18’’42’’8.9’’4.4’’19.1’’
2000 28’’43.6’’78’’58.4’’7’’11.5’’57.8’’18’’42’’8.9’’4.4’’19.1’’
2500 28’’56’’78’’68.4’’5.6’’11.5’’57.8’’18’’42’’6.4’’4.4’’’27.1’’
3000 28’’56’’78’’68.4’’5.6’’11.5’’57.8’’18’’42’’6.4’’4.4’’’27.1’’’
4000 34”63.5”78.2”80.6”6”12.4”56”21.4”44.4”9”5.5”28.7”
5000N 34”63.5”78.2”80.6”6”12.4”56”21.4”44.4”9”5.5”28.7”
© 2022 AERCO
AERCO International, Inc. • 100 Oritani Drive • Blauvelt, NY 10913
USA: T: [phone] • Toll Free: [phone] • AERCO.com
Heating and Hot Water Solutions
Dimensions
5000/6000
Dim: Inches
BMK Models (Width) A (Depth) B (Height) C
5000 35’’89.3’’79.8’’
6000 35’’89.3’’79.8’’

Heating and Hot Water Solutions
AERCO International, Inc. • 100 Oritani Drive • Blauvelt, NY 10913
USA: T: [phone] • Toll Free: [phone] • AERCO.com
Technical Support • [phone] • Mon-Fri, 8 am - 5 pm EST
© 2023 AERCO
Other documents for this product include:
OMM-0127 BMK750K-3000K Installation-Startup KOREA
OMM-0128 BMK750K-3000K Operation- Maintenance KOREA
OMM-0136 BMK750-6000 Edge [II] Installation-Startup
OMM-0137 BMK750-6000 Edge [II] Operation-Service
OMM-0138 BMK750-6000 Edge [II] Reference Manual
OMM-0144 BMK750-6000-Edge [I] Installation-Startup
OMM-0145 BMK750-6000-Edge [I] Operation-Service
OMM-0146 BMK750-6000-Edge [I] Reference Manual

TAG-0019 Benchmark Boiler Application Design Guide
TAG-0022 Benchmark Vent & Combustion Air Design Guide
TAG-0048 Benchmark Electrical Power Design Guide

TAG-0047_S • 11/14/2020

Disclaimer
The information contained in this manual is subject to change without notice
from AERCO International, Inc. AERCO makes no warranty of any kind with
respect to this material, including, but not limited to, implied warranties of
merchantability and fitness for a particular application. AERCO International is
not liable for errors appearing in this manual, not for incidental or
consequential damages occurring in connection with the furnishing,
performance, or use of these materials.

Gas Supply Design Guide
Benchmark® Boilers
Models 750 through 6000

BMK Series Boilers Pre-Installation Gas Supply Guide

TAG-0047_S • 11/14/2020 Technical Support • [phone] • Mon-Fri, 8 am - 5 pm EST Page 2 of 17

1. SAFETY PRECAUTIONS
AERCO Benchmark Low NOx gas fired boilers are modulating input devices that require an adequate
volume of natural gas at constant pressure for proper operation. The gas requirements specified in
this document must be satisfied to ensure efficient combustion. Designers and installers must adhere
to the AERCO specifications and those of the local authorities having jurisdiction. A thorough
understanding and knowledge of these guidelines is required for the successful design and
installation of Benchmark Low NOx series boilers.

1.1 Gas Train Components
AERCO Benchmark gas-fired boilers are equipped with standard UL approved/FM compliant gas
trains. These gas trains are factory tested and fired, with a minimum number of modular components.
The gas train components have been designed to operate at high combustion efficiencies by closely
controlling both the volume and air/fuel mixture to the burner. The major internal gas train
components are:
 SAFETY SHUT OFF VALVE (SSOV) With BUILT-IN SUPPLY GAS REGULATOR - An electro-
hydraulic gas valve, containing a proof of closure switch, is utilized to stop fuel from flowing into the
gas train of the boiler. This is a 100% tight shutoff device with a visible window indicator showing
valve position. Reliable, and a standard industry component, this valve is factory piped with a low
gas pressure switch on the inlet side of the valve which monitors the manifold pressure for minimum
supply conditions. There is also a high gas pressure switch installed on the outlet side of the gas
valve, which shuts down the boiler if gas manifold pressures exceed maximum conditions.
For minimum and maximum gas pressures, see Table 1, below.
 AIR/FUEL VALVE - The air/fuel valve controls the volume and mixture of air and fuel in perfect
proportion throughout the entire modulation range of the boiler. The valve utilizes one common shaft
to simultaneously vary the gas port area and air volume. The gas portion of the valve is a slide port
type valve with linear proportion-to-position characteristics. The air side uses a butterfly type valve
for adjusting the air volume. The driver of the valve shaft is a precision stepping motor which
provides continuous positioning from full input to minimum fire. The air/fuel valve also contains two
proof-of-position switches.
 CAST ALUMINUM BLOWER ASSEMBLY - A cast aluminum pre-mix blower ensures the precise
mixing of air and fuel prior to entering the burner thereby providing controlled combustion.
 LOW NOx BURNER – The burner provides the actual point of air/fuel contact and combustion into
the cylindrical combustion/heat exchanger. Fabricated from metal fiber mesh covering a stainless-
steel body, the burner is stable throughout the entire input range of the boiler. The spark igniter and
flame detector for the combustion supervision system are part of this assembly. The burner is easily
removable from the boiler.
 VALVE PROVING SYSTEM (VPS) – An external device designed to replace the Double Block
and Bleed (DBB) option. VPS is optional and available only on Benchmark 4000, 5000N, 5000 and
6000 standard and with Edge Controller. VPS tests the valves in the gas train by pumping fuel into
the space between the two valves for a set period of time and measures the resulting pressure
increase. If the pressure does not increase by at least 7.0 W.C. in the time allotted, perhaps because
either value is leaking, VPS prevents the boiler from firing. This system has the advantage over a
DBB systems in that if a valve is leaking, it does not need to vent any gas to the atmosphere, thus
eliminating the need for a bleed line.

BMK Series Boilers Pre-Installation Gas Supply Guide

TAG-0047_S • 11/14/2020 Technical Support • [phone] • Mon-Fri, 8 am - 5 pm EST Page 3 of 17

2. GAS PRESSURE REQUIREMENTS
AERCO Benchmark Low NOx series boilers require a stable natural gas and propane input pressure.
A low supply gas pressure switch in each gas train prevents the boiler from operating without
sufficient pressure. The allowable gas inlet pressure range when firing at maximum input for standard
gas trains, such as FM is shown in Table 1. For custom gas trains, such as DBB and dual fuel,
see Section 3: Custom gas Trains.
TABLE 1: Allowable Gas Inlet Pressure for Standard Gas Trains
Model NATURAL GAS PROPANE
Minimum Maximum Minimum Maximum
BMK750 4.0” W.C. (1.00
kPa)
14.0” W.C. (3.49
kPa)
7.0” W.C.
(1.74 kPa)
14.0” W.C.
(3.49 kPa)
BMK1000 4.0” W.C. (1.00
kPa)
14.0” W.C. (3.49
kPa)
11.0” W.C.
(2.74 kPa)
16.0” W.C.
(3.99 kPa)
BMK1500/2000 4.0” W.C. (1.00
kPa)
14.0” W.C. (3.49
kPa)
4.0” W.C.
(1.00 kPa)
14.0” W.C.
(3.49 kPa)
BMK2500/3000 4.0” W.C. (1.00
kPa)
14.0” W.C. (3.49
kPa)
4.0” W.C.
(1.00 kPa)
14.0” W.C.
(3.49 kPa)
BMK4000/5000N 4.0” W.C. (1.00
kPa)
14.0” W.C. (3.49
kPa)
6.0” W.C.
(1.49 kPa)
14.0” W.C. (3.49
kPa)
BMK5000/6000
(regular pressure models)
14.0” W.C. *
(3.49 kPa)
2.0 psig
(13.8 kPa)
10.5” W.C. (2.62
kPa)
2.0 psig
(13.8 kPa)
BMK5000/6000 LGP **
(Low Gas Pressure model)
4.0” W.C. (1.00
kPa)
10.0” W.C. (2.49
kPa)
NOTES:
* The regular pressure BMK5000 and 6000 may operate with inlet pressures less than 14 inches
W.C. (13.8 kPa) but will derate by approximately 265,000 BTU/hr. (77.7 kw) per inch (25.4 mm)
under 14-inch W.C. (13.8 kPa). The absolute minimum gas pressure while in operation is 11
inches W.C. (0.3974 psig).
** For BMK5000 & 6000 applications, if site natural gas pressure (measured when the unit is in
operation/firing) is greater than 10" and less than 14", use the LGP models and use a gas
pressure regulator to bring down the supply pressure to 10" or less.
Gas pressure must be measured when the unit is in operation (firing). Measure the gas pressure
with a manometer at the NPT ball valve provided at the SSOV inlet. In a multiple boiler installation,
gas pressure must initially be set for single boiler operation, and then the remaining boilers must be
staged on at full fire, to insure gas pressures never falls below the supply gas pressure when the
single unit was firing.
All Benchmark models have a low supply gas pressure switch in the gas train to prevent operation if
incoming gas pressure is insufficient.

BMK Series Boilers Pre-Installation Gas Supply Guide

TAG-0047_S • 11/14/2020 Technical Support • [phone] • Mon-Fri, 8 am - 5 pm EST Page 4 of 17

2.1 Manual Shutoff Valves
An external manual shutoff valve must be installed at each Benchmark boiler, as shown in Figure 1a
– 1d, below. This valve is supplied with the boiler.

2.2 Pressure Regulators
The lock-up type pressure regulator(s) must be sized as follows:
TABLE 2: Lock-Up Regulator Sizing
Boiler Size (MBH) Required Volume
CFH (m3/HR)
750 750 – 850 (21.2 – 24.1)
1000 1000 – 1200 (28.3 – 34.0)
1500 1500 – 1750 (42.5 – 49.6)
2000 2000 – 2300 (56.6 – 65.1)
2500 2500 – 2850 (70.8 – 80.7)
3000 3000 – 3400 (85.0 – 96.3)
4000 4000 – 4500 (113.3 – 127.5)
5000, 5000N 5000 – 5450 (141.6 – 154.3)
6000 6000 – 6500 (169.9 – 184.1)
An external lock-up type regulator MUST be installed downstream of the isolation valve at all
installations where gas supply pressure will exceed 14.0” W.C. (3.49 kPa).
External gas regulators are self-contained with tapped diaphragm vent ports allowing the diaphragm
to change its position as required. These vents typically require piping to the outside. For details,
see Section 8: Venting of Gas Supply Regulators, below. The SSOV/Regulator in the gas train is
factory piped and does not require any vent piping.
CAUTION!
AERCO BOILERS MUST BE ISOLATED FROM THE SYSTEM WHEN LEAK TESTING.
Drip legs are typically required at the gas supply of each boiler to prevent any dirt, weld slag, or debris
from entering the boiler gas train inlet pipe. When multiple boilers are installed, some utilities and
local codes require a full-size drip leg on the main gas supply line in addition to the drip leg at each
unit. The bottom of the gas drip leg(s) should be removable without disassembling any gas piping.
The weight of the gas pipe must not be supported from the bottom of the drip leg. The drip leg(s)
must not be used to support any or part of the gas piping.
On all Benchmark models it is strongly recommended that the pressure regulator be installed a
minimum distance of 10 pipe diameters between the pressure regulator and the nearest
downstream fittings (an elbow or the unit itself), and a minimum of 5 pipe diameters between the
pressure regulator and any upstream fitting, such as elbow or shutoff valve, as shown in Figure 1a,
below. This recommendation applies to all gas trains on all Benchmark models.
NOTE: It is the responsibility of the customer to source and purchase the appropriate gas
regulator as described above. However, AERCO offers for sale an appropriate regulator, which
may be ordered at the time of unit purchase or separately. Contact your AERCO sales
representative for more information.
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Figure 1a: BMK750/1000 Gas Regulator and Manual Shut-Off Valve

Figure 1b: BMK750/1000 Gas Regulator and Manual Shut-Off Valve – Dual Fuel
1” MANUAL
SHUTOFF VALVE
GAS PRESSURE
REGULATOR

DIRT LEG
GAS INLET
Minimum
length
conforms to
Figure 1a

Minimum
5 pipe
diameters
in length

PRESSURE
REGULATORS

MANUAL SHUTOFF VALVES
DIRT LEG
NATURAL GAS
INLET
DIRT LEG
PROPANE INLET
Minimum
10 pipe
diameters
in length
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Figure 1c: BMK1500-5000N Gas Regulator and Manual Shut-Off Valve

Figure 1d: BMK1500-5000N Gas Regulator and Manual Shut-Off Valve – Dual Fuel

GAS INLET
GAS PRESSURE REGULATOR
MANUAL SHUT-
OFF VALVE
NATURAL GAS
INLET
NATURAL GAS INLET
NATURAL GAS PRESSURE REGULATOR
PROPANE MANUAL SHUT-
OFF VALVE
NATURAL GAS
INLET
PROPANE
INLET
PROPANE PRESSURE
REGULATOR

NATURAL GAS MANUAL
SHUT-OFF VALVE
PROPANE INLET
Minimum length
conforms to
Figure 1a

Minimum length
conforms to Figure 1a

Minimum length
conforms to Figure 1a

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Figure 1e: BMK5000/6000 Manual Gas Shut-Off Valve Location – Dual Fuel

2.3 Massachusetts Installations Only
For Massachusetts installations, a mandatory external gas supply regulator must be positioned as
shown in Figure 1a – 1e. The gas supply regulator must be properly vented to outdoors. Consult the
local gas utility for detailed requirements concerning venting of the supply gas regulator.

2.4 Multiple Unit Installations
The following points apply to sites that have multiple Benchmark units installed:
Benchmark 750 to 5000N units:
• If inlet pressures are above 7” W.C. (1.74 kPa) a gas pressure regulator may be highly recommended,
based on site conditions. Consult your local AERCO representative or the factory.
• If inlet pressures are above 14” W.C. (3.49 kPa) a gas pressure regulator is mandatory.

Benchmark 5000 & 6000 units:
• If inlet pressures are above 1 psi (6.89 kPa), a gas pressure regulator may be highly
recommended, based on site conditions. Consult your local AERCO representative or the
factory.
• If inlet pressures are above 2 psi (13.79 kPa), a gas pressure regulator is mandatory.
• For BMK5000 & 6000 applications, if site natural gas pressure (measured when the unit is in
operation/firing) is greater than 10" and less than 14", use the LGP models and use a gas
pressure regulator to bring down the supply pressure to 10" or less.
NATURAL GAS INLET
2” MANUAL GAS SHUT-OFF VALVE
NATURAL GAS PRESSURE REGULATOR
PROPANE INLET
1-1/2” MANUAL GAS
SHUT-OFF VALVE
PROPANE PRESSURE
REGULATOR
DRIP LEG
Minimum length
conforms to Figure 1a

Minimum length
conforms to Figure 1a

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Figure 2: Multiple Boiler Gas Pipe Connections Guidelines (BMK2500 Shown)

The following are AERCO’s recommendations for installation of gas pressure regulator, unless
superseded by state and local codes and the regulator manufacturer’s specifications:
• Horizontal installation of gas pressure regulators is recommended unless stated otherwise by
the regulator manufacturer. Consult the manufacturer for additional recommendations and
installation options.
• For Benchmark 750 & 1000 units, when installed horizontally the required distance between
the gas pressure regulator and the nearest pipe fitting, elbow or valve is 20 inches (51 cm).
• For Benchmark 1500 through 6000 units, when installed horizontally, the required distance
between the gas pressure regulator and the nearest pipe fitting, elbow or valve is 5 to 10
pipe diameters, as shown in Figure 2, above.
• When pipe size reduction is required, use only bell reducers.
MANUAL SHUT-OFF
VALVE
GAS PRESSURE
REGULATOR

GAS
SUPPLY
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3. CUSTOM GAS TRAINS
Some utilities, insurance carriers, and industrial customers have special requirement gas
components on high input devices that are beyond what is normally supplied with AERCO boilers.
Secondary shutoffs, high- or low-pressure operators, and external regulators are typical of the
requirements of gas utilities. It is mandatory that a designer or installer comply with these
requirements. AERCO assumes no liability when these requirements are not satisfied for any
location or installation. Contact your local gas utility for their specific requirements before installing
AERCO equipment. Special gas trains with a Double Block and Bleed (DBB) configuration
(formerly IRI) and the Valve Proving System (VPS) are available from AERCO.
Table 3 lists the minimum gas inlet pressure requirements for custom Natural Gas (N.G.) and
Propane (LPG) gas trains:
TABLE 3: Minimum Gas Inlet Pressure Requirements for Custom Gas Trains
Model Fuel DBB Dual Fuel Dual Fuel-DBB VPS
BMK750 N.G. 4.5” W.C. (1.12 kPa) 7.0” W.C. N/A N/A
LPG N/A 7.0” W.C. N/A N/A
BMK1000 N.G. 4.5” W.C. (1.12 kPa) 7.0” W.C. N/A N/A
LPG N/A 7.0” W.C. N/A N/A
BMK1500 N.G. 4.5” W.C. (1.12 kPa) 6.0” W.C. (1.49 kPa) N/A
LPG N/A 4.0” W.C. (1.0 kPa) N/A
BMK2000 N.G. 4.5” W.C. (1.12 kPa) 8.5” W.C. (2.12 kPa) N/A
LPG N/A 4.0” W.C. (1.0 kPa) N/A
BMK2500 N.G. 4.5” W.C. (1.12 kPa) 8.5” W.C. (2.12 kPa) N/A
LPG N/A 4.0” W.C. (1.0 kPa) N/A
BMK3000 N.G. 4.5” W.C. (1.12 kPa) 8.0” W.C. (1.99 kPa) N/A
LPG N/A 4.0” W.C. (1.0 kPa) N/A
BMK4000/5000N N.G. 4.0” W.C. (1.0 kPa) 6.0” W.C. (1.49 kPa) 4” W.C. (1.00 kPa)
LPG N/A 6.0” W.C. (1.49 kPa) N/A
BMK5000/6000
N.G. N/A 14” W.C. (3.49 kPa) N/A 14” W.C. (3.49 kPa)
LPG N/A 10.5” W.C. (2.62
kPa) N/A 10.5” W.C. (2.62 kPa)
BMK5000/6000
Low Gas Pressure
N.G. 4” W.C. (1.00 kPa) N/A 4” W.C. (1.00 kPa)
LPG N/A

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4. GAS PIPING
All gas piping and components must comply with NFPA local codes, and utility requirements
minimum. Only gas approved fittings, valves, or pipe should be utilized.
Standard industry practice for gas piping is Schedule 40 iron pipe and fittings. All high and low gas
pressure piping systems must comply with local utility and building codes.
Assembled piping must be clean of all debris, pipe chips and foreign material to prevent any from
entering the boiler’s gas train. Piping must be tested as prescribed in NFPA 54. Equipment must be
isolated before testing any piping system over the allowable pressure. DO NOT EXCEED 14.0” W.C.
(3.49 kPa) on the inlet side of the Benchmark boiler at any time for BMK750 through BMK3000
Models. For BMK5000 & 6000 boilers, DO NOT EXCEED 2.0 P.S.I. (13.795 kPa) on the inlet side
of the boiler at any time.
The diameter of the gas inlet pipes is as follows:
Inlet Pipe Diameter
BMKModel Single Fuel Dual Fuel
Natural Gas Propane Natural Gas Propane
750-1000 1 Inch 1 Inch 1 Inch 3/4 Inch
1500-2000 2 Inch 1 Inch 2 Inch 1 Inch
2500-3000 2 Inch 2 Inch 2 Inch 2 Inch
4000-5000N 3 Inch 1.5 Inch 3 Inch 1.5 Inch
5000-6000 2 Inch 1.5 Inch 2 Inch 1.5 Inch
5000-6000 Low Gas Pressure 3 Inch N/A N/A N/A

5. GAS SUPPLY MAIN SIZING
Gas pipe sizing, for either a single or multiple boiler installation, must be sized for a maximum
pressure drop of 0.3” W.C. (75 Pa) from the source to the final boiler. The maximum gas flow
rate required is the sum of the maximum inputs of each unit divided by the heat of combustion of the
fuel supplied at the location, (approximately 1,030 BTU per cubic foot [38.35 megajoule/cubic meter]
for natural gas or 2,520 BTU per cubic foot [93.83 megajoule/cubic meter] for propane gas). The fuel
supplier or utility should be consulted to confirm that sufficient volume and normal pressure is
provided to the building at the discharge side of the gas meter or supply pipe. For existing
installations with gas equipment, gas pressure must be measured with a manometer to be certain
sufficient pressure is available. Before sizing gas piping, a survey of all connected gas devices must
be made. Gas piping supplying more than one gas device must be able to handle the total connected
input within the allowable gas pressure drop. The allowable minimum and maximum gas pressure for
each device must be considered. Whenever the minimum and maximum gas pressures vary
between devices, gas pressure regulators at each unit must be installed to allow regulation at any
individual unit. Gas pressure must never exceed the maximum allowable rating of any connected
device.
The total length of gas piping as well as fitting pressure drop must be considered when sizing the gas
piping. Total equivalent length must be calculated from the meter or source location to the last boiler
connected on the header. The values in the Gas Piping Tables 4, 5 and 6 (in Section 7: Gas Piping
Tables, below), which contain data extracted from NFPA 54, must be used as a minimum guideline.
Gas pipe size must be selected on the total equivalent length from the appropriate pressure table.
The gas volume for CFH (m3/hr.) flow will be the input divided by the calorific value of the fuel to be
supplied.
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6. GAS HEADER SIZING
Main supply gas pipe sizing must be developed for the total plant. Boiler gas manifold piping must
be sized based on the volume requirements and lengths between boilers and the fuel main. Header
sizes can be either full size or stepped in size as units are connected. A typical gas piping header
diagram for a 4-module Benchmark Boiler Plant is illustrated in Figure 3.

Figure 3: Typical Multiple Boiler Manifold Construction
* Based on Table 4 on the following pages for natural gas, 0.6 specific gravity, 1,000 CFH (28
m3/hr.) / unit, actual header sizes will vary with length of pipe run and fittings employed. For
propane gas (1.6 specific gravity, 2,520 BTU/FT3) header sizing, consult NFPA 54.
If supply gas pressure exceeds 14.0” W.C. (3.49 kPa), a single lock-up regulator in the header, or
individual lock-up regulators in each unit must be used to bring the gas pressure down to 14.0” W.C.
(3.49 kPa). The header should be located above or behind boiler. Gas piping should not be installed
directly over top or front of any part of boiler. Sufficient clearances for maintenance are required.

DIRT
TRAP
(TYP.)
MANUAL SHUTOFF
VALVE (TYP.) GAS SUPPLY GAS PRESSURE
REGULATOR
(TYP.)*
*NOTE
A supply gas regulator is
required on each boiler gas
inlet only for Massachusetts
installations.
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7. GAS PIPING TABLES
The data in the following pipe and vent sizing tables have been extracted from the National Fire
Protection Association Article 54 (NFPA 54).

TABLE 4: Maximum Capacity of Pipe for 0.5 PSI or Less (Imperial Units)
In Cubic Feet of Gas per Hour
For a Pressure Drop of 0.3-inch Water Column
Nominal Iron
Pipe Size
in Inches
Internal
Diameter
in Inches
Total Equivalent Length of Pipe (Feet)
10 20 30 40 50 60 70 80 90 125 150 175 200
2.00 2.067 3,050 2,100 1,650 1,450 1,270 1,150 1,050 990 930 780 710 650 610
2.50 2.469 4,800 3,300 2,700 2,300 2,000 1,850 1,700 1,600 1,500 1,250 1,130 1,050 980
3.00 3.068 8,500 5,900 4,700 4,100 3,600 3,250 3,000 2,800 2,600 2,200 2,000 1,850 1,700
4.00 4.026 17,500 12,000 9,700 8,300 7,400 6,800 6,200 5,800 5,400 4,500 4,100 3,800 3,500

TABLE 4: Maximum Capacity of Pipe for 3.45 kPa or Less (Metric Units)
In Cubic Meters of Gas per Hour (m3/hr.)
For a Pressure Drop of 75 Pa
Nominal
Iron Pipe
Size in mm
Internal
Diam.
in mm
Total Equivalent Length of Pipe (Meters)
3.05 6.1 9.14 12.19 15.24 18.28 21.33 24.38 27.43 38.1 45.72 53.34 60.96
50.80 52.50 86.37 59.47 46.72 41.06 35.96 32.56 29.73 28.03 26.33 22.09 20.10 18.41 17.27
63.50 62.71 135.92 93.45 76.46 65.13 56.63 52.39 48.14 45.31 42.48 35.40 32.00 29.73 27.75
76.20 77.93 240.69 167.07 133.09 116.10 101.94 92.03 84.95 79.29 73.62 62.30 56.63 52.39 48.14
101.60 102.26 495.54 339.80 274.67 235.03 209.54 192.55 175.56 164.24 152.91 127.43 116.10 107.60 99.11

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TABLE 5: Pipe Sizing Table for 1 Pound Pressure (Imperial Units)
Capacity of Pipes of Different Diameters and Lengths
In Cubic Feet per Hour with a 10% Pressure Drop and a Gas of 0.6 Specific Gravity
Pipe Size of
Schedule 40
Standard Pipe
in Inches
Internal
Diameter
in Inches
Total Equivalent Length of Pipe (Feet)
50 100 150 200 250 300 400 500
2.00 2.067 4245 2918 2343 2005 1777 1610 1378 1222
2.50 2.469 6766 4651 3735 3196 2833 2567 2197 1947
3.00 3.068 11962 8221 6602 5650 5008 4538 3884 3442
3.50 3.548 17514 12037 9666 8273 7332 6644 5686 5039
4.00 4.026 24398 16769 13466 11525 10214 9255 7921 7020
5.00 5.047 44140 30337 24362 20851 18479 16744 14330 12701
6.00 6.065 71473 49123 39447 33762 29923 27112 23204 20566
8.00 7.981 146849 100929 81049 69368 61479 55705 47676 42254
TABLE 5: Pipe Sizing Table for for 6.89 kPa Pressure: (Metric Units)
Capacity of Pipes of Different Diameters and Lengths
In Cubic Meters per Hour with a 10% Pressure Drop and a Gas of 0.6 Specific Gravity
Pipe Size of
Schedule 40
Standard
Pipe in mm
Internal
Diam.
in mm
Total Equivalent Length of Pipe (Meters)
15.24 30.48 45.72 60.96 76.2 91.44 121.92 152.4
50.80 52.50 120.21 82.63 66.35 56.78 50.32 45.59 39.02 34.60
63.50 62.71 191.59 131.70 105.76 90.50 80.22 72.69 62.21 55.13
76.20 77.93 338.73 232.79 186.95 159.99 141.81 128.50 109.98 97.47
88.90 90.12 495.94 340.85 273.71 234.27 207.62 188.14 161.01 142.69
101.60 102.26 690.88 474.85 381.32 326.35 289.23 262.07 224.30 198.79
127.00 128.19 1249.91 859.05 689.86 590.44 523.27 474.14 405.78 359.65
152.40 154.05 2023.90 1391.02 1117.02 956.04 847.33 767.73 657.07 582.37
203.20 202.72 4158.32 2858.01 2295.06 1964.29 1740.90 1577.40 1350.04 1196.51
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TABLE 6: Pipe Sizing Table for an Initial Pressure of 2.0 PSI (Imperial Units)
Capacity of Pipes of Different Diameters and Lengths
In Cubic Feet per Hour with a 10% Pressure Drop and a Gas of 0.6 Specific Gravity
Pipe Size of
Schedule 40
Standard Pipe
in Inches
Internal
Diameter
in Inches
Total Equivalent Length of Pipe (Feet)
50 100 150 200 250 300 400 500
2.00 2.067 6589 4528 3636 3112 2758 2499 2139 1896
2.50 2.469 10501 7217 5796 4961 4396 3983 3409 3022
3.00 3.068 18564 12759 10246 8769 7772 7042 6027 5342
3.50 3.548 27181 18681 15002 12840 11379 10311 8825 7821
4.00 4.026 37865 26025 20899 17887 15853 14364 12293 10895
5.00 5.047 68504 47082 37809 32359 28680 25986 22240 19711
6.00 6.065 110924 76237 61221 52397 46439 42077 36012 31917

TABLE 6: Pipe Sizing Table for an Initial Pressure of 13.79 kPa: (Metric Units)
Capacity of Pipes of Different Diameters and Lengths
In Cubic Feet per Hour with a 10% Pressure Drop and a Gas of 0.6 Specific Gravity
Pipe Size of
Schedule 40
Standard Pipe
in mm
Internal
Diameter
in mm
Total Equivalent Length of Pipe (Meters)
15.24 30.48 45.72 60.96 76.2 91.44 121.92 152.4
50.80 52.50 186.58 128.22 102.96 88.12 78.10 70.76 60.57 53.69
63.50 62.71 297.36 204.36 164.13 140.48 124.48 112.79 96.53 85.57
76.20 77.93 525.68 361.30 290.14 248.31 220.08 199.41 170.67 151.27
88.90 90.12 769.68 528.99 424.81 363.59 322.22 291.98 249.90 221.47
101.60 102.26 1072.22 736.95 591.80 506.51 448.91 406.75 348.10 308.51
127.00 128.19 1939.83 1333.22 1070.64 916.31 812.13 735.85 629.77 558.16
152.40 154.05 3141.03 2158.80 1733.60 1483.73 1315.01 1191.49 1019.75 903.79

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TABLE 7: Pipe Sizing Table for an Initial Pressure of 5.0 PSI (Imperial Units)
Capacity of Pipes of Different Diameters and Lengths
In Cubic Feet per Hour with a 10% Pressure Drop and a Gas of 0.6 Specific Gravity
Pipe Size of
Schedule 40
Standard Pipe
in Inches
Internal
Diameter
in Inches
Total Equivalent Length of Pipe (Feet)
15.24 30.48 45.72 60.96 76.2 91.44 121.92 152.4
2.00 2.067 11786 8101 6505 5567 4934 4471 3827 3391
2.50 2.469 18785 12911 10368 8874 7865 7126 6099 5405
3.00 3.068 33209 22824 18329 15687 13903 12597 10782 9556
3.50 3.548 48623 33418 26836 22968 20365 18444 15786 13991
4.00 4.026 67736 46555 37385 31997 28358 25694 21991 19490
5.00 5.047 122544 84224 67635 57887 51304 46485 39785 35261
6.00 6.065 198427 136378 109516 93732 83073 75270 64421 57095

TABLE 7: Pipe Sizing Table for an Initial Pressure of 34.47 kPa: (Metric Units)
Capacity of Pipes of Different Diameters and Lengths
In Cubic Feet per Hour with a 10% Pressure Drop and a Gas of 0.6 Specific Gravity
Pipe Size of
Schedule 40
Standard Pipe
in mm
Internal
Diameter
in mm
Total Equivalent Length of Pipe (Meters)
15.24 30.48 45.72 60.96 76.2 91.44 121.92 152.4
50.80 52.50 333.74 229.40 184.20 157.64 139.72 126.61 108.37 96.02
63.50 62.71 531.93 365.60 293.59 251.29 222.71 201.79 172.71 153.05
76.20 77.93 940.38 646.31 519.02 444.21 393.69 356.71 305.31 270.60
88.90 90.12 1376.86 946.30 759.92 650.38 576.68 522.28 447.01 396.18
101.60 102.26 1918.08 1318.30 1058.63 906.06 803.01 727.58 622.72 551.90
127.00 128.19 3470.08 2384.97 1915.22 1639.19 1452.78 1316.32 1126.59 998.49
152.40 154.05 5618.86 3861.82 3101.16 2654.21 2352.38 2131.42 1824.21 1616.76

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8. VENTING OF GAS SUPPLY REGULATORS
AERCO’s general guidelines for venting of gas regulators are listed below. AERCO requires that
these guidelines be followed to ensure the most reliable and proper operation of AERCO gas fired
equipment. It is also required that you consult local codes and the gas regulator manufacturer for
additional details. Always follow the most stringent guidelines available, including those listed below.
• When venting a gas supply regulator, the vent pipe must be no smaller than the regulator vent
size.
• In a multiple unit installation, each regulator must have a separate vent line.
• Vent lines must not be manifolded together or with any other equipment at the site that also
requires atmospheric vents.
• When sizing the vent, pipe diameters must be increased by one pipe diameter every 20
equivalent feet of pipe.
Each 90° elbow is equivalent to approximately:
 2.5 feet (0.76 m) for nominal pipe sizes of up to 3/4” (19 mm)
 4.5 feet (1.37 m) for nominal pipe sizes of up to 1-1/2” (38 mm)
 10.5 feet (3.2 m) for nominal pipe sizes of up to 4” (101 mm)

Each 45° elbow is equivalent to approximately:
 1 foot (0.3 m) for nominal pipe sizes of up to 3/4” (19 mm)
 2 feet (0.61 m) for nominal pipe sizes of up to 1-1/2” (38 mm)
 5 feet (1.52 m) for nominal pipe sizes of up to 4” (101 mm)

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Change Log:
Date Description Changed by
9/30/2020
Rev Q:
Added BMK4000 and BMK5000N Dual Fuel values to Minimum
Inlet Pressure table, Section 3.
Added a Note to Table 1 concerning BMK 5000/6000 LGP
models.
Revised gas pressure regulator recommendations for sites with
pressure above 7” W.C. (BMK 750-5000N) or above 1 psi (BMK
5000/6000), added a bullet point for BMK 5000/6000 units,
Section 2.4.
Chris Blair
11/14/2020
Rev R:
Updated to support Benchmark 750/1000 Dual Fuel models,
Sections 2.2, 3 and 4.
Revised figures in Section 2.2 to clarify minimum pipe lengths in
gas inlet piping for all models.
Revised/clarified Note ** under Table 1 (page 3) concerning when
use of BMK 5000/6000 LGP model is recommended, and
repeated recommendation in bullet in Section 2.4.
Chris Blair
5/16/2023 Rev S: Removed reference to Platinum; updated formatting DWBarron

© AERCO International, Inc., 2023