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									              ASPE/ASSE Meeting February 10, 2010
                       Cleveland, OH

Fuel Gas Systems
  Natural Gas
  Propane
  Butane
By: Ron George, CPD, President
President, Ron George Design & Consulting Services
3525 N. Dixie Hwy., Monroe, MI
Monroe, Michigan 48162
Ph: (734) 322-0225 Cell: (734) 755-1908
Fuel Gas Codes & Standards
 Mechanical Codes covering Fuel Gasses:
 BOCA - Basic Mechanical Code (no longer updated in favor of
    The International Codes)
 IAPMO - Uniform Plumbing Code (UPC) (Coordinated with
    NFPA 54)
 IMC - International Mechanical Code (Prior to 2000)
 IFGC - International Fuel Gas Code (Fuel gas sections from
    IMC were used to develop IFGC in 2000.
   Standards/Organizations dealing with Fuel Gas:
   AGA - American Gas Association
   NFPA 54 - National Fire Protection Association
   CSA - Canadian Standards Association
   ASME - Power & Process Piping Standards
How do I Size Gas Piping?
 Determine the heating and equipment
 loads in BTU’s, convert to CFH and size
 the piping based on acceptable pressure
 drops using the appropriate code
 approved pipe material.


 BTU/H       CFH       Distance   Pipe Size Chart

     Equipment Label
What does BTU stand for?
 BTU stands for “British Thermal Unit”.
A British Thermal Unit is the
 amount of heat required to raise one
 pound of water one degree
 Fahrenheit.
British Thermal Unit (BTU)
                          One pound of water
  1 pound of 60           will increase by 1
  degree water            degree F when 1 BTU
                          is added.
                  1 BTU

                          Example: One pound
                          of 60 degree F water
                          plus 1 BTU = one
  1 pound of 61
                          pound of 61 degrees F
  degree water            water.
What is CFH?
 CFH is an industry term used to describe the
  quantity of gas in Cubic Feet delivered during
  a specified time period. (Usually 1 hour)

 So CFH stands for Cubic Feet per Hour.
 1 Cubic foot of gas = 1000 BTUs + -
  (950-1100 BTUs/CF depending on the supplier)
Natural Gas Properties
  1 Cubic Foot of Natural Gas                               = 1,000    BTU’s
 Heat of combustion is measured in BTU’s/cu.ft.
  Natural Gas = 1,000 BTU’s/CF (Caloric Value)
 Specific Gravity of Nat. Gas = .60 - .65 (Air =1.00)
   – Natural Gas is Lighter than air. (It will dissipate)
 Flammability Limits (% Volume in air)
   – Lower = 3.9%, <<<<< Flame >>>>> Upper = 15.0%
     Below 3.9% too lean for Combustion   9-10% = Good Above 15% too rich for combustion

 Combustion air requirements in Cubic Feet:
  – Per cu. foot of Natural Gas = 10 cubic feet of air.
  – Per 100 BTU’s = 1 cubic foot of air.
Fuel Gas Properties Table:




            Odor Additives




 Source: NFPA 54 Handbook
Fuel Gas is Explosive!
Fuel Gas is Explosive!
Fuel Gas is Explosive!
Fuel Gas is Explosive!
 On May 19, 2008 a natural gas leak caused an explosion that
 injured 14 construction workers and damaged four floors on the
 unfinished hotel.
Fuel Gas is Explosive!
Fuel Gas is Explosive!
New Braunfels, TX. 1 dead, 1 seriously burned.
Natural Gas Distribution Pressures

Three Pressure Classifications
  – High Pressure (1,000’s PSI to 100’s)
  – Medium Pressure (5 PSI to 100’s PSI)
  – Low Pressure (Less Than 5 PSI)

      High Pressure gas is in typically only
      utilized in utility distribution lines, so
     most plumbing engineers will deal with
       only Medium or Low Pressure Gas
Natural Gas High Pressure
 High Pressure - 1,000’s to 100’s PSI
  – Transmission mains from pumping stations
    to Local utility distribution mains.
  – Typically High Pressures are utilized over
    long distances to reduce pipe sizes.
                                            Pumping Station

         PRV      Medium press. 60 psi +-


                       PRV                                    Well
     Low press.                  High press. 900 psi+-
     1/2 psi +-                  Energy Company lines
Natural Gas Medium Pressure

Medium Pressure
 – Local Utility Distribution
 – Large Industrial users.
 – Typically 5psi to 100’s of PSI
     Local Gas Utility Co. Distribution lines
                                            Pumping Station
                   Medium press.
       PRV
                   60 psi +-

                       PRV
   Low press.                  High press. 900 psi +-         Well
   1/2 psi +-
 Natural Gas Low Pressure

 Low Pressure
          – Commonly used inside buildings
          – Commercial and residential users.
          – Typically less than 5 PSI (code requirement indoors)
                                                 Pumping Station

                           Medium press. 60 psi +-
               PRV

furnace
                              PRV
            Low press.                  High press. 900 psi +-
            1/2 psi + -
            Homeowner Responsibility
Fuel Gas Pressure Conversions
Gas pressures in buildings are often given in Pounds,
Ounces or Inches. Make sure you convert to the
proper units for sizing.
Often a manufacturer refers to equipment pressure in inches or
ounces of pressure because it is a more accurate measurement.

               Gas Pressure Conversion Chart
  1 PSI = 2.31 feet of head = 28 inches of Water Column (WC)
  1 PSI = 16 Ounces = 28 Inches = 2.31 feet of head
  1/2 PSI = 8 Ounces = 14 Inches WC = 1.16 feet of head
  1/3 PSI = 6 Ounces = 10 Inches WC = .77 feet of head
  1/4 PSI = 4 Ounces = 7 Inches WC = .58 feet of head
How Do we Change from a High
Pressure to a Low Pressure?
 Pressure Regulators.
    Gas Regulator Operation




60 PSI
                    ½ PSI
                              1/2 PSI
Odor Added to Fuel Gas
Odor is added by most gas companies so leaks can be detected.
The physical properties of natural gas include color, odor, and flammability. The
principal ingredient of gas is methane, which is colorless, odorless, and highly
flammable. Some of the associated gases in natural gas include Mercaptin, a
hydrogen sulfide additive, it has a distinct and penetrating sulfur or Rotten Egg
odor, and a few parts per million is sufficient to impart a decided odor in the gas.
A Volcanic Problem - The engineers for the Mirage Casino in Las Vegas needed
to use Natural Gas to enhance the special effects for the volcano eruption in front
of the casino. The concern was prior to eruption a distinctive odor of of Natural
Gas or the sulfury Rotten Egg smell would be noticeable to the crowds if gas with
Mercaptin was used. The officials insisted on having some kind of odor so they
could detect a gas leak. The engineers designed a scrubber to remove the
Mercaptin odor and replace it with a Pina’ Colada odor.
 Natural Gas Pipe Material
 Cast Iron Not recommended/allowed on fuel gas piping systems. Older cities used CI (½ PSI limit)
 Black Steel (Schedule 40) ASME B36.10, 10M or ASTM A53 or ASTM A106
 Polyethylene (PE) Underground outside building where approved)
 Stainless Steel (CSST) ANSI/AGA LC 1.
 Copper (Not recommended if gas is more than 0.3 Grains of Hydrogen Sulfide/100 CF) Often
  used as semi rigid tubing for appliance connections.
 Aluminum ASTM B241 (Alum. Alloy 5456 is Prohibited)
 (All piping material selections should meet the local code’s approved materials list.)

             Copper or                                        Pumping Station
             CSST                  Polyethylene or
                                   wrapped & coated
                 PRV               Black Steel U.G.

furnace
                                       PRV
           Black Steel/CSST                         PE or asphalt wrapped Sch 80 - 160
           Abv. ground                              Black steel W/ Cathodic Protection
                                                    (Pressure often dictates material)
Corrugated Stainless Steel Tubing (CSST)

 CSST has made residential and light
  commercial gas-distribution much easier.
  Black steel pipe is still preferred for mains
  and trunks to manifolds. From the manifold
  the branch piping can be installed with ease.
 CSST is lightweight and flexible and will
  cut down on installation time up to 50%.
Underground Gas Piping Installations
Clearances - Far enough from U.G. structures to avoid contact
and provide protection against damage. U.G. plastic piping
shall be clear of or insulated from heat sources. (U.G. Steam
mains, Htg HW pipes Etc.)
Protection Against Damage - Unstable soil, Foundation Walls,
Heavy vehicles: Provide sufficient depth of cover or a pipe
sleeve.
When gas piping is buried in planting areas, bury piping
sufficiently below cultivating depth.
Warning Tape/Wire - Always put a tracer wire with plastic
piping and bury “WARNING BURIED GAS LINE” tape in
trench above all gas piping to warn excavators of pipe below.
Protection Against Damage

 Provide sufficient depth of cover or a pipe sleeve where there is
   unstable soil, a foundation wall penetration or heavy vehicle traffic.
 When gas piping is buried in planting areas, bury piping sufficiently
   below cultivating depth.




                                                  G
  Warning Tape/Tracer Wire
  Engineers should always require a tracer wire when using plastic piping
   to allow pipe locators to find the pipes.
  Also specify warning tape that states: “WARNING BURIED GAS LINE
   BELOW”. The tape should be in the trench at least 12 inches above the
   gas piping to warn excavators of the gas pipe below
 Warning Tape                              Tracer Wire (In trench above plastic pipe)
(In trench 12”above pipe)

        Caution - Buried Gas Line         Caution - Buried Gas Line




                        Buried Gas Line
Underground Gas Piping Installations
Cover Depth - Should be installed with at least 18 inches of cover. Can be
12 inches in areas where external damage is not likely. If less than 12
inches provide a protective conduit or bridging. Always use warning tape.
& tracer wire for plastic piping.
Backfilling Trenches - Pipe should have a firm, continuos bearing on
trench bottom. When installing gas piping, especially plastic, in a flooded
trench care should be exercised to prevent the pipe from floating up in the
trench during backfilling operations.

      Caution Tape
 Tracer Wire
 (for plastic pipe)

                                              Continuous pipe bedding
      Gas Pipe
Underground Gas Piping Installations
Protect Against Corrosion - Ferrous metal piping that is in
contact with earth should be protected from corrosion by
asphalt coating and wrapping piping below grade.
Protect Against Freezing - If the fuel gas supplier indicates,
hydrates or moisture is high, the gas piping should be
protected from freezing. Freezing of water in drip legs or low
points in the piping can split piping and lead to gas leaks and
possibly and explosion or fire.

                   Wet gas condenses     Locate Gas line below frost line or
                   water to this point   in a heated space.
Freezing can
crack pipe                               If Gas line is subject to freezing
allowing gas to     Boom                 provide heat tracing and Insulation.
leak out of pipe
Dirt Leg (For Dry Gas)


       Clean Gas




       Sediment falls

                         Source: NFPA 54
                         Handbook
Emergency Gas Shut-off Valve (Earthquake valve)

 Some seismic areas of the country require an Emergency Gas shut-
  off valve that automatically closes when there is an earthquake.
 The Earthquake Valve Industry has emerged because of the recent
  earthquakes and ensuing fires that have struck California and
  other parts of the world. Designers, Building Officials and Utility
  companies have become aware of the need for Earth Quake Valves
   (EQVs) after experiencing and viewing these disasters.




                                                    Source: Safe-T-Quake Co.
Gas Pipe through Foundation Wall Below
Grade not allowed in most areas!
     Piping through foundation walls below grade should
     have a sleeve with the annular space sealed from the
     building.
Gas Meter/
Regulator              M

                                           Void space

                                        Sealed sleeve


                                      Expansive or
      Foundation Wall                 Clay Soil
                                                Gas Pipe

       Section at Foundation Wall             End view U.G. Pipe
Gas Pipe Should enter Building above
Grade!
     Piping walls should have a sleeve sealed from inside
     the building.                     Sealed sleeve

Gas Meter/
Regulator               M




      Foundation Wall

      Section at Foundation Wall
Bonding of CSST Gas Pipe Inside Buildings
 Proper bonding and grounding of Corrugated Stainless Steel Tubing
    (CSST) systems may reduce the risk of damage and fire from a
    lightning strike. Lightning is a highly destructive force. Even a nearby
    lightning strike that does not strike a structure directly can cause
    systems in the structure to become electrically energized. Differences
    in potential between systems may cause the charge to arc between
    systems.
   Such arcing can cause damage to CSST, including blowing holes that
    can leak flammable gasses.
   Bonding and grounding should reduce the risk of arcing and related
    damage.
   Arcing from lightning strikes has been known to blow holes in un
    grounded CSST fuel gas lines causing Gas leaks and Fires.
   The building owner should confirm that a qualified contractor has
    properly bonded the CSST gas system to the grounding electrode
    system of the premises. Refer to the manufacturers installation manual
    for bonding and grounding instructions for CSST.
     – (Section 4.10 Electrical Bonding/Grounding in the Gastite Design &
       Installation Guide for details on bonding & grounding CSST.)
Lightning Protection Systems for CSST Piping

 All owners should consult a lightning safety consultant to determine
  whether installation of a lightning protection system would be required
  to achieve sufficient protection for all building components from
  lightning. Factors to consider include whether the area is prone to
  lightning. Areas with high lightning risk include but are not limited to:
  Alabama, Arkansas, Florida, Georgia, Illinois, Indiana, Iowa, Kentucky,
  Louisiana, Maryland, Michigan, Mississippi, Missouri, New Mexico,
  North Carolina, Ohio, Oklahoma, Pennsylvania, South Carolina,
  Tennessee, Texas, Virginia and West Virginia.
 One currently available source of information regarding areas more
  prone to lighting than others is the flash density map provided by the
  National Weather Service which can be found at
  http://www.lightningsafety.noaa.gov/lightning_map.htm.
 Lightning protection systems are beyond the scope of this presentation
  and the manufacturers installation guidelines, and are covered by
  National Fire Protection Association, NFPA 780, the Standard for the
  Installation of Lightning Protection Systems, and other standards.
Dielectric Connections in all Gas Pipes

 The owner should confirm with the local
 gas supply utility company that a suitable
 dielectric union is installed at the service
 entry of the structure between underground
 metallic piping and the gas pipes going into
 the building as required by code.
National Electrical Code
 National Electric Code (NEC), Section 250.104b, states
  that “bonding all piping and metal air ducts within the
  premises will provide additional safety”. Manufacturer’s
  recommend that all continuous metallic systems be bonded
  and grounded. The owner should confirm with an electrical
  or construction specialist that each continuous metallic
  system in a structure has been bonded and grounded by an
  electrical professional in accordance with local building
  codes. This should include, but is not limited to metallic
  chimney liners, metallic appliance vents, metallic ducting
  and piping, electrical cables, and structural steel.
Separation of Fuel Gas Pipe from
Electrically conductive systems.
 Care should be taken when installing any type of fuel gas
  piping (including CSST, iron, or copper) to maintain as
  much separation as reasonably possible from other
  electrically conductive systems in the building. Refer to
  the manufacturers’ Installation Manual. (Gastite D&I
  Guide sec. 4.3 Routing, for installation techniques.)
  Consult local building codes as to the required separations
  for CSST from such conductive systems including metallic
  chimney liners, metallic appliance vents, metallic ducting
  and piping, and electrical cables. See for instance the
  Indiana Residential Code, section 675 IAC 14-4.3-155.5
  Section G2411.1; gas pipe bonding.
Local Building Codes Have Jurisdiction

 Local building codes have jurisdiction, however, as a general
   practice, fuel gas piping, including CSST, should not be installed
   within a chase or enclosure that houses a metallic chimney liner or
   appliance vent that protrudes through the roof. In the event such an
   installation is necessary and conforms to local building codes, the
   metallic chimney liner or vent must be bonded and grounded by a
   qualified electrical professional, and a separation distance, as
   specifically permitted by the applicable local building code between
   the CSST and the metallic chimney liner or vent, is required. Physical
   contact between CSST and the metallic chimney liner and/or vent is
   prohibited. If this physical separation cannot be specifically identified
   in the local building code and achieved or any local building code
   requirements cannot be met along the entire length, then rerouting of
   the CSST is required unless such installation is specifically permitted
   by the local building inspector.
2009 National Fuel Gas Code Update

 As of October 2008 – the National Fuel
 Gas Code requires bonding of ALL CSST
 systems per section 7.13 – Electrical
 Bonding and Grounding.
CSST Coils and Fittings
CSST Pipe Layouts
CSST Pipe Layouts
CSST Pipe Layouts
Hybrid Multi-Unit Condo Building




                                   CSST
                                   Branches




                         Steel Riser
Hybrid System w/ Local Gas
Regulator and CSST
                          (4) 50,000 BTU/H

 5 PSI



              CAP.
         IP          OP

                             1/4 PSI
Multiple Manifold System
Gas Pipe Inside Buildings
    Gas Piping Prohibited Locations:
    In Circulating Air Duct
    Through Circulating Air Duct
    Clothes chutes                      Boom
    In Chimney
    In Gas Vent
    In Ventilation duct
    In Dumb Waiter                 Leaks in concealed
    In Elevator Shaft              locations can allow
                                   explosive gasses to
                                   accumulate unnoticed
Gas Pipe Inside Buildings
Gas Piping in concealed Locations:
Should have a casing or chase for solid walls
No unions, valves or joints in concealed spaces
No compression couplings
No Bushings
                                                     Boom
No swing joins made by multiple fittings
Exceptions:
Brazed Tubing
Fittings listed for concealed locations    Leaks in concealed
                                           locations can allow
                                           explosive gasses to
                                           accumulate unnoticed
How Do You Test For A Gas Leak?

 With a Match? No
 With Soap? Sometimes (Must be non-corrosive)
 With a Gas Detector? Yes
How Do Purge Fuel Gas Lines?

 Disconnect from the equipment at a union.
 Connect a grounded purge hose the end of
  the pipe.
 Use a Gas Detector at the end of the hose.
  (Odor Fade)
 Route the end of the hose outdoors to a well
  ventilated space away from any ignition
  sources.
    Fuel Gas Valves
 Valves above 0.5 psi should meet ANSI/ASME B16.33 (Ball Va, Plug Va.)
 Valves below 0.5 psi should meet ANSI Z21.15 (Lubricated Plug) or
    ANSI/ASME B16.33
   Access should be provided to each valve (No Va’s in Concealed Spaces)
   Protect valves from Damage
   Provide a valve prior to the Gas Meter
   Shut off valve locations:
     – Each building or tenant
 Identification of service should be on each gas shut-off Valve.
 A listed shut-off valve should be installed ahead of each regulator.
 Equipment shut-off valve should be installed upstream of the union
    and within 6 feet of gas equipment. (There are exceptions for vented
    decorative appliances and gas fireplaces)
Lubricated Plug Valve exposed to more than ½ PSI
Fuel Gas Valve Types
Ball Valve    Lubricated Plug Valve




                            Plug
                            Grease Seal
Gas Pressure Regulators

 Regulator should be selected for inlet and outlet pressures for the
    application.
   Regulator should maintain a reduced outlet pressure at no-flow
    condition.
   Capacity of the regulator should be determined by the
    manufacturers published flow rates.
   Access to the regulator should be provided.
   Sediment trap and test plug upstream of Regulator after 1st shut-
    off valve.
   Test Plug 10 diameters downstream of regulator before 2nd shut-
    off valve.
   Regulator should be protected from damage.
   Indoor Regulators should be vented to the outdoors.
Gas Meter with Protection Post
    Gas Regulator Failure




60 PSI
                    ½ PSI
                            1/2 PSI
60 PSI - 2 PSI
Regulator




                 2 PSI – 1/2 PSI
                 Regulator
                                      2 PSI gas
Kitchen Hood


                      Gas Shut-off Valve




                 50,000 BTU/h at
                 6 in’s WC = ¼ PSI

               199,000 BTU/h at
               6 in’s WC = ¼ PSI
Local Gas Regulator w/ CSST

 CSST                       (4) 50,000 BTU/H

 5 PSI
                     CSST


              CAP.
         IP           OP

                               1/4 PSI
Vented Indoor Gas Regulator
                                                         Gas regulator vent to outside
                                                         provide weatherproof cap or
                                                         gooseneck with insect screen
               Roof

              Truss Space

           Gas Pressure Regulator                             Downstream shut-off
           located indoors                                    valve




Upstream Shut-off                                          Plugged tee for downstream
valve                        Plugged tee in dirt leg for   pressure measurement
                             upstream pressure measurement
Rooftop Piping
Typical Gas Appliance Piping Connection
Typical Gas Appliances
      Donut Fryer




    Consult Manufacturer’s Literature for BTU’s/H Input
Typical Gas Appliances




                                                              AGA
                                                              Appliance
                                                              Nameplate


        Consult manufacturer’s literature for BTU’s/H input
Typical AGA Appliance Nameplate
                        Source: NFPA 54 Handbook


Input BTUH

Fuel Type
                            Venting Category
Max. Press.

Min. Press.                 Manifold Press.

Units (In. WC)


                             Min. Clearances
Typical Water Heater Installation
Source: NFPA 54 Handbook   Flue to Category I Type “B” vent




                           Appliance Regulator/Controls
Single vs Double wall Flue
                              Source: NFPA 54 Handbook




                     Double wall provides a
                     safer installation




                     Single wall more
                     susceptible to carbon
                     monoxide leaks
Corroded Flue Pipe from High Efficiency
       Condensing Equipment.
Typical Appliance Flue Installation
Source: NFPA 54 Handbook
Combustion Air
 Transfer Grille



 Ventilation louvers
  through ceiling &
  floors


Source: NFPA 54 Handbook
Combustion Air
 Transfer grille /
  combustion air
  duct from attic to
  one foot above
  floor.

 Ducted to outside
  walls.
Source: NFPA 54 Handbook
Commercial Propane Properties
1 Cubic Foot of Propane                      = 2,500 BTU’s

 Heat of combustion is measured in BTU’s/cu.ft.
  Propane = 2,500 BTU’s/CF (Caloric Value)
 Specific Gravity of Propane = 1.52 (Air =1.00)
    – Propane is heavier than air. (It will pool in low places)
 Flammability Limits (% Volume in air)
   – Lower = 2.4%, <<<<< Flame >>>>> Upper = 9.6%
    –   Below 2.4% too lean for Combustion      Above 9.6% too rich for combustion

 Combustion air requirements in Cubic Feet:
  – Per cu. foot of Propane = 25 cubic feet of air.
  – Per 100 BTU’s = 1 cubic foot of air.
Commercial Butane Properties
1 Cubic Foot of Butane                       = 3,200 BTU’s

 Heat of combustion is measured in BTU’s/cu.ft.
  Butane = 3,200 BTU’s/CF (Caloric Value)
 Specific Gravity of Butane = 1.95 (Air =1.00)
    – Butane is heavier than air. (It will pool in low places)
 Flammability Limits (% Volume in air)
   – Lower = 1.9%, <<<<< Flame >>>>> Upper = 8.6%
    –   Below 1.9% too lean for Combustion      Above 8.6% too rich for combustion

 Combustion air requirements in Cubic Feet:
  – Per cu. foot of Propane = 32 cubic feet of air.
  – Per 100 BTU’s = 1 cubic foot of air.
Multipliers for Gases other than .6 Specific Gravity

Convert CFH in Gas pipe sizing tables to CFH for a fuel with a specific gravity other than 0.6




                Nat. Gas                                       Propane


                                                                Butane
Sizing Exercise #1
Approximate Gas input for Typical Gas Appliances




                                   Source: NFPA 54 Handbook
Determining Gas Loads for sizing

 Gas pipe sizing is accomplished by
  converting the gas input loads for HVAC,
  domestic water heating, cooking equipment
  and process equipment from BTUH to CFH
  of gas.
 A delivery pressure and acceptable pressure
  drop are selected and the proper sizing chart
  or calculation can be used to size the pipe.
Converting from BTU’s/H to CFH of
Natural Gas
 Determine heat load by
  calculating demand in BTU’s
 Convert BTUH into CFH by
  dividing by 1000 for Natural
  Gas
 Example: 2,500,000 BTUH
  divided by 1000 = 2,500 CFH
HVAC Heating Load Calculation

 Engineer determines temperature to maintain
 Engineer calculates BTUH heat loss through
  walls, floors and ceiling exposures.
 This is basis of BTU’s/Hour required to
  maintain space heating. (Heating Load)
Domestic HW load Calc.                             Review



 Determine HW demand in GPH or GPM:
 For the following sizing examples we will assume 500
  GPH demand of 140 degree HW
 Determine if Storage, Semi-instantaneous or
  Instantaneous Water heaters will be used. Instantaneous
  Heaters require greater fuel loads.



     500
     Gallon
 Calculating HW Demand                                             Review



 Multiply: (Gallons Per Hour) x (8.33 pounds per gallon) =
  (pounds of water/hr. at 1 deg. rise)
   – Example: 500 GPH x 8.33 pounds per gallon = 4165 Pounds of
     HW per hour at 1 degree rise.
 Multiply pounds of HW per hour by Temperature Rise (40
  Degree to 140 degree rise = 100 degree rise)   to get BTU’s/H.
   – Example: 4165 Pounds of HW x 100 degree rise = 416,500
     BTU’s/H
 Convert BTU’s to CFH
   – Example: 416,500 BTU’s/H divided by 1000 BTU’s / Cubic Foot =
     416.5 CFH
Fuel Gas Pipe Sizing
 Determine the total developed length of pipe from the Gas
  Regulator to farthest the appliance connection.
 Select a delivery pressure and determine allowable
  pressure drop. (0.3 - 0.5 in WC for low press. Up to 10%
  for medium pressure)
 Total the CFH and select appropriate pipe sizes from the
  appropriate gas sizing tables.
 For Branch sizing you can continue using the same
  developed length column for sizing or you can measure the
  actual developed length to the farthest fixture in each
  branch and use the appropriate developed length table for
  sizing only the branch piping.
Gas Pipe Sizing                           250 feet includes equivalent length
                                          allowance for fittings and valves.
Longest Run Method                        See following page for equivalent
                                          length allowances table.


                     Total developed length = 250 feet.



                                                                       Regulator
      Water
                             Furnace
      Heater

        400,000 BTUH /        2,000,000 BTUH /           Meter
        400 CFH burner        2,000 CFH burner

Determine length of piping from farthest appliance to gas pressure regulator
and refer to sizing chart column that exceeds that length. (2,400 CFH total
load @ 250 feet)
Nat. Gas Pipe sizing Table - 1/2 psi
CFH of Gas at .6 specific gravity, Press. drop = 0.3 in WC
Pipe              Length of tubing, Feet Distance from Regulator
                                            To farthest outlet
Diam.   50         100       250       500            1000
1”            215      148           90              62                43

1-1/4”        442      304           185             127               87

1-1/2”        662      455           277             191               131
2”            1275     877           534             367               252

3”            3594     2470          1505            1034              711

4”            7330     5038          3069            2109              1450
6”            21472    14758         8990            6178              4246
                               All sizing should be done from this column for 250’ system
     Source: NFPA 54
Equivalent Lengths in Feet of Straight pipe.
For fittings and Valves            Source: NFPA 54 Handbook
1/2 PSI
Example:
      Gas Pipe Sizing - 1/2 PSI
       (See sizing charts on following page for pipe sizing for 1/2 PSI gas.)


                      Total developed length = 250 feet.
                        2”@ 400 CFH                    4” @ 2,400 CFH
                                                       (250’ Column)
                                                   Length for Branch            Regulator
        Water                       Furnace        Sizing = 100’
        Heater
                                                    3” @ 2,000 CFH


      400,000 BTUH =               2,000,000 BTUH =               Meter
      400 CFH                      2,000 CFH
Determine length of piping from branch piping appliance to gas
the pressure regulator and refer to sizing chart column that
exceeds the branch length for sizing only the branch piping.
(2,000 CFH branch load @ 100 feet)
Nat. Gas Pipe sizing Table - 1/2 psi
CFH of Gas at .6 specific gravity, Press. drop = 0.3 in WC
Pipe              Length of tubing, Feet
Diam.   50         100       250       500       1000
1”        215      148       90       62        43

1-1/4”    442      304       185      127       87

1-1/2”    662      455       277      191       131
2”        1275     877       534      367       252

3”        3594     2470      1505     1034      711

4”        7330     5038      3069     2109      1450
6”        21472    14758     8990     6178      4246
5 PSI
Example:
Gas Pipe Sizing - 5 PSI
      (See sizing charts on previous pages for pipe sizing for 5 PSI gas.)


                      Total developed length = 250 feet.
                        1”@ 400 CFH                1-1/2” @ 2,400 CFH
                                                   (250’ Column)
                                                  Length for Branch          Regulator
       Water                       Furnace        Sizing = 100’
       Heater
                                                  1-1/4” @ 2,000 CFH


      400,000 BTUH =              2,000,000 BTUH =                Meter
      400 CFH                     2,000 CFH
Determine length of piping from branch piping appliance to gas
the pressure regulator and refer to sizing chart column that
exceeds the branch length for sizing only the branch piping.
(2,000 CFH branch load @ 100 feet)
Nat. Gas Pipe sizing, Table - 5 psi
CFH gas at .6 specific gravity, Press. drop = 10% or 1/2 psi
Pipe               Length of tubing, Feet
Diam.     50         100       250       500      1000
 1”        1989     1367      833       572       393

 1-1/4”    4084     2807      1710      1175      808

 1-1/2”    6120     4204      2562      1761      1210
 2”        11768    8101      4934      3391      2331

 2-1/2”    18785    12911     7865      5405      3715

 3”        33209    22824     13903     9556      6568
 4”        67736    46555     28358     19490     13396
Sizing Exercise #2

           Use 1/2 PSI Table to Size
           Gas Piping to Gas Roof Top
           Units on a the roof of the
           “ASPE Industrial Building”




                     Place Sizing Chart on Overhead Projector
Nat. Gas Pipe sizing Table - 1/2 psi
CFH of Gas at .6 specific gravity, Press. drop = 0.3 in WC
Pipe              Length of tubing, Feet
Diam.   50         100       250       500       1000
1”        215      148       90       62        43

1-1/4”    442      304       185      127       87

1-1/2”    662      455       277      191       131
2”        1275     877       534      367       252

3”        3594     2470      1505     1034      711

4”        7330     5038      3069     2109      1450
6”        21472    14758     8990     6178      4246
    Gas Pipe Sizing Exercise #2
    Size the Natural Gas Piping for 1/2 PSI Gas at .03 PSI Press. Drop.
                                                                                                  20’ down to
                          Roof Top AHU 200,000                                                    Regulator
                                                                                      80’            Regulator
                          BTUH (Typical)
                                                                                                     (PRV)
                             100’
                                                          1800
                                                          ________ CFH / ___” 6
                                                                                                     Meter
                                                           1600           6
                                                          ________ CFH / ___”
     200 CFH
                                    200
                                 ______ CFH / ___”
                                                      2
                   100’



     1000’- 2”
                             400              3             200 CFH 150’ - 1-1/2”
                            ______ CFH / ___”                                                      Pipe Guard
                                                                                                   (Typical)
 200 CFH - 2”                                             1400             4
                               ______ CFH / ___” ________ CFH / ___”
                                600          3
                                                           1200
                                                          ______ CFH / ___”
                                                                           4
                                800
                               ______ CFH / ___”
                                                  4
                                                                                        200 CFH 210’ 1-1/2”
                   100’




                                                          1000            4
                                                          ______ CFH / ___”
                                    100’                     100’         100’
 200 CFH - 2”                                                                               200 CFH 320’ - 2”
                          200 CFH 520’ - 2”           200 CFH 420’ - 2”

                                                       900’+90’(10% Fit’gs) =990’
     Total feet of piping from PRV to last appliance = _____________
Big Box Industrial Bldg. - Mech. Roof Plan
                                                                          North
                                                                                  Use 1000’ Column
        No Scale                                                                  on 1/2 PSI Chart
Nat. Gas Pipe sizing Table - 1/2 psi
CFH of Gas at .6 specific gravity, Press. drop = 0.3 in WC
Pipe              Length of tubing, Feet
Diam.   50         100       250       500       1000
1”        215      148       90       62        43

1-1/4”    442      304       185      127       87

1-1/2”    662      455       277      191       131
2”        1275     877       534      367       252

3”        3594     2470      1505     1034      711

4”        7330     5038      3069     2109      1450
6”        21472    14758     8990     6178      4246
                                                       1800 CFH
Sizing Exercise #3

           Use 5 PSI Table to Size Gas
           Piping to the same Gas Roof
           Top Units on a the roof of the
           “ASPE Industrial Building”
Nat. Gas Pipe sizing, Table - 5 psi
CFH gas at .6 specific gravity, Press. drop = 10% or 1/2 psi
Pipe               Length of tubing, Feet
Diam.     50         100       250       500      1000
 1”        1989     1367      833       572       393

 1-1/4”    4084     2807      1710      1175      808

 1-1/2”    6120     4204      2562      1761      1210
 2”        11768    8101      4934      3391      2331

 2-1/2”    18785    12911     7865      5405      3715

 3”        33209    22824     13903     9556      6568
 4”        67736    46555     28358     19490     13396
 Gas Pipe Sizing Exercise #3
 Size the Natural Gas Piping for 5 PSI Gas at 10% (0.5 PSI) Press. Drop.
                                                                                            20’ down to
                        Roof Top AHU 200,000                                                Regulator
                                                                                80’            Regulator
                        BTUH (Typical)
                           100’
                                                     1800            2”
                                                     ________ CFH / ____
                                                                                               (PRV)

                                                                                               Meter
                                                      1600           2”
                                                     ________ CFH / ____
   200 CFH
                                  200         1”
                 100’



                               ______ CFH / ____
   810’= 1”
                           400           1-1/4”             200 CFH 150’ = 1”
  200 CFH                 ______ CFH / ______                                                Pipe Guard
                                                                                             (Typical)
  710’ = 1”                                          1400           2”
                             ______ CFH /1-1/4”________ CFH / ____
                              600         ____
                                                      1200        1-1/2”
                                                     ______ CFH / ____
                              800           1-1/4”
                             ______ CFH / _____
                                                                                  200 CFH 210’ = 1”
                 100’




                                                     1000        1-1/2”
                                                     ______ CFH / ____
  200 CFH -                       100’                  100’         100’
  620’ = 1”                                                                           200 CFH 320’ = 1”
                        200 CFH 520’ = 1”     200 CFH 420’ = 1”

                                                     900’+90’(10% Fit’gs) =990’
   Total feet of piping from PRV to last appliance = _____________
ASPE Industrial Bldg. - Mech. Roof Plan
                                                                  North
                                                                            Use 1000’ Column
      No Scale                                                              on 5 PSI Chart
Nat. Gas Pipe sizing, Table - 5 psi
CFH gas at .6 specific gravity, Press. drop = 10% or 1/2 psi
Pipe               Length of tubing, Feet
Diam.     50         100       250       500      1000
 1”             1989             1367              833     572     393

 1-1/4”         4084             2807              1710    1175    808

 1-1/2”         6120             4204              2562    1761    1210    1800 CFH
          1/2 PSI gas required 6 inch pipe size.
 2”             11768            8101              4934    3391    2331

 2-1/2”         18785            12911             7865    5405    3715

 3”             33209            22824             13903   9556    6568
 4”             67736            46555             28358   19490   13396
Gas Sizing Tables
Increasing Gas Pressure
 Increasing gas pressure can increase the
  pipe CFH capacity and reduce pipe sizes.
 The following are some examples of ¾ inch
  pipe and 1 inch pipe at various pressures.
 Note the one inch pipe capacity at ½ PSI =
  100 CFH and at 50 PSI = 6,138 CFH.
Capacity of Semi-Rigid Tubing in CFH for 0.5 PSI or less
gas pressure and pressure drop of 0.3 Inches WC
(0.60 Specific Gravity Gas)                   Source: NFPA 54 Handbook




             0.5 PSI - 3/4” Pipe @ 200 feet = 30 CFH
Capacity of Semi-Rigid Tubing in CFH for 0.5 PSI or less
gas pressure and pressure drop of 0.5 Inches WC
(0.60 Specific Gravity Gas)                   Source: NFPA 54 Handbook




             0.5 PSI - 3/4” Pipe @ 200 feet = 39 CFH
Maximum Capacity of Pipe in CFH for 0.5 PSI or less gas
pressure and pressure drop of 0.3 Inches WC
(0.60 Specific Gravity Gas)                 Source: NFPA 54 Handbook




              1 PSI - 1” Pipe @ 200 feet = 100 CFH
Maximum Capacity of Pipe in CFH for 0.5 PSI or less gas
pressure and pressure drop of 0.5 Inches WC
(0.60 Specific Gravity Gas)                 Source: NFPA 54 Handbook




             0.5 PSI - 1” Pipe @ 200 feet = 135 CFH
Maximum Capacity of Pipe in CFH for 1    PSI gas pressure
and a pressure drop of 10%
(0.60 Specific Gravity Gas)                    Source: NFPA 54 Handbook




            1 PSI - 1” Pipe @ 200 feet = 338 CFH
Maximum Capacity of Pipe in CFH for 2   PSI gas pressure
and a pressure drop of 10%
(0.60 Specific Gravity Gas)                   Source: NFPA 54 Handbook




           2 PSI - 1” Pipe @ 200 feet = 525 CFH
Maximum Capacity of Pipe in CFH for 5    PSI gas pressure
and a pressure drop of 10%
(0.60 Specific Gravity Gas)                    Source: NFPA 54 Handbook




            5 PSI - 1” Pipe @ 200 feet = 940 CFH
Maximum Capacity of Pipe in CFH for 10     PSI gas pressure
and a pressure drop of 10%
(0.60 Specific Gravity Gas)                    Source: NFPA 54 Handbook




           10 PSI - 1” Pipe @ 200 feet = 1,539 CFH
Maximum Capacity of Pipe in CFH for 20     PSI gas pressure
and a pressure drop of 10%
(0.60 Specific Gravity Gas)                    Source: NFPA 54 Handbook




           20 PSI - 1” Pipe @ 200 feet = 2,680 CFH
Maximum Capacity of Pipe in CFH for 50     PSI gas pressure
and a pressure drop of 10%
(0.60 Specific Gravity Gas)                   Source: NFPA 54 Handbook




          50 PSI - 1” Pipe @ 200 feet = 6,138 CFH
           Questions?
       Fuel Gas Systems
           by: Ron George, CPD


Ron George Design & Consulting Services
       5818 Newport South Rd.
         Newport, MI 48166
           Ph: 734-322-0225
          Cell: 734-755-1908

								
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