exams.htm

NFPA 54-2002 -- ANSI Z223.1-2002

National Fuel Gas Code 2002

Study Guide Only (not affiliated with NFPA)

The purpose of this work is to help students of plumbing learn how to use the gas code to help prepare for the Journey or Master Plumbers License Examination for Maryland (2008). If interested these are the code sections that are based on questions a plumbing/gas inspector suggested I study for my Masters Gas-Fitters License in 1971.

Disclaimer: Charles A. Kruger, Sr., Kruger’s Training Academy or anyone else involved with this training evolution is not guaranteeing the accuracy or completeness of or assume any liability for any of the following material or the way it is presented.

An * indicates explanatory material contained in Annex A. that usually provides the answer to gas questions used on gas examinations. (so says Charlie) Code changes from previous edition are indicated by a vertical rule beside the changed section and code section deletion is indicated by a bullet between the paragraphs that remain.

To study this material first I would read the Contents pages, 54-5 and 54-6, to get an overall view of code. Than read all the following pages in this handout even if it does not sense. The index is next and when you do not understand what it says, look up said code section and start to read it. If unable to figure out what the code is making reference to, write the question down and give me a call. Please make sure you have written question (s) in hand along with the Gas Code. Hopefully I may be able to explain what they are talking about and if not than we will both learn something. This goes for plumbing, math and OSHA questions also. Lets do this together I am offering my help – take advantage of it. Remember write questions down at least in note form, have code book handy and call. Thanks, Charlie Kruger - cell 410.713.2486 call anytime during March, April or May, 2008. This needs to be said, when working on gas I would use the 2006 National Fuel Gas Code Handbook it is a lot different.

Gas School - take it if you can - S & S Training, Inc. in Baltimore. Bill 410-852-7093 or Jim 410-491-5494. This is the old BG&E gas school. The Gas Instructors are outstanding.

The following code reference sheets are not the complete gas code. Check with the Authority having jurisdiction before working on Gas. They can provide the local edition of the Gas Code or at least the amendments to NFPA-54 that is enforced.

1.1 Scope.

1.1.1 Applicability.

1.1.1.1 Safety code which applies to installation of fuel gas systems,

equipment and accessories.

Natural Gas:

Piping system extends from the point of delivery to the connections with each gas utilization device (5 to 8 inches of water column {1/4 psi} Specific gravity .60)

LP Gas:

For undiluted liquefied petroleum gas systems, the point of delivery is the outlet of the service regular or valve second stage (sometimes first) pressure regulator - 9 to 11 inches of water column (first stage usually on larger storage tank and set between 10 and 20 psig).

1.1.1.1B Maximum operating pressure shall be 125 psi - except piping

systems for gas-air mixtures the flammable range is limited to

a max. Pressure of 10 psi. LP systems limited to 20 psi

1.1.1.1D See code for where code does not apply

1.1.2 Other Standards: read manufacturer's instructions.

1.3 Retroactivity:

Can not make change existing gas system if in compliance at time of installation. Note: side arm water heater must be vented.

1.5* Enforcement

Shall be administered and enforced by the authority having jurisdiction

3.0 Definitions – remember to check Annex K “Other Useful

Definitions” page 54-141

4.1 Qualified Agency.

Installed by licensed plumber or gas fitter, check with local authority having jurisdiction for licensing requirements

4.2.1 Notification of Interrupted service:

Notify each affected user before if not an emergency

4.2.2 Work Interruptions:

When complete make safe by plugging all open-ended piping and relight all pilot lights.

4.3.1 Potential Ignition Sources:

Old pipe may still contain gas.

Don't disconnect an electrical ground (provisions for electrical

continuity)

When gas present do not operate electric switches only listed

safety-type flashlights

5.1 Piping Plan

5.1.2 Addition to Existing System:

Check sizing – adjust or run separate pipe from meter

5.2 Provision for Location of Point of Delivery: Check with gas

supplier usually expressed in feet

5.4 Sizing of Gas Piping systems: sized to prevent pressure loss

5.4.1*A a. allowable pressure loss from point of delivery to

equipment is according to manufacture

b. maximum gas demand

c. developed length

d. specify gravity of gas

e. diversity factor

f. foreseeable future demand

5.5 Piping System Operating Pressure Limitations

5.5.1 Maximum Design Operating Pressure

5 psi

5.6 Acceptable Piping Materials and Joining Methods:

Approved by local jurisdiction, 5.6.1.2 used material only used when approved by AA.

5.6.2 Metallic Pipe:

Cast iron is not permitted (exceptions when over 3" dia., outside and underground and joints restrained inside, see local code).

5.6.2.2 Steel pipe minimum schedule 40 (suggest over 2 " not be

threaded see 5.6.8.4 or over 5 psig be welded see 2.5.1).

5.6.3.2* Copper or brass when gas contains more than an average of 0.3

grains of hydrogen sulfide per 100 cubic feet of gas.

5.6.3.3 Aluminum alloy, not underground or in exterior locations.

5.6.3 Metallic Tubing: (not permitted by Balto. City)

Steel, copper, brass, and aluminum-alloy tubing or corrugated stainless steel conduit check with local code.

5.6.9 Plastic Pipe, Tubing and Fittings:

Underground outside only

5.7* Gas Meters

5.7.2.3 Location (premises-owned gas meters):

located readily accessible, not subject to damage, in ventilated space, 3' from sources of ignition measured horizontally (induction motor type electric meters not considered source of ignition, off-peak or timed meters are problem so install 3 feet away)

5.10 Back Pressure.

do not allow air, oxygen or stand-by gases to be forced back into gas main

5.11 Low Pressure Protection.

do not allow gas to be sucked out of gas main (i.e. on gas compressors)

5.12 Shutoff Valves.

When pilot takes nose-dive when burner comes on it may be that the gas cock reduces pressure too much and should be replaced with a full flow gas cock.

5.13 Expansion and Flexibility:

Slip joints or turning threads prohibited, use offsets, control expansion and contraction through anchors and guides.

6.1.2 Protection Against Damage:

protect against external damage from traffic and when passing through flower beds etc.

6.1.2.1 Cover Requirements

buried with a minimum cover of 18", or 12" when external

damage not likely, when less install in conduit or shield

6.1.3* Protection Against Corrosion

No contact with cinders, uncoated threaded or socket welded

joints, if in new area check with gas Co.

6.1.4* Protection Against Freezing:

Only when gas is wet (it takes -260 degrees F. to freeze Natural

gas), Balto City says below frost line when underground

6.1.6 Piping Underground Beneath Buildings:

When unavoidable than encase in approved conduit so when leakage occurs the gas is vented to outside the building.

6.2.3 Other Than Dry Gas:

Requirements for drips, sloping, protection from freezing & branch pipe connections only apply to wet gas. (wet gas has water added by supplier to maintain caulked cast iron joints in old piping systems and cast iron bends in large underground piping). According to the Baltimore Gas and Electric Company consider gas as wet local supplier may be different, if not called dry gas than answer test questions as gas being wet.

6.2.4 Gas Piping to be Sloped:

Sloped 1/4" in 15 feet to prevent traps. Grade back to meter if possible. Otherwise grade to the lowest piece of equipment.

6.2.5* Prohibited Locations:

Piping not run in or through ducts, clothes chutes, chimneys, vents or shafts.

6.3 Concealed Piping in Buildings:

Gas piping may be installed in concealed locations in accordance with section

6.3.2 Connections:

No unions, tubing fittings (even if brazed), running threads, right and left couplings, bushings or swing joints permitted installed in concealed locations. Center-punched ground joint unions are permitted.

6.3.3 Piping in Partitions:

Concealed gas piping shall not be located in solid partitions (may run through a ventilated chase)

6.3.4 Tubing in Partitions:

If run horizontally inside hollow walls shall be encased full length inside of pipe sleeve.

If run vertically provide a steel striker barrier (16-gage), extend 4" beyond concealed penetrations of plates, sill, fire stops ect.; the tubing in shall not be rigidly secured (when free to move less chance of a nail being driven into it).

6.3.5 Piping in Floors:

In concrete floors piping shall be laid in accessible channels

(suggest channels be vented). See code for nonindustrial applications when Portland cement is used. (Note. Salt ions not permitted see data sheet if chloride ions used to cause Portland cement to set up fast)

6.4 Piping in Vertical Chases:

Build chase in accordance with local building code and vent to outdoors at the top only (check if LP vented at bottom). Use welded joints on horizontal line instead of chase.

6.5 Gas Pipe Turns.

Approved fittings, factory or field bends (use special tools not around your knee).

6.6 Drips and Sediment Traps.

Install where condensate may collect, when condensation is excessive provide a drip on the outlet of the meter, installed as to constitute a trap protecting meter from backflow of condensate.

A drip (leg) when required is installed at a low point to catch condensate and has to be protected against freezing and serviced (gas cock required on incoming side). A sediment trap is required if the appliance does not have one build in. It does not require servicing or protection against freezing. It catches dirt and pipe cuttings placed in the system during the original installation (gas cock on either side).

6.6.2 Location of Drips:

Installed readily accessible and where not subject to freezing

6.7 Outlets.

6.7.1 Location and Installation:

Outlets shall be securely fastened in place, not located behind doors, located so wrenches can be used without hurting pipe threads. The unthreaded portion shall extend not less than 1 inch through ceilings or walls and 2 inches above floors, patios or slabs (check local code before installing gas pipe under concrete).

6.7.2 Cap All Outlets:

Seal all outlets with a threaded plug or cap. This includes downstream side of gas cocks and valves.

6.8 Branch Pipe Connection:

Except on LP gas, connect to top or side of main not to bottom. Branch outlet for future use same size as main.

6.9 Shutoff Valves for Multiple House Lines:

If meter or regulator shutoff are not readily accessible than and individual shutoff valve is required for each tenant line or each building on a common system serving several building.

6.10 Prohibited Devices:

No device that may obstruct the free flow of gas permitted unless approved (i.e. orifice meter set assembly on large boiler).

6.13 Electrical Bonding and Grounding:

Aboveground portion of a gas piping system upstream from the equipment shutoff valve shall be electrically continuous and bonded to appliances (3-pronged plug is grounded) it serves if not and the appliance (2-pronged type) fails and causes the gas pipe to become energized than backup ground by separate bonding system should be in place

6.14 Electric Circuits

Pipe not to be used as a grounding electrode except for bonding.

6.15 Electrical Connections:

Electric safety controls shall shut off gas in the event of current failure. (When electric goes off electric vent damper must go off)

7.1.2 Test Medium:

Test with air; nitrogen, + carbon dioxide) NEVER USE OXYGEN Gas may be used in system operating pressure ½psi or less

7.1.3 Test Preparation:

Leave piping exposed, secure expansion joints, shut off or disconnect equipment, the piping system is to be tested not the equipment itself.

7.1.4.1 Highest end of gage scale not more than 5 times test pressure

7.1.4.2 1 1/2 times the maximum working pressure or at least 3 psig.

7.1.4.3 Test Duration:

min. 10 minutes or 1/2 hour per 500 cu. foot of pipe

7.2.2 Before Turning Gas On:

Check and make sure all openings closed.

7.2.3* Check for Leakage:

When looking for a leak do not operate electric switches. If electric lights are already turned on they should not be turned off.

A.Appen D Checking for Leakage Using the Gas Meter (NaturalGas)

Watch the test dial of the gas meter, wet a small piece of paper and paste its edge over dial hand, wait 5 minutes for a 1/2-foot dial. If no leak than turn on something and make sure dial registers gas usage.

B. Checking for Leakage Not Using a Meter (Natural Gas)

Use manometer (U-gauge or dial type), attach manometer to appliance orifice, read, turn gas off, wait 3 minutes, read again, should be no pressure drop

(2) LP-gas, charge section between first and second regulator to normal pressure, reduce to 10 psi initial pressure. Watch the meter test hand or test gage for 10 minutes.

7.2.4 Placing Equipment in Operation:

All piping purged on equipment before placed in operation

7.3.3 Discharge of Purged Gases:

To well ventilated area, avoid a flammable gas-air mixture.

8.1* Appliances, Accessories and Equipment to be "Approved"

Acceptable to the authority having jurisdiction. (Min. Safety Standard AGA, NFPA, ANSI, ASME ect.)

8.1.3 Added or Converted Equipment:

Check for combustion and ventilation air (5.3), and clearances to combustible material 5.2.2)

8.1.3 Type of Gas(es):

Make sure equipment set up for use with gas supplied. Convert to different gas only after consulting manufacturer's instructions and/or serving gas supplier. If burners are ok for both fuels than you may only have to change the burner and pilot orifice(s) and regulator.

8.1.6* Protection of Gas Equipment from Fumes or Gases

Other than Products of Combustion:

Provide safe disposal of corrosive or flammable process fumes (i.e. carbon monoxide, hydrogen sulfide, ammonia, chlorine ect.).

8.1.10.1 Installation in Residential Garages:

Burners and burner ignition devices min. 18" above the floor

8.1.11 Installation in Commercial Garages:

Overhead heaters min. 8' from floor and burners and burner ignition devices min. 18" above the floor.

8.1.16 Adequate Capacity of Piping:

When adding equipment on existing system check size & upgrade or run separate pipe from meter

8.1.17 Avoid Strain on Gas Piping:

Installed so no strain on connections & use stanchions.

8.1.18 Gas Appliance Pressure Regulators:

Install when pressure higher than equipment demand or varies beyond the design pressure limit.

8.1.19 Venting of Gas Appliance Pressure Regulators:

Bleed lines shall terminate outside of building, point down, screened and flared abut 40 degrees. Check instructions, not needed if vent limiting device part of listed equipment.

8.1.22 Installation Instructions:

Follow manufacturer's instructions and leave same on premises for use by inspectors, servicemen and owner or operator.

8.2.1 Accessibility for Service:

Permit access to equipment. Sufficient clearance for cleaning, maintenance (building codes 30 inches in front of units) Floored passageway (building code 24 inches) in attic to equipment.

8.2.2 Clearance to Combustible Materials:

equipment and vent connectors in part 6. Not installed on carpeting unless listed.

8.3.1* Air for Combustion and Ventilation:

See code does not apply to direct vent equipment. Check building code may be more fresh air requirements for many occupancies than Gas code combustion and ventilation air sections

8.3.7 Louvers and Grilles:

Screens used shall not be smaller than 1/4" mesh. It may be assumed that wood louvers will have 20-25 percent free area and metal louvers and grills have 60-75 percent.

8.4.2.2 Installation of Equipment on Roofs:

At least 6 ft. of clearance between gas equipment and roof edge or need guard rails - See Code

8.5.1 Connecting Gas Equipment:

1. Rigid metallic pipe and fittings.

2. Semi-rigid tubing extensions of a tubing piping system (not

allowed in Balto. City) Aluminum alloy not permitted outside

3. Listed connectors in same room.

4. CSST per manufacture instructions

5. Listed gas hose connectors.

6. Commercial cooking equipment ok to use quick

listed disconnect

7. protect tubing against physical damage

8.5.4 Equipment Shutoff Valves and Connections:

Accessible manual shutoff within 6 foot of equipment, if connector is used a valve installed upstream & with union downstream.

8.5.7 Sediment Trap:

Required if one not part of the gas utilization equipment. Not required on ranges, clothes dryers and outdoor grills.

8.6.3 Electrical Circuit:

In accordance with manufacturers wiring diagrams.

9.2.2 Connection of Gas Engine-Powered Air Conditioners:

Shall not be rigidly connected.

9.2.7 Switches in Electrical Supply Line:

Interrupting means within sight and not over 50 feet away

9.3.4 Temperature or Pressure Limiting Devices:

Shuts gas off and not used as an operating control

9.3.5 Low Water Cutoff:

On steam boilers and hot water boilers installed above radiation level - shuts of gas when low on water

9.3.6* Steam Safety and Pressure Relief Valves:

Conform to ASME requirements. No shutoff valve before or

after

9.11 Floor Furnaces

9.11.1 Thermostats:

Located in same room as grill

9.11.8 Access:

Foundation opening & passageway min 24" x 18" or trap door 24" by 24"

9.11.10 Wind Protection:

Protect pilot from wind when craw space does not have a foundation wall

9.11.3 Ventilation:

Properly ventilate the space to permit proper combustion of the gas

9.12 Food Service (Commercial Cooking) Equipment, Floor Mounted

See Code

9.13.1 Vertical Clearance:

Min. 48" between top of commercial hot plates & griddles to combustible material

9.14 Hot Plates and Laundry Stoves.

1. Listed min. 6" horizontal distance to combustible material

2. Unlisted min 12" horizontal distance to combustible material

3. Min. 30" vertical distance to combustible material

9.22 Refrigerators:

Gas fired need room to breathe, min. 2" behind the back and 12" above the top.

9.23 Room Heaters.

9.23.1* Prohibited Installations:

Unvented type not installed in sleeping areas or bathrooms. Reason lack of combustion air and close proximity to flammable materials like towels. Some listed wall-mounted with oxygen depletion safety shutoff system are approved in some areas

9.23.2 Installations in Institutions:

Prohibited in residential board and care or health care like homes for the aged, sanitariums, convalescent homes, orphanages, etc

9.23.3 Clearance: - see code (never let interfere with combustion air or

accessibility)

9.25 Gas-Fired Toilets:

Follow manufacturer's instructions.

9.27 Wall Furnaces

9.27.1.3 Type B-W Gas Vents: (behind wall) listed vented wall furnaces

9.28 Water Heaters:

9.28.1 Prohibited Installations:

Not installed in bathrooms, bedrooms or any occupied rooms normally kept closed except direct vent type or is a weather-stripped closet with outside combustion air

9.28.1.2 Location:

Close as practicable to chimney or gas vent. Permit observation, maintenance & servicing.

9.28. Clearance:

In accordance with manufacturer's instructions

9.28.3 Pressure Limiting Devices:

overpressure protection

9.28.4 Temperature Limiting Devices:

Over temperature protection, heaters come with an energy cut-off (ECO) device and install a pressure and temperature relief valve (P & T). (ECO device is like a fuse on electric)

Part 10 Venting of Equipment.

10.1 General:

"The operating characteristics of vented gas utilization equipment can be categorized with respect to: (1) positive or negative pressure within the venting system; and (2) whether or not the equipment generates flue or vent gases which may condense in the venting system".

When manufacturers boost efficiency by lowering the temperature of flue gases condensation is formed.

Four different categories;

Category I. non-positive vent pressure (natural, gravity or chimney draft, conventional vent system i.e. single wall pipe, type B pipe or masonry chimney, etc.) temperature is at least 140 degrees F. above its dew-point

Category II. non-positive, temperature is less than 140 degrees F. above its dew-point, see manufacturers instructions

Category III. positive (induced draft); temperature is at least 140 degrees F. above its dew-point, see manufacturers instructions

Category IV. positive, temperature is less than 140 degrees F. above its dew-point, see manufacturers instructions

10.2.2 Equipment not required to be vented:

1. Listed ranges

2. Built-in domestic cooking units

3. Hot plates & laundry stoves

4. Type 1 clothes dryers (domestic type)

5. Dishwasher type booster heaters (see code)

6. Refrigerators

7. Counter appliances

8. Listed unvented room heaters

9. Direct fired make-up air heaters

10. Listed equipment for unvented use and not provided with

flue collars

11. Laboratory burners or gas lights

10.2.3* Ventilating Hoods

can be used to vent gas equipment in commercial work

10.3.1 Minimum Safe Performance

Adequate for positive flow of vent gases to outside

10.3.2 Equipment Draft Requirements: (Adequate Draft)

shall develop a positive flow adequate to remove flue gases to the outside atmosphere on high efficiency models check manufacturers instructions

10.3.6 Circulating Air Ducts and Plenums:

no venting system shall not extend into or pass through

10.4.1 Type of Venting System to be Used in accordance with table

Category I equipment ok to use and chimneys (10.5), type B gas vent (10.6) or single wall metal pipe (10.7), listed chimney lining system (10.5.1.3) wall furnaces type B-W gas vent (10.6, 9.27) outside incinerators & gas-fired toilets use single wall (10.7.3) direct vent (10.2.5) integral vent (10.2.6) comb. Gas and oil fuel uses type L vent (10.6 or .5)

Category 2, 3, or 4 shall be according to the manufacturers instructions 10.4.2 + 3) for rest of equipment see code

10.5 Masonry, Metal and Factory-Build Chimneys: ok to use for venting

10.5.1.3 if chimney lining is listed just for gas appliances with draft hoods than do not connect solid or liquid fuel-burning appliances or incinerators and post same

10.5.2 Termination

10.5.2.1 chimney for residential or low-heat extends min 3 ft above roof and 2 ft above anything within 10 ft.

10.5.2.2 chimney for medium-hear equipment extends min 10 ft. higher than anything within 25 ft. residential or low-heat

10.5.2.3 chimney shall extend a min 5 ft above the highest connected draft hood or flue collar

10.5.2.4 decorative shrouds not permitted

10.5.3 Size of Chimneys

10.5.3.1 (2) individual chimney venting a single appliance with draft hood the effective areas of the vent connector: min the same area of draft hood outlet but never more than seven times the area, ok to use listed vent caps when min 8 ft from a vertical wall and in accordance with table 10.6.2

10.5.3.1 (3) if serving two appliances with draft hoods the effective area of larger draft hood plus 50 % of the area of the smaller draft hood.

10.5.4 if Chimney used for different fuel (like solid instead of gas) it shall be cleaned prior to being put back in service.

10.5.5.1 Gas utilization equipment shall not be connected to solid fuel burning equipment.

10.5.5.3* listed combination gas and solid fuel-burning appliance connected to the same chimney shall have a manual reset device to shut of gas in the event of back draft or flue gas spillage.

10.6 Gas Vents

10.6.1(4) Type B or L vents horizontal section shall not exceed 75% of vertical section

10.6.1(6) gas vents installed within masonry chimneys shall be tagged stating used only to vent gas no solid or liquid fuel-burning equipment vented

10.6.2 Gas Vent Termination:

3' above the highest point where it passes through a roof and at least 2' higher than any portion of building within a horizontal distance of 10'

10.6.2 (1) shall terminate a min of 2 ft above anything located within 10 feet and a listed cap minimum 8 ft from a vertical wall and in accordance with table 10.6.2

10.6.2 (2) Type B or L gas vent shall terminate at least 5 above the highest draft hood or flue collar

10.6.2 (3) Type B-W (behind wall) gas vent shall terminate at least 12 ft above the wall furnace

10.6.2 (4) vent terminates above roof not adjacent to eaves or parapets except see code 10.2.5 and 10.3.4

10.6.2 (5) decorative shrouds per manufacturers’ instructions

10.7.5 Single Wall Metal Pipe (stove pipe). see 10.7 10.7.3

used on residential-type low-heat equipment with draft hoods, incinerators used outdoors and gas-fired toilets

10.10.3* Size of Vent Connector:

usually area of larger vent plus %50 of smaller

10.10.6 Avoid Unnecessary Bends:

Avoid excessive resistance to gas flow

10.10.7 Joints: sheet metal screws or manufacturers’ instructions

10.10.8 Slope: slope (rise)upward at least 1/4" per foot, no drips or sags

10.10.9 Length of Vent Connector:

10.10.9.1 keep as short as possible

10.10.9.2*

except when part of a designed vent system, hor. run of an uninsulated vent shall not be more than 75 percent of the vertical height of the vent or chimney, when insulated 100 percent of the vertical height

10.10.11 Chimney Connection:

installed above extreme bottom and prevent connector from entering too far

10.10.12 Inspection:

entire vent connector readily accessible

10.10.13 Fireplaces:

not connected to a fireplace flue unless fireplace opening is permanently sealed.

11.1 Burner Input:

adjusted to its proper input according to manufacturer's instructions

11.1.1* Adjusting Input:

by changing a fixed orifice size, adjustment of an adjustable orifice, by readjustment of gas pressure regulator outlet pressure (when provided), consult the serving gas supplier

use a "U Gauge" manometer or pressure gauge.

11.1.2 High Altitude: 2000’ above sea level adjust pressure

11.2* Primary Air Adjustment.

In accordance with manufactures instructions [note: on injection (Bunsen) type burners adjust to a point where the yellow (luminous) tips disappear. When shutter is open hard blue flame and closed soft flame with yellow-orange appearance. On LP-gas, a slight yellow tip may be normal]

11.3 Safety Shutoff Devices.

check for proper operation and fix or replace if needed

11.4 Automatic Ignition.

check for proper operation and adjust if needed

11.5 Protective Devices.

limit control, fan control to blower, p & t relief valve, low water cutoff device, manual operating features, etc, shall be checked

11.6 Checking the Draft.

Operate equipment, check draft with match test , if not extinguish then there is draft

11.7 Operating Instructions.

leave manufacturers instructions in a prominent position near the equipment for use by the consumer or inspector