NEW MEXICO GF-9 UTILITY LINES VERIFIED EXAM SOLUTIONS -
COMPREHENSIVE QUESTIONS AND ANSWERS - CURRENT VERSION
(2026/2027)
Q1: What does GF-9 stand for in New Mexico utility line work?
ANSWER GF-9 refers to the Gas Fitter license classification for utility lines,
specifically for those working on natural gas and propane distribution systems in New
Mexico.
Q2: Which agency regulates utility line work in New Mexico?
ANSWER The New Mexico Public Regulation Commission (PRC) and the New
Mexico Gas Company regulations, along with the New Mexico Construction
Industries Division (CID), regulate utility line work.
Q3: What is the minimum safe distance a worker must maintain from an energized
overhead power line?
ANSWER Workers must maintain a minimum of 10 feet from energized overhead
power lines up to 50kV, with additional distance required for higher voltages.
Q4: What federal regulation governs natural gas pipeline safety?
ANSWER 49 CFR Parts 191-199 (Pipeline Safety Regulations) governed by the
Pipeline and Hazardous Materials Safety Administration (PHMSA) govern natural gas
pipeline safety.
Q5: What is 'Call Before You Dig' in New Mexico?
ANSWER New Mexico's 'Call Before You Dig' program requires contacting 811 (the
national dig safe number) at least 2 business days before any excavation to have
underground utilities marked.
Q6: How many hours before excavation must you notify New Mexico 811?
ANSWER You must notify New Mexico 811 at least 2 full business days (48 hours)
before excavation begins, excluding weekends and holidays.
Q7: What color markings indicate natural gas or petroleum gas lines?
ANSWER Yellow markings/flags/paint indicate natural gas, oil, steam, petroleum,
and other gaseous/flammable materials per the APWA Uniform Color Code.
Q8: What color indicates electric power lines in utility marking?
New Mexico GF-9 Utility Lines Study Guide | Page 1
, ANSWER Red markings indicate electric power lines, conduit, and cables.
Q9: What color indicates water lines in utility marking?
ANSWER Blue markings indicate potable water lines.
Q10: What color indicates sewer lines in utility marking?
ANSWER Green markings indicate sanitary sewer and drain lines.
Q11: What color indicates telecommunications and alarm lines?
ANSWER Orange markings indicate telecommunications, alarm, signal lines, cables,
and conduit.
Q12: What color indicates reclaimed water or irrigation lines?
ANSWER Purple markings indicate reclaimed water, irrigation, and slurry lines.
Q13: What is the maximum allowable operating pressure (MAOP) for most
residential gas service lines?
ANSWER The MAOP for residential gas service lines is typically 0.5 psig (14 inches
water column) for low-pressure systems, or up to 2 psig for medium-pressure
residential systems.
Q14: What is a tracer wire and why is it required?
ANSWER A tracer wire is a continuous metallic wire installed with non-metallic
pipelines to allow electronic detection of the pipe's location. It is required by NFPA 54
and local codes to facilitate future locating of buried plastic gas lines.
Q15: What minimum cover depth is required for gas distribution lines in road
crossings in New Mexico?
ANSWER Gas distribution lines at road crossings must have a minimum cover of 24
inches (2 feet) in normal soil, with greater depth in areas subject to frost or heavy
traffic.
Q16: What is the minimum cover required for gas lines in normal (non-road) areas?
ANSWER The minimum cover depth for gas distribution lines in normal areas is 18
inches in residential and commercial areas, and 24 inches in agricultural land.
Q17: What type of pipe material is most commonly used for modern underground
gas distribution?
ANSWER Polyethylene (PE) plastic pipe is most commonly used for modern
underground gas distribution due to its corrosion resistance, flexibility, and ease of
installation.
Q18: What is the purpose of a cathodic protection system on metallic gas pipes?
New Mexico GF-9 Utility Lines Study Guide | Page 2
, ANSWER Cathodic protection prevents corrosion of metallic gas pipes by using an
impressed electrical current or sacrificial anodes to make the pipe cathodic (negatively
charged), preventing electrolytic corrosion.
Q19: What does OSHA Standard 1926.651 cover?
ANSWER OSHA Standard 1926.651 covers excavation and trenching safety
requirements, including requirements for safe access and egress, hazardous
atmospheres, and protective systems.
Q20: At what depth does an excavation require a protective system per OSHA?
ANSWER Any excavation 5 feet or deeper in which an employee may be exposed to
cave-in requires a protective system (sloping, shoring, or trench box) unless the
excavation is in stable rock.
Q21: What are the four soil types classified by OSHA for excavation safety?
ANSWER OSHA classifies soils as: Stable Rock, Type A (most stable), Type B
(moderately stable), and Type C (least stable, including submerged or fissured soils).
Q22: What is the maximum allowable slope for Type C soil in a trench?
ANSWER Type C soil requires a maximum slope of 1.5:1 (horizontal to vertical),
meaning for every 1 foot of depth, 1.5 feet of horizontal setback is required.
Q23: What is a competent person in excavation safety?
ANSWER A competent person is one who can identify existing and predictable
hazards, has authority to take corrective action, and is capable of classifying soil and
inspecting protective systems.
Q24: How often must an excavation be inspected by a competent person?
ANSWER Excavations must be inspected by a competent person daily before work
begins, after any hazard-increasing event (rain, etc.), and as working conditions
change.
Q25: What is the maximum distance from an excavation that spoils (excavated
material) must be placed?
ANSWER Spoils must be placed at least 2 feet (0.6 meters) from the edge of an
excavation to prevent cave-ins.
Q26: What personal protective equipment (PPE) is required for gas line work?
ANSWER Required PPE typically includes hard hat, safety glasses or goggles, steel-
toed boots, gloves, high-visibility vest, and hearing protection when operating loud
equipment.
Q27: What should you do if you strike a gas line during excavation?
New Mexico GF-9 Utility Lines Study Guide | Page 3
, ANSWER Stop excavation immediately, evacuate the area, eliminate ignition
sources, call 911 and the gas company emergency line, do not use radios or cell
phones near the leak, and establish a safety perimeter.
Q28: What is the lower explosive limit (LEL) of natural gas in air?
ANSWER The Lower Explosive Limit (LEL) of natural gas (methane) in air is
approximately 5% by volume.
Q29: What is the upper explosive limit (UEL) of natural gas in air?
ANSWER The Upper Explosive Limit (UEL) of natural gas (methane) in air is
approximately 15% by volume.
Q30: What odorant is added to natural gas and why?
ANSWER Mercaptan (ethyl mercaptan or tertiary butyl mercaptan) is added to
natural gas to give it a distinctive rotten egg odor for leak detection, since natural gas
is otherwise odorless.
SECTION 2: PIPE INSTALLATION & MATERIALS
Q31: What does ASTM stand for and why is it relevant to utility lines?
ANSWER ASTM stands for American Society for Testing and Materials. It
establishes standards for pipe materials, fittings, and testing procedures used in utility
line installation.
Q32: What is SDR pipe and what does SDR stand for?
ANSWER SDR stands for Standard Dimension Ratio, which is the ratio of the pipe's
outside diameter to its wall thickness. A lower SDR number indicates a thicker-
walled, higher-pressure-rated pipe.
Q33: What SDR rating is commonly used for gas distribution polyethylene pipe?
ANSWER SDR 11 and SDR 17 are commonly used for gas distribution PE pipe,
with SDR 11 having a higher pressure rating and being preferred for higher-pressure
applications.
Q34: What is the preferred method for joining polyethylene gas pipe in the field?
ANSWER Heat fusion (butt fusion, socket fusion, or electrofusion) is the preferred
method for joining polyethylene gas pipe, creating a continuous, leak-free joint as
strong as the pipe itself.
Q35: What is butt fusion welding of PE pipe?
ANSWER Butt fusion is the process of heating the squared ends of two PE pipe
sections against a heated plate until molten, then pressing them together to form a
monolithic fused joint.
New Mexico GF-9 Utility Lines Study Guide | Page 4
COMPREHENSIVE QUESTIONS AND ANSWERS - CURRENT VERSION
(2026/2027)
Q1: What does GF-9 stand for in New Mexico utility line work?
ANSWER GF-9 refers to the Gas Fitter license classification for utility lines,
specifically for those working on natural gas and propane distribution systems in New
Mexico.
Q2: Which agency regulates utility line work in New Mexico?
ANSWER The New Mexico Public Regulation Commission (PRC) and the New
Mexico Gas Company regulations, along with the New Mexico Construction
Industries Division (CID), regulate utility line work.
Q3: What is the minimum safe distance a worker must maintain from an energized
overhead power line?
ANSWER Workers must maintain a minimum of 10 feet from energized overhead
power lines up to 50kV, with additional distance required for higher voltages.
Q4: What federal regulation governs natural gas pipeline safety?
ANSWER 49 CFR Parts 191-199 (Pipeline Safety Regulations) governed by the
Pipeline and Hazardous Materials Safety Administration (PHMSA) govern natural gas
pipeline safety.
Q5: What is 'Call Before You Dig' in New Mexico?
ANSWER New Mexico's 'Call Before You Dig' program requires contacting 811 (the
national dig safe number) at least 2 business days before any excavation to have
underground utilities marked.
Q6: How many hours before excavation must you notify New Mexico 811?
ANSWER You must notify New Mexico 811 at least 2 full business days (48 hours)
before excavation begins, excluding weekends and holidays.
Q7: What color markings indicate natural gas or petroleum gas lines?
ANSWER Yellow markings/flags/paint indicate natural gas, oil, steam, petroleum,
and other gaseous/flammable materials per the APWA Uniform Color Code.
Q8: What color indicates electric power lines in utility marking?
New Mexico GF-9 Utility Lines Study Guide | Page 1
, ANSWER Red markings indicate electric power lines, conduit, and cables.
Q9: What color indicates water lines in utility marking?
ANSWER Blue markings indicate potable water lines.
Q10: What color indicates sewer lines in utility marking?
ANSWER Green markings indicate sanitary sewer and drain lines.
Q11: What color indicates telecommunications and alarm lines?
ANSWER Orange markings indicate telecommunications, alarm, signal lines, cables,
and conduit.
Q12: What color indicates reclaimed water or irrigation lines?
ANSWER Purple markings indicate reclaimed water, irrigation, and slurry lines.
Q13: What is the maximum allowable operating pressure (MAOP) for most
residential gas service lines?
ANSWER The MAOP for residential gas service lines is typically 0.5 psig (14 inches
water column) for low-pressure systems, or up to 2 psig for medium-pressure
residential systems.
Q14: What is a tracer wire and why is it required?
ANSWER A tracer wire is a continuous metallic wire installed with non-metallic
pipelines to allow electronic detection of the pipe's location. It is required by NFPA 54
and local codes to facilitate future locating of buried plastic gas lines.
Q15: What minimum cover depth is required for gas distribution lines in road
crossings in New Mexico?
ANSWER Gas distribution lines at road crossings must have a minimum cover of 24
inches (2 feet) in normal soil, with greater depth in areas subject to frost or heavy
traffic.
Q16: What is the minimum cover required for gas lines in normal (non-road) areas?
ANSWER The minimum cover depth for gas distribution lines in normal areas is 18
inches in residential and commercial areas, and 24 inches in agricultural land.
Q17: What type of pipe material is most commonly used for modern underground
gas distribution?
ANSWER Polyethylene (PE) plastic pipe is most commonly used for modern
underground gas distribution due to its corrosion resistance, flexibility, and ease of
installation.
Q18: What is the purpose of a cathodic protection system on metallic gas pipes?
New Mexico GF-9 Utility Lines Study Guide | Page 2
, ANSWER Cathodic protection prevents corrosion of metallic gas pipes by using an
impressed electrical current or sacrificial anodes to make the pipe cathodic (negatively
charged), preventing electrolytic corrosion.
Q19: What does OSHA Standard 1926.651 cover?
ANSWER OSHA Standard 1926.651 covers excavation and trenching safety
requirements, including requirements for safe access and egress, hazardous
atmospheres, and protective systems.
Q20: At what depth does an excavation require a protective system per OSHA?
ANSWER Any excavation 5 feet or deeper in which an employee may be exposed to
cave-in requires a protective system (sloping, shoring, or trench box) unless the
excavation is in stable rock.
Q21: What are the four soil types classified by OSHA for excavation safety?
ANSWER OSHA classifies soils as: Stable Rock, Type A (most stable), Type B
(moderately stable), and Type C (least stable, including submerged or fissured soils).
Q22: What is the maximum allowable slope for Type C soil in a trench?
ANSWER Type C soil requires a maximum slope of 1.5:1 (horizontal to vertical),
meaning for every 1 foot of depth, 1.5 feet of horizontal setback is required.
Q23: What is a competent person in excavation safety?
ANSWER A competent person is one who can identify existing and predictable
hazards, has authority to take corrective action, and is capable of classifying soil and
inspecting protective systems.
Q24: How often must an excavation be inspected by a competent person?
ANSWER Excavations must be inspected by a competent person daily before work
begins, after any hazard-increasing event (rain, etc.), and as working conditions
change.
Q25: What is the maximum distance from an excavation that spoils (excavated
material) must be placed?
ANSWER Spoils must be placed at least 2 feet (0.6 meters) from the edge of an
excavation to prevent cave-ins.
Q26: What personal protective equipment (PPE) is required for gas line work?
ANSWER Required PPE typically includes hard hat, safety glasses or goggles, steel-
toed boots, gloves, high-visibility vest, and hearing protection when operating loud
equipment.
Q27: What should you do if you strike a gas line during excavation?
New Mexico GF-9 Utility Lines Study Guide | Page 3
, ANSWER Stop excavation immediately, evacuate the area, eliminate ignition
sources, call 911 and the gas company emergency line, do not use radios or cell
phones near the leak, and establish a safety perimeter.
Q28: What is the lower explosive limit (LEL) of natural gas in air?
ANSWER The Lower Explosive Limit (LEL) of natural gas (methane) in air is
approximately 5% by volume.
Q29: What is the upper explosive limit (UEL) of natural gas in air?
ANSWER The Upper Explosive Limit (UEL) of natural gas (methane) in air is
approximately 15% by volume.
Q30: What odorant is added to natural gas and why?
ANSWER Mercaptan (ethyl mercaptan or tertiary butyl mercaptan) is added to
natural gas to give it a distinctive rotten egg odor for leak detection, since natural gas
is otherwise odorless.
SECTION 2: PIPE INSTALLATION & MATERIALS
Q31: What does ASTM stand for and why is it relevant to utility lines?
ANSWER ASTM stands for American Society for Testing and Materials. It
establishes standards for pipe materials, fittings, and testing procedures used in utility
line installation.
Q32: What is SDR pipe and what does SDR stand for?
ANSWER SDR stands for Standard Dimension Ratio, which is the ratio of the pipe's
outside diameter to its wall thickness. A lower SDR number indicates a thicker-
walled, higher-pressure-rated pipe.
Q33: What SDR rating is commonly used for gas distribution polyethylene pipe?
ANSWER SDR 11 and SDR 17 are commonly used for gas distribution PE pipe,
with SDR 11 having a higher pressure rating and being preferred for higher-pressure
applications.
Q34: What is the preferred method for joining polyethylene gas pipe in the field?
ANSWER Heat fusion (butt fusion, socket fusion, or electrofusion) is the preferred
method for joining polyethylene gas pipe, creating a continuous, leak-free joint as
strong as the pipe itself.
Q35: What is butt fusion welding of PE pipe?
ANSWER Butt fusion is the process of heating the squared ends of two PE pipe
sections against a heated plate until molten, then pressing them together to form a
monolithic fused joint.
New Mexico GF-9 Utility Lines Study Guide | Page 4
