SECTION 17 - RESIDENTIAL/LIGHT
COMMERCIAL BASED ON NC H3-1 SAMPLE
LICENSE EXAM WITH ALL CORRECT &
VERIFIED ANSWERS
what is the minimum width of the required continuous solid flooring along the required access path
to an attic appliance?
1. 22 inches
2.24 inches
3.16 inches
4. none required Correct answer-Answer 2/ 2018 NC mechanical code section 306.3 pages 22 and
section 306.3 2018 NCFGC page 21
when smoke detectors are required by the code, they shall be installed based on which of the
following?
1. the 2018 NC mechanical code
2. NFPA 70
3. the 2018 NC fire code
4. NFPA 72 Correct answer-Answer 4/ 2018 NC mechanical code section {F}606.3 page 74
what is the latent load for 200 people working in a factory as a machine tool operator?
1. 125,000 btu/hr
2. 35,000 btu/hr
3. 12,300 btu/hr
4. 96,500 btu/hr Correct answer-Answer 1
ACCA manual-N version 5 table 6B
625 btu/hr per person x 200 people = 125,000 btu/hr
a building used for light industrial assembly is in ashville , north carolina and has a roof deck that sits
on structural steel with a suspended ceilling below. the roof deck consists of 1.5" thick wood with R-3
insulation board and a suspended ceiliing below with R-19 insulation located on the ceiling tile . what
is the heat loss for this assembly on a design winter day if the roof measures 250 feet long by 40 feet
wide and the indoor temperature is to be maintained at 70'F?
1. 26,450 btu/hr
2. 19,980 btu/hr
3. 29,220 btu/hr
4. 10,900 btu/hr Correct answer-Answer 2
ACCA Manual-N version 5 table 6B
table 4 construction # 17B-3w-x provides a u-value for the assembly of 0.037
Ashville outdoor winter design temperature is 16'F and the indoor temperature is 70'F making the
temperature difference(delta-T) across the heat transfer surface 54'F
.037x54(250x40)=19,980 btu/hr
a 24" round spiral duct is being used for a main return duct in a high-class restaurant, what is the
approximate maximum cfm based on the velocity restrictions in ACCA manual -Q?
,1. 4600 cfm
2. 3800 cfm
3. 5800 cfm
4.6000 cfm Correct answer-Answer 1
ACCA manual-Q figure A3-6, page A3-9 specifies a maximum velocity of 1500 feet per minute
using auxiliary calculations side of the duct calculator the volume would be 4600 cfm
you have calculated the longest length in an existing a CSST gas piping system to be 80 feet . you will
be adding a line to a new gas appliance that needs 45,000 btu/hr of natural gas that will be 15 feet
long. the existing system your adding on to consists of a 1/2 pound gas meter with a design pressure
drop of 0.5 IWC and the gas has a specific gravity of 0.60. what is the minimum size CSST size you can
run to the new appliance according the code?
1. EHD 18
2. EHD 19
3. EHD 23
4. EHD 25 Correct answer-Answer 3
2018 NC fuel gas code table 402.4(15) page 45
when running a residential load estimate for climate zone 3 in north carolina, what is the minimum
solar heat gain coefficient you can use for the glass?
1. .20
2. .30
3. .35
4. .40 Correct answer-Answer 2
2018 NC energy code table R402.1.2 page R-16
when running PVC pipe underground for use as part of a domestic kitchen exhaust system , no more
than _______ inches of PVC duct is allowed to extend above the concrete floor surface .
1. 1 inch
2. 4 inches
3. 6 inches
4. no limit Correct answer-Answer 1
2018 NC mechanical code section 505.1 exception 2.3 page 49
a rectangular duct measures 40" x 34" on the outside and has 2" of duct insulation lining the duct.
what is the equivalent round duct size?
1. 36" round
2. 35.9" round
3. 38" round
4. 40" round Correct answer-Answer 2
convert duct to clear inside dimensions
40" - 4" of liner = 36"
34"-4" of liner=30"
per ACCA manual - Q A3-1 on page A3-2 the equivalent round duct size is 35.9"
sediment traps are required in gas piping systems and must be located _______?
, 1. where the gas piping enters the building
2. near the equipment in a convenient location
3. located in the same room and within 6 feet of the appliance
4.after the appliance shutoff valve and as close as possible to the inlet of equipment Correct
answer-Answer 4
2018 NC fuel gas code section 408.4 page 76
a residential system design requires 1000 cfm. the air handler you chose can deliver 1000 cfm at an
external static pressure of .30 the duct system has a total equivalent length of 475 feet , so the
design friction rate is ?
1. 0.1 fr/100'
2. 0.08 fr/100'
3. 0.05 fr/100'
4. 0.063 fr/100' Correct answer-Answer 4
ACCA manual -D appendix 1
friction rate equation A1-5, page 126 version 1.0 through version 1.4 and page 88 of version 2.5
.3 available pressure x fett of equivalent length =.063 friction rate per 100' of duct
you have a 45,000 btu/hr hot water heater and a 60,000 btu/hr furnace installed inside a building .
how many cubic feet of combustion air is required for these two appliances when using indoor air for
combustion.
1. 7000 cubic feet of air
2. 5250 cubic feet of air
3. 8000 cubic feet of air
4. 4950 cubic feet of air Correct answer-Answer 2
2018 NC fuel gas code section 304.1 page 17 the standard method
304.5.1 requires 50 cubic feet of the indoor air per 1000 btu/hr of total connected load of appliances
in the space .
60k btu/hr for the furnace and 45k btu/hr for the water heater equals 105k btu/hr of total connected
load.
105 btu/hr total x 50 cubic feet per 1000 btu/hr (required by 304.5.1)=5250 cubic feet required for
combustion air for the space to be considered unconfined.
in a residential duct system , a 1R fitting has how many more feet of equivalent length than a 1Q
fitting?
1. 30 feet
2. 50 feet
3. 70 feet
4. 90 feet Correct answer-Answer 3
ACCA manual - D group 1 fittings shows a 1E fitting with 120 equivalent feet and a 1Q fitting with 50
equivalent feet.
The difference is 70 feet of equivalent feet
version 1.0 through 2.4 page # 150
version 2.5 is page N19
a block wall in a residential building has a stucco outside finish , mental studs with R-11 insulations,
hollow cells , medium color and an interior finish , If 500 square feet of this wall face west in raleigh,
north carolina , what is the heat gain from this wall in the summer at design load conditions?
COMMERCIAL BASED ON NC H3-1 SAMPLE
LICENSE EXAM WITH ALL CORRECT &
VERIFIED ANSWERS
what is the minimum width of the required continuous solid flooring along the required access path
to an attic appliance?
1. 22 inches
2.24 inches
3.16 inches
4. none required Correct answer-Answer 2/ 2018 NC mechanical code section 306.3 pages 22 and
section 306.3 2018 NCFGC page 21
when smoke detectors are required by the code, they shall be installed based on which of the
following?
1. the 2018 NC mechanical code
2. NFPA 70
3. the 2018 NC fire code
4. NFPA 72 Correct answer-Answer 4/ 2018 NC mechanical code section {F}606.3 page 74
what is the latent load for 200 people working in a factory as a machine tool operator?
1. 125,000 btu/hr
2. 35,000 btu/hr
3. 12,300 btu/hr
4. 96,500 btu/hr Correct answer-Answer 1
ACCA manual-N version 5 table 6B
625 btu/hr per person x 200 people = 125,000 btu/hr
a building used for light industrial assembly is in ashville , north carolina and has a roof deck that sits
on structural steel with a suspended ceilling below. the roof deck consists of 1.5" thick wood with R-3
insulation board and a suspended ceiliing below with R-19 insulation located on the ceiling tile . what
is the heat loss for this assembly on a design winter day if the roof measures 250 feet long by 40 feet
wide and the indoor temperature is to be maintained at 70'F?
1. 26,450 btu/hr
2. 19,980 btu/hr
3. 29,220 btu/hr
4. 10,900 btu/hr Correct answer-Answer 2
ACCA Manual-N version 5 table 6B
table 4 construction # 17B-3w-x provides a u-value for the assembly of 0.037
Ashville outdoor winter design temperature is 16'F and the indoor temperature is 70'F making the
temperature difference(delta-T) across the heat transfer surface 54'F
.037x54(250x40)=19,980 btu/hr
a 24" round spiral duct is being used for a main return duct in a high-class restaurant, what is the
approximate maximum cfm based on the velocity restrictions in ACCA manual -Q?
,1. 4600 cfm
2. 3800 cfm
3. 5800 cfm
4.6000 cfm Correct answer-Answer 1
ACCA manual-Q figure A3-6, page A3-9 specifies a maximum velocity of 1500 feet per minute
using auxiliary calculations side of the duct calculator the volume would be 4600 cfm
you have calculated the longest length in an existing a CSST gas piping system to be 80 feet . you will
be adding a line to a new gas appliance that needs 45,000 btu/hr of natural gas that will be 15 feet
long. the existing system your adding on to consists of a 1/2 pound gas meter with a design pressure
drop of 0.5 IWC and the gas has a specific gravity of 0.60. what is the minimum size CSST size you can
run to the new appliance according the code?
1. EHD 18
2. EHD 19
3. EHD 23
4. EHD 25 Correct answer-Answer 3
2018 NC fuel gas code table 402.4(15) page 45
when running a residential load estimate for climate zone 3 in north carolina, what is the minimum
solar heat gain coefficient you can use for the glass?
1. .20
2. .30
3. .35
4. .40 Correct answer-Answer 2
2018 NC energy code table R402.1.2 page R-16
when running PVC pipe underground for use as part of a domestic kitchen exhaust system , no more
than _______ inches of PVC duct is allowed to extend above the concrete floor surface .
1. 1 inch
2. 4 inches
3. 6 inches
4. no limit Correct answer-Answer 1
2018 NC mechanical code section 505.1 exception 2.3 page 49
a rectangular duct measures 40" x 34" on the outside and has 2" of duct insulation lining the duct.
what is the equivalent round duct size?
1. 36" round
2. 35.9" round
3. 38" round
4. 40" round Correct answer-Answer 2
convert duct to clear inside dimensions
40" - 4" of liner = 36"
34"-4" of liner=30"
per ACCA manual - Q A3-1 on page A3-2 the equivalent round duct size is 35.9"
sediment traps are required in gas piping systems and must be located _______?
, 1. where the gas piping enters the building
2. near the equipment in a convenient location
3. located in the same room and within 6 feet of the appliance
4.after the appliance shutoff valve and as close as possible to the inlet of equipment Correct
answer-Answer 4
2018 NC fuel gas code section 408.4 page 76
a residential system design requires 1000 cfm. the air handler you chose can deliver 1000 cfm at an
external static pressure of .30 the duct system has a total equivalent length of 475 feet , so the
design friction rate is ?
1. 0.1 fr/100'
2. 0.08 fr/100'
3. 0.05 fr/100'
4. 0.063 fr/100' Correct answer-Answer 4
ACCA manual -D appendix 1
friction rate equation A1-5, page 126 version 1.0 through version 1.4 and page 88 of version 2.5
.3 available pressure x fett of equivalent length =.063 friction rate per 100' of duct
you have a 45,000 btu/hr hot water heater and a 60,000 btu/hr furnace installed inside a building .
how many cubic feet of combustion air is required for these two appliances when using indoor air for
combustion.
1. 7000 cubic feet of air
2. 5250 cubic feet of air
3. 8000 cubic feet of air
4. 4950 cubic feet of air Correct answer-Answer 2
2018 NC fuel gas code section 304.1 page 17 the standard method
304.5.1 requires 50 cubic feet of the indoor air per 1000 btu/hr of total connected load of appliances
in the space .
60k btu/hr for the furnace and 45k btu/hr for the water heater equals 105k btu/hr of total connected
load.
105 btu/hr total x 50 cubic feet per 1000 btu/hr (required by 304.5.1)=5250 cubic feet required for
combustion air for the space to be considered unconfined.
in a residential duct system , a 1R fitting has how many more feet of equivalent length than a 1Q
fitting?
1. 30 feet
2. 50 feet
3. 70 feet
4. 90 feet Correct answer-Answer 3
ACCA manual - D group 1 fittings shows a 1E fitting with 120 equivalent feet and a 1Q fitting with 50
equivalent feet.
The difference is 70 feet of equivalent feet
version 1.0 through 2.4 page # 150
version 2.5 is page N19
a block wall in a residential building has a stucco outside finish , mental studs with R-11 insulations,
hollow cells , medium color and an interior finish , If 500 square feet of this wall face west in raleigh,
north carolina , what is the heat gain from this wall in the summer at design load conditions?
