GAS Flashcards
How far past a finished floor must the unthreaded portion of a gas pipe extend?
2”
What is the largest diameter of gas pipe that can have threaded joints?
2”
What is the minimum height above a roof penetration for a vent terminal?
2’
When can a manual vent damper be installed?
Only in a commercial application on appliances without a draft hood
What is the maximum length of a connector for a clothes dryer?
6’
What is the minimum clearance between a single wall vent connector and a combustible material?
6”
What is the minimum distance away from an openable window for a direct vent appliance with an input of 75,000 BTU?
12”
How is a direct vent appliance identified?
Always has an exhaust and an intake piped to outdoors
In what two states can propane be stored?
Liquid and vapour
Why can a fan assist appliance use a smaller air supply than a draft hood appliance with the same input?
Fan assist appliances do not require dilution air
What is the maximum length of a 4” single wall vent connector with two 90° elbows installed on a Category 1 appliance?
6’
What joining method is not permitted for gas lines?
Soldering
What is the minimum test pressure when pressure testing a low pressure gas installation?
15 psi
How much combustion air is required to burn 100,000 Btu’s of CH4?
1000 cubic feet
Why must a masonry chimney be lined when connecting a gas fueled appliance?
Condensation in the chimney will ruin mortar joints
What is the calorific value of propane as a liquid?
109560 BTU/imperial gallon
What shall be done with used fittings before re-using them on a new gas installation?
The must be inspected and ascertained to be as good as new
What marking is important for a decorative appliance designed to be installed in a fireplace?
FOR USE IN NONCOMBUSTIBLE FIREPLACES
How much of the thermocouple tip should be in the pilot flame?
3/8” to 1/2” of the tip
What is the minimum distance between a vent terminal and a mechanical air intake?
6’
What protection is required when a single wall venting material passes through a combustible ceiling?
6” clearance all the way around
What is the minimum bury depth of a gasline in a residential installation?
15”
What must be done to an appliance that has been involved in a fire or flood before it can be returned to service?
The appliance must be inspected
What does the abbreviation LPG mean?
Liquefied petroleum gas
What is the importance of a drop-out test?
To determine the lowest mV that will keep the power unit energized
How many BTU’s are available in 10 ft3 of propane gas?
25000 BTU
Hydrocarbons are made up of?
Hydrogen and carbon
What is the maximum length and operating pressure of an addition to the gasline that would be exempt from a standard air pressure test?
20’ and 0.5psi
What is the maximum BTU capacity of a vent terminal installed 12” from an openable window or door?
100 MBH
True or False
It is permissible to attach ductwork to any space heater
False
Where would you find the amount of gas the appliance should consume?
Rating plate
What is the maximum hanger spacing for copper tubing?
6’
What is the purpose of a response time test?
To confirm that the gas will shut off to the main burner within a specified time
Which gas fired appliance must be connected with a hose?
Infra-red tube heater
What minimum dimension is required for a clear and unobstructed passageway for an appliance?
36” x 36”
What is the minimum clearance above a horizontal furnace?
6”
When passing thorough a combustible wall or partition with a single wall vent connector, how are the combustibles protected?
A ventilated thimble is used
What would happen to the pressure drop if the length of the gas line were increased?
Pressure drop increases
What is the minimum clearance to combustibles for type B vent?
1”
What is the minimum wall thickness for copper tubing used in a low pressure gas installation?
Type G
How must a suspended unit heater be supported?
Mounted firmly with metal hangers or brackets
What is the minimum required height clearance from the floor for an infrared heater that is installed in either a repair or a shop area that communicates with an aircraft hanger?
8’
True or False
A horizontal furnace installed in an attic must have a walkway
True
What is the minimum gauge of a single wall vent connector?
28 GSG
How is an undersized gas line determined?
The pressure drop will exceed 1” WC
What is the closed circuit range for a thermocouple?
8-17mV
What is true in regard to propane burning appliances and safe hook up?
Propane can only be used for 100% safe hook-up
What type of vent is approved for venting a solid fuel appliance?
Factory built chimney
The range of flammability for CH4 is?
5-15%
Where in a gas system is it allowable to use aluminum tubing?
To supply gas to a pilot burner only
What is the smallest round pipe size used for venting a Category I appliance?
3”
When sizing a gas line, to determine length, what would you take into consideration?
Distance from the meter to the furthest appliance
What is the range of flammability for propane gas?
2.3-9.5%
What is the pressure test requirement for welded natural gas pipe?
The greater of 50 psig or 1.5 times operating pressure for 3 hrs
What is the required clearance from the edge of a roof or other hazard for an appliance?
6’
What is the pressure test requirement for natural gas piping with a working pressure of 10 psi and a total length of 150ft?
50 psig for 60 minutes
When vent connectors enter the common vent, which one is the lowest?
The largest size
What type of appliance may be vented into a type B vent?
Any Category I appliance
Why is it important to have a conversion burner correctly positioned and firmly secured?
To eliminate direct flame impingement on any surface other than a flame spreader
What is the primary/secondary air requirement for natural gas?
10 cubic feet of air/cubic foot of gas
What is the maximum equivalent length of an air supply duct before increasing the size?
20’
Does thermostat location affect a millivolt gas valve powered by a thermopile?
Yes, wire thickness will increase as installation distance increases
How is a venting system serving a single draft hood equipped appliance sized using rule of thumb?
The vent connector and the vent are the same size as the appliance outlet
Except where permitted by Clause 4.13.2, what minimum clearance to combustible material is needed for a domestic type clothes dryer front?
24”
How many table size reductions are permitted on a vent connection to a 5” draft hood?
1 size reduction is allowed
What is the pressure in the vent when a power venter is connected to the B-vent wall termination?
Non-positive
Natural Gas must never exceed _______ under any circumstance in any building.
65 psi
Using “rule of thumb sizing”, what size is a common vent with a 6”, a 4”, and a 3” vent connector attached?
7”
What is the difference between a safe hook up and 100% safe hookup?
A 100% safe hook-up will shut off the gas to the main burner and the pilot burner if the pilot flame is extinguished
What kind of flame would be present on a pilot burner if an appliance was converted to propane without replacing the pilot orifice?
Pilot flame would be carbonizing
What size is the vent serving a single gas appliance?
Same size as the draft hood
What is the minimum rated working pressure for gas hose and fittings?
350 psi
What important requirement is necessary for a return air duct of an air handling unit located where a spillage susceptible appliance is located?
That the return air duct connection to the air handler and duct joints are sealed
What is the minimum clearance between a single wall vent connector and combustible material if the combustible material is protected with 28 ga heat sheild spaced 1” apart?
2” (refer to table 8.7)
Which meter dial is used to determine the consumption of a gas appliance?
Proving dial
When is it permissible to block an air supply for Category 1 appliances?
Never
Two draft hood boilers each with an input of 1.5 MMBH are installed in a mechanical room. What size air supply is required?
285.7 in squared
True or false
A radiant type room heater can be installed in a fireplace as long as a permanent stop is installed on the damper control to prevent complete closure of the flue outlet.
True
True or false
A boiler can be installed on a combustible floor provided it is installed with a manufacturer’s certified special base.
True
How is a vent serving two or more draft hood appliances sized using rule of thumb?
It will be 100% of the diameter of the largest outlet, plus 50% of the diameter of the other outlets
What is required whenever air supply is provided to appliances by mechanical means?
Airflow sensing device
If a propane appliance will burn 75,000 BTU/hr at an elevation of 0-2000 ft, what would the input be adjusted to if the appliance was installed at an elevation of 8100 ft?
56,700 BTU/hr
What is the minimum side clearance for a bracket or pendant fixture from combustible materials?
5”
What is the maximum length of a 3”single wall vent connector with two 90° elbows installed on a Category 1 appliance?
5’
A chimney must terminate _____ feet higher than any obstruction within 10 feet.
2’
What is the minimum above clearance from combustible material for a free standing circulating or radiant type room heater?
36”
What determines the amount of air supply required by a gas appliance?
Venting method and input rating
What is the smallest dimension allowed for a rectangular air supply duct?
3”
What is the minimum height of an air supply inlet above grade level?
12”
True or False
It is permissible to attach ductwork to any space heater?
False
What protection is required when a single wall vent connector passes through a combustible wall?
A ventilated thimble
What item does the thermocouple energize?
Power unit in a safety gas valve or safety switch
The gas orifice determines the _________ of the gas delivered to the burner.
Volume
Where is the best place to connect a manometer while measuring standing and operating pressures on a gas line?
At the dirt pocket of the farthest appliance from the gas meter
According to the Code, when searching for a gas leak, what classification of electrical illumination is required for hazardous locations?
Class 1, Group 11A
In a storage garage any component of an appliance capable of igniting a flammable vapor must be located at what minimum distance above the floor?
18”
The underground portion of the gasline between a propane storage tank and the building it serves will have propane in what state?
May carry propane in it’s gaseous or liquid state
True or False
When a downflow furnace is located in an enclosure, the circulating air and combustion air shall be taken from the same space.
What is the equivalent length of a 90° change of direction in an air supply pipe?
10’
What is the minimum gauge of a single wall vent connector for an incinerator?
20 GSG
What is the normal pressure setting for a Natural Gas service regulator?
7” w.c.
True or False
A decorative appliance can be installed in a bathroom or bedroom if it is a direct vent type.
True
An increase in pressure will cause the boiling point of a liquid to?
Increase
What size is the vent serving a single gas appliance?
Same size as the draft hood
True or False
A vent connector should never be attached to a range
False
What is the above clearance to combustible material for a hot plate?
30”
Why can a fan assist appliance use a smaller air supply than a draft hood appliance with the same input?
Fan assist appliances do not require dilution air
What method of joining underground piping or tubing is prohibited?
Threaded
The main burner flame of a furnace should be?
Slightly carbonizing
True or False
A conversion range burner with controls at the rear of the range is acceptable provided the valves are readily accessible
True
What would happen to the pressure drop if the number of fittings on the gas line are reduced?
Pressure drop decreases
What important requirement is necessary for the installation of gas appliances where combustible dust or fibers are present in a building?
The appliance must be certified or approved for such an installation
What is the pressure test requirement for natural gas piping with a working pressure of 10 psi and a total length of 150ft?
50 psi for 60 minutes
True or False
A furnace installed parallel to a refrigeration coil must be equipped with a damper to prevent the circulation of cool air through the furnace or of heated air over the refrigeration coil.
True
When does the gas code allow for the Rule of Thumb method for vent sizing?
Only on draft hood appliances
What is coaxial pipe?
Vent piping system which uses an oversized intake pipe with a smaller diameter exhaust pipe through the center
What is the smallest size of a rectangular chimney?
12in squared
