Exam Cheat Sheet · Quick Reference
Kansas City, MO Master Plumber with Gas Exam (ICC G27, 2018 IFGC/IPC)
Missouri · Pearson Vue
Missouri State Portion 100 questions
Key Distinctions
Under the longest length method every section and branch is sized from the table row for the system's longest length (e.g., a 12-ft branch is still sized on the 70-ft row), while under the branch length method each branch is sized using its own length from the meter (e.g., 15 ft of main + 8 ft of branch = 23 ft → 30-ft row).
IFGC Section 402.4.1, Longest Length Method; Table 402.4(2), Schedule 40 Metallic Pipe (natural gas, 0.5 in. w.c. drop)Full-open valves are required at locations such as the discharge side of every water meter, the water supply pipe to every water heater, the entrance to the structure and the base of every water riser (in occupancies other than multiple-family two stories or less and one- and two-family dwellings), whereas individual fixture supplies take shutoff valves.
IPC 2018 Sections 606.1 and 606.2A stack vent is the extension of a soil or waste stack above the highest horizontal drain connected to that stack; a vent stack is a vertical vent pipe installed primarily to provide circulation of air to and from the drainage system.
IPC 2018 Chapter 2 — Section 202, definitions of Stack Vent and Vent StackHorizontal pipe is any pipe or fitting making an angle of less than 45 degrees with a horizontal plane (so 40 degrees is horizontal pipe); vertical pipe makes an angle of 45 degrees or more with the horizontal.
IPC 2018 Chapter 2 — Section 202, definitions of Horizontal Pipe and Vertical PipeWater service pipe runs from the water main or other potable source — or from the meter only where the meter is at the public right of way — to the building's water distribution system; water distribution pipe conveys water from the water service pipe, or from the meter where the meter is at the structure, to the points of utilization (so with the meter inside the building, the service pipe ends and distribution begins at that meter, and a meter not at the right of way does not shorten the service pipe).
IPC 2018 Chapter 2 — Section 202, definitions of Water Pipe (Water service pipe and Water distribution pipe)An appurtenance is an adjunct device/assembly that demands no additional water supply and adds no discharge load to a fixture or the drainage system, while devices dependent on energized components are plumbing appliances.
IPC 2018 Chapter 2 — Section 202, definitions of Plumbing Appurtenance and Plumbing ApplianceThe double check assembly (ASSE 1015, AWWA C510, CSA B64.5/B64.5.1) is rated for low hazard only but works for both backpressure and backsiphonage; the pressure vacuum breaker (ASSE 1020, CSA B64.1.2) protects against backsiphonage only.
IPC 2018 Section 608.1, Table 608.1Both are prohibited traps under IPC 1002.3, but the S-trap has no exception, while drum traps are permitted by exception when used as solids interceptors or when serving chemical waste systems.
IPC 2018 Section 1002.3Potable water-supplied trap seal primer valves conform to ASSE 1018 (1002.4.1.1) while barrier-type floor drain trap seal protection devices conform to ASSE 1072 (1002.4.1.4); waste water-supplied trap primer devices use ASSE 1044 (1002.4.1.3).
IPC 2018 Section 1002.4.1.1An application is abandoned 180 days after filing unless pursued in good faith, but the code official may grant one or more written-request extensions of not more than 180 days each; a permit extension under 106.5.4 may be granted only once.
IPC 2018 Chapter 1 Scope and Administration — Section 106.3.3 Time Limitation of ApplicationIn covered and open mall buildings facilities must be not more than one story above or below the space served and the path of travel shall not exceed 300 feet from the main entrance of the store or tenant space, while the 500-foot limit applies to occupancies other than malls.
IPC 2018 Chapter 4, Section 403.3.4 (Location of Toilet Facilities in Malls)Urinals shall not be substituted for more than 67 percent of required water closets in assembly and educational occupancies; in all other occupancies the limit is 50 percent.
IPC 2018 Section 424.2Key Terms
Formulas to Know
cfh = total appliance input in Btuh ÷ 1,000 (e.g., 50,000 + 40,000 + 100,000 = 190,000 ÷ 1,000 = 190 cfh)Btuh = table capacity in cfh × 1,000 Btu per cu ft (e.g., 247 cfh → 247,000 Btuh; 44 cfh → 44,000 Btuh; 117 cfh → 117,000 Btuh)Spare cfh = table capacity at that length − demand (e.g., 170 cfh capacity − 60 cfh demand = 110 cfh spare; 137 cfh − 135 cfh = 2 cfh margin)Section load = sum of the Btuh of all outlets it serves, ÷ 1,000 (e.g., 40,000 + 35,000 + 100,000 = 175,000 Btuh = 175 cfh; 40,000 + 50,000 = 90 cfh)Size every section and branch from Table 402.4(2) using the row for the system's longest length, not the branch's own length (e.g., 40 cfh branch on the 70-ft row → 1/2 inch carries 60 cfh)Size each branch from the table row for its own length measured from the meter (main to tee + branch), e.g., 15 ft + 8 ft = 23 ft → 30-ft row; 120 cfh at 50 ft → 3/4 inch (151 cfh), whereas the longest length method 90-ft row would require 1 inchCompare the length from the meter to each outlet; the longest one is the most remote outlet and its length (rounded up to the next table row) sizes the mains feeding it (e.g., 55 ft → 60-ft row; 85 ft → 90-ft row; 70 ft → 70-ft row)Round the measured run up to the next table length row before reading capacity (e.g., 15-ft run → 20-ft row; 35-ft run → 40-ft row; 95-ft run → 100-ft row; 140-ft run → 150-ft row)Maximum distance downstream of the drainage stack = 10 × drainage stack diameter (4-inch stack: 10 × 4 in. = 40 inches)Where discharge is known only in gpm, 1 gpm = 2 DFU; for fixture counts, divide total occupant load in half for each sex and apply the Table 403.1 ratio (150 ÷ 2 = 75 females; 75 ÷ 75 per water closet = 1 water closet)