Amendments to the International Residential Code 2018 Edition

 University of Arizona






The following provisions of the International Residential Code, 2018 Edition, as published by the International Code Council, Inc. are hereby revised as follows:


Chapter 1


Section R101.1 Title.  Revise as follows:

Insert: [NAME OF JURISDICTION] as, “University of Arizona.”


Add the following section:

“Section R102.8 Fire flow and fire access. 

New construction under this code shall conform to the International Fire Code Sections 102.5 Application of Residential Code, 503 Fire Apparatus Access Roads, 507.3 Fire Flow, 3310 Access for Fire Fighting, 3312 Water Supply for Fire Fighting, Appendix B Fire-Flow Requirements for Buildings and Appendix D Fire Apparatus Access Roads.”


Section R105.2 Work exempt from permit.  Revise as follows:   


2. Add to the end of this sentence:

“and masonry or concrete walls not over 7’-0” (1682 mm) high, which do not retain earth.”

Section R110.3 Certificate issued.  Revise as follows:

At the end of this section add the sentence:

“The building final inspection approval shall be the Certificate of Occupancy for detached single family residences.”

Chapter 3

Site Conditions

Table R301.2(1) Climatic and Geographic Design Criteria.  Revise as follows:


Ground Snow Load

Less 4000 ft 0 psf


4 to 5000 ft 20 psf


7 to 8000 ft 60 psf


Over 8000 ft 80 psf

Topographic effects

As Required

Wind Speed

150 mph 3 second gust

Seismic Design Category

Category B within the City of Tucson, outside City of Tucson, refer to local codes


Up to 4,000 ft-Negligible

Above 4,000 ft-Moderate

Frost Line Depth

Up to 4,000 ft-0 in

Above 4,000 ft-24 in



Winter Design Dry Bulb Temperature

Under 4,000 feet elevation - 35º F

4,000 feet & above - 4°F

Summer Design Dry Bulb Temp

Under 4,000 feet elevation - 105º F

4,000 feet & above - 90°F

Summer Design Wet Bulb Temp

Under 4,000 feet elevation - 66º F

4,000 feet & above - 61°F

Climate zone

Under 4,000 feet elevation – 2B

4,000 feet & above – 5B


Chapter 8

Roof-Ceiling Construction

Section R802.11.1 Uplift resistance. REVISE section by DELETING section in its entirety and ADDING the following: Uplift resistance to minimize microburst effects shall be determined by either method 1 or 2 below:

1. Design-based wind uplift criteria Wind uplift requirements shall be determined by using the design wind value of 115 mph within Table R802.11 for the continuous load path transmitting the uplift forces from the rafter or truss ties to the foundation.

2. Prescriptive-based wind uplift criteria (Please note that the requirements of this section are in addition to those required for the structural connection of wood members).

2.1. Conventionally-framed wood or cold-formed steel structures All bearing wall vertical connections shall be clipped with either approved structural sheathing or approved clips to provide a continuous load path from the joist or truss through the ledger or top plate to the bottom wall plate. Where clips are used, they shall be minimum Simpson H2.5 (A34 at ledger), or equivalent load capacity, of configuration to match connection and spaced at intervals not to exceed 24". At openings, lower cripple studs do not require clipping but king/trimmer studs require double clips at bottom and upper cripples, require both full clipping to header as well as header to king stud. All platform framing requires either strapping listed for the purpose or continuous sheathing over rim joist from stud to stud vertically at each floor level.

All non-bearing exterior walls shall be clipped as above except that the spacing may be extended not to exceed every other stud.

2.2. Masonry or concrete structures If lateral design requires larger anchors or more conservative spacing, these may be used in lieu of those called out in this section. 2018 International Residential Code Page 3 of 6

2.2.1. Roof bearing on wall top plate Top plates shall be secured to masonry or concrete walls with minimum 0.5" embedded anchor bolts spaced at intervals not to exceed 48". Each joist or truss shall be clipped to plate at bearing with minimum Simpson H2.5 or equivalent load capacity and of configuration to match connection. Gable end joists or trusses shall also be clipped at intervals not to exceed 48".

2.2.2. Roof bearing on wall ledger Joists or trusses bearing on a wall ledger shall be secured to masonry or concrete walls with minimum Simpson PAI23 purlin anchors or equal with equivalent load capacity listed for the application and embedded into wall per listing at intervals not to exceed 48”. Nonbearing roof diaphragm edges shall have the outermost joist or truss likewise anchored to the wall through blocking.

2.3. Structural steel structures Structural steel buildings shall have roof members attached by either welds, bolts, screws or other similarly approved connections at intervals not to exceed 48". Ledger designs shall connect to roof trusses with strapping listed for the purpose at intervals not to exceed 48" on all diaphragm sides. If lateral design requires larger anchors or more conservative spacing, these may be used in lieu of those called out in this section.

Chapter 11

Energy Conservation

Delete Chapter 11 (in its entirety).

Chapter 14

Heating and Cooling Equipment and Appliances

Add the following section: “Section M1413.2 Water conservation. Evaporative cooling systems shall be provided with a recirculating water system. Any bleed off rate used by the system shall be limited to that recommended by the manufacturer. Once-through evaporative cooling systems using potable water shall not be permitted.”

Chapter 26

General Plumbing Requirements

Section P2603.5.1 Sewer depth. Revise as follows: Insert: [NUMBER] as “12,” in both locations.

Chapter 28

Water Heaters

Section P2801.6.1 Pan size and drain. Revise as follows: Add the following at the end of the second sentence: “A drain shall not be required for replacement water heaters in locations where no previously installed drain is available.”

Chapter 29

Water Supply and Distribution

Section P2902.5.4 Connection to automatic fire sprinkler systems. Revise as follows:

Delete this section (in its entirety) and replace with the following: “The potable water supply to automatic fire sprinkler and standpipe systems shall be protected against backflow in accordance with ARS § 41-2168”

Chapter 30

Sanitary Drainage

Section P3003.2 Prohibited joints. Revise as follows: Delete the period at the end of item 5 and add: “, unless the solvent-cement is listed for the purpose.”


Section P3008.1 Sewage backflow. Revise as follows: Delete section (in its entirety) and replace with: “Where the finish floor elevation is less than 12 inches above the elevation of the next upstream manhole cover in the sewer, a backwater valve shall be installed in the building drain or branch of the building drain serving that floor. Floors discharging from above that reference point shall not discharge through the same back water valve.”


Section P3009 Subsurface landscape Irrigation Systems. Delete section (in its entirety) and replace with: “Shall comply with Arizona Administrative Code Title 18, Chapter 9.”


Chapter 32


Section P3201.2.1 Trap seals and trap seal protection. Revise as follows:

Delete the second sentence and replace with: “Where a trap seal is subject to loss by evaporation, a trap seal primer valve or a trap seal protection device shall be installed.”


Chapter 37

Wiring Methods

Section E3703

Required Branch Circuits

Add the following section:

“Section E3703.7 Dishwasher and Garbage Disposer Branch Circuits – Dwelling Units. In residential occupancies, dishwasher and garbage disposer may be on the same 20-ampere branch circuit.”