The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures.
Minimum attic access size irc.
2015 irc mechanical 1305 1 3 2 access for cooling or heating appliance for residential application the attic space in which any cooling or heating appliance is installed shall be provided with a permanent ladder for folding away ladder or direct access door opening from the house on the same floor level.
Where the access is located in a ceiling minimum unobstructed headroom in the attic space shall be 30 inches 762 mm at some point above the access measured vertically from the bottom of ceiling framing members.
See section m1305 1 3 for access requirements where mechanical equipment is located in attics.
See the california mechanical code for access requirements where mechanical equipment is located in attics.
When the access is located in a ceiling minimum unobstructed headroom in the attic space shall be 30 inches 762 mm at some point above the access measured vertically from the bottom of ceiling framing members.
The rough framed opening must be a minimum of 22 inches by 30 inches.
Minimum opening size the 2012 international residential code requires an attic access opening for attics with an area greater than 30 square feet and a vertical height in excess of 30 inches.
See section m1305 1 3 for access requirements where mechanical equipment is located in attics.
If there are no obstructions on the passageway to the attic furnace and it has a minimum 6 feet 1829 mm height and 22 inches 559 mm width along its entire run the walkway length limit goes up to 50 feet 15250 mm in irc international residential code and has no limit in umc universal mechanical code.
Chapter 10 city amendment.
When the access is located in a ceiling minimum unobstructed headroom in the attic space shall be 30 inches 762 mm at some point above the access measured vertically from the bottom of ceiling framing members.
If the access is located in the ceiling the minimum unobstructed headrom above the opening must be 30 inches measured vertically at some point over the access.
The international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process.