February 23rd 2011
To: XXXXXXXX Construction
Re: Modification Request for XXXXXX residence
Permit #XX-XXXX; TPN XXXXX
You have requested a modification of IRC (International Residential Code 2006 edition) section R310.1
R310.1 Emergency escape and rescue required.
(partial text only) “…shall have a sill height of not more than 44 inches above the floor….”
The main floor on the residence under construction has a bedroom with the egress window positioned 50” above rough floor framing. The exterior lower roof is pitched and constructed in a manner such that cutting the window opening to lower the opening to 44” would have a substantial detrimental effect on the building.
IRC section R104.10 allows the AHJ to grant such modifications when “special individual reason makes the strict letter of this code impractical and the modification is in compliance with the intent and purpose of this code and that such modification does not lessen health, life and fire safety requirements or structural.”
DISCUSSION:
The emergency escape and rescue openings required in sleeping rooms are one of the key fire and life safety elements of residential construction. The intent of the code is very clear. A room used for sleeping shall be provided with a method for occupants to leave the building in the event of a fire when passage through other portions of the house may not be possible. The intent is also to provide fully equipped rescue personnel access in to the building. The minimum sizes, heights, and other operational requirements establish a uniform standard to which rescue personnel can train.
Your proposal of creating a permanent window bench or seat, as referenced in the attached diagram provides an 18”-24” wide platform the entire length of the window. The method of construction provided will essentially create a raised floor (capable of withstanding the required 30# LL in sleeping rooms). The Washington State Building Code Council has specifically amended the IRC to allow “Stairs or ladders within an individual dwelling used for access to areas 200 square feet or less……” to be exempt from the requirements for code compliant stairs. Therefore, it can be reasonably be interpreted that a raised floor area is being created that is permitted to be accessed via means other than a code compliant stairway. In this instance, a step of approximately 18” will be utilized for access. The measurement from the egress window can be taken from the floor directly adjacent to it; that which would be utilized in the event of an emergency.
Review of the proposed configuration for compliance with the intent of the code reveals that it meets the intent. The area under the window will provide less than a 44 inch drop to any rescue personal attempting to enter in the event of an emergency. The reduced clearance from the top of the seat/raised floor, provided even greater access to the emergency exit that is afforded by a code maximum 44 inches.
When all the components are considered as a whole for this project, the structure is in compliance with the intent and purpose of the codes, as defined in IRC R101.3.
The configuration shall comply with the following requirements:
1) Shall be 18” minimum depth, as shown on the submitted drawing.
2) Shall be 24” maximum height
3) Shall be uniform height and depth under the entire window
4) Shall be constructed in a permanent manner, so as not to be readily removable, including but not limited to, permanent framing covered with finish material.
5) The required window shall comply with all other requirements found in R310
The request for modification is hereby granted. This modification is specific to the project referenced. All work for this project is subject to field inspection and approval.
Sincerely,
