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Home My WebLink About06112009 ZPC Agenda Item 5 Regulation of basements and other "below-grade spaces" Alternate approaches, 3-19-09 Issue Blue Approach Green Approach Yellow Approach Definition of "below Floor more than 12 Floor more than 3 ft. Floor more than 3 ft. grade space" inches below standard below standard base below standard base q) R u~ 1 base level level level Size limit jJ Yes: t 00SF No No Counts as framed area Yes Only if >100SF No Counts as a story Only if >100SF Only if >100SF No Height limit 7 ft. 7 ft. No limit Plumbing fixtures Not allowed Not allowed Not allowed (does not apply t lines) Use restriction Storage or mechanical Storage or mechanical Storage or mechanical only only, unless there are only, unless there are two EEP's two EEP's? Number of emergency Only one required Two if >100SF Two if >200SF egress paths (EEP's , EEP directly to, Not required ? ? outdoors J ' Indoor swimming pool Not allowed Not allowed Allowed? in below grade spac t Excavation limits 1 :1 1.5: 1 1.5: 1 (ratio of distance from (45-degree angle of (greater setback; (greater setback; property line to depth repose) shallower angle of shallower angle of of hole) repose) re ?se IVY CA-.,4~1 CW~Zt-L '`tJ Excavations limited Deeper than 12 inches, Deeper than 12 inches, Deeper than 12 inches, X11 volume larger than wider or longer than _ wider or longer than _ 5/ cu. ft. inches? inches? Location in "footprint" Not required Not required Required, except for of principal building EEP directly to (below other building outdoors? space) i BUILDING PLANNING rrtents of Section R324, and are otherwise constructed in •3 Because so many fire deaths occur as the result of oc- x accordance with this code. cupants of residential buildings being asleep during a fire, the IRC requires that all basements and sleeping f 4 garage floors of buildings in flood hazard areas must rooms have windows or doors that may be used for meet one of two requirements. The first option is to emergency escape or rescue. These emergency .Imply construct the garage floor above the design openings must open directly into a public street, public flood elevation. The second option allows the floor of alley, yard or court. The requirement for emergency the garage to be below the design flood elevation if escape and rescue openings in sleeping rooms exists c construction is compliant with the applicable provi- because a fire will usually have spread before the oc- %lons of Section R324 for enclosures, including: 1) the cupants are aware of the problem, and the normal exit z door is at or above finished exterior grade (not a base- channels may be blocked. The requirement for base- ment); 2) it complies with provisions for enclosed ar- ments exists because they are so often used as sleep- oas below the design flood elevation (Section ing rooms. For example, a fire in a mechanical room 12324.2.2); 3) materials and finishes below the design adjacent to a stair could engulf the only means of t flood elevation are flood-resistant (Section R324.1.7); egress for the basement without the egress window or and 4) service equipment and systems comply with door. d Section R324.1.5. If a garage below the design flood Openings required for emergency escape or rescue elevation does not meet the requirements for enclo- must be located on the exterior of the building so that cures, the garage floor is the "lowest floor," and the rescue can be performed from the exterior. Altema- building is noncompliant. Noncompliance means that tively, occupants may escape through that opening to although the living area is elevated, flood insurance the exterior of the building without having to travel will be rated as though the building is not, through the building itself. Therefore, where openings LWA Automatic garage door openers. Automatic garage are required, they should open directly into a public ollJw t,peners, if provided, shall be listed in accordance with UL street, public alley, yard or court. After the occupants 44. pass through the emergency escape and rescue opening, their continued egress is essential. Where a f this code does not require an automatic garage door basement contains sleeping rooms and a habitable opener. However, if one is installed, it must be listed in space, an emergency escape and rescue opening is accordance with UL 325. Federal law requires auto- required in each sleeping room, but is not required in matic residential garage door openers to conform to adjoining areas of the basement. Me entrapment protection requirements of UL 325. There is an exception for basements used only to house mechanical equipment with a total floor area not exceeding 200 square feet. SECTION R310 The dimensions prescribed in the code, and as illus- IMERGENCY ESCAPE AND RESCUE OPENINGS trated in Commentary Figure R310.1 for exterior wall openings used for emergency egress and rescue, are PIS,I Emergency escape and rescue required. Basements based in part on extensive testing by the San Diego 0,0r%vey sleeping room shall have at least one operable emer- Building and Fire Departments to determine the proper +way c u ,ipe and rescue opening. Such opening shall open relationships of the height and width of window open W- Ji uilo a public street, public alley, yard or court. Where ings to adequately serve for both rescue and escape. too- li -w, contain one or more sleeping rooms, emergency The minimum of 20 inches (508 mm) for the width is 4fof" md rescue openings shall be required in each sleeping based on two criteria: the width necessary to place a "-w, hul hall not be required in adjoining areas of the base- ladder within the window opening and the width neces- foell, A hk•rc emergency escape and rescue openings are pro- sary to admit a fire fighter with full rescue equipment s ihv hall have a sill height of not more than 44 inches including breathing apparatus. The minimum 24-inch +I I it min) ;shove the floor. Where a door opening having a (610 mm) height is based on the minimum size neces- 4*4%,1d hdow the adjacent ground elevation serves as an sary to admit a fire fighter with full rescue equipment. !+11t wou v ,cape and rescue opening and is provided with a By requiring a minimum net clear opening size of the "tomI cnk. losure, the bulkhead enclosure shall comply with least 5.7 square feet (0.53 ml), the code provides for 4 rwwi it I I O.3. The net clear opening dimensions required by an opening of adequate dimensions. To be accessible s4 n, ,n hall be obtained by the normal operation of the from the interior of the sleeping room or basement, the w+ an, , u%ape and rescue opening from the inside. Emer- emergency escape and rescue opening cannot be lo- f •„-,I)c ;end rescue openings with a finished sill height cated more than 44 inches (1118 mm) above the floor. li 1w dij scent ;round elevation shall be provided with a The measurement is to be taken from the floor to the 4`40-ft i1 ui accordance with Section 8310.2. Emergency bottom of the clear opening. ~ ,rue openings shall open directly into a public The required opening dimensions must be achieved * M , ud or court that opens to a public way. by the normal operation of the window, door or hatch turlitilln: Basements used only to house mechanical from the inside without the use of keys, tools or special 111.11)(1 not exceeding total floor area of 200 square knowledge. The window industry is a highly competi- tive market. Manufacturers are constantly developing '4 +WtxttNA rIONAL RESIDENTIAL CODE" COMMENTARY 13 en $WWW4 ►LANNING v } W products that are easier to clean and possess 8310.1.1 Minimum opening area. All emergency escape and higher thermal protection properties. It is important to rescue openings shall have a minimum net clear opening of 5.7 koop in mind that no special knowledge for operation square feet (0.530 m-). a Of the egress window is a key operational constraint. It Exception: Grade door openings shall have a minimum net "r I$ Impractical to assume that all occupants can oper- clear opening of 5 square feet (0.465 m2). ate a window that requires a special sequence of oper- ations to achieve the required opening size. Although Where an emergency escape and rescue window is ` most occupants are familiar with the normal operation located at grade level, the opening size requirement is to open the window, children and guests are frequently reduced to be 5 square feet (0.46 m2). This results ,T unfamiliar with special procedures necessary to re- from the increased ease of access from the exterior move the sashes. The time spent comprehending spe- and the probability that a ladder will not be needed. " cial operations unnecessarily delays egress from the 8310.1.2 Minimum opening height. The minimum net clear bedroom and could lead to panic and further confu- opening height shall be 24 inches (610 mm). sion. Thus, windows that achieve the required opening • dimensions only by performing a special sequence of The minimum opening height for emergency space operations such as the removal of sashes or mullions and rescue opening is 24 inches (610 mm), based on '.f are not permitted. For example, if a specific area of the the minimum dimension of a fire fighter with full rescue window has to be depressed or manipulated to allow equipment. the sash to be removed or released to achieve the 8310.1.3 Minimum opening width. The minimum net clear open area requirement of 5.7 square feet (0.53 m2), opening width shall be 20 inches (508 mm). the window does not qualify as an egress window. 4- This section establishes a minimum width of 20 inches (508 mm) for emergency space and rescue openings, L s. 34 IN. CLEAR " 20 IN. CLEAj, MIN /OPENABLE / AREA 411N. \ 5.7 SQ FT CLEAR 111 N \ , / \ OPENABLE AREA 24 IN. \ 5.7 SQ FT MIN CLEAR MIN MINIMUM SIZE MINIMUM SIZE WINDOW WINDOW FOR 20 IN. FOR 24 IN. CLEAR HEIGHT CLEAR WIDTH 9 • SILL HEIGHT Rw 44 IN. MAX_ GIs 3y~. TU FLOOR For SI:1 inch = 25.4 mm, 1 square foot = 0.0929 m2. Figure R310.1 41 EMERGENCY ESCAPE AND RESCUE WINDOW fZ y 3-60 2006 INTERNATIONAL RESIDENTIAL CODE® COM BUILDING PLANNING based on the minimum dimension of a fire fighter with The minimum size requirements in cross-section full rescue equipment. are similar to the emergency escape and opening cri- IIII.310.1.4 Operational constraints. Emergency escape and teria; that is, they are sufficient to provide a nominal Fes cue openings shall be operational from the inside of the size to allow for the escape of occupants or the entry of #*)in without the use of keys, tools or special knowledge. fire fighters (see Commentary Figure 8310.2). The ladder or steps requirement is the main difference. !►Qpenings for emergency escape and rescue must be 8310.2.1 Ladder and steps. Window wells with a vertical r% operational from the inside. Keys, tools or special tools depth greater than 44 inches (1118 mm) shall be equipped with knowledge must not be needed to operate these open- Ntgs. If keys or tools were necessary, they might not be a permanently affixed ladder or steps usable with the window readily available in an emergency or panic situation, and in the fully open position. Ladders or steps required by this sec- M an Individual might not be able to use them, so the open- lion shall not be required to comply with Sections 8311.5 and d kV would be unusable. Section R310.1 also requires the 8311.6. Ladders or rungs shall have an inside width of at least ry Opening size to be obtained by the normal operation of 12 inches (305 mm), shall project at least 3 inches (76 mm) window. See Section R310.1 commentary. from the wall and shall be spaced not more than 18 inches (457 g r ;.k mm) on center vertically for the full height of the window well. 610.2 Window wells. The minimum horizontal area of the %";w well shall be 9 square feet (0.9 in'), with a minimum When the depth of a window well exceeds 44 inches ~ Pituntal projection and width of 36 inches (914 mm). The (1118 mm), a ladder or steps from the window is re- quired. The details for construction of ste Itgf the window well shall allow the emergency escape and ps are not Me opening to be fully opened. identified in the provisions; however, the design of the I v ladder is specifically addressed. Because ladders and ption: The ladder or steps required by Section R310.2.1 steps in window wells are provided for emergency use **11 be permitted to encroach a maximum of 6 inches (152 only, they are not required to comply with the provisions 0M) into the required dimensions of the window well. for stairways found in Sections R311.5 and R311.8. ~Iflllrlt)w wells in front of emergency escape and res- R310.3 Bulkhead enclosures. Bulkhead enclosures shall pro- openings also have minimum size requirements. vide direct access to the basement. The bulkhead enclosure with ss~ provisions address those emergency escape the door panels in the fully open position shall provide the mini- it it Wlows that occur below grade. Just applying the mum net clear opening required by Section 8310.1.1. Bulkhead kVi '^'1l derd emergency escape window criteria to these enclosures shall also comply with Section R311.5.8.2. , Wows will result in an opening that occupants can Bulkhead enclosures, when provided for access to be- ( through, but the window well may actually trap the low-grade openings used for emergency escape and amts against the building without providing for rescue, must meet the net openable area provisions **cape from the window well or providing for a of Section R310.1.1. Also, bulkhead enclosures must 00ter to enter the residence. comply with Section 8311.5.8.2. sx w,, i WINDOW WELL MUST BE SUFFICIENT LADDER OR STAIR PERMITTED SIZE TO ALLOW THE EMERGENCY TO ENCROACH MAXIMUM OF ESCAPE AND RESCUE OPENING TO 6 INCHES INTO REQUIRED BE FULLY OPENED DIMENSIONS v, a WINDOW WELL 'z N14 O STAIR =111 fw.;: -1I I L' / 36 IN. MIN >44ft V Y S NF a I I EMERGENCY ESCAPE - - - THE MINIMUM OR RESCUE OPENING =11 11=11 I I HORIZONTAL AREA -1I I1= WITH FINISHED SILL = OF THE WINDOW HEIGHT BELOW - WELL IS TO BE s I I- I I I ADJACENT GRADE I { lt~ a 36 IN. MIN 9 SQ FT , =1 i l l -1 I I I=1 I I I =1111 t e40 -.15 4 mm, 1 square foot = 0.0929 ms. Figure R310.2 q Fy } i ryr~~ WINDOW WELLS IhAIfVNAL RESIDENTIAL CODO COMMENTARY