Use | Live Load |
Uninhabitable attics without storageb | 10 |
Uninhabitable attics with limited storageb, g | 20 |
Habitable attics and attics served with fixed stairs | 30 |
Balconies (exterior) and deckse | 60i |
Fire escapes | 40 |
Guards and handrailsd | 200h |
Guard in-fill componentsf | 50h |
Passenger vehicle garagesa | 50a |
Rooms other than sleeping rooms | 40 |
Sleeping rooms | 30 |
Stairs | 40c |
For SI: 1 pound per square foot = 0.0479 kPa, 1 square inch = 645 mm, 1 pound = 4.45 N | |
a. | Elevated garage floors shall be capable of supporting a 2,000 pound load applied over a 20 square-inch area. |
b. | Uninhabitable attics without storage are those where the clear height between joists and rafters is not more than 42 inches, or where there are not two or more adjacent trusses with web configurations capable of accommodating an assumed rectangle 42 inches in height by 24 inches in width, or greater, within the plane of the trusses. This live load need not be assumed to act concurrently with any other live load requirements. |
c. | Individual stair treads shall be designed for the uniformly distributed live load or a 300 pound concentrated load acting over an area of 4 square inches, whichever produces the greater stresses. |
d. | A single concentrated load applied in any direction at any point along the top. |
e. | See Section R507.1 for decks attached to exterior walls. |
f. | Guard in-fill components (all those except the handrail), balusters and panel fillers shall be designed to withstand a horizontally applied normal load of 50 pounds on an area equal to 1 square foot. This load need not be assumed to act concurrently with any other live load requirement. |
g. | Uninhabitable attics with limited storage are those where the clear height between joists and rafters is 42 inches or greater, or where there are two or more adjacent trusses with web configurations capable of accommodating an assumed rectangle 42 inches in height by 24 inches in width, or greater, within the plane of the trusses. The live load need only be applied to those portions of the joists or truss bottom chords where all of the following conditions are met: |
g.1. | The attic area is accessed from an opening not less than 20 inches in width by 30 inches in length that is located where the clear height in the attic is not less than 30 inches. |
g.2. | The slopes of the joists or truss bottom chords are not greater than 2 inches vertical to 12 units horizontal. |
g.3. | Required insulation depth is less than the joist or truss bottom chord member depth. The remaining portions of the joists or truss bottom chords shall be designed for a uniformly distributed concurrent live load of not less than 10 pounds per square foot. |
h. | Glazing used in handrail assemblies and guards shall be designed with a safety factor of 4. The safety factor shall be applied to each of the concentrated loads applied to the top of the rail, and to the load on the in-fill components. These loads shall be determined independent of one another, and loads are assumed not to occur with any other live load. |
i. | Where structural tables in Section R507 only specify snow loads, the values corresponding to 70 psf snow loads shall be used. |