Cal. Code Regs. tit. 8, § 4923
(c) Load ratings where stability governs lifting performance.
(1) The margin of stability for determination of load ratings, with booms of stipulated lengths at stipulated working radii for the various types of crane mountings is established by taking a percentage of the loads which will produce a condition of tipping or balance with the boom in the least stable direction, relative to the mounting. The load ratings shall not exceed the following percentages for cranes, with the indicated types of mounting under conditions stipulated in (2) and (3).
Type of Crane Mounting
Maximum Load Ratings (% of Tipping Loads)
Locomotive, without outrigger (stabilizer) support1
Booms 60 feet or less
85
Booms over 60 feet
852
Locomotive, using outriggers (stabilizers) fully extended and set
80
Crawler, without outrigger support
75
Crawler, using outrigger fully extended and set
85
Wheel mounted using outriggers fully extended and set, with wheels off supporting surface
85
Commercial truck vehicle mounted crane with stabilizer extended and set
85
Wheel mounted without outrigger support
75
Note: 1. As a precaution while testing for free ratings, outriggers should be loosely applied; rail clamps should not be used.
Note: 2. The difference between the backward stability moment and the forward moment resulting from the load should not be less than 30,000 lb-ft with the backward stability moment being the greater.
(2) The following stipulations shall govern the application of the values in (1) for locomotive cranes:
(3) Stipulations governing the application of the values in (1) for crawler, truck and wheel-mounted cranes shall be in accordance with the Crane Load-Stability Test Code, SAEJ765, 1969 or 1980 as applicable.
Note: The effectiveness of these preceding stability factors will be influenced by such additional factors as freely suspended loads, track, wind, or ground conditions, condition and inflation of rubber tires, boom lengths, proper operating speeds for existing conditions, and in general, careful and competent operation. All of these shall be taken into account by the user.
Note: Authority cited: Section 142.3, Labor Code. Reference: 142.3, Labor Code.
1. Amendment of subsection (a) filed 2-13-75; effective thirtieth day thereafter (Register 75, No. 7).
2. Amendment of subsection (a) filed 5-1-81; effective thirtieth day thereafter (Register 81, No. 18).
3. Amendment filed 8-29-86; effective thirtieth day thereafter (Register 86, No. 39).