ASME B30.4:2020 pdf download.Safety Standard for Cableways, Cranes, Derricks, Hoists, Hooks, Jacks, and Slings.
4-1.3.4 Backward StabiLity
(a) The backward stability of a crane is its ability to resist overturning in the direction opposite the boom point while in the unloaded condition. The minimum acceptable backward stability condition, as determined by calculation, is such that the horizontal distance between the center of gravity of the crane and the axis of rotation shall not exceed 60% of the radial distance from the axis of rotation to the backward tipping fulcrum in the least stable direction.
(b) The general requirements applicable for determination of the backward stability condition are as follows:
(1) crane to be equipped for normal operation with shortest boom permitted (as applicable)
(2) boom to be positioned at minimum achievable radius
(3) crane to be unloaded (no hook, block, or attachment weight)
(4) crane standing on level track or foundation
(5) maximum operating wind speed acting in a direction to reduce stability
4-1.3.5 Out-of-Service StabiLity
The manufacturer shall ascertain by calculation that in each recommended configuration, traveling cranes shall have a margin of stability against incipient tipping when exposed to wind forces appropriate to the installation site as given in ASCE/SEI 7 when the crane is out of service. Overturning moments shall not exceed 80% of the stahllizing moments, without consideration of any anchorage devices or rail clamps. For weathervaning cranes, the boom shall be taken in the attitude dictated by its wind area balance; nonweathervaning cranes shall be taken in their least favorable attitude. For fixed cranes, see para. 4-1.1.1(a).
4-1.3.6 ALtered (Modified) Cranes
Whenever cranes are altered, unless the work is done by the original manufacturer, the owner of the crane shall maintain records of the work performed. The records shall include calculations and drawings prepared and signed by a qualified person that delineate the alterations and that verify that the entire crane and/or the affected components satisfy the applicable portions of this Volume. The calculations shall include a recitation of the engineering criteria governing the design. After alterations, tests shall be performed in accordance with paras. 4-2.3.1 and 4-2.3.2.
4-1.4.1 Site Preparation and Crane Support Design Data
For use of the crane support designers, data such as what is listed below should be provided.
(a) vertical and horizontal forces and torsional and overturning moments applicable to the crane configuration and location of the particular installation; the data should indicate whether governing forces are due to in-service or out-of-service winds and the applicable wind velocities and direction(s); for traveling cranes, the data can be stated in terms of wheel loads
(b) maximum wind velocity for which traveling cranes possess adequate resistance to sliding, as determined by calculation, in the configuration for the particular installation and precautions that shall be taken to secure cranes at higher wind velocities.ASME B30.4 pdf download.