20 API SPECIFICATION 2C
NE dB(A) Equation (36) Permissible noise exposure
OL Equation (10) Substitution variable for Equation (9)
P lb/in.2 D.1 Pressure in cylinder
Pb lb E.5, Equation (34) Load on individual swing-bearing fastener or element
Pcr lb D.2 Elastic buckling force for cylinder
PF Equation (25) Factor applied to vertical and horizontal loads on the pedestal in addition to
the factored load
Pn lb E.5, Equation (35) Ultimate capacity of load element of swing circle assembly
PbNb lb E.5 Maximum swing-bearing load times number of load elements
PnNb lb E.5 Ultimate capacity of swing-bearing load elements
Pwind lb/ft2 Equation (23) Wind pressure acting on the projected area
p in. D.1 Screw thread pitch
q1 in. D.2 Substitution variable for Pcr equation
q2 in. D.2 Substitution variable for Pcr equation
S Equation (30) Number of sheave wheels in reeving system
Sa lb/in.2 D.1 Maximum allowable tensile stress in cylinder
SF E.3.2, E.4.4 Factor relating load in the boom suspension to a load on the hook
St lb/in.2 D.1 Maximum allowable thread shear stress in cylinder
s1 D.2 Substitution variable for Pcr equation
s2 D.2 Substitution variable for Pcr equation
T hr Equation (36) Duration of noise exposure
Tn hr Equation (37) Total permitted hours of exposure to a specific noise level
Ts lb/in.2 D.1, E.5 Ultimate tensile stress of material
t in. E.5 Height/thickness of swing-bearing geometry
twall in. D.1 Minimum cylinder tube wall thickness
thead in. D.1 Minimum cylinder head thickness
U knot Equation (23) Wind velocity
Vc ft/s Equation (5) Crane boom tip vertical velocity
Vd ft/s Equation (5) Supply boat deck vertical velocity
Vh ft/s Equation (5) Maximum possible steady hoisting velocity
Vhmin ft/s Equation (6) Required minimum steady hoisting velocity
Vr ft/s Equation (2) Relative velocity between hook and supply boat
W lb Equation (31) Total applied load in a wire rope system
WhorizontalCM lb Equation (16) Horizontal load acting on suspended load due to crane base motion
Woff(wind) lb Equation (21) Horizontal offlead load acting on crane due to wind
Table 1—Description of Symbols (Continued)
Symbol Units Equation or Section
Used Description
Copyright American