STANDARD HANDBOOK OF PETROLEUM & NATURAL GAS ...

Design Specifications
Derricks and Portable Masts 511
In addition to withstanding some minimum load or loads (sections titled
“Load Capacities” and “Design Specifications”), derricks and masts that satisfy
API standards must also satisfy certain requirements regarding materials,
allowable stresses, wind, dynamic loading, earthquakes and extremes of temperature.
Materials
The unrestricted material acceptance is not intended since physical properties
are not the sole measure of acceptability. Metallurgical properties, which affect
fabrication and serviceability, must also be considered.
Steel. Steel shall conform to one of the applicable ASTM specifications referred
to by applicable AISC specifications. Other steels not covered by these specifications
may be used provided that the chemical and physical properties conform
to the limits guaranteed by the steel manufacturer. Structural steel shapes having
specified minimum yield less than 33,000 psi shall not be used. Certified mill
test report or certified reports of tests made in accordance with ASTM A6 and
the governing specification shall constitute evidence of conformity with one of
the specifications listed.
Bolts. Bolts shall conform to one of the applicable SAE, ASTM, or AISC
specifications. Other bolts not covered by these specifications may be used
provided the chemical, mechanical, and physical properties conform to the limits
guaranteed by the bolt manufacturer. Certified reports shall constitute sufficient
evidence of conformity with the specification. Bolts of different mechanical
properties and of the same diameter shall not be mixed on the same drilling
or servicing structure to avoid the possibility of bolts of relatively low strength
being used where bolts of relatively high strength are required.
Welding Electrodes. Welding electrodes shall conform to applicable AWS and
ASTM specifications or other governing codes. Newly developed welding
processes shall use welding electrodes conforming to applicable AWS or other
governing publications. Certified reports shall constitute sufficient evidence of
conformity with the specifications.
Wire Rope. Wire rope for guy lines or erection purposes shall conform to API
Specification 9A “Specification for Wire Rope.”
Nonferrous Materiais. Nonferrous materials must conform to appropriate
governing codes. Certified reports shall constitute sufficient evidence of
conformity with such codes.
Allowable Stresses
AISC specifications for the design fabrication and erection of structural steel
for buildings shall govern the design of these steel structures (for AISC
specifications, see the current edition of Steel Construction Manual of the
American Institute of Steel Construction). Only Part I of the AISC manual, the
portion commonly referred to as elastic design, shall be used in determining
allowable unit stresses; use of Part 11, which is commonly referred to as plastic