2c e7 purch guidelines r1 20131107

American Petroleum Institute

Purchasing Guidelines

API

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Equipment Purchase API Spec 2C online at www.api.org/publications

API Specification

2C 7

th Edition, March 2012

Errata March, 2013

Offshore Pedestal-mounted Cranes

Copyright 2013 API-American Petroleum Institute 2C-1

Section 4.2

Purchaser-supplied Information prior to Purchase

Unlike land based cranes, offshore cranes have a fixed location on a structure and are not

capable of moving relative to the load. The capacity of all offshore cranes depends on the

structure the crane is mounted on, the environmental conditions, and the location of the load

relative to the structure. For these reasons it is not possible to define a crane using a single

parameter or load (i.e. a 50-ton crane). To define a cranes capability, many parameters are

provided to the crane manufacturer. The purchaser shall supply the crane manufacturer with the

minimum information listed below for each crane required to be purchased. This data shall be

used to correctly size the requested crane. Annex F lists added information the purchaser may

want to supply to further define his requirements to the manufacturer to include the following:

a) safe working load (SWL) at desired lifting radius;

b) type of liftonboard and offboard lifts;

c) boom length and configurationfixed length, minimum and maximum for telescopic

or folding and articulating boom crane;

d) type of vessel the crane is installed onbottom-supported structure, ship and barge

in calm water, tension leg platform, spar, semi-submersible, drill ship, or FPSO in

accordance with Table 3, Table 4, and Table 5;

e) crane elevation from heel pin to mounting deck and from mounting deck to mean sea

level (MSL);

f) significant wave height(s) for crane operation;

g) wind speed(s) for crane operation;

h) crane calculation and ratings methodGeneral Method, Vessel-specific Method or

Legacy Dynamic Method in accordance with Section 5 loads and all associated design

parameters specific to the chosen method of calculation; and

i) crane duty cycle classificationin accordance with Section 7;

j) hazardous area classification for crane and crane boom in accordance with 7.5.4.



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API Specification

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Errata March, 2013



Annex F

Additional Purchaser Supplied Information

In addition to the required information listed in 4.2, the following is additional information the

purchaser may wish to supply to define crane options, configuration, and rating methodology.

a) Crane type:

lattice boom crane,

box boom cranefixed boom length,

box boom cranetelescopic boom, and

box boom cranefolding and articulating boom.

b) Required crane lifts and hook speed (if greater than API 2C minimum speed):

onboard lifts at radii and hook speed (if greater than API 2C minimum

speed),

offboard lifts at radii and hook speed (if greater than API 2C minimum

speed), and

(optional) personnel lifts at radii and hook speed (if greater than API 2C

minimum speed).

c) Crane rating methodfixed platform cranes:

General method;

1) significant wave height required, and

2) operating wind velocity,

Legacy Dynamic Method; and

other methods may be specified by purchaser (i.e. significant wave height

provided with special offlead and sidelead).

d) Crane Rating Methodfloating support cranes:

Vessel-specific Method;

1) significant wave height required,

2) operating wind velocity,

3) vessel static list and trim,



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API Specification

2C 7


Errata March, 2013



4) boom tip vertical acceleration,

5) crane horizontal acceleration, and

6) vessel RAOs and crane location on vessel (alternative to accelerations

above),

General Method;

significant wave height required;

vessel list and trim if different from defaults;

operating wind velocity; and

Legacy Dynamic Method is NOT to be used for floating platform and vessel

installations.

e) Crane options that affect SWL of the crane:

boom maintenance walkway, and

excessive limits on pedestal reactions.

2c e7 purch guidelines r1 20131107

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