Lors de la vérification approfondie, on contrôlera que les conditions d’utilisation du pont n’ont pas varié par rapport à l’analyse des risques et à la définition du cahier des charges initial, notamment la classe d’utilisation et le spectre de charge FEM.
http://www.risquesprofessionnels.ameli.fr/media/R423.pdf

Espérance de vie
Lorsqu'on a défini la résistance à la fatigue (groupe d'engins) et la sollicitation (classe de spectre), il est possible d’en déduire l'espérance de vie de la grue (classe d’utilisation).
:
Classe d’utilisation (nombre de cycles)
U0 U1 U2 U3 U4 U5 U6 U7 U8 U9
http://www.gottwald.com/gottwald/site/gottwald/de/news/pdf/C...

Service Life
If the loading capacity (crane group) and the expected load (spectrum class) are known, the service life (class of utilisation) of the crane can be determined on that basis.
:
Class of utilisation and duration of use (number of work cycles)
U0 U1 U2 U3 U4 U5 U6 U7 U8 U9
http://www.gottwald.com/gottwald/export/gottwaldsite/de/news...

In the design of crane structures only those members which support cranes of a particular utilisation class need to checked for fatigue.
http://www.tudelft.nl/live/binaries/0f0614c0-30cf-4318-8180-...

Pour un autre sujet (réducteurs) :

Définier la classe d'utilisation avec facteur de spectre et de durée correspendants.
Determine the class of utilisation and the relevant spectrum and duration factors.
:
Classes of utilisation
Classes d'utilisation
T2 T3 T4 T5 T6 T7 T8
http://www.tespo.cz/download/brevini/Katalopg prevodovek pro...

The choice of a drive unit is based upon the needed power with regard to gear ratio and utilisation class.
Le choix d'un moto-réducteur se base sur la puissance efficace à employer par rapport au rapport souhaité de réduction et à la classe d'utilisation.

The choice of a winch is mainly based on the SWL with regard to the utilisation class according to FEM specs 1.001, ed. 1987.
http://www.gmt-india.in/pdfs/Catalogue OMIS.pdf



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Note added at 13 hrs (2010-07-08 05:50:50 GMT)
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Another classification system is used by the CMMA:

All American Crane & Equipment Corporation cranes are manufactured to rigid quality standards and factory tested prior to shipment. American Crane's pre-engineered industrial cranes are designed to meet the requirement of the Crane Manufacturers Association of America (CMAA) in duty class "A" through "F".
:
CLASS A (STANDBY OR INFREQUENT SERVICE)
This service class covers cranes where precise handling of equipment at slow speeds with long, idle periods between lifts is required. Capacity loads may be handled for initial installation of equipment and for infrequent maintenance.

Class A may be used in installations such as:
• Powerhouses
• Public Utilities
• Turbine Rooms
• Motor Rooms
• Transformer Stations
http://www.americancrane.com/industrial/doublewopen/doublegi...

4. Prepare the ampere load figure that will be used to size
the conductors as follows:
List the full load ampere rating of each motor used on the crane or monorail unit. Determine the duty cycle from the following paragraphs and apply the corresponding factor.
Light Duty — Class A and B Crane Service
Standby or infrequent use. Up to two motors started at a time. Two to five lifts per hour. Use a factor of 90% of the calculated ampere load.
http://www.milwaukeecrane.com/duct-o-wire_downloads/FEight-0...

But I found no loading spectrum class or crane group inside these documents.