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Crane Knowledge


CMAA Crane Duty Classifications IP (Ingress Protection) Enclosure Classifications
Explosion Proof Definitions Governing Bodies
OSHA Regulations and Interpretations:
OSHA Regulations 1910.179 Relating to Hoists and Cranes
Interpretations of OSHA Standards

CMAA Classifications

CMAA has established crane service classes so that the most economical crane for a particular installation maybe specified in accordance with Specifications for Top Running Bridge & Gantry Type Multiple Girder Electric Overhead Traveling Cranes-No. 70 or Specifications for Top Running and Under Running Single Girder Electric Overhead Cranes Utilizing Under Running Trolley Hoist-No. 74. The crane service classification is based on the load spectrum reflecting the actual service conditions as closely as possible. The CMAA Crane Service Classes are as follows:

CLASS A (STANDBY OR INFREQUENT SERVICE) This service class covers cranes which maybe used in installations such as power houses, public utilities, turbine rooms, motor rooms and transformer stations where precise handling of equipment at slow speeds with long, idle periods between lifts are required. Capacity loads maybe handled for initial installation of equipment and for infrequent maintenance.

CLASS B (LIGHT SERVICE) This service covers cranes which maybe used in repair shops, light assembly operations, service buildings, light warehousing, etc. where service requirements are light and the speed is slow. Loads may vary from no load to occasional full rated loads with two to five lifts per hour, averaging ten feet per lift.

CLASS C (MODERATE SERVICE) This service covers cranes which maybe used in machine shops or paper mill machine rooms, etc., where service requirements are moderate. In this type of service the crane will handle loads which average 50 percent of the rated capacity with 5 to 10 lifts per hour, averaging 15 feet, not over 50 percent of the lift at rated capacity.

CLASS D (HEAVY SERVICE) This service covers cranes which maybe used in heavy machine shops, foundries, fabricating plants, steel warehouses, container yards, lumber mills, etc., and standard duty bucket and magnet operations where heavy duty production is required. In this type of service, loads approaching 50 percent of the rated capacity will be handled constantly during the working period. High speeds are desirable for this type of service with 10 to 20 lifts per hour averaging 15 feet, not over 65 percent of the lifts at rated capacity.

CLASS E (SEVERE SERVICE) This type of service requires a crane capable of handling loads approaching a rated capacity throughout its life. Applications may include magnet, bucket, magnet/bucket combination cranes for scrap yards, cement mills, lumber mills, fertilizer plants, container handling, etc., with twenty or more lifts per hour at or near the rated capacity.

CLASS F (CONTINUOUS SEVERE SERVICE) This type of service requires a crane capable of handling loads approaching rated capacity continuously under severe service conditions throughout its life. Applications may include custom designed specialty cranes essential to performing the critical work tasks affecting the total production facility. These cranes must provide the highest reliability with special attention to ease of maintenance features.

 

IP Enclosure

IP is an international standard for protection of an electrical apparatus including motors, pushbuttons, electronic devices, etc. It is designated by the letters IP followed by two numbers. The first number states the category of protection against operator contact and protection against intrusion of foreign objects. The second number states the category of protection against the entry of water. The following chart explains the categories of each protection.

IP _ _
Contact and Foreign Object
Protection Categories Degree of Protection
Water Protection Categories
 
# Degree of Protection # Water protection Categories
0 No special protection 0 No special protection
1 Protection against the entry of solid foreign objects, having a diameter larger than 50mm (large foreign object). No protection against intended access, i.e. with the hand. 1 Protection against the vertically falling drip water. No No harmful effects are allowed (drip water)
2 Protection against the entry of solid foreign objects having a diameter l;arger than 12mm (medium-sized foreign object) Protection for fingers or similar objects. 2 Protection against vertically falling drip water. When the enclosure is tipped up to an angle to 15 deg from its normal position, there should be no harmful effects (drip water falling at an angle)
3 Protection against the entry of solid foreign objects (small foreign object). Protection for tools, wires or similar objects that are thicker than 2.5mm. 3 Protection against water which falls at an angle of up to 60 deg from the vertical. No harmful effects are allowed (spray water).
4 Protection against the entry of solid foreign objects having a diameter larger than 1mm (grain-type foreign object). Protection for tools, wires or similar objects that are thicker than 1 mm. 4 Protection against water which sprays against the equipment from all directions. No harmful effects are allowed (spray water).
5 Protection against the harmful dust deposits. The entry of dust is not totally prevented but the entry of dust is not allowed in such quantities that the operation of quipment will be impaired (dust protection). Complete contact protection. 5 Protection against water from a hose which is directed on the enclosure from all directions. No harmful effects are allowed (hose directed water).
6 Protection against the entry of dust (dustproof). Complete contact protection. 6 Protection against strong seas of strong water jets. Entry of water into the enclosure in harmful amounts is not allowed (overflow).
7 Protection against water when the enclosure is dipped in water under given pressure and time conditions. Entry of water onto the enclosure on harmful amounts is not allowed. (submersion).
8 The enclosure is suitable for constant submersion in water under given conditions which are determined by the manufacturer. (submersion).

Explosion Proof Definisions

Class I - Locations: Are those in which flammable gases or vapors are or maybe present in the air in quantities sufficient to produce explosive or ignitable mixtures.
  • Division
    • Division I - Locations in which hazardous concentrations in the air exist continously, intermittently, or periodically under normal operating conditions.
    • Division II - Locations in which hazardous concentrations are handled, processed, or used but are normally within closed containers or closed systems from which they can escape only in case of accidental rupture or breakdown.
  • Group
    • Group A - Atmospheres containing acetylene.
    • Group B - Atmospheres containing hydrogen, or gases or vapors of equivalent hazard, such as manufactured gas. (not available in Division 1 design)
    • Group C - Atmospheres containing ethyl-ether vapors, ethylene or cyclo propane.
    • Group D - Atmospheres containing gasoline, hexane, naptha, benzine, butane, alcohol, acetone, benzol, lacquer solvent vapors, or natural gas.

Class II - Locations: Are those which are hazardous due to the presence of combustible dust.
  • Division
    • Division I - Locations in which hazardous concentrations in the air exist continously, intermittently, or periodically under normal operating conditions.
    • Division II - Locations in which hazardous concentrations are handled, processed, or used but are normally within closed containers or closed systems from which they can escape only in case of accidental rupture or breakdown.
  • Group
    • Group E - Atmospheres containing metal dust, including aluminum, magnesium and their commercial alloys and other metals of similarly hazardous characteristics.
    • Group F - Atmospheres containing carbon black, coal or coke dust.
    • Group G - Atmospheres containing flour, starch, or grain dust.

Governing Bodies

ABMA - American Bearing Manufacturers Association
1101 Connecticut Avenue, N.W., Suite 700
Washington , DC 20036
www.abma-dc.org

AGMA - American Gear Manufacturers Association
1500 King Street, Suite 201
Alexandria , Virginia 22314
http://www.agma.org

AISC - American Institute of Steel Construction
1 East Wacker, Suite 3100
Chicago , Illinois 60601-2001
http://www.aisc.org

AIST - Association for Iron & Steel Technology
186 Thorn Hill Road, Warrendale, PA 15086-7528
(724) 776-6040
TR-06- Specification for EOT Cranes for Steel Mill Service
http://www.aist.org

ANSI - American National Standards Institute
11 West 42nd Street
New York , New York 10036
http://www.ansi.org

ASME - The American Society of Mechanical Engineers
22 Law Drive, P.O. box 2300
Fairfield, New Jersey 07007-2300
http://www.asme.org

ASTM - American Society for Testing & Materials
1916 Race Street
Philadelphia , Pennsylvania 19103
http://www.astm.org

AWS - American Welding Society
550 N. LeJeune Road
Miami , Florida 33126
http://www.aws.org

CMAA - Crane Manufacturers Association of America, Inc.
8720 Red Oak Blvd., Suite 201
Charlotte, North Carolina 28217-3992
http://www.mhia.org/industrygroups/cmaa

HMI - Hoist Manufacturers Institute
8720 Red Oak Blvd,Suite 201
Charlotte, NC 28217
Phone 704-676-1190
http://www.mhia.org/psc/PSC_Products_Hoists.cfm

ISO/FEM - European Spec ISO/FEM
ISO Central Secretariat
Case postale 56
CH-1211 Geneve 20, Switzerland
+41 22 749 01 11

MBMA - Metal Building Manufacturers Association 1300 Sumner Avenue
Cleveland, OH 44115-2851
Phone: (216) 241-7333
Fax: (216) 241-0105
http://www.mbma.com

NEC - National Electrical Code
National Fire Protection Association
1 Batterymarch Park , P.O. Box 9101
Quincy , Massachusetts 02269 -9101
http://www.nfpa.org

NEMA - National Electrical Manufacturers Association
2101 “L” Street, N.W., Suite 300
Washington , DC 20037
http://www.nema.org

OSHA - U.S. Department of Labor
Directorate of Safety Standards Programs
200 Constitution Avenue, N.W.
Washington, D.C. 20210
http://www.osha.gov/pls/oshaweb