1. The purpose of this engineering article is to explain technical specification and minimum requirements for the supply, delivery, and erection of electrical and hand-operated overhead travelling cranes and hoists.
2. Technical Specification Overhead Travelling Cranes
2.1 This specification applies to all overhead travelling cranes to be used in plants designed or operated by Company .
2.2 This specification applies to materials, workmanship, shipment, erection, and testing for indoor or outdoor cranes.
3. RELATED DOCUMENTS
3.1 Company Engineering Documents
3EQ68001 Selecting Paint Systems and Identifying Paint Codes including
Requirements for under Thermal Insulation
4WEQ-6804 Painting and Corrosion Protection of New Construction for Design
Temperatures to 649oC (1200°F).
3.2 British Standards Institute (BSI)
The following British standards may be substituted by the standards of the country of destination, but the intent of this specification must be maintained.
BS 466 Power Driven Overhead Travelling Cranes, Semi-Goliath and Goliath
Cranes, for General Use
BS EN 13001 Cranes – General Design
BS 2853 Specification for the Testing of Steel Overhead Runway Beams for Hoist Blocks
BS EN 1991-3 Actions on Structures – Actions Induced by Cranes and Machinery
BS EN 1993-6 Design of Steel Structures, Crane Supporting Structures
BS EN 1090 Execution of Steel Structures and Aluminium Structures BS EN 10025 Hot Rolled Products of Structural Steels
BS EN 15011 Cranes: Bridge and Gantry Cranes
- GENERAL REQUIREMENTS
4.1 Definitions
- Hoist—A mechanism that is used for lifting and lowering a load.
- Runway beam—Overhead track for carrying loads which are moved along it.
4.2 All cranes shall be designed, fabricated, and tested in accordance with national standards and specifications referenced in Section 3. National standards of the country of destination must be used, when it is a legal requirement to do so.
4.3 The structural design of runway beams on which a hoist moves shall be designed to BS EN 1991-3 and BS EN 1993-6.
4.4 A full width maintenance platform, accessible from crane rail level, with handrailing, toe plates, and open grid-type steel flooring shall be provided with twin girder cranes. For single girder cranes, no platforms are required. The position of platform shall be as specified in the accompanying documentation.
4.5 The safe working load shall be as specified at the hook level on the Company ‘ project drawings. This shall include the maximum item to be lifted together with all the lifting equipment – slings, hooks, spreader beam, and the like.
4.6 The factor of safety applicable to hoist ropes shall be 6. Relevant test certificates shall be submitted to Company for record.
4.7 An adequate lubrication system shall be provided for all mechanical components of the cranes, and greasing points shall be so grouped as to ensure safety and ease of maintenance.
4.8 All outdoor cranes shall be completely weatherproofed to Company approval.
4.9 Overhead cranes within Compressor Buildings shall have a normal operating condition with an ambient temperature range from 0 oC to 40oC. The environment will be free from excessive dust, moisture, and corrosive fumes.
4.10 Where the crane/hoist shall be supplied for a plant within the European Union, all the equipment, and steelwork shall be fully compliant with the appropriate directives and the Construction Product Regulation. The CE marking shall be applied with the necessary documentation and certification as part of the quality documentation.
4.11 Design working life of the crane shall be a minimum of 25 years.
- TYPES OF CRANES
5.1 Cranes shall conform to the following requirements.
5.2 Electric Cranes
5.2.1 The hoist, transverse and longitudinal motions shall be powered by separate electric motors.
5.2.2 The hoist motion shall have two speeds in vertical, transverse, and longitudinal directions. The control shall be arranged so that transfer between speeds is achieved smoothly and without snatch. The low speed shall allow for softer starts, more accurate positioning, and gentler stops. The hoist (vertical) lower speed should be 0.5 m/min +/- 10% and the hoist (vertical) higher speed should be 2.5 m/min +/-10%. The transverse and longitudinal movements low speed shall be 5m/min +/-10% and the higher speed 15 m/min.
5.2.3 The hoist motors shall automatically brake in event of power supply failure.
5.2.4 All motors shall be three phase.
5.2.5 A top limit switch shall be provided on the hoist to prevent overwinding.
5.2.6 Supplier shall provide downshop leads, suitably protected and insulated, and located as specified on the Company project drawings.
5.2.7 The crane shall be controlled by pendant push button control, suspended 1 m above operating floor level. The pendant shall be suspended from a track attached to the crane bridge, and shall move independently of the crab in such a manner that the crane may be operated in any transverse location between one end of the crane and the other. The pendant shall have a minimum end approach of 2 m from end of crane bridge.
5.2.8 Brakes shall be fitted to transverse and longitudinal travel motors.
5.3 Hand Operated Cranes-Electrical Hoist
5.3.1 Hoist motions shall be electrically powered. The requirements of paragraphs 5.2.2 through
5.2.5 shall apply. A pendant control operating the hoist motion as specified in paragraph
5.2.6 shall be provided, but it shall be attached to the crab.
5.3.2 The transverse and longitudinal motions shall be operated by hand chains suspended 1 m above operating floor level and located as specified on the Company project drawings.
5.4 Hand Operated Cranes
5.4.1 Hoist, transverse, and longitudinal motions shall be operated by hand chains whose location shall be specified on the Company project drawings.
5.4.2 The crane hoist mechanism shall be provided with an automatic brake system.
- FABRICATION
6.1 Friction-type lock washers or self-locking nuts shall be used on all bolted connections.
6.2 Welding shall be in accordance with BS EN 1090, or other national code.
- INSPECTION
7.1 Supplier shall afford Company Inspector all reasonable facilities for inspection of the crane and parts.
7.2 The crane shall not be despatched without written approval from Company Inspector.
- TESTING
8.1 All electrical and mechanical equipment shall be tested at Supplier’s works before dispatch. The Supplier shall submit to Company a testing procedure before undertaking the tests. Upon completion of the tests the Supplier shall issue a certificate to confirm compliance.
8.2 The testing of the crane shall be undertaken in accordance with BS 466 Section 6 or similar local and National Standards. When erection of the crane is done on site by others, the crane structure shall be tested at Supplier’s works, but when the erection is by the Supplier, the testing shall be conducted on site. See paragraph 12.3.
8.2.1 Insulation Tests – After completion of erection and before connection of the power supply, the insulation of the electrical systems shall be tested. The insulation resistance of the system tested shall be not less than 0.5 megaOhms.
8.2.2 Earth Continuity – Earth continuity of the equipment shall be checked to ensure that at no point is this greater than 0.5 Ohms.
8.2.3 Overload Tests – The crane shall be tested such that each lifting unit each crab and the crane as a whole are subjected to 125% of their safe working load. During the test the crane motions shall be tested such that the gear teeth are tested under overload condition. Full motion speeds need not be attained during overload tests. The tests shall be considered successful if no cracks, permanent deformation, paint flaking, or damage that effects the function and safety of the crane is visible and no connection has loosened or been damaged.
8.2.4 Deflection Test – A test shall be performed to verify that the vertical deflection of the crane bridge under the safe working load with the weight of the crab/hoist at the worse position does not exceed the limit of span/750.
8.2.5 Performance Test – Performance tests shall be conducted on each motion of the crane with the safe working load suspended to ensure that they are capable of meeting the specified speeds of operation. During these tests the correct functioning of the mechanism and brakes shall be verified.
8.3 The testing of the runway beams for manually or electric hoists shall be done in accordance with BS 2853 or similar local or National code.
- DRAWINGS AND INFORMATION
9.1 With Bid
9.1.1 Supplier shall provide 3 copies of the following information with the bid:
- Line sketches of proposed crane arrangement
- Detailed data and description of crane
- Priced lists of all spare parts
- Recommended spares for two year’s operation
9.2 After Order—After receipt of order, Supplier shall provide drawings and documents in accordance with the Company Schedule of Drawings and Data required from Supplier.
9.2.1 This shall include:
- A schedule to identify various milestones dates – design completion, fabrication duration, expected arrival on site, erection and commissioning/testing
- The Characteristic Actions/Forces applied at the Crane rail under the various operating conditions.
- As appropriate, the details of the setting out of the crane rail- size location together with the tolerances
- A drawing showing the extent of crane travel
9.2.2 The Supplier shall submit the design information for Company review before the start of the fabrication.
10. SURFACE PREPARATION AND PAINTING
10.1 A paint system shall be used that shall provide the needed corrosion protection which depends on the environmental conditions and the expected longevity. Environmental conditions shall consider the whole life of the crane from transportation to operating.
10.2 The paint system applied to the structural components of the crane (that is, end carriages, crane bridge girders, and crab frames) shall be determined in accordance with the exposure conditions given in the Company standard 3EQ68001 The final colour shall be yellow with 150 mm wide equal width diagonal black bands (main girders only).
10.3 The crane assembly shall be shop painted to the maximum extent with very little touch up on site.
10.4 Maintenance platforms, when provided, shall have the same paint system as structural components, but final colour shall be yellow for handrailing and galvanising for platform steelwork.
10.5 All surface preparation and painting shall conform to the Company Standard 4WEQ- 6804 or similar approved. The colour reference numbers for yellow and black are:
Yellow RAL 1023
Black RAL 6008
10.6 All surfaces, which for mechanical or other reasons are not painted, shall be protected against corrosion in accordance with good engineering practice.
11. PREPARATION FOR SHIPMENT (IF ERECTED BY OTHERS)
11.1 Erection Lists: When erection is not done by Supplier, all documents shall bear the same identification marks as the erection drawings and every part shall be listed individually. Complete lists of erection bolts shall be provided in duplicate.
11.2 Domestic Shipment: For materials delivered within United Kingdom, the following paragraphs shall apply:
11.2.1 10% extra bolts, nuts, and washers shall be provided.
11.2.2 Structural parts shall be transported in bundles, when possible.
11.2.3 All fabricated frames shall be suitably braced to prevent distortion during transit.
11.2.4 Gusset plates, cleats, and other small items shall be despatched securely wired together or packed in timber crates.
11.2.5 Bolts and nuts shall be supplied in a double fabric bag tagged as per paragraph 11.2.6, or in a number of single bags inside a box.
11.2.6 The shipping mark, including the name ‘Company PLC,’ purchase order number, weight (when exceeding 1000 kg), and materials contents, shall be stenciled on each separate part, and on the outside of each wooden case. The marking on each item shall be placed so that it is not visible after assembly.
11.3 Export Shipment—Materials destined for overseas shall comply with Section 11.2 and the following paragraphs:
11.3.1 Paragraph 11.2.5 is substituted by the following:
- ‘Bolts and nuts shall be supplied in bags, all securely tied. The bags shall be enclosed in timber cases securely battened and bound with hoop iron.’
11.3.2 No package shall exceed 5000 kg in weight, except when approved by Company .
12. OFF-LOADING STORAGE AND ERECTION (WHEN APPLICABLE)
12.1 Suppliers shall be responsible for off-loading and storing the crane at site in the area allocated by Company .
12.2 Supplier shall conduct the work so as to avoid interference with the work of other contractors or traffic on site.
12.3 On completion of erection, Supplier shall test the crane and shall provide Company with a test certificate, acceptable to the insurance company, in triplicate. Supplier shall also provide necessary test weights. The testing shall follow the requirements in Section 8.2.
12.4 Supplier shall hand over the completed crane, in working order, to Company Representative.