PNNL Hoisting and Rigging Manual
| Scope | General Requirements | Inspection Requirements | Wire Rope Inspection Summary | Wire Rope Inspection, Acceptance Criteria | Wire Rope Receiving, Storage, and Maintenance | Replacement Rope | Replacement Rope Installation | Qualification of Wire Rope |
Wire Rope
Scope
This section specifies inspection and replacement requirements and acceptance criteria for wire rope on overhead cranes, monorail cranes, jib cranes, and hoists that are used in lifting service.
Wire rope slings are not included in this section. For wire rope slings, see Slings. Wire rope that has been removed from a crane or hoist shall not be used to fabricate slings.1
General Requirements
Design Factors For Wire Ropes
The design factor (safety factor) is the nominal strength of the rope divided by the rated load.
Hoists and Overhead Crane Wire Ropes
On hoists and overhead cranes, the wire rope design factor is 5:1.
Rotation-Resistant Rope
Use of rotation-resistant rope shall be approved by the manufacturer of the equipment on which it is used. Application of rotation-resistant rope requires special installation procedures, higher design factors, and special inspection and maintenance procedures.
Requirement for Independent Wire Rope Core
Overhead cranes and hoists exposed to ambient temperatures at the rope in excess of 180ºF shall use rope with independent wire rope core (IWRC).
Inspection Requirements
Only inspection can determine whether or not rope must be replaced (see Table 1). Based on experience, and in accordance with wire rope inspection criteria in this section, a qualified rope inspector must determine the following:
- The rope's existing condition presents a likelihood of failure.
- The rate of deterioration of the rope is such that it will remain in safe condition until the next scheduled inspection by a qualified wire rope inspector.
CAUTION: Proper maintenance of the drums and sheaves over which ropes operate is important to rope life (e.g., worn grooves or poorly aligned sheaves can cause short service life for wire rope). If equipment maintenance problems are found during wire rope inspection, the inspector shall promptly notify the equipment custodian.
Wire Rope Inspection Summary
Inspection type |
Equipment type |
Frequency |
Performed by |
Records |
| Frequent | All | Each day of use | Operator | Not required |
| Monthly | Overhead and gantry, crawler locomotive and truck crane | Monthly | Wire rope inspector | Checklist or inspection report. Signed and dated. |
| Periodic | All | To meet conditions, but no less than annually. When returning to lift service | Wire rope inspector | Inspection report. Signed and dated |
| When equipment has been idle for 1 month or more | All | Before service | Wire rope inspector | Inspection report. Signed and dated. |
Frequent Inspection
Running ropes should be visually inspected once each working day by the equipment operator. This visual inspection shall consist of observing any rope that can reasonably be expected to be in use during the day's operations. These visual observations should be concerned with discovering gross damage that may be an immediate hazard, such as the following:
- rope distortion such as kinking, crushing, unstranding, birdcaging, main strand displacement, or core protrusion
- corrosion
- broken or cut strands.
Monthly Inspection2
For overhead and gantry cranes,3 a monthly inspection of running ropes shall be performed and documented by a qualified wire rope inspector. Documentation shall include the date of inspection, the signature of the person who performed the inspection and the identity of the ropes that were inspected. This documentation shall be kept readily available. A checklist near the operator's station is recommended. This inspection does not necessitate a breakdown of the crane. For overhead and gantry cranes, lower the hook block(s) to the floor or lowest attainable position. Inspect the rope(s) from the floor and bridge walkway or trolley floor where there is a means of access.
Visually inspect running ropes for any condition that could result in an appreciable loss of strength and thus constitute a safety hazard. Some conditions that could result in an appreciable loss of strength are the following:
- reduction of rope diameter below nominal diameter as a result of loss of core support, internal or external corrosion, or wear of outside wires
- a number of broken outside wires and the degree of distribution or concentration of such broken wires
- worn outside wires
- corroded or broken wires at end connections
- corroded, cracked, bent, worn, or improperly applied end connections
- severe kinking, crushing, cutting, or unstranding.
Note: A monthly inspection of running rope is not required if a periodic inspection of running and standing rope is accomplished during that month.
Periodic Wire Rope Inspection (Active Cranes and Hoists)
Periodic Inspection Intervals
A thorough inspection of running rope and standing rope shall be made at least annually or more frequently as determined by a qualified person. The inspection frequency shall be based on such factors as expected rope life, determined by experience on the particular equipment or similar equipment, severity of environment, percentage of capacity lifts, frequency of operation, and exposure to shock loads. Inspections need not be at equal calendar intervals and should be more frequent as the rope approaches the end of its useful life.
Inspector
Periodic wire rope inspections shall be performed by a qualified wire rope inspector.
Inspection Area
The inspection shall cover the entire length of each rope. Only the surface wires of the rope must be inspected. No attempt should be made to open the rope. Any deterioration resulting in loss of original strength shall be documented and a determination made as to whether further use of the rope would constitute a hazard. As a minimum, ropes shall be inspected for the following:
- items listed for frequent wire rope inspection
- reduction of rope diameter below nominal diameter resulting from loss of core support, internal or external corrosion, or wear of outside wires
- severely corroded or broken wires at end connections
- severely corroded, cracked, bent, worn, or improperly applied end connections
- improper and insufficient rope lubrication
- evidence of heat damage from any source.
Sections of Rapid Deterioration
Additional care shall be taken when inspecting sections of rapid deterioration, such as the following:
- sections in contact with saddles, equalizer sheaves, or other sheaves where rope travel is limited
- sections of the rope at or near terminal ends where corroded or broken wires may protrude.
Inspection of Ropes Not in Regular Use
Rope that has been idle for a period of 1 month or more due to shutdown or storage of the hoist or crane on which it is installed shall be given a thorough inspection by a qualified wire rope inspector, which shall include running and standing ropes, and be equal to a periodic inspection, as described previously. (The condition of wire rope lubricant is a key concern.) This inspection shall be completed before the equipment is returned to service.
Inspection of Ropes Before Returning to Lift Service
Cranes that have been used for excavation or demolition work shall have a periodic wire rope inspection before being returned to lifting service.
Wire Rope Inspection, Acceptance Criteria
Wire Rope Replacement Criteria–Overhead and Gantry Cranes, Monorail Cranes and Hoists, Overhead Hoists
The following criteria determine when a wire rope is no longer acceptable for service:
- 12 randomly distributed broken wires in one lay or four broken wires in one strand in one lay in running ropes
- one outer wire broken at the contact point with the core of the rope, which has worked its way out of the rope structure and protrudes or loops out from the rope structure
- wear of one-third the original diameter of outside individual wires
- kinking, crushing, birdcaging, or any other damage resulting in distortion of the rope structure
- evidence of heat damage from any cause
- reduction from nominal diameter greater than those listed in the following table:
Rope Diameter (inch) |
Maximum allowable reduction from Nominal Diameter (inch) |
Less than or equal to 5/16 |
1/64 |
More than 5/16 to 1/2 |
1/32 |
More than 1/2 to 3/4 |
3/64 |
More than 3/4 to 1-1/8 |
1/16 |
More than 1-1/8 to 1-1/2 |
3/32 |
Note: Attention shall be given to end connections. Upon development of two broken wires adjacent to socket end connections, the rope shall be resocketed or replaced. Resocketing shall not be attempted if the resulting rope length will be insufficient for proper operation.
Wire Rope Receiving, Storage, and Maintenance
Receiving at the Work Site
Before the wire rope is installed on the machine, it must be carefully checked for size, construction and core, to ensure that it matches the description on the tags, requisition, packing slips, purchase order, or invoice.
Rope Storage
If the rope is to be held for a considerable length of time (longer than 3 months) it must be protected from the elements. A dry, well-ventilated building is the proper storage place. Avoid closed, unheated, tightly sealed places. Wire rope shall not be stored in areas subject to elevated temperatures or subject to dust, grit, or a chemically laden atmosphere. If the delivery site precludes inside storage and the rope must be kept outside, the rope shall be covered with a waterproof tarp. The reel should be on a platform so as to keep it from direct contact with the ground.
Unreeling, Cutting, and Seizing
Unreeling
Unreeling or uncoiling of rope shall be done in a manner to avoid kinking or inducing a twist. (A qualified engineer should be consulted, if necessary.)
Cutting
Before cutting a rope, seizing should be placed on each side of the place where the rope is to be cut to prevent unlaying of the strands. (For pre-formed rope, one seizing each side of the cut. For non-pre-formed rope, 7/8-inch diameter or smaller, two seizings on each side of cut; for larger diameter, three seizings each side of cut.)
Wire Rope Lubrication
Lubrication by the Rope Manufacturer
The lubrication ropes receive during manufacture is adequate only for initial storage and the early stages of the rope's service life.
Rope Lubrication on Active Cranes and Hoists
Rope on active hoists and cranes shall be maintained in a well-lubricated condition. It is important that lubricant be applied as part of the maintenance program. The lubricant must be compatible with the original lubricant, so the rope manufacturer should be consulted. The lubricant applied shall be of the type that does not hinder visual inspection. Rope sections that are located over sheaves, or otherwise hidden during inspection and maintenance procedures, require special attention when lubricating rope.
Lubrication Frequency
This manual does not specify the time interval between lubrications. A thorough periodic inspection will indicate when lubrication is required and whether lubrication frequencies, as part of the maintenance program, must be adjusted.
Replacement Rope
Rope Replacement Frequency (Recommended)
Where equipment is consistently in use, it is recommended that wire rope be given a certain length of service (e.g., several hundred operating hours or a certain number of months) and then the rope replaced regardless of its condition. This method will eliminate the risk of fatigue causing rope failure.
Extra-Long Rope
If a longer rope than necessary can be installed, well-defined, localized abrasion and fatigue may be dealt with without discarding the whole rope. In such a case, one end shall be cut to expose a different section of rope to the place where the deterioration occurs. (This method is most applicable to running ropes on mobile cranes.)
Replacement Rope as Recommended by Equipment Manufacturer
Replacement ropes shall be of a construction recommended by the rope manufacturer or the crane or hoist manufacturer. Replacement rope shall be the same size, grade and construction, and have a strength rating equal to the original rope furnished or recommended by the crane or hoist manufacturer.
Terminal Ends
Terminal ends shall be prepared and socketed in the manner specified by the manufacturer of the wire rope or fitting.
Replacement Rope Installation
Before Initial Load Cycle
After wire rope replacement, and before the initial load cycle, a qualified inspector shall verify the following conditions:
- rope attachment points to the hoist drum and dead end (if applicable) are properly installed
- fasteners are properly torqued
- overhead cranes and hoists will have no less than two full wraps of rope on the drum when the hoist is at the lower limit. Mobile cranes will have an adequate rope length so that neither the load nor the boom lowering will result in less than two full wraps of rope on respective drums.
- reeving is in accordance with the manufacturer's recommendations.
Initial Cycle
After rope replacement and before returning the equipment to service, it is recommended that the hoist unit be cycled from maximum down position to maximum up position eight to ten times with 10% to 20% of rated load.
New Rope Stretch
On equipment having multiple part lines (other than rotation-resistant wire rope) a new rope will stretch and unlay slightly, causing turns to appear in the load block. The anchorage, if not fitted to a swivel, may be disconnected, the turns removed and reconnected.
Verification of Fasteners
After the initial load cycle has been completed, a qualified inspector shall verify that the fasteners on drum and/or dead end have been re-torqued.
Documentation of Rope Replacement
A Wire Rope Replacement Checklist (.doc) signed and dated by a qualified inspector, shall document proper installation of replacement rope.
Qualification of Wire Rope
Qualification of Original Rope Supplied with New Equipment
Original rope, supplied with new equipment, is qualified for service by the inspection performed on the new equipment.
Qualification of Replacement Rope
A completed wire rope replacement checklist, documenting the most recently installed replacement rope (see Wire Rope Replacement Checklist [.doc]), signed and dated by a qualified inspector, shall be in the equipment maintenance file. In addition to inspection records in the equipment maintenance file, replacement rope shall have certification from the rope manufacturer. The manufacturer's certification shall contain adequate information to identify the rope and should contain the following information:
- Rope diameter (e.g., 1/2 inch).
- Rope classification (number of strands X wires per strand) (e.g., 6 x 37).
- Lay (e.g., right regular lay, or left lang lay).
- Grade of wire (e.g., Improved Plow Steel, or Extra Improved Plow Steel).
- Type of core (e.g., Independent Wire Rope Core, or Fiber Core).
- Nominal strength (e.g., 10.7 tons).
- Rope's purchase order number, if known.
Wire Rope Replacement Checklist – Example (.doc)
1The term "non-rotating" wire rope, originally referred to 19 x 7 or 18 x 7 rope. "Non-rotating" has been replaced by the term "rotation-resistant" wire rope. Many other rotation-resistant ropes, besides 19 x 7 and 18 x 7, are currently available.
2Basis: Overhead and gantry cranes—29 CFR 1910.179(m), Crawler, locomotive, and truck cranes—29 CFR 1910.180(g).
3The overhead and gantry crane equipment classification includes semigantry, cantilever gantry, wall cranes, storage bridge cranes, and others having the same fundamental characteristics. These cranes have trolleys and similar travel characteristics. This classification does not include hoists, monorail hoists, or jib cranes.